Dissertations / Theses on the topic 'Water – Purification – Oxidation'

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2019.
A shortage of water has resulted in the need to enhance the quality of wastewater that is released into the environment. The advanced oxidation process (AOP) using heterogeneous catalysis is a promising treatment process for the management of wastewater containing recalcitrant pollutants as compared to conventional processes. As AOP is a reliable wastewater treatment process, it is expected to be a sustainable answer to the shortage of clean water. AOP using heterogeneous catalysis based on Co3O4 particles and PMS, in particular has been found to be a powerful procedure for the degradation and mineralization of recalcitrant organic contaminants. In addition, due to the growing application of Co3O4 in lithium batteries, large quantities of these particles will be recovered as waste from spent lithium batteries, so there is a need to find a use for them. Although this method has received some promising feedback, challenges still need to be addressed, such as the toxicity of cobalt particles, the poor chemical and thermal stability and particle aggregation, and the prompting of lower catalytic efficiency in long haul application. Furthermore, the removal of the catalyst after the treatment of pollutants is also an issue. In order to be applicable, a novel catalyst must be produced requiring the combination of Co3O4 with a support material in order to inhibit cobalt leaching and generate better particle stability. From the available literature, TiO2 was found to be the best support material because it not only provides a large surface area for well dispersed Co3O4, but it also forms strong Co-O-Ti bonds which greatly reduced cobalt leaching as compared to other support materials. Moreover, it also greatly encourages the formation of surface Co–OH complexes, which is considered a crucial step for PMS activation. Therefore, the issues cited above could be avoided by producing a Co3O4/TiO2 heterojunction catalyst.

Metal-Ethylenediaminetetraacetic acid (EDTA) complexes are found in a variety of industrial process. The stability of the formed complexes makes these compounds often inert to conventional wastewater treatment systems. In this work, the photocatalytic oxidation of NiEDTA was investigated as a means of breaking up the chelated nickel. The studied variables included the light intensity rate, the catalyst (TiO2), oxygen and NiEDTA concentrations. Photocatalytic experiments showed that increasing the catalyst concentration (0.5-3.0 g/L) decreases the light penetration inside the reactor resulting in a decrease in the reaction rate. The effect of oxygen and NiEDTA concentration was shown to exhibit Langmuir-Hinshelwood type kinetics. Total organic carbon (TOC) did not show any significant mineralization of NiEDTA for all investigated conditions. As a result, the by-products of the reaction were measured and found to include ED3A (ethylenediaminetriacetic acid), N-N'-EDDA (ethylenediamindiaacetic acid), IDA (iminodiacetic acid), oxalic acid, oxamic acid, glyoxylic acid, formaldehyde, ammonia, nitrate and nitrite. ED3A was found to be the major by-product of the reaction and nitrogen added from NiEDTA was found to be released as ammonia nitrogen. Oxygen consumption experiments were demonstrated as an effective way to monitor the rate of the reaction through measurement of the electron oxygen utilization rate. Nickel precipitation experiments showed that some of the by-products of NiEDTA degradation formed complexes with nickel. Finally, a light distribution model was generated using a CFD software (Fluent 6.1.22). For the catalyst concentration range of 0.5 to 3.0 g/L, this model showed that all of the light energy supplied by a centered UV lamp is absorbed within a one centimeter distance. Using the local volumetric rate of energy absorption (LVREA) calculated from the model the rate of the reaction was expressed in terms of quantum yield. For experiments carried out with air the quantum yield showed that the degradation rate was limited from an insufficient oxygen supply for electron scavenging. Increasing the oxygen concentration to 0.60 mmole O2/L increased the quantum yield for the highest light intensity rate; however the quantum yield never reached an optimum value thus indicating that other limiting conditions exist.

In this thesis, a combination of laboratory experimentation under well defined conditions coupled with a kinetic modelling approach is used to verify the existence and respective kinetic rates of previously unconfirmed or postulated mechanisms that drive and limit dark Fenton (Fe(II)/H2O2) - mediated As(III) oxidation at pH 3 and 8 and dark Cu(II) - H2O2 - mediated As(III) oxidation at pH 8. Dark Fenton - mediated oxidation of As(III) at pH 3 is first examined and the effects of the variation in the concentration of reactants (As(III), Fe(II) and H2O2), oxygen, phosphate and organics (2 - propanol, formate, and citrate) are reported and analysed. The kinetic models developed for these systems show high applicability to full scale water treatment application and key mechanistic findings include the significance of the cycling of Fe(II) / Fe(III) via HO2 ???/O2 ??????, the effects of As(IV) termination reactions in the absence of oxygen and the retarding effects of phosphate due to the postulated formation of a Fe(III) - phosphate complex (at a derived rate constant of 2.2 x 106 M-1s-1, that also appears to have negligible kinetic activity in terms of reduction to Fe(II) by HO2 ???/O2 ??????). The work also demonstrates the significance of the free radical by products of formate and citrate oxidation by ???OH (HCOO???/CO2 ?????? and 3HGA???2???). The examination of the dark Cu(II) - H2O2 - mediated oxidation of As(III) at pH 8 with variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate and organics (2 - propanol, formate and citrate) demonstrated for the first time the high applicability of this system to the pre - oxidation of As(III) in water treatment and mechanistically that ???OH and CO3 ?????? are the dominant As(III) oxidants in this system. The As(III) oxidant CO3 ??????, is suggested to be generated by the interaction of ???OH and O2 ?????? with the carbonate matrix, at the respective rate constants of 4.9 x 107 M-1s-1 and 5.5 x 106 M-1s-1. Examination of the dark Fenton - mediated oxidation of As(III) at pH 8 and the effects of variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate, organics (2 - propanol, formate and citrate) and Cu(II) demonstrates the varied potential mechanistic pathways in relation to the generation of As(III) oxidants from the Fenton reaction, Fe(II) + H2O2 such as Fe(IV) and CO3 ?????? and the previously dismissed ???OH, due to the presence of Fe(II) - citrate complexes. This work also demonstrates and models the enhancement of As(III) oxidation in the presence of an additional transitional metal ion, Cu(II).

In recent years, the increasing release of trace organic chemicals to the aquatic environment have been problematic to both the ecosystem and the human society. These trace organic chemicals, regarded as emerging contaminants, include different categories of chemicals, which are either deemed to be safe for human consumption or they are naturally occurring compounds. As a newly recognized class of emerging contaminant, artificial sweeteners are proven to be one of the most ubiquitous classes of emerging contaminants in environmental waters. Its transformation to different suite of TPs during water treatment processes generated more toxic influence than the parent compound is problematic. The realization of the widespread of emerging contaminants, together with their ambiguous fate and impact to the environment have led to the development of advanced oxidation processes that can effectively attenuate this wide range of contaminants. In this work, several catalytic advanced oxidation processes were studied. On one hand, it aimed to evaluate their effectiveness on the removal of the artificial sweetener - acesulfame; and on the other hand, to shed lights on the future development of catalytic advanced oxidation processes. In the first part of this thesis, the photo-Fenton treatment was evaluated on its potential to effectively remove acesulfame together with the produced transformation products, and the post-treatment toxicity screening. The photo-Fenton treatment was found to be effective in removing both the parent compound and the transformation products, without leading to an increase in toxicity, which is largely related to the effective removal of the transformation products. In attempt to reduce the reliance on UV irradiation, newly synthesized carbon and nitrogen co-doped TiO2-based photocatalyst was applied to capture the simulated sunlight for the degradation of acesulfame. The heterogenous photocatalytic treatment was found to involve several different oxidative reactive species for both degradation and transformation by using several scavengers to alter the degradation profile. Unexpected transformation product was also formed upon treatment in actual water matrix, suggesting the impact of water constituents to the transformation of emerging contaminants. Toxicity results indicated the inability to achieve detoxification, suggesting that a more effective degradation process was needed. To accelerate the degradation process, and enhance the performance at neutral pH, the use of redox mediators for Fenton/Fenton-like system was evaluated. Developed novel Fenton-like system involving copper(II) as transition metal ion, persulfate as oxidant and mercaptosuccinic acid as redox mediator led to effective removal of different contaminants. Elucidation of the proposed oxidation mechanism suggested the role of each components of the system, and the generation of different reactive species for degradation as indicated by the different acesulfame transformation profile obtained. The implementation of redox mediators to Fenton/Fenton-like system was beneficial and an effective approach. In short, this work presents several kinds of catalytic advanced oxidation process and shed lights on improving the degradation performance with directions for the future development of better and more effective water treatment processes.

The removal mechanisms of soluble manganese [Mn (1l)] through mixed-media filters were investigated. Experimentation was directed toward the continuous supply of an oxidant during column filter studies. Free chlorine (HOCl, OC1â ) was chosen to increase soluble manganese removal efficiency because chlorine is readily available and inexpensive. Filter media from four different water treatment plants were used in this study. Continuous-flow filter columns were operated in the presence and absence of 2.0 milligrams per Liter (mg/ L) free chlorine. Maintaining constant influent manganese concentrations of 1.0 mg/L and flow rates of 2.5 gallons per minute per foot squared (gpm/ft2), the operational pH values of 6-6.2, 7.8 and 8.8 were investigated. Results indicate that a continuous feed of free chlorine (2 mg/L) applied to the filter columns could increase manganese (II) removal efficiency. However, the amount and oxidation state of the MnOx(S) surface coating initially on the media and the influent pH had major influences upon the uptake of soluble manganese. From numerous Mn (II) uptake studies with different media and varying pH conditions, oxide-coated filter media continuously regenerated with free chlorine could result in increased soluble manganese removal through adsorption upon the MnOx(s) surface coating and subsequent oxidation directly on the media surface. The relationships of manganese removal and chlorine consumed were also explored. To further investigate the mechanisms of free chlorine oxidation for the removal of reduced manganese, pH 5.0 backtitrations were conducted following exhaustion of the filter media. The exposure of such low pll conditions to columns operated in the presence and absence of HOCI would ascertain if oxidation of the adsorbed Mn2+ was always occurring, regardless of an oxidant feed. Results indicated that in the absence of HOCI, the mechanisms for manganese removal on oxide-coated filter media were adsorption only. With the additional of HOCI, the adsorbed Mn2+ is oxidized directly on the surface of the media, thereby, continuously regenerating the surface oxide coating. Additional work was begun to ascertain if free chlorine could be used as a viable alternative to potassium permanganate (KMnO4) regeneration of oxide-coated filter media. Preliminary findings indicate from column cycling experiments that free chlorine could be used to regenerate oxide-coated filter media prior to backwashing.
Master of Science

Thesis (MScIng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: Recent years have seen the development of various treatment methods for the purification of industrial waste waters due to the increased demand for reduced pollutant effluents. Aqueous waste streams containing toxic organic compounds are of special interest, since conventional treatment methods such as biological waste treatment can not always be used. Other popular treatment methods are often ineffective. Catalytic oxidation of organic wastes has been investigated since the 1960s with varying degrees of success. A major problem associated with this method is the high temperatures and pressures required to improve the activation energies involved. Electrochemical oxidation has become a popular method in the literature of treating these wastes, since the applied voltage determines the activation energy, and therefore the process can often be performed at ambient conditions. This thesis investigates the capability of a unique reactor system in the treatment of these wastes. The reactor utilises proton-exchange membrane technology to eliminate the requirement of conductivity in treated waste streams; thus the membrane serves as a solid electrolyte. The reactor system has therefore been referred to as a solid-polymer-electrolyte reactor. Novel metal oxide anodes are responsible for the oxidation of the organic molecules. These metal oxide catalysts show promise in the treatment of a wide variety of organic wastes. A SnO2 catalyst doped with ZrO2 is used as anode in this study. Dopants are added to the catalyst to improve properties such as catalytic activity and conductivity. Kinetic data was obtained on a wide range of values for the chosen experimental parameters (current density and flow rate). Phenol, an organic molecule often referred to in the literature as model contaminant due to its resistance to oxidation,was also used as contaminant in this study. The use of the reactor system in the disinfection of water containing selected pathogens, were included in the experimental work. This kinetic data served in the development of a simple model of the process, and provided the basis for a full analysis regarding potential scale-up and economic feasibility. A requirement of the study was the accurate determination of the various oxidation breakdown products of phenol. This led to the refinement of an HPLC analytical method in order to quantitatively determine these products. The full analysis showed that the current reactor system would not be economically viable — mainly due to very long reactor lengths required for the complete removal of all organic material. Both mass transfer and charge transfer at the chosen experimental conditions influenced the electrochemical oxidation of phenol. High pressure drops, causing low flow rates in the reactor, accounted for this because of the narrow flow channels required in the reactor. Some catalyst deactivation was also suspected to affect the overall reaction, but the full extent of the deactivation was not investigated thoroughly. There is still room for improvement in the electrochemical oxidation of organic wastes. The design of the flow channels, a factor that was not investigated, can significantly improve efficiency. Another aspect that was not investigated was the catalyst type. The catalyst has been identified in the literature as the main contributing factor to the success of the oxidation reaction. A wide variety of metal oxide catalysts are currently being researched and may improve the kinetics of the process even further. Further improvement needs to be made on the membrane/electrode assembly to improve current density distribution. Every improvement of the process in terms of the reactor design and catalyst will impact on the economics of the process, thus making the process more competitive with current treatment technologies.
AFRIKAANSE OPSOMMING: In die afgelope paar dekades, is daar ’n wye verskeidenheid metodes ontwikkel wat gebruik kan word om industri¨ele afvoer strome te behandel. Hierdie ontwikkeling het plaasgevind as gevolg van die verhoogde eis aan skoner afvoerstrome. Wateragtige afvoerstrome wat organiese verbindings bevat, is van besonderse belang omdat hierdie tipe strome soms besonders moeilik kan wees om te behandel. Gebruiklike metodes is in die meeste gevalle ongeskik vir behandelings-doeleindes. Katalitiese oksidasie is sedert die 1960’s gebruik, maar hierdie prosesse benodig dikwels ho¨e drukke en temperature om suksesvol te wees. Elektrochemiese oksidasie het intussen ’n populˆere behandelingsmetode geword, aangesien die aktiveringsenergie vir die oksidasieproses hoofsaaklik afhanklik is van die aangewende potensiaal en dus kan die proses by atmosferiese toestande gebruik word. In hierdie tesis word die geskiktheid van ’n unieke reaktorstelsel vir water-suiwering ondersoek. Die reaktor gebruik ’n proton-uitruilings-membraan om die behoefte vir konduktiwiteit in die water uit te skakel. Die membraan dien dus as ’n tipe soliede elektroliet en as gevolg hiervan word na die reaktorstelsel verwys as ’n soliede-polimeer-elektroliet reaktor. Nuwe metaal-oksied anodes word in die reaktor gebruik aangesien hulle belowende resultate toon in die oksidasie van organiese verbindings. In die navorsing, is ’n SnO2 katalis wat klein hoeveelhede ZrO2 bevat gebruik. Oksiede soos ZrO2 word dikwels gebruik om die aktiwiteit en konduktiwiteit van hierdie kataliste te bevorder. Kinetiese data is oor ’n wye bereik van parameter waardes ingesamel. Die hoof parameters in die eksperimentele werk was stroom digtheid en vloeitempo. Fenol, ‘n komponent wat volgens die literatuur in hierdie tipe van werk gebruik word, isas die besoedelende komponent gekies. Die doeltreffendheid van die reaktor in die ontsmetting van water, wat met ’n verskeidenheid skadelike mikro-organismes besmet is, is ook getoets. ‘n Eenvoudinge model is opgestel m.b.v. die kinetiese data, waarna ’n volledige analise met betrekking tot grootskaalse bedryf en ekonomiese uitvoerbaarheid gedoen is. ‘n Vereiste van die studie was om die konsentrasie van die afbreek-produkte van die oksidasie akkuraat vas te stel. As gevolg hiervan is ‘n ho¨e-druk-vloeistofchromatografie analitiese metode verfyn. Die analise het getoon dat die reaktorstelsel nie ekonomies sou wees nie. Een van die hoofredes hiervoor is die onrealistiese reaktorlengtes wat benodig sou word. Resultate het getoon dat die reaksie deur beide massa-oordrag en lading-oordrag be¨ınvloed word. Ho¨e drukvalle in die reaktor wat gelei het tot lae vloeitempo’s was hiervoor verantwoordelik. Die deaktivering van die katalis be¨ınvloed waarskynlik die reaksie, maar die deaktiveringsverskynsel is nie ten volle ondersoek nie. Die reaktorstelsel kan verder verbeter word deur verskeie elemente van die reaktor te ondersoek. Die ontwerp van die vloeikanale in die reaktor is nie ondersoek nie en kan die werksverrigting van die reaktor verhoog. Uit die literatuur is gevind dat die tipe metaaloksied wat as katalis gebruik word, die reaksie direk be¨ınvloed. Dus kan navorsing wat tans op die kataliste gedoen word nuwe kataliste na vore bring wat meer doeltreffend sal wees. Laastens, is die huidige membraan/elektrode samestelling nog oneffektief en kan die reaktor-opstelling dus nog verbeter word. Elke verbetering wat op die bogenoemde faktore van die reaktor ontwerp verkry word, sal die ekomoniese uitvoerbaarheid van die proses be¨ınvloed. So, sal die proses al meer kompeterend met huidige behandelingsmetodes word.

Manganese is typically found in all water supplies in the United States. Manganese concentrations are usually higher in water obtained from groundwater sources or resei:voir hypolinutlons. This is because manganese is more soluble in the reducing conditions normally found in these waters. Although manganese is not known to cause any health related problems, the secondary drinking water MCL for manganese is 0.05 mg/L. This standard was set to eliminate aesthetic problems associated with manganese bearing waters. In this study continuous-flow filters were operated in both pre-oxidative (oxidized Mn applied to filters) and auto-oxidative (soluble Mn applied) modes. The oxidants used were dllorine (HOCl/OCl⁻) , potassium permanganate (KMnO₄), chlorine dioxide (ClO₂), and ozone (O₃). Other experimental parameters included: filter media type - manganese coated or non-coated, filter loading rate --2 to 5 gpm/f², operating pH -- pH 6 to pH 9, and temperature --5 to 25℃. The most important experimental parameter was whether or not the filter media had a prior oxidized coating of manganese. If this was the case the filter produced an effluent concentration of manganese below the MCL under all pre-oxidative conditions and under auto-oxidative conditions when the pH was above neutral. Increased flow rate through the filter caused deeper penetration of manganese into the filter bed. This should not prove to cause an effluent breakthrough problem for filter depths typically used in water treatment plants. Temperature and pH effected the reaction rate of manganese oxidation in both the pre- and auto-oxidative modes. In most cases th.is did not effect the effluent quality from manganese coated filter media. However, when non-coated media was used and no oxidant was added, a decrease in pH or temperature usually adversely effected effluent quality.
M.S.

This project determined the thermodynamic potentials for various reactions between reduced manganese (Mn⁺²), manganese oxide (MnO₂(s)), chlorine dioxide (C10₂), and potassium permanganate (KMnO₄). Based on these findings, laboratory analyses were performed to determine if these reactions would occur under simulated water treatment plant conditions. In addition, a speciation procedure was developed to quantify the various species of manganese and chlorine dioxide present in a single sample. The reactions and the speciation procedure were evaluated at TOC concentrations ranging from < 1.0 mg/L to 5.0 mg/L and at pH 6.0 and 8.0. The speciation procedure yielded a reliable measure of Mn⁺², insoluble manganese, and Mn⁺⁷; however, the Mn⁺⁷ evaluation could be disrupted by the presence of free chlorine. The determination of C10₂ and C10₂- concentrations was also possible; however, the C10₂- concentration was subject to error.

The laboratory analyses revealed that C10₂ was unable to oxidize either Mn⁺² or MnO₂(s) to Mn⁺⁷ under any of the thermodynamically favored conditions. Both KMn0₄ and C10₂ selectively oxidized reduced organic material before reducing the concentration of Mn⁺². When C10₂ and KMnO₄ were added simultaneously, the ClO2 reacted preferentially with the reduced materials. Only after the C10₂ concentration was exhausted did the MnO^- begin to oxidize the reduced species.

Master of Science

Orientador: Ruben Bresaola Junior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A presente pesquisa teve por objetivo avaliar a formação de subprodutos da desinfecção (SPDS), gerados a partir da oxidação de soluções contendo substâncias húmicas e estas com adição de íons brometo, pelo dióxido de cloro, de forma isolada, ou associada com o cloro livre, sob diferentes concentrações e tempos de contato. A detecção dos trialometanos (THM), aldeídos e ácidos orgânicos formados foi realizada utilizando a técnica de cromatografia gasosa. Os resultados das análises cromatográficas proporcionaram a escolha da amostra que apresentou maior concentração de cada SPD para a realização de ensaios de adsorção, em diferentes concentrações de carvão ativado em pó (CAP), seguido de simulação, em condições de laboratório, de processos de tratamento físico-químico do tipo convencional de água para abastecimento. Os resultados obtidos indicaram que o uso do dióxido de cloro na oxidação de soluções contendo ácidos húmicos, com e sem a presença de brometos, gerou concentrações de THM abaixo do preconizado pela portaria 518 do MS; enquanto que a aplicação do cloro livre, após o uso do dióxido de cloro como oxidante primário, combinado com a presença de íons brometo, produziu maiores concentrações dos mesmos. Variando-se as dosagens de dióxido de cloro, houve formação de aldeídos em concentrações baixas, e a variação da dosagem de ácidos húmicos e íons brometo não acarretaram na formação significativa dos mesmos. Para as dosagens de ácidos húmicos, brometos e oxidantes estudadas não houve formação significativa de ácidos orgânicos. A utilização do CAP seguido de tratamento convencional promoveu a adequação da água nos valores máximos permitidos pelas normas vigentes para os parâmetros cor aparente e turbidez, não causando prejuízo à qualidade da água original. A variação da dosagem de CAP influenciou no tratamento da água, com remoção de THM mais efetiva para as dosagens mais altas. Já para aldeídos, dosagens mais baixas mostraram ser mais eficientes
Abstract: The objective of the present research was to analyze the formation of disinfection by products (DPB), generated by the oxidation of solutions containing humic substances with the addition of bromide ions through the use of chlorine dioxide, isolated or associated with free chlorine in different concentrations and reaction times. The technique of gaseous chromatography was applied in order to detect the formed trihalomethanes (THM), aldehydes and organic acids. The results of the chromatographic analyses allowed to choose the sample that presented the higher concentration of each DBP to carry out the assays of adsorption in different concentrations of powdered activated carbon (PAC), followed by simulation, under laboratory conditions, of conventional process of water treatment. The obtained results indicated that the use of chlorine dioxide in the oxidation of solutions containing humic acids with and without the presence of bromides resulted in THM concentrations under the ones established by the resolution n. 518 of Brazilian Health Ministry, while the use of free chlorine, after the use of chlorine dioxide as a primary oxidant, combined with the presence of bromide ions, produced higher concentrations of these. The variation of chlorine dioxide dosages resulted in the formation of aldehydes in lower concentrations, and the variation of humic acids and bromide ions dosages did not result in a significant formation of these. For the dosages of humic acids, bromides and oxidants there was no significant formation of organic acids. The use of PAC, followed by the conventional process of water treatment promoted the adequacy of the water in the maximum values allowed by the national regulations for the color and e turbity parameters, maintaining the quality of the original water, not causing loss of quality to the original water. The variation of PAC dosage influenced the treatment of the water, with more effective removal of THM for the higher dosages. On the contrary, for aldehyds, lower dosages showed to be more efficient
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Co-Chair: Huang, Ching-Hua; Committee Co-Chair: Kim, Jae-Hong; Committee Member: Li, Qilin; Committee Member: Mulholland, James; Committee Member: Wine, Paul; Committee Member: Yiacoumi, Sotira. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Orientador: Ruben Bresaola Junior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A presente pesquisa avaliou, em escala de laboratório, a formação de trihalometanos (THM) produzidos em reações de oxidação, com cloro livre, de amostras de água contendo ácidos húmicos, sob diferentes concentrações e tempos de contato. O estudo também abrangeu a presença do íon brometo, como forma de se avaliar, qualitativa e quantitativamente, as diferentes espécies de THM produzidas. A detecção dos trihalometanos formados foi realizada, comparativamente, através de duas técnicas analíticas. A cromatografia gasosa, indicada para a análise de tais moléculas, permitiu a quantificação dos compostos clorofórmio, diclorobromometano, dibromoclorometano e bromofórmio. A espectrofotometria foi avaliada como metodologia alternativa à primeira, permitindo a expressão dos resultados apenas em THM totais. Foram realizados ensaios de remoção de THM por adsorção em diferentes concentrações de carvão ativado em pó (CAP), seguido de processos de coagulação com sulfato de alumínio, floculação, sedimentação e filtração, em reatores estáticos. Os resultados obtidos indicaram que a formação de THM é diretamente proporcional às concentrações de cloro, ácidos húmicos, íon brometo e ao tempo de contato das reações. Os procedimentos de adsorção em CAP, seguido de processos convencionais de tratamento de água, demonstraram remoções de THM das amostras da ordem de até 89%. O aumento da concentração de CAP de 10 para 150 mg/L, e do tempo de contato de adsorção de 60 para 120 minutos, contribuiu para os melhores desempenhos nos experimentos realizados. As técnicas de detecção de THM por cromatografia gasosa e por espectrofotometria apresentaram resultados diferentes nas condições destes ensaios
Abstract: The present research evaluated, in laboratory scale, the formation of trihalomethanes (THM) produced in oxidation reactions, with free chlorine, of water samples with humic acids, in different concentrations and reaction time. This research also studied the presence of the bromide ion, to evaluate, qualitatively and quantitatively, the different species of THM produced. Trihalomethanes detection was comparatively investigated through two analytical techniques. The gaseous chromatography, indicated for the analysis of such molecules, resulted in the quantification of chloroform, dichlorobromomethane, dibromochloromethane and bromoform. The spectrophotometric technique was evaluated as an alternative methodology to the first one, allowing the expression of the results only in total THM. Static reactors were used to carry out assays of THM removal by adsorption in different concentrations of powdered activated carbon (PAC), followed by coagulation processes with aluminium sulphate, flocculation, sedimentation and filtration. The results indicated that THM formation is directly proportional to the concentrations of chlorine, humic acids, bromide ion and reaction time. The procedure of PAC adsorption, followed by conventional processes of water treatment were effective, showing THM removal from the samples of up to 89%. The increase in PAC concentration from 10 to 150 mg/L, and adsorption reaction time from 60 to 120 minutes, resulted in the best performances. The methodologies for THM based on gaseous chromatography and espectrophotometric presented different results in the laboratory conditions of these assays
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

O cloro é o agente desinfetante e oxidante mais utilizado no mundo em sistemas de tratamento de água. Entretanto, a aplicação de cloro em águas superdiciais pode levar a formação de subprodutos de desinfecção, além da ineficiência do oxidante na degradação de micropoluentes. Este trabalho teve como objetivo avaliar a eficiência dos agentes peroxidados, peróxido de hidrogênio (H2)2) e ácidoperacético (PAA), em processo oxidativo avançado (POA) Assistido por UVC, na degradação de matéria orgânica natural e 2-MIB e geosmina em água de abastecimento. A matriz utilizada foi água do Rio Iratí, amostra na região metropolitana de Curitiba/PR. Como pré-tratamento da água, foram abordadas as etapas de coagulação, floculação, sedimentação e filtração com o agente coagulante PAC. Os POAs doram realizados em reatores UVC com lâmpadas de baixa pressão, em modo batelada e modo contímuo. No tratamento UV/H2O2, eficiência máxima de redução nos valores de UVA254 (92%) e fluorescência (95%), foram obtidas em modo contínuo após 15 minutos reacionais e 15 mg.L­­-¹ de H2)2, na ausência de 2-MIB/geosmina. A formação de TTHM foi reduzida, situando-se em 15,7 ÞL-¹ . A degradação dos contaminantes 2-MIB e geosmina, após prétratamento e processo UV/H2O2, resultou em teores à 0,1 þg.L-¹. A presença do solvente metanol nos contaminantes-padrão foi considerada como fator interferente negativo ao processo UV/H2O2. No tratamento UV/PAA, verificou-se a contribuição negativa de CODNP inerente ao próprio oxidante. No entanto o processo foi eficiente em até 89% na redução de intensidade de fluorescência, com formação de 21,5 þg.L-¹ de TTHM. A análise experimental indicou efeito positivo e significativo para a variável tempo de resistência em todos os ensaios e POAs realizados. Em nenhum dos ensaios foi possível obter a mineralização total do conteúdo carbônico presente nas amostragens. Os tratamentos UV/H2O2 e UV?PAA apresentaram um perfil de resposta não-linear, sendo necessários ajustes para o enquadramento em modelo quadrático.
As a disinfectant and an oxidizing agent, chlorine is the most used chemical in various water may lead the formation of desinfection byproducts, furthermore, the inefficiency on micropollutants degradation. the main purpose of this work is to evaluate the efficiency of hydrogen peroxide (H2O2) and peracetic acid (PAA), in advanced oxidation process under UVC radiation, on degradation of natural organic matter and contaminats 2-MIB/geosmin in supplying water. The environmental matrix involved was water from Iratí River, located near Curitiba/PR. Waterpretreatment included coagulation, floculation and sedimentation operations at jar test equipement, with PAC as coagulant agent. Advanced oxidative treatments were executed at UV reactors, with low-pressure lamps, in batch and continuous mode. in UV?H@O@ treatment, maximum efficiency on UVA254 reduction (92%) and fluorescence (95%), was obtained in continuos flowing mode, after 15 minutes (reaction taime) and 15 mg.L-¹ of hydrogen peroxide, in the absence of 2-MIB and geosmin. The formation of total trihalomethanes was one of the lowest at 15.7 þg.L-¹. Degradation of pollutants 2-MIB and geosmin, after pretreatment and AOP UV/H2O2, ended in concentrations lower than 0.1 þg.L-1. According to these UV/H2O2 tests, certain reduction was obsorved at efficiency results of all response factors monitored, since the presence of methanol intrinsic to the contaminat standard solution applied. In UV/PAA, was noticed some contribution of NPDOC provided by the own oxidizing agent (PAA). However, UV/PAA treatment was efficient at 89% according to fluorescence intensity reduction, associated with the formation of total trihalomethanes at 21,5 þg.L-¹. Experimental analysis indicated positive and significant effect for the variable retention time in all tests. None of the tests resulted in carbon complete mineralization. Treatment with UV/H2O2 and Uv/PAA presented non-linear response profile, being necessary adjustments for quadratic fitting.

Past research regarding complexed iron has focused on the resistance to and kinetics of oxidation by O₂(aq) and the extent of stabilization. The 0.45 um filter was typically used to differentiate between dissolved and particulate iron. This research investigated Fe(II) oxidation by free chlorine and ClO₂ in the presence of DOC by varying the pH, DOC to Fe ratios, DOC sources, oxidant dosages, and contact time. Complexed iron removal by alum coagulation with and without oxidant addition was also examined. Particulate, colloidal, and soluble iron were differentiated by the use of 0.2 um filters and 100K ultrafilters. Ultrafiltration and oxidation studies revealed that, at the DOC-to-iron ratios used for this research, not all of the Fe(II) in solution was actually complexed. Thus, oxidation studies represented the oxidation of uncomplexed Fe(II) to Fe(III), which was then complexed by the higher molecular weight DOC. Results indicated that particulate iron formation (as defined as retention by a 0.2 um filter) was a function of the DOC source and oxidant used for testing. The formation of colloidal iron (as defined by retention on 100K ultrafilter) due to oxidation was dependent upon the initial DOC-to-iron ratio and the DOC source. A correlation between DOC adsorption to iron oxide solids and the solution pH, initial DOC-to-iron ratio, and the oxidant used was also evident. Complexed Fe(II) was removed from solution by alum coagulation. Oxidant addition to alum coagulation was necessary to effectively remove uncomplexed Fe(II) (in the presence of DOC) from solution.
Master of Science

Wastewaters from textile industry contain organic dyes, which cannot be easily treated by biological methods. Therefore, pretreatment by an advanced oxidation process (AOP) is needed in order to produce more readily biodegradable compounds and to remove color and chemical oxygen demand (COD) simultaneously. In this research, ozone (O3) is combined with hydrogen peroxide (H2O2) for the advanced oxidation of an azo dye solution, namely aqueous solution of Acid Red 151, which is called as &ldquo
Peroxone process&rdquo
. The aim of the study is to enhance the ozonation efficiency in treating the waste dye solution. The effects of pH, initial dye and initial ozone concentrations and the concentration ratio of initial H2O2 to initial O3 on color and COD removals were investigated. Also, the kinetics of O3-dye reaction in the presence of H2O2 was approximately determined. As a result of the experimental study, it was seen that an increase in the initial dye concentration at a constant pH and initial ozone concentration did not change the COD % removal significantly, from a statistical analysis of the data. The results obtained at pH values of 2.5 and 7 gave higher oxidation efficiencies in terms of color and COD removals compared to those at pH of 10. The best initial molar ratio of H2O2 to O3 was found to be 0.5, which yielded highest treatment efficiency for each pH value studied. The results of the excess dye experiments suggest that the ozonation of Acid Red 151 follows an average first order reaction with respect to ozone at pH=2.5 and pH=7 whereas it is around 0.56 at pH=10. By Initial Rate Method, the orders with respect to individual reactants of O3 and dye were determined as one, the total order of the reaction being two for all the studied pH. As a conclusion, a further study of the peroxone process at a pH of 10 can be recommended to determine the reaction kinetics and mechanism at this pH, where radicals play an important role.

Orientador: Ruben Bresaola Junior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A presente pesquisa teve por objetivo analisar a formação de THM através do uso de permanganato de potássio, de forma isolada ou associada com o cloro livre, no processo de pré-oxidação, e, numa segunda etapa, avaliar a eficiência de remoção destes subprodutos através da adsorção em carvão ativado em pó seguida de tratamento convencional. Foram realizadas oxidações de soluções contendo ácidos húmicos e brometos, em diversas dosagens, analisando-se a formação de THM por espectrofotometria e cromatografia gasosa. A remoção dos subprodutos formados foi realizada com dosagens de CAP variando de 10,0 a 150,0 mg/L e com dosagem de coagulante e valor de pH determinados experimentalmente para cada uma delas. Os resultados obtidos, pelos dois métodos de detecção, mostraram que não houve formação significativa de THM quando a oxidação foi realizada apenas pelo permanganato de potássio e que, com o uso conjunto dos dois oxidantes, houve uma redução média de 30 % na formação quando comparada ao uso exclusivo de cloro livre. O processo de tratamento se mostrou eficiente para as dosagens mais altas de CAP, adequando a qualidade da água final nas normas vigentes.
Abstract: The present research had for objective to analyze the formation of THM through the use of potassium permanganate, isolated or associate with free chlorine, in the process of pre-oxidation, and, in a second stage, to evaluate the removal efficiency of these by-products through the adsorption in powdered activated carbon followed by conventional treatment. The oxidations of solutions contend humic acids and bromides, in diverse dosages had been carried through, analyzing the formation of THM with spectrofotometric and gas chromatography methods. The removal of by-products was carried through with dosages of PAC between 10,0 and 150,00 mg/L and dosages of coagulant and pH value determined experimentally for each one of them. The gotten results, for the two methods of determination, had shown that there wasn't significant formation of THM when the oxidation was carried through only by the potassium permanganate and that, with the joint use of the two oxidants, it had an average reduction of 30 % in the formation when compared with the exclusive use of free chlorine use. The treatment process showed efficient for the highest dosages of PAC, adjusting the quality of the final water in the effective regulations.
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

Thesis (MScEng)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: The purpose of this study was to develop modi ed tract-etched membranes using nanocomposite TiO2 for advanced water treatment processes. Photocatalytic oxidation and reduction reactions take place on TiO2 surfaces under UV light irradiation, therefore sunlight and even normal indoor lighting could be utilised to achieve this effect. In membrane ltration, caking is a major problem, by enhancing the anti-fouling properties of photocatalysts to mineralise organic compounds the membrane life and e ciency can be improved upon. In this study the rst approach in nanocomposite membrane development was to directly modify the surface of polyethylenetherephthalate (PET) track-etched membranes (TMs) with titanium dioxide (TiO2) using inverted cylindrical magnetron sputtering (ICMS) for TiO2 thin lm deposition. The second approach was rst to thermally evaporate silver (Ag) over the entire TM surface, followed by sputtering TiO2 over the silver-coated TM. As a result a noble metal-titania nanocomposite thin lm layer is produced on top of the TM surface with both self-cleaning and superhydrophilic properties. Reactive inverted cylindrical magnetron sputtering is a physical vapour deposition method, where material is separated from a target using high energy ions and then re-assimilated on a substrate to grow thin lms. Argon gas is introduced simultaneously into the deposition chamber along with O2 (the reactive gas) to form TiO2. The photocatalytic activity and other lm properties, such as crystallinity can be in uenced by changing the sputtering power, chamber pressure, target-to-substrate distance, substrate temperature, sputtering gas composition and ow rate. These characteristics make sputtering the perfect tool for the preparation of di erent kinds of TiO2 lms and nanostructures for photocatalysis. In this work, the utilisation of ICMS to prepare photocatalytic TiO2 thin lms deposited on track-etched membranes was studied in detail with emphasis on bandgap reduction and TM surface regeneration. Nanostructured TiO2 photocatalysts were prepared through template directed deposition on track-etched membrane substrates by exploiting the good qualities of ICMS. The TiO2-TM as well as Ag-TiO2-TM thin lms were thoroughly characterised. ICMS prepared TiO2 lms were shown to exhibit good photocatalytic activities. However, the nanocomposite Ag-TiO2 thin lms were identi ed to be a much better choice than TiO2 thin lms on their own. Finally a clear enhancement in the photocatalytic activity was achieved by forming the Ag-TiO2 nanocomposite TMs. This was evident from the band-gap improvement from 3.05 eV of the TiO2 thin lms to the 2.76 eV of the Ag-TiO2 thin lms as well as the superior surface regenerative properties of the Ag-TiO2-TMs.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om verbeterde baan-ge etste membrane (BMe) met behulp van nano-saamgestelde titaandioksied (TiO2) vir gevorderde water behandeling prosesse te ontwikkel. Fotokatalitiese oksidasie- en reduksie reaksies vind plaas op die TiO2 oppervlaktes onder UV-lig bestraling, en dus kan sonlig en selfs gewone binnenshuise beligting gebruik word om die gewenste uitwerking te verkry. In membraan ltrasie is die aanpaksel van onsuiwerhede 'n groot probleem, maar die verbetering van die self-reinigende eienskappe van fotokatalisators deur organiese verbindings te mineraliseer, kan die membraan se leeftyd en doeltre endheid verbeter word. In hierdie studie was die eerste benadering om nano-saamgestelde membraan ontwikkeling direk te verander deur die oppervlak van polyethylenetherephthalate (PET) BMe met 'n dun lagie TiO2 te bedek, met behulp van reaktiewe omgekeerde silindriese magnetron verstuiwing (OSMV).Die tweede benadering was eers om silwer (Ag) termies te verdamp oor die hele BM oppervlak, gevolg deur TiO2 verstuiwing bo-oor die silwer bedekte BM. As gevolg hiervan is 'n edelmetaal-titanium nano-saamgestelde dun lm laag gevorm bo-op die oppervlak van die BM, met beide self-reinigende en verhoogde hidro liese eienskappe. OSMV is 'n siese damp neerslag metode, waar materiaal van 'n teiken, met behulp van ho e-energie-ione, geskei word, en dan weer opgeneem word op 'n substraat om dun lms te vorm. Argon gas word gelyktydig in die neerslag kamer, saam met O2 (die reaktiewe gas), vrygestel om TiO2 te vorm. Die fotokatalitiese aktiwiteit en ander lm eienskappe, soos kristalliniteit, kan be nvloed word deur die verandering van byvoorbeeld die verstuiwingskrag, die druk in die reaksiekamer, teiken-tot-substraat afstand, substraattemperatuur, verstuiwing gassamestelling en vloeitempo. Hierdie eienskappe maak verstuiwing die ideale hulpmiddel vir die voorbereiding van die verskillende soorte TiO2 lms en nanostrukture vir fotokatalisasie. In hierdie tesis word OSMV gebruik ter voorbereiding van fotokatalitiese TiO2 dun lms, wat gedeponeer is op BMe. Hierdie lms word dan in diepte bestudeer, met die klem op bandgaping vermindering en BM oppervlak hergenerasie. Nanogestruktureerde TiO2 fotokataliste is voorberei deur middel van sjabloongerigte neerslag op BM substrate deur die ontginning van die goeie eienskappe van OSMV. Die TiO2-BM dun lms, sowel as Ag-TiO2-BM dun lms, is deeglik gekarakteriseer. OSMV voorbereide TiO2 dun lms toon goeie fotokatalitiese aktiwiteite. Nano-saamgestelde Ag-TiO2 dun lms is egter ge denti seer as 'n veel beter keuse as TiO2 dun lms. Ten slotte is 'n duidelike verbetering in die fotokatalitiese aktiwiteit bereik deur die vorming van die Ag-TiO2 nano-saamgestelde BMe. Dit was duidelik uit die bandgapingverbetering van 3,05 eV van TiO2 dun lms in vergelyking met die 2,76 eV van Ag-TiO2 dun lms. 'n Duidelike verbetering is behaal in die fotokatalitiese aktiwiteit deur die vorming van die Ag-TiO2 nano-saamgestelde TMs.

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O objetivo deste estudo foi verificar a influencia de sanitizantes (ozônio e hipoclorito de sódio) no conteúdo de compostos bioativos e na atividade antioxidante durante o armazenamento refrigerado e na simulação de comercialização de mangas (Mangifera indica L.) 'Palmer' cultivadas em sistema orgânico e convencional e verificar as alterações durante o armazenamento de dois diferentes smoothies. Para atingir esse objetivo a tese foi dividida em cinco capítulos, no primeiro as mangas 'Palmer' orgânicas adquiridas no município de Borborema-SP e as convencionais, doadas pela Ogata Citrus (Taquaritinga-SP) foram transportadas ao laboratório de Bioquímica, onde foram submetidas a quatro tratamentos de imersão: imersão em água; em água clorada com 100 mg L-1 de hipoclorito de sódio por 10 minutos e em água ozonizada por 10 ou 20 minutos. As avaliações foram realizadas após a colheita e aos 7 e 15 dias de armazenamento refrigerado. Aos 7 dias, os frutos foram levados ao ambiente e as avaliações seguiram por 4 e 8 dias, para simular o período de comercialização. Determinaram-se a firmeza da polpa, pH, ácido ascórbico, sólidos solúveis, acidez titulável, polifenóis totais, flavonóides totais, β-caroteno, DPPH e FRAP. As análises microbiológicas foram realizadas após a colheita, aos 7 dias de armazenando refrigerado e aos 7 dias mais 4 em ambiente. O delineamento utilizado foi inteiramente casualizado (DIC) com esquema fatorial 5 x 8 (dias de avaliação x tratamentos) com 3 repetições. Houve uma tendência dos frutos orgânicos e ozonizados apresentarem maiores conteúdos dos compostos bioativos, com isso maior atividade antioxidante, o que evidenciou que o ozônio pode substituir o cloro sem prejuízos aos frutos. No segundo capitulo, foi realizada a quantificação das aminas bioativas das polpas de manga 'Palmer' orgânicas e convencionais, submetidas a ...
The aim of this study was to investigate the influence of sanitizers (ozone and sodium hypochlorite) in the bioactive compounds content and antioxidant activity during cold storage and marketing simulation grown in mango (Mangifera indica L.) grown in organic and conventional system and verify changes during storage of two different smoothies. To achieve this thesis objective was divided into five sections, the first the mango 'Palmer' organic acquired in Borborema-SP and conventional, donated by Ogata Citrus (Taquaritinga-SP) were transported to the laboratory of Biochemistry, which were submitted four immersion treatments: immersion in water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonated water for 10 and 20 minutes. The evaluations were performed after harvest and at 7 and 15 days of cold storage. At 7 days, fruit were taken to the environment and evaluations followed by 4 and 8 days, to simulate marketing period. Were determined firmness, pH, ascorbic acid, soluble solids, titratable acidity, total polyphenols, total flavonoids, β-carotene, DPPH and FRAP. The microbiological analyzes were carried out after harvest, after 7 days of cold storage and 7 days over 4 environment. The design was completely randomized (CRD) with factorial 5 x 8 (day trial x treatments) with three repetitions. There was a trend of organic fruit and ozonated have higher bioactive compounds contents, therefore higher antioxidant activity, which shows that ozone could replace chlorine without damage to fruit. In the second chapter, it performed the bioactive amines quantification of the pulp mango 'Palmer' organic and conventional, undergo four sanitization treatments: immersion in the tap water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonization for 10 and 20 minutes postharvest and after seven days of cold storage followed by 4 and 8 ...

Orientador: Giuseppina Pace Pereira Lima
Coorientador: Juan Saavedra del Aguila
Banca: Fabio Vianello
Banca: Francisco Artes Calero
Banca: Camila Renata Correa Camacho
Banca: Igor Otavio Minatel
Resumo: O objetivo deste estudo foi verificar a influencia de sanitizantes (ozônio e hipoclorito de sódio) no conteúdo de compostos bioativos e na atividade antioxidante durante o armazenamento refrigerado e na simulação de comercialização de mangas (Mangifera indica L.) 'Palmer' cultivadas em sistema orgânico e convencional e verificar as alterações durante o armazenamento de dois diferentes smoothies. Para atingir esse objetivo a tese foi dividida em cinco capítulos, no primeiro as mangas 'Palmer' orgânicas adquiridas no município de Borborema-SP e as convencionais, doadas pela Ogata Citrus (Taquaritinga-SP) foram transportadas ao laboratório de Bioquímica, onde foram submetidas a quatro tratamentos de imersão: imersão em água; em água clorada com 100 mg L-1 de hipoclorito de sódio por 10 minutos e em água ozonizada por 10 ou 20 minutos. As avaliações foram realizadas após a colheita e aos 7 e 15 dias de armazenamento refrigerado. Aos 7 dias, os frutos foram levados ao ambiente e as avaliações seguiram por 4 e 8 dias, para simular o período de comercialização. Determinaram-se a firmeza da polpa, pH, ácido ascórbico, sólidos solúveis, acidez titulável, polifenóis totais, flavonóides totais, β-caroteno, DPPH e FRAP. As análises microbiológicas foram realizadas após a colheita, aos 7 dias de armazenando refrigerado e aos 7 dias mais 4 em ambiente. O delineamento utilizado foi inteiramente casualizado (DIC) com esquema fatorial 5 x 8 (dias de avaliação x tratamentos) com 3 repetições. Houve uma tendência dos frutos orgânicos e ozonizados apresentarem maiores conteúdos dos compostos bioativos, com isso maior atividade antioxidante, o que evidenciou que o ozônio pode substituir o cloro sem prejuízos aos frutos. No segundo capitulo, foi realizada a quantificação das aminas bioativas das polpas de manga 'Palmer' orgânicas e convencionais, submetidas a ...
Abstract: The aim of this study was to investigate the influence of sanitizers (ozone and sodium hypochlorite) in the bioactive compounds content and antioxidant activity during cold storage and marketing simulation grown in mango (Mangifera indica L.) grown in organic and conventional system and verify changes during storage of two different smoothies. To achieve this thesis objective was divided into five sections, the first the mango 'Palmer' organic acquired in Borborema-SP and conventional, donated by Ogata Citrus (Taquaritinga-SP) were transported to the laboratory of Biochemistry, which were submitted four immersion treatments: immersion in water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonated water for 10 and 20 minutes. The evaluations were performed after harvest and at 7 and 15 days of cold storage. At 7 days, fruit were taken to the environment and evaluations followed by 4 and 8 days, to simulate marketing period. Were determined firmness, pH, ascorbic acid, soluble solids, titratable acidity, total polyphenols, total flavonoids, β-carotene, DPPH and FRAP. The microbiological analyzes were carried out after harvest, after 7 days of cold storage and 7 days over 4 environment. The design was completely randomized (CRD) with factorial 5 x 8 (day trial x treatments) with three repetitions. There was a trend of organic fruit and ozonated have higher bioactive compounds contents, therefore higher antioxidant activity, which shows that ozone could replace chlorine without damage to fruit. In the second chapter, it performed the bioactive amines quantification of the pulp mango 'Palmer' organic and conventional, undergo four sanitization treatments: immersion in the tap water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonization for 10 and 20 minutes postharvest and after seven days of cold storage followed by 4 and 8 ...
Doutor

Ozonation is nowadays a competent technology for micropollutant oxidation in wastewater effluents. The combination of ozone with hydroxyl radical formed through ozone decomposition is effective in the abatement of a number of organic compounds. However, there are still some points to be addressed for a more efficient application of ozone-based processes to wastewater treatment and reclamation. There are, for instance, several organic compounds that react very slowly with ozone. They are known as ozone-resistant micropollutants. If a high quality water is wanted to be obtained, these substances should be also removed from the effluent. In addition, modelling the abatement of micropollutants during wastewater ozonation is essential for process simulation, optimization and real-time control. To make this possible, performance characterization in terms of oxidation efficiency is required, as well as some kinetic information regarding the abatement of micropollutants. The first can be addressed by using normalizing parameters allowing the estimation, for instance, of hydroxyl radical availability as a function of the consumed ozone, or any other parameter whose measurement during the process is simple. The most accurate way of obtaining kinetic data of micropollutants oxidation is conducting individual studies on this chemicals degradation by ozone and hydroxyl radicals. Some complementary tests, in addition, may be useful to obtain valuable data regarding the mechanisms of degradation and the potential ecotoxicological effects of formed transformation products. This thesis was divided in two parts: first, individual batch ozonation studies of selected concerning micropollutants were conducted. Particularly, the pesticides methiocarb, acetamiprid and dichlorvos were selected for that work. The second part consisted of the application of single ozonation and the combination O3/H2O2 was tested in the removal of ozone-refractory micropollutants from actual wastewater effluents. The latter was done through semi-batch ozonation experiments. The objectives were, on one hand, obtaining kinetic, mechanistic and toxicological data of some priority/emerging concern chemicals. On the other, ozonation studies with real effluent samples were performed with the aim of exploring the removal of ozone-recalcitrant chemicals and potential strategies for the modelling and real-time control of this process. In addition, improvement strategies for O3/H2O2 process application were investigated. Different kinetics were observed for pesticides reaction with ozone, being acetamiprid the most recalcitrant compound. In addition, toxicity of some of the pesticides transformation products was revealed, especially in the case of methiocarb degradation. Regarding ozone-based processes application to actual wastewater effluents, the removal of model ozone-recalcitrant compounds was found difficult, concluding that ozone doses higher than the immediate ozone demand (IOD) value are required for a more effective abatement of these substances regardless of the process employed. In the case of the O3/H2O2 process application, dosing hydrogen peroxide simultaneously to ozone bubbling was found to potentially entail important energy savings related to oxidants use. The oxidation performance of ozone-based processes and thus the abatement of ozone-refractory compounds could be effectively modelled using kinetic parameters, the monitoring of water quality parameters and empirical relationships obtained for each effluent. Furthermore, side reactions of involved oxidants with effluent organic compounds was found to increase the content in small and oxidized organic compounds in all cases. In the case of effluents containing suspended solids, ozone application also caused a net increase in the dissolved organic load.
El proceso de ozonización constituye una de las tecnologías de tratamiento de aguas con mayor potencial para la eliminación de microcontaminantes de los efluentes de depuradoras municipales. Pese a ello, algunos aspectos como la eliminación de aquellos contaminantes resistentes al ataque del ozono y la modelización cinética de este proceso ofrecen aún amplias posibilidades de mejora. La formación de productos de transformación a partir de reacciones del ozono y el radical hidroxilo con la materia orgánica del efluente es otro aspecto escasamente considerado. Dados los problemas técnicos y ambientales que dichos subproductos pueden ocasionar, la investigación de este fenómeno es también de gran interés. En esta tesis se estudiaron en primer lugar los fundamentos (cinética, mecanismos de reacción y efectos toxicológicos de los productos de transformación) del proceso de degradación de tres microcontaminantes orgánicos de preocupación emergente mediante el proceso de ozonización. A continuación, éstos y otros compuestos típicamente detectados en aguas residuales urbanas se emplearon como sustancias modelo en el estudio de la aplicación del ozono en efluentes reales de depuradora de calidad variada, con el fin de evaluar la eficiencia del proceso y proponer estrategias para la modelización del mismo. En este sentido, se propuso la combinación de parámetros cinéticos y la monitorización de parámetros de calidad del agua para el control a tiempo real del proceso. Las predicciones de eliminación de contaminantes llevadas a cabo mediante esta metodología mostraron una gran concordancia con los datos experimentales, tanto para el proceso de ozonización simple como para la combinación ozono-peróxido de hidrógeno, que por otro lado exhibió una gran eficiencia en la eliminación de contaminantes resistentes al ozono cuando se aplicó con dosificación simultánea de ambos oxidantes. Finalmente, la evaluación de los cambios experimentados por la materia orgánica del efluente durante la aplicación del ozono reveló una acumulación de compuestos de bajo peso molecular en todas las aguas ensayadas, además de la solubilización de materia orgánica en suspensión en efluentes con mayor carga orgánica.

Orientadores: Marcos Roberto de Vasconcelos Lanza, Rodnei Bertazzoli
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho foram estudados a identificação de produtos de degradação da ametrina (AME), agrotóxico utilizado em larga escala na agroindústria canavieira. A melhora no tratamento das condições ambientais é de suma importância para as regiões agrícolas, já que a contaminação do solo e das águas subterrâneas é quase inevitável. Em relação às indústrias que produzem/formulam os agrotóxicos, um tratamento alternativo é interessante, pois os Processos Oxidativos Avançados (POAs), e dentre esses, o emprego da Tecnologia Eletroquímica. Uma vez os parâmetros definidos podem gerar a combustão total da carga orgânica, ou geral produtos de degradação, que podem ser identificados, e assim, entender melhor o processo de degradação da AME. Desta maneira foram realizadas reações de oxidação parcial do herbicida utilizando a adição de H2O2 em uma solução contendo 100 mg L-1 de AME e catalisadas com Fe2+ em diferentes pH e temperatura. Os produtos foram identificados por um espectrômetro de massa, Ion-Trap com ionização por electrospray (ESI). O produto 4-amino-6-(metilamina)-1,3,5-triazin-2-ol (m/z 141) fora identificado, praticamente em todos os ensaios realizados. A melhor condição experimental para oxidar quimicamente a AME, ocorreu na proporção de 20 % (v/v) de H2O2, pH 7 e temperatura de 65 °C. Outra maneira de estudar a degradação da AME foi controlar a geração do H2O2 eletrogerado, desta maneira as degradações eletroquímicas do herbicida foram realizadas utilizando 200 mg L-1 do principio ativo a partir de uma solução comercial (Herbipak®). Eletrólises a potencial constante foram realizadas de -0,7 V ? E ? -1,2 V vs Ag/AgCl para geração de H2O2, alcançando o máximo da concentração de 508 mg L-1 para o potencial de -0,9 V vs. Ag/AgCl. O monitoramento da AME analisadas por CLAE, apresentou uma taxa de decaimento da concentração de 55% via geração de H2O2, com redução de 45% do COT quando utilizado a eletrossíntese H2O2/Fe2+. Estes ensaios de degradação também monitoraram a degradação da AME via CI, identificando a formação de íons NO3- e NO2-. A identificação da formação dos produtos de degradação da AME foi realizada por CG-EM/EM.
Abstract: In this study the identification of degradation products ametrina (AME), pesticides used on a large scale in the sugar industry. The improvement in the treatment of environmental conditions is of paramount importance to the agricultural regions, since the contamination of soil and groundwater contamination is almost inevitable. In relation to industries producing/formulate pesticides, an alternative treatment is interesting because the Advanced Oxidation Processes (AOPs), and among these, the use of Electrochemical Technology. Once the parameters set can generate combustion total organic content, or general degradation products, which can be identified, and thus better understand the degradation process of AME. Thus were partial oxidation reactions of the herbicide using the addition of H2O2 in a solution containing 100 mg L-1 of AME and catalyzed with Fe2+ at different pH and temperature. The products were identified by mass spectrometry, Ion-Trap electrospray ionization (ESI.) The product 4-amino-6-(methylamine)-1,3,5-triazine-2-ol (m/z 141) was identified, almost all trials. The best experimental condition to oxidize chemically AME, occurred at a rate of 20% (v/v) H2O2, pH 7 and temperature of 65°C. Another way to study the degradation of AME was controlling the generation of electrogenerated H2O2, thus the electrochemical degradation of the herbicide were performed using 200 mg L-1 of the active principle from a commercial solution (Herbipak®). Constant potential electrolyses were performed from -0.7 V ? E ? -1.2 V vs. Ag / AgCl for generation of H2O2, reaching the maximum concentration of 508 mg L-1 for the potential of -0.9 V vs Ag/AgCl. The monitoring of AME analyzed by HPLC, showed a rate of decay of the concentration of 55% via H2O2 generation, with 45% reduction of TOC when used at eletrossíntese H2O2/Fe2+. These tests also monitored the degradation via AME IC, identifying the formation of NO3- and NO2-. The identification of the formation of degradation products was performed by AME CG-MS/MS.
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica

The collaboration between the University of Barcelona and Acciona Agua was focused on optimizing greenhouses hydric resources. The functionality of a combined treatment had to be assessed, when applied to the discard stream of a recycling system of the Advanced Greenhouse leachates. The coupling consisted on an Advanced Oxidation Processes (AOP), photo-Fenton, based on hydroxyl radical oxidative potential, produced by the interaction between Fe2+ and H2O2, and a slow sand filtration column acting as a bioreactor. The recycling system will require the synergy of chemical and biological processes to be able to work efficiently with the particular characteristics of greenhouses effluents: high salinity content and the presence of pesticides. Two recycling strategies proposed by the project defined two conductivity thresholds that the coupled system should be able to cope with. The first strategy proposed a simple semi-closed system that recycled nutrient solution from the hydroponics crops until a maximum value of 11 mS•cm(-1), phytotoxicity limit. Part of the current was then diverted to be treated by the integrated system. The second strategy introduced reverse osmosis membrane technology that concentrated that diverted stream, sending the permeate for its reuse directly to the greenhouse, while the brine had to be treated by the coupled process. In this case the maximum level of salinity in the effluents could reach conductivities close to those for seawater, around 50 mS•cm(-1). The performance of photo-Fenton reaction was essayed in order to improve the knowledge regarding this treatment technique. On the first place, this AOP and the ozonation process were compared. Results shown that increasing toxicity of ozonation effluents confirmed the choice of photo-Fenton as the most adequate treatment for pesticide polluted effluents. Experimental design criteria allowed then to determine optimal working conditions depending on the content of the reaction media, and enabled to prove the existence of endogenous catalyst inhibition in the presence of fosetyl-Al. Salinity essays were finally performed, yielding positive results even for highest conductivity effluents. Those positive results were also reflected in the increase of the biodegradability of the treated effluents, what leaded to the next step of the research. Biocompatibility of pretreated effluents was essayed by means of sequencing batch reactors (SBR). These devices were used to show how photo-Fenton indeed increased biodegradability of the effluents, and how it grown until a certain point when more hydrogen peroxide did not lead to better results. They were also utilized to assess the biocompatibility of high salinity pretreated effluents, as a first step towards the coupling with the slow sand filtration at high conductivities. Results obtained were extremely encouraging, given that even for the highest salinity concentrations (10 and 50 mS•cm(-1)), the performance of the bioreactor achieved an organic content reduction for more than 80% of the loaded concentration, which compared to the 10-20% removal achieved by photo-Fenton, justifies the need of combining both treatments. Guided by those positive results, the load of the slow sand filtration column with different salinity pretreated effluents was performed. Also positive results were obtained. The achieved elimination of the organic content was more than 75% when loaded with 10 mS•cm-1 effluent, and the refractory fraction (the remaining organic matter that cannot be oxidized either by photo-Fenton reaction or by the biomass metabolism) was the lowest also for this high conductivity. Molecular biology tools, MTBs, used in this thesis were based on cloning and sequencing techniques of 16S rRNA genes. They allowed characterizing the bacterial population of one of the assessed SBRs and of the different loading stages of the slow sand filtration column. They showed how with the increase of salinity, the population in the slow sand filtration column loosed diversity, despite the fact that the performance of the column was still proficient. This fact stated how a very different microbial consortium could be developing the same functions as others. According to obtained results, it could be finally concluded that the coupling between photo-Fenton reaction and slow sand filtration column could be an effective treatment alternative for implementing the recycling strategies of hydroponics greenhouse leachates proposed by CENIT-MEDIODIA Project. For its part, MBTs were revealed as powerful tools to characterize microbial population and increase the understanding of the bioreactions taking part in bioremediation.
Esta tesis se enmarca en la colaboración entre el Departamento de Ingeniería Química de la Universidad de Barcelona y el Departamento de I+D de Acciona Agua S.A.U, en el marco del Proyecto CENIT- MEDIODIA (2007-2010). Esta iniciativa la componen un consorcio de empresas un consorcio de empresas y centros de investigación que unieron esfuerzos de innovación en el desarrollo de un nuevo concepto de Invernaderos Hidropónicos Avanzados. La colaboración entre la Universidad de Barcelona y Acciona Agua se centró en la optimización de los recursos hídricos de dichos invernaderos. Así se evaluó la funcionalidad de un tratamiento combinado que integrara un Proceso de Oxidación Avanzada (reacción foto-Fenton), y un reactor biológico (columna de arena de filtración lenta), aplicados a la corriente de desecho de un sistema de recirculación de lixiviados provenientes del nombrado invernadero avanzado. Las particularidades de dicho sistema de reciclado harían que el sistema combinado tuviese que trabajar con efluentes con alto contenido en pesticidas (metomilo, imidacloprid y fosetyl-Al, fueron escogidos para simular los lixiviados de invernadero) y conductividades entre 11 y 50 mS•cm-1. De este modo el principal objetivo del proceso integrado sería el de conseguir la máxima eliminación de los compuestos xenobióticos y de la carga orgánica que los acompañe en el efluente tratado. Así pues, la experimentación se llevó a cabo frente a tres aspectos relacionados con el sistema combinado: estudio de la reacción foto-Fenton, ensayos con biorreactores, y empleo de herramientas de biología molecular (MBT, en sus siglas en inglés) aplicadas a la caracterización de la biomasa desarrollada en los biorreactores ensayados. Según los resultados obtenidos, se llegó a la conclusión de que la combinación de la reacción foto-Fenton y la columna de filtración lenta podría ser una alternativa de tratamiento eficaz para la aplicación de las estrategias de reciclaje de los lixiviados hidroponía presentadas en Proyecto CENIT-MEDIODIA. Además, MBT se revelaron como poderosas herramientas para caracterizar la población microbiana de distintos biorreactores y las funciones que desempeñan.

Esta tesis doctoral versa sobre el tratamiento de aguas contaminadas con fármacos sulfamidas como el ácido sulfanílico (SA), la sulfanilamida (SNM) y la sulfametazina (SMZ). Estos compuestos se han degradado en una disolución sintética ácida mediante diversos procesos electroquímicos de oxidación avanzada (EAOPs) tales como la oxidación anódica (AO) en celda dividida y no dividida y los procesos electro-Fenton (EF), fotoelectro-Fenton UVA (PEF) y fotoelectro-Fenton solar (SPEF). En AO se ha usado un ánodo de diamante dopado con boro (BDD) y un cátodo de acero inoxidable en celdas de 100 mL, mientras que en EF, PEF y SPEF se ha utilizado un ánodo de BDD o de Pt y un cátodo de difusión de aire (ADE) o de fieltro de carbón en una celda de 100 o 230 mL. Se ensayó el efecto de variables experimentales como la intensidad de corriente, la concentración del fármaco y del catalizador de Fe2+ y el pH sobre la cinética de mineralización del SA, SNM y SMZ. Los procesos de AO en celda dividida y de PEF operando entre 50 y 450 mA conducían a una mineralización total con una reducción del carbono orgánico total (TOC) superior al 98%. El aumento de la intensidad siempre daba lugar a una mayor velocidad de mineralización debido a la mayor producción de radicales hidroxilo (●OH) vía oxidación del agua en AO, junto a la acción sinérgica del ●OH formado por la reacción de Fenton y de la luz UVA en PEF. También se consiguió una mineralización total para disoluciones concentradas hasta 2530 mg L-1 de SA, 2390 mg L-1 de SNM y 1930 mg L-1 de SMZ, tardando más tiempo aquellas con mayor contenido de sustrato. La cinética de desaparición del sustrato siempre obedecía una reacción de pseudo-primer orden. Se siguió la evolución con el tiempo de electrólisis de la hidroquinona, la p-benzoquinona y los ácidos oxálico y oxámico para el SA, y del catecol, resorcinol, hidroquinona, p-benzoquinona, 1,2,4- trihidroxibenceno y los àcidos maleico, fumárico, acético, oxálico, fórmico y oxámico para la SNM mediante HPLC. Para la SMZ, se detectaron la 4,6-dimetil-2-pirimidinamina, el catecol, el resorcinol, la hidroquinona y la p-benzoquinona por GCMS, y los ácidos maleico, fumárico, acético, fórmico, oxálico y oxámico por HPLC. Se confirmó que el N inicial se convertía principalmente en ion NH4 + y en mucha menor proporción en ion NO3-. A partir de estos resultados, se ha propuesto un camino de reacción plausible para la mineralización de cada compuesto por los EAOPs ensayados. Además, se evaluó la toxicidad de la disolución a partir de la inhibición de la luminiscencia de las bacterias Vibrio fischeri en EF. La toxicidad adquirió su valor máximo a cortos tiempos de electrólisis cuando se producían los productos aromáticos más tóxicos, pero la disolución se desintoxicó totalmente al final del tratamiento, independientemente del ánodo utilizado. En vista de los excelentes resultados encontrados para el PEF, el estudio de la degradación del SA se amplió a una planta pre-piloto solar de 2,5 L como un primer paso de la aplicación del proceso de SPEF a nivel industrial. El reactor era de Pt/ADE y se probó comparativamente el tratamiento de EF para clarificar la acción sinérgica de la luz solar. Ambos procesos se optimizaron mediante la aplicación de un diseño central compuesto acoplado con metodología de superficie de respuesta. Se obtuvo que las variables óptimas eran 100 mA cm-2, 0,5 mM de Fe2+ y pH 4,0. Se encontraron resultados similares para la SNM usando la misma planta pre-piloto. El proceso de SPEF permitió una mineralización del 94%, de forma más rápida a medida que la densidad de corriente aumentaba de 50 a 150 mA cm-2, mientras que las degradaciones comparables por EF dieron menor descontaminación.
This doctoral thesis is devoted to the degradation of sulfanilic acid (SA) and sulfa drugs as sulfanilamide (SNM) and sulfamethazine (SMZ) in acidic aqueous medium using electrochemical advanced oxidation processes (EAOPs) like anodic oxidation (AO) in divided and undivided cells and electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF). AO experiments were made in 100 mL cells with a boron-doped diamond (BDD) anode and a stainless steel cathode, whereas in EF, PEF and SPEF, the cell of 100 or 230 mL was equipped with a BDD or Pt anode and an airdiffusion (ADE) or carbon-felt cathode. The AO process in divided cell and PEF between 50 and 450 mA gave total mineralization with > 98% total organic carbon reduction. Increasing current always accelerated the mineralization due to the higher production of ●OH via wáter oxidation in AO, along with ●OH formed from Fenton’s reaction and UVA action in PEF. Total mineralization was achieved up to 2530 mg L-1 SA, 2390 mg L-1 SNM and 1930 mg L-1 SMZ. The substrate decay always obeyed a pseudo-first-order kinetics. HPLC allowed detecting intermediates like hydroquinone, p-benzoquinone and oxalic and oxamic acids for SA, and catechol, resorcinol, hydroquinone, p-benzoquinone, 1,2,4-trihydroxybenzene and fumaric, maleic, acetic, oxalic and formic acids for SNM. In the case of SMZ, 4,6-dimethyl-2-pyrimidinamine and catechol, resorcinol, hydroquinone and p-benzoquinone were detected by GC-MS and mainly oxalic and oxamic acids by HPLC. The initial N was lost mainly as NH4+ ion and, in lesser proportion, as NO3- ion. These results allowed the proposal of a reaction sequence for each compound by the EAOPs tested. The study of SA degradation was further extended to a solar pre-pilot plant of 2.5 L with a Pt/ADE reactor as a first step of the application of SPEF to industrial level. The EF and SPEF processes were optimized by means of response surface methodology, yielding 100 mA cm-2, 0.5 mM Fe2+ and pH 4.0 as best variables. Similar results were found for SNM using the same pre-pilot plant. The SPEF process allowed 94% mineralization, more rapidly when current density rose from 50 and 150 mA cm-2, while the comparative EF process yielded lower decontamination.

[ES] La presente Tesis Doctoral se centra en el estudio del comportamiento electroquímico de nuevos electrodos cerámicos basados en SnO2 dopado con Sb2O3. El estudio está orientado a la posterior aplicación de estos electrodos en procesos electroquímicos de oxidación avanzada. Inicialmente, se consideraron diferentes temperaturas de sinterización (entre 1050°C y 1250°C) y se observó que un aumento en la temperatura de sinterización favorecía la deposición del Sb2O3 en la superficie anódica, disminuyendo así la resistividad del electrodo. Posteriormente, se estudió el comportamiento electroquímico de estos nuevos electrodos obteniendo el potencial de descarga del oxígeno mediante la técnica de voltametría de barrido lineal. Los resultados obtenidos revelaron que el valor del potencial de descarga del oxígeno disminuye con el aumento de la temperatura de sinterización. Además, estos electrodos presentaron un comportamiento intermedio entre el ánodo de Pt y el ánodo de BDD. Este último electrodo se emplea habitualmente en los procesos electroquímicos de oxidación avanzada debido a su elevada capacidad para generar radicales hidroxilo, los cuales son capaces de oxidar los compuestos orgánicos a dióxido de carbono y agua. A continuación, se llevaron a cabo ensayos de oxidación electroquímica con estos electrodos cerámicos para seleccionar la temperatura de sinterización. Los resultados mostraron que con el electrodo cerámico sinterizado a 1250°C se alcanza una menor degradación del compuesto orgánico, mientras que los electrodos sinterizados a menores temperaturas presentan un comportamiento similar entre ellos. Por tanto, se seleccionó el electrodo cerámico sinterizado a 1200°C ya que presenta una baja resistividad y un buen comportamiento electroquímico para ser utilizado como ánodo en los procesos electroquímicos de oxidación avanzada. Seguidamente se analizó la vida útil de estos electrodos cerámicos, y se comprobó que la matriz cerámica incrementa en gran medida la estabilidad a la polarización anódica de los electrodos basados en SnO2. Posteriormente, se llevaron a cabo procesos de electro-oxidación en modo galvanostático de distintos contaminantes difíciles de eliminar por las técnicas convencionales utilizando como ánodo los nuevos electrodos cerámicos y el electrodo de BDD, para así poder comparar los resultados obtenidos. Se observó que, aunque con los electrodos cerámicos se consigue degradar el 100% de los distintos contaminantes, el electrodo de BDD es el más eficiente ya que genera mayor cantidad de especies oxidantes activas en su superficie. Para un mismo electrodo, se observó que un aumento en la densidad de corriente aplicada mejora la velocidad de degradación y mineralización de cada contaminante, mientras que la eficiencia eléctrica disminuye. Por otro lado, se estudió el efecto de la presencia de una membrana de intercambio catiónico entre ánodo y cátodo. Los resultados mostraron que el uso de la membrana beneficia la degradación y la mineralización del contaminante, ya que mejora la cinética de reacción anódica y evita la reducción de las especies oxidantes electrogeneradas. A continuación, se analizó la influencia de la concentración del Na2SO4 como electrolito soporte. En este estudio se observó que un aumento en la concentración del Na2SO4 mejora la mineralización del contaminante para el electrodo de BDD y, por el contrario, empeora para el electrodo cerámico. Esto se debe a la capacidad de cada electrodo para oxidar los sulfatos a persulfatos. Por último, se llevaron a cabo ensayos de ecotoxicidad de las muestras tratadas, y se demostró que, en presencia de membrana, a mayor densidad de corriente y con el electrodo de BDD la toxicidad de la muestra es mayor debido a la mayor presencia en disolución de iones persulfato. Por tanto, con el electrodo cerámico, además de alcanzar un elevado grado de degradación del contamina
[CAT] La present Tesi Doctoral es centra en l'estudi del comportament electroquímic de nous elèctrodes ceràmics basats en SnO2 dopat amb Sb2O3. L'estudi està orientat a la posterior aplicació d'aquests elèctrodes en processos electroquímics d'oxidació avançada. Inicialment, es van considerar diferents temperatures de sinterització (entre 1050°C i 1250°C) i es va observar que un augment en la temperatura de sinterització afavoria la deposició de Sb2O3 en la superfície anòdica, disminuint així la resistivitat de l'elèctrode. Posteriorment, es va estudiar el comportament electroquímic d'aquests nous elèctrodes obtenint el potencial de descàrrega de l'oxigen mitjançant la tècnica de voltametria de passada lineal. Els resultats obtinguts van revelar que el valor del potencial de descàrrega de l'oxigen disminueix amb l'augment de la temperatura de sinterització. A més, aquests elèctrodes ceràmics van presentar un comportament intermedi entre l'ànode de Pt y l'ànode de BDD. Aquest últim elèctrode s'utilitza habitualment en els processos electroquímics d'oxidació avançada a causa de la seua elevada capacitat per a generar radicals hidroxil, els quals són capaços d'oxidar els compostos orgànics a diòxid de carboni i aigua. A continuació, es van dur a terme assajos d'oxidació electroquímica amb aquests elèctrodes ceràmics per a seleccionar la temperatura de sinterització. Els resultats van mostrar que amb l'elèctrode ceràmic sinteritzat a 1250°C s'aconsegueix una menor degradació del compost orgànic, mentre que els elèctrodes sinteritzats a menors temperatures presenten un comportament similar entre ells. Per tant, es va seleccionar l'elèctrode ceràmic sinteritzat a 1200 °C ja que presenta una baixa resistivitat i un bon comportament electroquímic per a ser utilitzat com a ànode en els processos electroquímics d'oxidació avançada. Seguidament, es va analitzar la vida útil d'aquests elèctrodes ceràmics, i es va comprovar que la matriu ceràmica incrementa en gran mesura l'estabilitat a la polarització anòdica dels elèctrodes basats en SnO2. Posteriorment es van dur a terme processos d'electro-oxidació en mode galvanostàtic de diferents contaminants difícils d'eliminar per les tècniques convencionals utilitzant com a ànode els nous elèctrodes ceràmics i l'elèctrode de BDD, per a així poder comparar els resultats obtinguts. Es va observar que, encara que amb els elèctrodes ceràmics s'aconsegueix degradar el 100% dels diferents contaminants, l'elèctrode de BDD és el més eficient ja que genera una major quantitat d'espècies oxidants actives en la seua superfície. Per a un mateix elèctrode, es va observar que un augment en la densitat de corrent aplicada millora la velocitat de degradació i mineralització de cada contaminant, mentre que l'eficiència elèctrica disminueix. D'altra banda, es va estudiar l'efecte de la presència d'una membrana d'intercanvi catiònic entre ànode i càtode. Els resultats van mostrar que l'ús de la membrana beneficia la degradació i la mineralització del contaminant, ja que millora la cinètica de reacció anòdica i evita la reducció de les espècies oxidants electrogenerades. A continuació, es va analitzar la influència de la concentració del Na2SO4 com a electròlit suport. En aquest estudi es va observar que un augment en la concentració del Na2SO4 millora la mineralització del contaminant per a l'elèctrode de BDD i, per contra, empitjora per a l'elèctrode ceràmic. Això es deu a la capacitat de cada elèctrode per a oxidar els sulfats a persulfats. Finalment, es van dur a terme assajos d'ecotoxicitat de les mostres tractades, i es va demostrar que, en presència de membrana, a major densitat de corrent i amb l'elèctrode de BDD la toxicitat de la mostra és major a causa de la major presència en dissolució d'ions persulfat. Per tant, amb l'elèctrode ceràmic, a més d'aconseguir un elevat grau de degradació del con
[EN] The present Doctoral Thesis focuses on the study of the electrochemical behaviour of new ceramic electrodes based on SnO2 doped with Sb2O3. The study is oriented at the subsequent application of these electrodes in electrochemical advanced oxidation processes. Initially, different sintering temperatures were considered (between 1050°C and 1250°C) and it was observed that an increase in the sintering temperature favoured the deposition of Sb2O3 on the anodic surface, thus decreasing the resistivity of the electrode. Later, the electrochemical behaviour of these new electrodes was studied by means of the oxygen discharge potential using the linear sweep voltammetry technique. The results obtained revealed that the value of the oxygen discharge potential decreases with increasing the sintering temperature. Furthermore, these electrodes showed an intermediate behaviour between the Pt anode and the BDD one. This last electrode is commonly used in advanced electrochemical oxidation processes due to its high capacity to generate hydroxyl radicals, which are capable of oxidizing the organic compounds to carbon dioxide and water. Then, electrochemical oxidation tests were carried out with these ceramic electrodes to select the sintering temperature. The results showed that with the ceramic electrode sintered at 1250°C, a lower degradation and mineralization of the organic compound is achieved, while the electrodes sintered at lower temperatures showed a similar behaviour. Therefore, the ceramic electrode sintered at 1200°C was selected as it presents low resistivity good electrochemical behaviour to be used as anode in electrochemical advanced oxidation processes. Next, the service life of these ceramic electrodes was analyzed, and it was found that the ceramic matrix greatly increases the anodic polarization stability of the electrodes based on SnO2. Subsequently, electro-oxidation processes were carried out in galvanostatic mode for different contaminants that are difficult to remove by conventional techniques, using the new ceramic electrodes and the BDD electrode as anodes, in order to compare the results obtained. It was observed that ceramic electrodes can be used as anodes for electrochemical oxidation, since for high current densities it is possible to degrade a 100% of the different contaminants. However, the BDD electrode is the most efficient one since it generates more active oxidant species on its surface. For a given electrode, an increase in the current density improves the degradation and mineralization of each contaminant, while the electrical efficiency decreases. On the other hand, the effect of the presence of a cation-exchange membrane between anode and cathode was studied. The results showed that its use benefits the degradation and mineralization of the contaminants, since it improves the kinetics of the anodic reaction and avoids the reduction of the electrogenated oxidant species. Next, the influence of the concentration of Na2SO4 as supporting electrolyte was analyzed. In this study it was observed that an increase in the Na2SO4 concentration improves the mineralization of the contaminant for the BDD electrode and, on the contrary, worsens for the ceramic electrode. This is due to the ability of each electrode to oxidize sulfates to persulfates. Finally, ecotoxicity tests on the treated samples were carried out, and it was shown that, in the presence of the membrane, at higher current density and with the BDD electrode, the toxicity of the sample is greater due to the higher presence of persulfate ions. Therefore, with the ceramic electrode, in addition to achieving a high degree of contaminant degradation, the treated samples are less toxic than the samples treated with the BDD electrode.
Agradezco al Ministerio de Economía y Competitividad por la financiación recibida mediante los proyectos CTQ2015-65202-C2-1-R y RTI2018-101341-B-C21, y a la cofinanciación con los fondos FEDER, que han permitido llevar a cabo la investigación en la Universitat Politècnica de València para la realización de la presente Tesis. También agradecer a Sergio Mestre Beltrán por proporcionarnos los nuevos electrodos cerámicos en los que se ha basado este trabajo.
Mora Gómez, J. (2020). Eliminación de contaminantes orgánicos emergentes mediante procesos electroquímicos de oxidación avanzada [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/158751
TESIS

Organic micropollutants, including pharmaceuticals, personal care products (PCPs), pesticides, dyes and many other industrial chemicals have become one of the most solid barriers for the effective and safe wastewater remediation and reclamation. Some of these contaminants are able to act as endocrine disrupting chemicals (EDCs), thus posing emerging concerns. Their concentration in water is usually at trace level and most of them are highly resistant to conventional treatment technologies like biodegradation and physicochemical methods. The inefficient removal of micropollutants causes their occurrence in final water distribution systems, even reaching drinking water, which jeopardizes the entire biosphere and human health. Over the last decades, the electrochemical technologies, especially the electrochemical advanced oxidation processes (EAOPs), have been proven to behave as clean and effective alternatives to eliminate the organic micropollutants from wastewater effluents due to the direct or indirect generation of strong oxidizing agents such as the hydroxyl radical. However, the utilization of conventional electro-Fenton (EF) and photoelectro-Fenton (PEF) is limited by several drawbacks: (i) long time needed to destroy large contents of organics; (ii) requirement of pH adjustment to 2.5-3.5; (iii) poor electroreduction and photoreduction of Fe(III); (iv) high amount of iron catalyst required; (v) deactivation of iron species; and (vi) production of iron sludge. Aiming to overcome these disadvantages, several processes and catalysts are proposed in this Thesis to modify the conventional EF and PEF. In the first part, electrocoagulation (EC) was envisaged as a valid pre-treatment before the application of the EAOPs, thus addressing the abovementioned limitation (i). This involved the in situ generation of coagulants upon dissolution of a sacrificial anode, yielding flocs that precipitated and adsorbed part of the organics rapidly. Furthermore, when an Fe/Fe cell was employed, the residual dissolved iron species after precipitation acted as the required catalyst for subsequent EF/PEF treatment. The efficient removal of butylated hydroxyanisole (BHA) and benzophenone-3 (BP-3) from urban wastewater was successfully achieved by means of sequential EC/EAOPs. The second part investigated, for the first time, the feasibility of employing a soluble Fe(III)–EDDS complex as homogeneous EF or PEF catalyst to destroy micropollutants. The systems allowed working at near-neutral pH, exhibiting a high quantum yield for Fe2+ generation from Fe(III)–EDDS photoreduction. The Fe(III)– EDDS-assisted EF and PEF processes exhibited excellent performance for the degradation of BHA and fluoxetine (FLX) in sulfate medium, as well as in urban wastewater. Heterogeneous EF and PEF processes using solid catalysts have been developed in the third part as promising alternatives to overcome the drawbacks (ii)-(vi). The development of new types of catalysts with high activity, stability and recyclability is still a great challenge in the field. Metal-organic frameworks (MOFs) have attracted substantial attention in recent years as ordered porous materials with many potential applications. In this Thesis, raw Fe-MOFs or their derivatives were introduced as efficient and innovative heterogeneous EF or PEF catalysts to treat micropollutants in urban wastewater. FeS2/C nanocomposite, fabricated by sulfidation and pyrolysis of an Fe-MOF precursor, as EF catalyst outperformed natural pyrite and Fe2+ due to the cooperation of homogenous and heterogeneous Fenton’s reaction. The thermal treatment of NH2-MIL(Fe)-88B gave rise to N-doped nano-ZVI@C, which exhibited superior catalytic activity in EF. Finally, the direct use of a Fe-bpydc 2D MOF as PEF catalyst yielded a fast bezafibrate decay due to the synergy between photocatalysis and Fenton’s reaction. Their unique properties conferred an unprecedented degradation ability to EF and PEF at mild pH. In conclusion, this Thesis has provided several strategies to unravel the difficulties for the future application of EAOPs at industrial scale.
Los microcontaminantes orgánicos se han convertido en un gran obstáculo para asegurar un tratamiento de aguas residuales eficaz y seguro, ya que suelen ser resistentes a las tecnologías de tratamiento convencionales. En las últimas décadas, se ha demostrado que los procesos electroquímicos de oxidación avanzada (EAOPs) constituyen alternativas limpias y efectivas para eliminar microcontaminantes orgánicos de aguas residuales, gracias a la generación del radical hidroxilo. Sin embargo, la utilización de los procesos electro-Fenton (EF) y fotoelectro-Fenton (FEF) convencionales se ve limitada por: (i) el largo tiempo requerido para eliminar elevadas concentraciones; (ii) necesidad de ajuste del pH (2,5-3,5); (iii) pobre electrorreducción y fotorreducción del Fe(III); (iv) elevada cantidad de catalizador requerida; (v) desactivación de las especies de hierro; y (vi) producción de lodos. Para superar estas desventajas, en esta Tesis se proponen varios procesos y catalizadores. En la primera parte, la electrocoagulación (EC) se propuso como pretratamiento para abordar la limitación (i), lo cual implicó la generación de flóculos como adsorbentes. Además, el hierro disuelto actuó como el catalizador en el posterior tratamiento EF o FEF. Mediante EC/EAOPs se logró una eliminación eficiente de hidroxianisol butilado (BHA) y la benzofenona-3 (BP-3) en agua residual urbana. En la segunda parte se investigó, por primera vez, la viabilidad del complejo Fe(III)– EDDS soluble como catalizador EF o FEF homogéneo. Se obtuvo un excelente rendimiento para la degradación de BHA y fluoxetina (FLX) en medio de sulfato y en agua residual. En la tercera parte se desarrollaron procesos EF y FEF heterogéneos que utilizan catalizadores sólidos para superar los inconvenientes (ii)-(vi). Se introdujeron Fe-MOFs (i.e., metal-organic frameworks) y sus derivados como catalizadores innovadores eficientes. Se fabricó un nanocomposite de FeS2/C con un mayor rendimiento que la pirita natural y el Fe2+ en el proceso EF. El tratamiento térmico de NH2-MIL(Fe)-88B dio lugar a un nano-ZVI@C dopado, el cual exhibió una capacidad catalítica superior en EF. Finalmente, la utilización de un MOF 2D de Fe-bpydc en FEF promovió una eliminación rápida de benzafibrato. En conclusión, esta Tesis ha proporcionado varias estrategias para superar las dificultades para la aplicación de EAOPs a escala industrial.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2016.
Trihalomethanes are disinfection byproducts of chlorinated waters, and there is a growing interest to understand plant responses to organohalogens. This study investigates the effects of increasing trihalomethane dose on the physiology of tomato (Solanum lycopersicum) and determines whether the extent of physiological impacts of trihalomethane exposure on seedling radicle length, biomass accumulation, concentration levels of 12 key nutrients, oxidative stress, fatty acids and α-tocopherol content in membrane lipids of tomato correlated with either the number of bromine or chlorine atoms in the trihalomethane molecules. The 2 x 4 x 5 factorial experiment was laid out in CRD with four replications. Two cultivars of tomato were exposed to 4 levels of trihalomethanes (bromodichloromethane, bromoform, chloroform and dibromochloromethane) and 5 levels of concentration (0.0, 2.5, 5.0, 7.5, and 10.0 mg.L-1) in a green house. The decrease in seedling biomass and the inhibition of radicle growth increased with increasing trihalomethane concentrations in a dose dependent manner. Also, both these parameters decreased in response to an increase in the number of bromine atoms in the trihalomethane molecule. However, in growing plants the decrease in concentration levels of seven essential nutrients namely nitrogen (N), phosphorus (P), potassium (K), sulphur (S), copper (Cu), zinc (Zn) & boron (B) correlated to an increase in the number of chlorine atoms. Increase in trihalomethane dose also induced a decrease in all the above mentioned nutrients with the addition of manganese (Mn), although the decrease in P and S were not significant at P ≤ 0.05. The increase in trihalomethane dose induced an increase in oxidative stress parameters such as the total phenolic content, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and lipid peroxidation. The increase in the above parameters correlated to an increase in the number of chlorine atoms, however, no such correlations were observed in superoxide dismutase (SOD) activity, general lipid peroxidation, α-tocopherol content and totalsoluble proteins. In plant membrane lipids, increase in the saturated fat hexadecanoic acid was observed in both tomato cultivars that correlated to the degree of chlorination in the trihalomethane molecule. The increase in α-linolenic acid stress signaling correlated with an increase in the degree of chlorination in only one tomato cultivar suggesting variable tolerance between cultivars to chemical action. Membrane lipids adjustments in tomato plants exposed to increasing trihalomethane dose were based on two factors; first the adjustments of membrane fluidity with the increase in plant sterols and fatty acids content and secondly, the increase in lipophyllic antioxidants such as phenols, quinones and α-tocopherol content. The phenolic lipophyllic antioxidant was tentatively identified to be 2,2’-methylenebis [6-(1,1-dimethylethyl)-4-methyl] phenol. In conclusion, the magnitude of plant responses to trihalomethanes is more dependent on the halogenation number of the molecule and less on its concentration.

Depuis le début des années 2000, la station d’épuration n’est plus seulement perçue comme une installation industrielle traitant les eaux résiduaires urbaines afin d’en minimiser leurs impacts sur le milieu naturel, mais aussi comme un moyen de récupérer des ressources : eau, nutriments, énergie. Ce travail de thèse traite de cette dernière ressource, l’énergie. Comment tendre vers la station d’épuration auto-suffisante en énergie, voire encore productrice d’énergie sans en affecter l’efficacité de traitement? A l’aide d’une filière de traitement ancienne revisitée : le procédé A/B (Adsorption/Bio-oxydation), le bilan énergétique de la station peut tendre vers la neutralité en réduisant les demandes liées à l’aération et en optimisant la production de biogaz. Ce travail de doctorat se concentre principalement sur la méthanisation des boues issues de ce procédé A/B afin d’en connaître leurs caractéristiques et leur digestibilité, de les comparer avec la digestion anaérobie de boues davantage connues et enfin d’utiliser ces résultats pour dresser le bilan énergétique du procédé A/B, ceci à partir des données récoltées sur un pilote de 50 m3/j installé sur la station d’épuration de Kranji à Singapour. Les boues A et B présentent respectivement les productions spécifiques de méthane respectives de 290 et 135 LCH4/kgMVentrante en conditions mésophiles. Le procédé A/B avec ses deux étages de boues activées permet de capter un maximum de carbone en première étape de traitement pour le transférer directement en digestion. En effet, la production totale de boues provient à 90% des boues A et seulement à 10% des boues B ce qui porte à 95% la production de méthane attribuée aux boues A. Ces résultats induisent une production d’énergie supérieure par rapport à une filière de traitement conventionnelle avec un seul étage de boues activées. Par ailleurs, ce procédé permet de diminuer les besoins en aération pour le traitement des pollutions carbonée et azotée, tout en gardant les mêmes efficacités de traitement. Il est ainsi possible de conclure que la filière de traitement des eaux usées en procédé A/B présente un degré d’efficacité énergétique proche de 300% (ratio entre l’énergie électrique produite à partir du biogaz et la consommation énergétique liée à l’aération), ce qui représente 73% d’auto-suffisance énergétique globale en considérant le cas de la station de Kranji en boues activées conventionnelles traitant les pollutions en carbone et en azote
Since the early 2000’s, wastewater treatment plants (WWTP) have not been only seen as a mean to reduce the impact of the harmful emissions towards water bodies but also as a way to recover the resources contained in the raw wastewater: water, nutrients and energy. This doctorate seeks to study the latter one. How to tend to the energy self-sufficient or even energy positive WWTP without altering its treatment efficiencies? Using an old wastewater treatment process: the A/B process (Adsorption/Bio-oxidation) and state-of-the-art technologies, the energy autarky of a WWTP can become a reality by reducing its electricity consumption related to the aeration and by optimizing its energy production through anaerobic digestion. This work mainly focuses on the anaerobic digestion of the sludge produced by the A/B process. It aims at evaluating their characteristics and digestibility and thus at comparing these to the ones of better-known sludge such as primary, secondary and mixed sludge from a conventional wastewater treatment system. Eventually, these results with the addition of data collected on a 50 m3/d A/B process pilot plant on the Water Reclamation Plant of Kranji, Singapore, are used to draw the energy balance of the A/B process and to try to make a comparison to conventional systems. The A/B process produces the A and B sludge which respectively show specific methane productions of 290 and 135 LCH4/kgVSintroduced in mesophilic anaerobic digestion and can be considered quite similar to primary and secondary sludge respectively from conventional WWTPs. With its two stages of activated sludge, this process enables the early entrapment of carbon to be directly transferred to the digesters. Indeed, 90% of the sludge production comes from the A sludge in matter of Volatile Solids, which brings to 95% the biogas production to be ascribed to this sludge. Hence, the A/B process does produce more energy than a conventional single-stage activated sludge. It also reduces the aeration demand for the biological treatment of the carbon and nitrogen pollutions whilst complying with the same treatment performances. Drawing the energy balance of the A/B process leads to the conclusions that this process presents an energy efficiency of 300% by comparing only the electrical needs for the aeration (40-70% of the whole plant demand) and the electricity production from biogas generation, which, at the end, represents an energy self-sufficiency of 73% considering the Kranji conventional water reclamation plant

So, Wai Man.
Thesis submitted in: October 2007.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 112-124).
Abstracts in English and Chinese.
Acknowledgements --- p.i
Abstract --- p.ii
Table of Contents --- p.vi
List of Figures --- p.x
List of Plates --- p.viii
List of Tables X --- p.v
Abbreviations --- p.xvii
Equations --- p.xix
Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Importance of water disinfection --- p.1
Chapter 1.2 --- Conventional disinfection methods --- p.2
Chapter 1.2.1 --- Chlorination --- p.2
Chapter 1.2.2 --- Ozonation --- p.3
Chapter 1.2.3 --- Ultraviolet-C (UV-C) irradiation --- p.4
Chapter 1.2.4 --- Sunlight irradiation --- p.5
Chapter 1.2.5 --- Others --- p.6
Chapter 1.3 --- Photocatalytic oxidation --- p.7
Chapter 1.3.1 --- Reactions in PCO --- p.8
Chapter 1.3.2 --- Disinfection mechanism of PCO --- p.11
Chapter 1.3.3 --- Photocatalysts --- p.14
Chapter 1.3.3.1 --- Titanium dioxide (TiO2) --- p.14
Chapter 1.3.3.2 --- Modification of TiO2 --- p.15
Chapter 1.3.3.2.1 --- Sulphur cation-doped TiO2 (S-TiO2) --- p.17
Chapter 1.3.3.2.2 --- Copper(I) oxide-sensitized P-25 (Cu20/P-25) --- p.18
Chapter 1.3.3.2.3 --- Silicon dioxide-doped TiO2 (SiO2-TiO2) --- p.18
Chapter 1.3.3.2.4 --- Nitrogen-doped TiO2 (N-TiO2) --- p.19
Chapter 1.4 --- Bacterial defense systems against oxidative stress --- p.20
Chapter 1.5 --- Bacterial species --- p.22
Chapter 1.5.1 --- Salmonella typhimurium --- p.23
Chapter 1.5.2 --- Klebsiella pneumoniae --- p.24
Chapter 1.5.3 --- Bacillus thuringiensis --- p.25
Chapter 1.5.3 --- Bacillus pasteurii --- p.26
Chapter 2. --- Objectives --- p.27
Chapter 3. --- Material and Methods --- p.28
Chapter 3.1 --- Culture media and diluents --- p.28
Chapter 3.2 --- Screening of target bacteria --- p.28
Chapter 3.3 --- PCO disinfection reaction --- p.29
Chapter 3.3.1 --- Photocatalysts --- p.29
Chapter 3.3.2 --- Bacterial cultures --- p.31
Chapter 3.3.3 --- PCO reactor --- p.32
Chapter 3.3.4 --- PCO efficacy test --- p.34
Chapter 3.3.5 --- Comparison of different photocatalysts --- p.35
Chapter 3.4 --- Optimization of PCO disinfection conditions --- p.35
Chapter 3.5 --- Transmission electron microscopy (TEM) --- p.39
Chapter 3.6 --- Superoxide dismutase (SOD) activity assay --- p.42
Chapter 3.7 --- Catalase (CAT) activity assay --- p.44
Chapter 3.8 --- Spore staining --- p.45
Chapter 3.9 --- Atomic absorption spectrophotometry (AAS) --- p.45
Chapter 3.10 --- X-ray photoelectron spectrometry (XPS) --- p.46
Chapter 4. --- Results --- p.47
Chapter 4.1 --- Screening of wastewater bacteria --- p.47
Chapter 4.2 --- PCO efficacy test --- p.49
Chapter 4.3 --- PCO under visible light irradiation --- p.53
Chapter 4.3.1 --- Fluorescence lamps with UV filter --- p.53
Chapter 4.3.2 --- Solar lamp with UV filter --- p.61
Chapter 4.3.3 --- Sunlight with UV filter --- p.67
Chapter 4.4 --- Optimization of PCO disinfection conditions --- p.75
Chapter 4.4.1 --- Effect of visible light intensities --- p.75
Chapter 4.4.2 --- Effect of photocatalyst concentrations --- p.77
Chapter 4.4.3 --- Optimized conditions --- p.79
Chapter 4.5 --- Transmission electron microscopy (TEM) --- p.79
Chapter 4.6 --- Superoxide dismutase (SOD) activity assay --- p.83
Chapter 4.7 --- Catalase (CAT) activity assay --- p.84
Chapter 4.8 --- Spore staining --- p.85
Chapter 4.9 --- Studies on Cu20/P-25 --- p.88
Chapter 4.9.1 --- Atomic absorption spectrophotometry (AAS) --- p.88
Chapter 4.9.2 --- X-ray photoelectron spectrometry (XPS) --- p.88
Chapter 5. --- Discussion --- p.90
Chapter 5.1 --- Screening of wastewater bacteria --- p.90
Chapter 5.2 --- PCO efficacy test --- p.90
Chapter 5.3 --- Comparison between different light sources --- p.90
Chapter 5.4 --- Comparison between different photocatalysts --- p.93
Chapter 5.5 --- Optimization of PCO disinfection conditions --- p.95
Chapter 5.5.1 --- Effect of visible light intensities --- p.95
Chapter 5.5.2 --- Effect of photocatalyst concentrations --- p.96
Chapter 5.6 --- Transmission electron microscopy (TEM) --- p.97
Chapter 5.7 --- Comparison between different bacterial species --- p.99
Chapter 5.8 --- Possible factors affecting susceptibility of bacteria towards PCO --- p.99
Chapter 5.8.1 --- Formation of endospores --- p.99
Chapter 5.8.2 --- Differences in cell wall structure --- p.100
Chapter 5.8.3 --- SOD and CAT activities --- p.101
Chapter 5.9 --- Dark control of Cu20/P-25 --- p.103
Chapter 5.10 --- Studies on Cu20/P-25 --- p.104
Chapter 6. --- Conclusion --- p.107
Chapter 7. --- References --- p.112
Chapter 8. --- Appendix --- p.125
Chapter 8.1 --- Production of S-Ti02 --- p.125
Chapter 8.2 --- Production of Si02-Ti02 --- p.125
Chapter 8.3 --- Production of N-Ti02 --- p.125

Wong Man Yung.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 106-120).
Abstracts in English and Chinese.
Acknowledgements --- p.i
Abstract --- p.ii
Table of Contents --- p.vi
List of Figures --- p.xi
List of Plates --- p.xiii
List of Tables --- p.xv
Abbreviations --- p.xvi
Equations --- p.xviii
Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Water disinfection --- p.1
Chapter 1.2 --- Bacterial species --- p.2
Chapter 1.2.1 --- Staphylococcus saprophyticus --- p.2
Chapter 1.2.2 --- Enterobacter cloacae --- p.3
Chapter 1.3 --- Disinfection methods --- p.4
Chapter 1.3.1 --- Physical methods --- p.4
Chapter 1.3.1.1 --- UV-C irradiation --- p.4
Chapter 1.3.1.2 --- Solar disinfection --- p.5
Chapter 1.3.2 --- Chemical methods --- p.6
Chapter 1.3.2.1 --- Chlorination --- p.6
Chapter 1.3.2.2 --- Ozonation --- p.7
Chapter 1.3.2.3 --- Mixed disinfectants --- p.8
Chapter 1.3.3 --- Other disinfection methods --- p.8
Chapter 1.4 --- Advanced oxidation processes (AOPs) --- p.9
Chapter 1.5 --- Photocatalytic oxidation (PCO) --- p.10
Chapter 1.5.1 --- PCO process --- p.12
Chapter 1.5.2 --- Photocatalysts --- p.14
Chapter 1.5.2.1 --- Titanium dioxide (P25) --- p.15
Chapter 1.5.2.2 --- Silver sensitized P25 (Ag/P25) --- p.16
Chapter 1.5.2.3 --- Silicon dioxide doped titanium dioxide (SiO2-TiO2) --- p.17
Chapter 1.5.2.4 --- Copper(I) oxide sensitized P25 (Cu2O/P25) --- p.18
Chapter 1.5.3 --- Irradiation sources --- p.19
Chapter 1.5.4 --- PCO disinfection mechanisms --- p.20
Chapter 1.6 --- Bacterial defense mechanisms against oxidative stress --- p.22
Chapter 2. --- Objectives --- p.25
Chapter 3. --- Materials and Methods --- p.26
Chapter 3.1 --- Chemicals --- p.26
Chapter 3.2 --- Bacterial culture --- p.26
Chapter 3.3 --- Photocatalytic reactor --- p.27
Chapter 3.4 --- PCO efficacy test --- p.30
Chapter 3.5 --- Optimization of PCO conditions --- p.31
Chapter 3.5.1 --- Effect of P25 concentrations --- p.31
Chapter 3.5.2 --- Effect of UV intensities --- p.32
Chapter 3.5.3 --- Combinational study of P25 concentrations and UV intensities --- p.32
Chapter 3.5.4 --- Effect of stirring rates --- p.32
Chapter 3.5.5 --- Effect of initial cell concentrations --- p.33
Chapter 3.6 --- PCO disinfection using different photocatalysts --- p.33
Chapter 3.6.1 --- Effect of CU2O/P25 concentrations --- p.33
Chapter 3.6.2 --- Effect of CU2O powder on the two bacterial species --- p.33
Chapter 3.7 --- Transmission electron microscopy (TEM) --- p.34
Chapter 3.8 --- Catalase (CAT) test --- p.37
Chapter 3.9 --- Superoxide dismutase (SOD) activity assay --- p.39
Chapter 4. --- Results --- p.40
Chapter 4.1 --- Efficacy test --- p.40
Chapter 4.2 --- PCO disinfection under UV irradiation --- p.40
Chapter 4.2.1 --- Control experiments --- p.40
Chapter 4.2.2 --- Optimization of PCO conditions using P25 as a photocatalyst --- p.42
Chapter 4.2.2.1 --- Effect of P25 concentrations --- p.42
Chapter 4.2.2.2 --- Effect of UV intensities --- p.45
Chapter 4.2.2.3 --- Combinational study of P25 concentrations and UV intensities --- p.48
Chapter 4.2.2.4 --- Effect of stirring rates --- p.54
Chapter 4.2.2.5 --- Effect of initial cell concentrations --- p.57
Chapter 4.2.3 --- Comparison of PCO inactivation efficiency between S. saprophyticus and E. cloacae --- p.60
Chapter 4.2.4 --- PCO disinfection using different photocatalysts --- p.62
Chapter 4.2.4.1 --- Control experiments --- p.62
Chapter 4.2.4.2 --- Ag/P25 --- p.62
Chapter 4.2.4.3 --- SiO2-TiO2 --- p.64
Chapter 4.2.4.4 --- Cu2O/P25 --- p.64
Chapter 4.3 --- PCO disinfection under visible light irradiation --- p.66
Chapter 4.3.1 --- Effect of Cu2O/P25 concentrations --- p.67
Chapter 4.3.2 --- Effect of CU2O powder on the two bacterial species --- p.70
Chapter 4.4 --- Feasibility use of indoor light (fluorescent lamps) for PCO disinfection --- p.71
Chapter 4.5 --- Transmission electron microscopy (TEM) --- p.74
Chapter 4.5.1 --- Morphological changes induced by PCO using P25 as a photocatalyst --- p.74
Chapter 4.5.2 --- Morphological changes induced by PCO using Cu2O/P25 as a photocatalyst --- p.77
Chapter 4.6 --- Catalase (CAT) test --- p.80
Chapter 4.7 --- Superoxide dismutase (SOD) activity assay --- p.82
Chapter 5. --- Discussion --- p.83
Chapter 5.1 --- Efficacy test --- p.83
Chapter 5.2 --- PCO disinfection under UV irradiation --- p.83
Chapter 5.2.1 --- Optimization study --- p.84
Chapter 5.2.1.1 --- Effect of P25 concentrations --- p.84
Chapter 5.2.1.2 --- Effect of UV intensities --- p.85
Chapter 5.2.1.3 --- Combinational study of P25 concentrations and UV intensities --- p.86
Chapter 5.2.1.4 --- Effect of stirring rates --- p.86
Chapter 5.2.1.5 --- Effect of initial cell concentrations --- p.87
Chapter 5.2.2 --- Comparison of PCO inactivation efficiency between S. saprophyticus and E. cloacae --- p.88
Chapter 5.2.3 --- PCO disinfection using different photocatalysts --- p.89
Chapter 5.2.3.1 --- Ag/P25 --- p.89
Chapter 5.2.3.2 --- SiO2-TiO2 and Cu2O/P25 --- p.90
Chapter 5.3 --- PCO disinfection under visible light irradiation --- p.90
Chapter 5.3.1 --- Effect of Cu20/P25 concentrations --- p.91
Chapter 5.3.2 --- Effect of CU2O powder on the two bacterial species --- p.92
Chapter 5.4 --- Feasibility use of fluorescent lamps for PCO disinfection --- p.93
Chapter 5.5 --- Transmission electron microscopy (TEM) --- p.95
Chapter 5.5.1 --- Morphological changes induced by PCO using P25 as a photocatalyst --- p.95
Chapter 5.5.2 --- Morphological changes induced by PCO using CU2O/P25 as a photocatalyst --- p.96
Chapter 5.6 --- Catalase (CAT) test --- p.98
Chapter 5.7 --- Superoxide dismutase (SOD) activity assay --- p.99
Chapter 6. --- Conclusion --- p.101
Chapter 7. --- References --- p.106
Chapter 8. --- Appendix --- p.121

碩士
國立臺灣海洋大學
河海工程學系
95
Abstract This research aims to analyze one Gravel Contact Oxidation Engineering by Nanhu Bridge located at one benchland outside the left embankment of the lower section of Keelung River. Such engineering is built to process the “dry weather flow” gathering by “Nanhu Storm Water Pumping Station” sending into Keelung River, of which the capacity of the on-site wastewater treatment equipment is 8,000 cubic meters, and the average processed quantity each day is 5,500 cubic meters. In order to realize the actual effect of the pollution-removal of such engineering, this research is designed to take example out of the water at the inflow and outlet channel thereof, for the reason that the inflow and outflow only flow in the single way, and further that there is no recirculation equipment built in the system thereof. Therefore the variation of the density between the inflow and outflow channel can be used to analyze the effect of the pollution-removal made by such system. For the further research of the state and the process of the decomposition of the various pollutive materials occurring inside of the system, and for the analysis of the example taken constantly in the full process, the sampling position is set to be seriate inlet, sampling pipe 1 (aeration zone of the former section of the sampling well), sampling pipe 2 (aeration zone of the later section of the sampling well), sampling pipe 3 (non-aeration zone of the sampling well) and the outflow trough. The purpose of the arrangement is to analyze the mechanism of the removal of variety of pollutive materials. The major items of the water-analysis are B.O.D (Biochemical Oxygen Demand), S.S. (Suspended Solids), NH3 -N (Ammonia Nitrogen) and D.O. (Dissolved Oxygen). Based on the outcome of the analysis, the removal-rate of each item is as following: B.O.D., between 49%~96.5% (averagely 84.5%), S.S., over 85%, NH3-N, over 96% (averagely 98.8%), and the concentration of D.O. stands between 4.1 to 8.9 mg/L, which is approximately 3 mg/L higher than inflow. Meanwhile, the adjustment to the aeration has significantly affected the nitrification efficiency of NH3-N. If we analyze all those pollutive materials item by item, we have found that the removal-rate of NH3-N under double-aerator operation stands at 99.8%, however such rate under single-aerator operation decreases to the level of 89.6%, which indicates aeration is the important factor to the removal of NH3-N. This research has set the fully-nitrification as the goal of the design of the equipment construction and allocation, as well as the operating process. And such goal has been confirmed through the water examination during the trial of the system. Given by the facts that the removal of NH3-N and the aeration are directly relevant, if it’s by the need of power-saving or because of the unnecessary of the fully-nitrification, it can be taken into consideration to test the decrease of 50% or of all of the aeration for long period, so that the influence of each item of the quality of water under different operating condition can be fully understood. Keywords: on-site wastewater treatment, Gravel Contact Oxidation,nitrification

碩士
國立臺灣大學
環境工程學研究所
103
Under the current problems of government financial shortage, low progress on both sewer pipeline construction and coping with sewage by the wastewater treatment plant, it is more effective to adopt on-site treatment method to deal with sewage. Needless to say, when using the on-site treatment method, it can not only purify the quality of water, but also create the ecological scenery and have an environmental education meaning. Therefore, the on-site treatment method is definitely a good sewage purification method which is worth being popularized; moreover, it is an important breakthrough comparing with the current bottleneck that waste water treatment and sewer pipeline facing with. The Erren River in southern Taiwan flows through the Rende district and Guiren district with its catchment area above 350 square kilometer. However, due to the long period of untreated discharge of industrial waste and domestic sewage into the Erren River, the water quality of Erren River is deteriorated, especially on the midstream and downstream of San Ye River and Gang Wei Guo River. Consequently, the local government adopts the on-site treatment method of natural purifying technique and anticipates improving the water quality in order to provide the local residents a better living quality. And the materials of the on-site treatment method it use are natural gravel or artificial filter, which can adsorb and decompose bacteria by its pore surface of bio-membrane. This study focuses on both the natural gravel site and the artificial contact filter site by monitoring and sampling its own effluent quality and observing its own operation maintenance in order to comprehensively discuss the effect of current treatment. And the method adopting in this study is factor analysis of multivariate analysis in SPSS Statistics (Statistical Product and Service Solutions, SPSS). By using factor analysis, we can analyze the chemical and physical characters of water in order to figure out the hotspot of pollutants in waste water, which can both increase the treatment efficiency and provide future design good criteria. The results show that the SS, BOD and ammonia nitrogen removal rate in natural gravel site are 73%, 85% and 68% separately, while the artificial contact filter site are 65%, 66%, 49% respectively. Multivariate statistical analysis of the results of suspended solids in the water quality of the main influencing factors, nutritional factors can be considered, showing its contribution to the interaction between water quality improvement.

Kwong Tsz Yan Alex.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 77-84).
Abstracts in English and Chinese.
Abstract --- p.i
Declaration --- p.iii
Acknowledgement --- p.iv
Table of contents --- p.v
List of tables --- p.ix
List of figures --- p.x
Chapter Chapter One : --- Introduction --- p.1
Chapter 1.1 --- The outbreak of SARS --- p.1
Chapter 1.2 --- Characteristics of triclosan --- p.2
Chapter 1.3 --- Environmental fate of triclosan --- p.3
Chapter 1.4 --- Treatment methods for triclosan --- p.5
Chapter 1.5 --- Ti02 photocatalysis --- p.6
Chapter 1.6 --- Addition of hydrogen peroxide to the photocatalytic system --- p.9
Chapter 1.7 --- Gas chromatography/ ion trap mass spectrometry analysis --- p.10
Chapter 1.8 --- Scope of work --- p.11
Chapter Chapter Two : --- Experimental --- p.13
Chapter 2.1 --- Chemical reagents --- p.13
Chapter 2.2 --- Photocatalytic experiments --- p.14
Chapter 2.3 --- "Analysis of 2,8-DCDD and triclosan by GC/ITMS" --- p.15
Chapter 2.4 --- Optimization of GC/ITMS conditions --- p.17
Chapter 2.5 --- Analysis of other reaction intermediates by GC/MS (full scan mode) --- p.18
Chapter 2.6 --- "Analysis of 2,4-dichlorophenol and triclosan by GC/MS (SIM mode)" --- p.20
Chapter 2.7 --- Effect of hydrogen peroxide concentration on triclosan degradation --- p.20
Chapter 2.8 --- Determination of total organic carbon (TOC) removal --- p.21
Chapter 2.9 --- UV-Visible spectrometry --- p.21
Chapter Chapter Three : --- Results --- p.22
Chapter 3.1 --- Selection of precursor ions for GC/ITMS analysis --- p.22
Chapter 3.2 --- Optimization of GC/ITMS conditions --- p.25
Chapter 3.3 --- "Analysis of 2,8-DCDD and triclosan by GC/ITMS" --- p.27
Chapter 3.4 --- "Analysis of 2,4-dichlorophenol and triclosan by GC/MS (SIM mode)" --- p.29
Chapter 3.5 --- "Quantitative measurement of 2,8-DCDD in UV irradiated samples" --- p.31
Chapter 3.6 --- Photocatalytic oxidation of triclosan by UV at 365nm --- p.33
Chapter 3.7 --- TOC removal in triclosan degradation --- p.35
Chapter 3.8 --- Identification of intermediates in photocatalytic oxidation of triclosan --- p.36
Chapter 3.9 --- Quantitative measurement of the intermediates in photocatalytic oxidation of triclosan --- p.41
Chapter 3.10 --- Effect of hydrogen peroxide concentration on triclosan degradation --- p.43
Chapter 3.11 --- Effect of hydrogen peroxide concentration on TOC removal --- p.46
Chapter 3.12 --- "Effect of hydrogen peroxide concentration on 2,4-dichlorophenol generation during triclosan degradation" --- p.47
Chapter 3.13 --- "Photocatalytic degradation of 2,4-dichlorophenol" --- p.49
Chapter 3.14 --- "Identification of intermediates in photocatalytic oxidation of 2,4-dichlorophenol" --- p.50
Chapter 3.15 --- "Quantitative measurement of the intermediates in photocatalytic oxidation of 2,4-dichlorophenol" --- p.54
Chapter Chapter Four : --- Discussions --- p.56
Chapter 4.1 --- "Photochemical conversion of triclosan to 2,8-DCDD" --- p.56
Chapter 4.2 --- Proposed mechanism of triclosan degradation --- p.57
Chapter 4.3 --- "Proposed mechanism of 2,4-dichlorophenol degradation" --- p.63
Chapter 4.4 --- TOC removal in triclosan degradation --- p.65
Chapter 4.5 --- Effect of hydrogen peroxide concentration on photocatalytic oxidation of triclosan --- p.65
Chapter 4.6 --- "Adverse environmental and human health effects of 2,8-DCDD" --- p.69
Chapter 4.7 --- "Adverse environmental and human health effects of 2,4-dichlorophenol" --- p.71
Chapter 4.8 --- "Discharge limitations for 2,4-dichlorophenol" --- p.73
Chapter Chapter Five : --- Conclusions --- p.75
References --- p.77

Cheng Yee Wan.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 95-112).
Abstracts in English and Chinese.
Acknowledgements --- p.i
Abstract --- p.ii
Table of Contents --- p.vi
List of Figures --- p.xi
List of Plates --- p.xiv
List of Tables --- p.xvi
Abbreviations --- p.xviii
Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Legionella pneumophila --- p.1
Chapter 1.1.1 --- Bacterial morphology and ultrastructure --- p.2
Chapter 1.1.2 --- Microbial ecology and natural habitats --- p.4
Chapter 1.1.2.1 --- Association with amoeba --- p.5
Chapter 1.1.2.2 --- Association with biofilm --- p.5
Chapter 1.2 --- Legionnaires' disease and clinical significance --- p.6
Chapter 1.2.1 --- Epidemiology --- p.6
Chapter 1.2.1.1 --- Worldwide distribution --- p.6
Chapter 1.2.1.2 --- Local situation --- p.7
Chapter 1.2.2 --- Clinical presentation --- p.7
Chapter 1.2.3 --- Route of infection and pathogenesis --- p.8
Chapter 1.2.4 --- Diagnosis --- p.10
Chapter 1.2.4.1 --- Culture of Legionella --- p.10
Chapter 1.2.4.2 --- Direct fluorescent antibody (DFA) staining --- p.13
Chapter 1.2.4.3 --- Serologic tests --- p.13
Chapter 1.2.4.4 --- Urine antigen testing --- p.14
Chapter 1.2.4.5 --- Detection of Legionella nucleic acid --- p.15
Chapter 1.2.5 --- Risk factors --- p.15
Chapter 1.2.6 --- Treatment for Legionella infection --- p.16
Chapter 1.3 --- Detection of Legionella in environment --- p.16
Chapter 1.4 --- Disinfection methods --- p.17
Chapter 1.4.1 --- Physical methods --- p.19
Chapter 1.4.1.1 --- Filtration --- p.19
Chapter 1.4.1.2 --- UV-C irradiation --- p.20
Chapter 1.4.1.3 --- Thermal eradication (superheat-and-flush) --- p.21
Chapter 1.4.2 --- Chemical methods --- p.21
Chapter 1.4.2.1 --- Chlorination --- p.21
Chapter 1.4.2.2 --- Copper-silver ionization --- p.22
Chapter 1.4.3 --- Effect of biofilm and other factors on disinfection --- p.23
Chapter 1.5 --- Photocatalytic oxidation (PCO) --- p.24
Chapter 1.5.1 --- Generation of strong oxidants --- p.24
Chapter 1.5.2 --- Disinfection mechanism(s) --- p.27
Chapter 1.5.3 --- Major factors affecting the process --- p.28
Chapter 2. --- Objectives --- p.30
Chapter 3. --- Materials and Methods --- p.31
Chapter 3.1 --- Chemicals --- p.31
Chapter 3.2 --- Bacterial strains and culture --- p.31
Chapter 3.3 --- Photocatalytic reactor --- p.33
Chapter 3.4 --- PCO efficacy tests --- p.33
Chapter 3.5 --- PCO sensitivity tests --- p.35
Chapter 3.6 --- Optimisation of PCO conditions --- p.35
Chapter 3.6.1 --- Optimization of TiO2 concentration --- p.36
Chapter 3.6.2 --- Optimization of UV intensity --- p.36
Chapter 3.6.3 --- Optimization of depth of reaction mixture --- p.36
Chapter 3.6.4 --- Optimization of stirring rate --- p.37
Chapter 3.6.5 --- Optimization of initial pH --- p.37
Chapter 3.6.6 --- Optimization of treatment time and initial cell concentration --- p.37
Chapter 3.6.7 --- Combinational optimization --- p.37
Chapter 3.7 --- Transmission electron microscopy (TEM) --- p.38
Chapter 3.8 --- Fatty acid profile analysis --- p.40
Chapter 3.9 --- Total organic carbon (TOC) analysis --- p.42
Chapter 3.10 --- UV-C irradiation --- p.44
Chapter 3.11 --- Hyperchlorination --- p.44
Chapter 3.12 --- Statistical analysis and replication --- p.45
Chapter 3.13 --- Safety precautions --- p.45
Chapter 4. --- Results --- p.46
Chapter 4.1 --- Efficacy test --- p.46
Chapter 4.2 --- PCO sensitivity --- p.47
Chapter 4.3 --- Optimization of PCO conditions --- p.48
Chapter 4.3.1 --- TiO2 concentration --- p.48
Chapter 4.3.2 --- UV intensity --- p.48
Chapter 4.3.3 --- Depth of reaction mixture --- p.51
Chapter 4.3.4 --- Stirring rate --- p.56
Chapter 4.3.5 --- Effect of initial pH --- p.56
Chapter 4.3.6 --- Effect of treatment time and initial concentrations --- p.56
Chapter 4.3.7 --- Combinational effects --- p.63
Chapter 4.4 --- Transmission electron microscopy (TEM) --- p.66
Chapter 4.4.1 --- Morphological changes induced by PCO --- p.66
Chapter 4.4.2 --- Comparisons with changes caused by UV-C irradiation and chlorination --- p.67
Chapter 4.5 --- Fatty acid profile analysis --- p.71
Chapter 4.6 --- Total organic carbon (TOC) analysis --- p.73
Chapter 4.7 --- UV-C irradiation --- p.74
Chapter 4.8 --- Hyperchlorination --- p.74
Chapter 5. --- Discussion --- p.76
Chapter 5.1 --- Efficacy test --- p.76
Chapter 5.2 --- PCO sensitivity --- p.76
Chapter 5.3 --- Optimization of PCO conditions --- p.77
Chapter 5.3.1 --- Effect of TiO2 concentration --- p.77
Chapter 5.3.2 --- Effect of UV intensity --- p.78
Chapter 5.3.3 --- Effect of depth of reaction mixture --- p.79
Chapter 5.3.4 --- Effect of stirring rate --- p.79
Chapter 5.3.5 --- Effect of initial pH --- p.80
Chapter 5.3.6 --- Effect of treatment time and initial concentrations --- p.81
Chapter 5.3.7 --- Combinational effect --- p.82
Chapter 5.4 --- Transmission electron microscopy (TEM) --- p.83
Chapter 5.4.1 --- Morphological changes induced by PCO --- p.83
Chapter 5.4.2 --- Comparisons with changes caused by UV-C irradiation and chlorination --- p.85
Chapter 5.5 --- Fatty acid profile analysis --- p.85
Chapter 5.6 --- Total organic carbon (TOC) analysis --- p.86
Chapter 5.7 --- Comparisons of the three disinfection methods --- p.88
Chapter 6. --- Conclusion --- p.91
Chapter 7. --- References --- p.95
Chapter 8. --- Appendix --- p.113

The deteriorating water quality in South Africa and changing legislation requiring the industrial implementation of waste minimisation and pollution prevention technologies has highlighted the need for the investigation of new effluent treatment technologies such as advanced oxidation processes. This investigation details the evaluation of ultrasound, an emerging advanced oxidation process, to degrade organic compounds during water treatment. The objectives of the investigation included the design of a suitable ultrasonic laboratory reactor to investigate ultrasound chemistry and the sub-processes occurring during sonication. Atrazine was used as a model compound to compare the performance of ultrasound with that of ozone and hydrogen peroxide, already established advanced oxidation processes. Recommendations have also been made for the scale-up of ultrasonic processes. A 500 mL ultrasonic cell containing an ultrasonic horn as an energy source was designed and constructed. The measurement of hydrogen peroxide concentration was used as a tool to indicate the process conditions under which the formation of free radical reactions during sonication are enhanced. These include the application of oxygen and air sparging or the addition of a commercial source of hydrogen peroxide. It was found that oxygen sparging and a high acoustic power input should be used in ultrasonic processes with a short retention time, and conversely, that air sparging and a lower acoustic energy source should be used in processes with a long retention time. A flow loop system should be considered to maximise oxidation both within and beyond the sonicated zone, gas sparging should only occur within the sonication zone else the degradation of hydrogen peroxide is encouraged. Ultrasound is most effectively applied in water treatment as a pretreatment stage in combination with other technologies and not as a stand-alone process. Atrazine was used. as a model compound to compare the performance of ultrasound with ozone because of its persistence in the environment and resistance to degradation. Atrazine was degraded during sonication and ozonation. degradation increased wim the addition of hydrogen peroxide. Ozone decomposition (and hence free radical reactions) was enhanced when ozone was combined with ultrasound or hydrogen peroxide. Enhanced ozone decomposition during ozonation combined with sonication is due to the conditions (high temperatures and pressures) as well as the free radical reactions occurring within the collapsing cavitation bubbles and at the gas-liquid interface. The enhancing effect of combining ultrasound with ozone was greatest at the low ozone concentrations typically applied during water treatment. Atrazine degradation during sonication and ozonation is predominantly due to the reaction with hydroxyl radicals. Atrazine degradation products identified using gas chromatography and mass spectrometry were deethylatrazine. hydroxyatrazine and deethyldeisopropylatrazine (tentatively identified).
Thesis (Ph.D.)-University of Natal, Durban, 2001.

by Fong Wai-lan.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (leaves 138-152).
Text in English; abstracts in English and Chinese.
by Fong Wai-lan.
Acknowledgements --- p.i
Abstracts --- p.ii
Contents --- p.vi
List of figures --- p.xii
List of Plates --- p.xviii
List of tables --- p.xix
Abbreviations --- p.xxi
Chemical equations --- p.xxiii
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Pentachlorophenol --- p.1
Chapter 1.1.1 --- Characteristics of pentachlorophenol --- p.1
Chapter 1.1.2 --- Use of pentachlorophenol --- p.4
Chapter 1.1.3 --- Annual consumption and regulations for the use of pentachlorophenol --- p.4
Chapter 1.1.4 --- Pentachlorophenol in the environment --- p.4
Chapter 1.1.5 --- Toxicity of pentachlorophenol --- p.5
Chapter I. --- Mechanism --- p.5
Chapter II. --- Toxicity towards plant and animals --- p.7
Chapter III. --- Toxicity towards human --- p.7
Chapter 1.2 --- Treatments of pollutant --- p.9
Chapter 1.2.1 --- Physical treatment --- p.9
Chapter 1.2.2 --- Chemical treatment --- p.9
Chapter 1.2.3 --- Biological treatment --- p.12
Chapter 1.2.4 --- Advanced Oxidation Processes (AOPs) --- p.14
Chapter Chapter 2 --- Objectives --- p.28
Chapter 3 --- Materials and methods --- p.29
Chapter 3.1 --- Chemical reagents --- p.29
Chapter 3.2 --- Photocatalytic reactor --- p.29
Chapter 3.3 --- Determination of pentachlorophenol concentration --- p.31
Chapter 3.4 --- Optimization of reaction conditions for UV-PCO --- p.34
Chapter 3.4.1 --- Batch system --- p.34
Chapter 3.4.1.1 --- Effect of initial hydrogen peroxide concentration --- p.34
Chapter 3.4.1.2 --- "Effect of initial titanium dioxide concentration, light intensity and initial pH" --- p.34
Chapter 3.4.1.3 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during UV-PCO --- p.36
Chapter 3.4.2 --- Continuous system --- p.36
Chapter 3.5 --- Optimization of reaction conditions for VL-PCO --- p.38
Chapter 3.5.1 --- "Effect of VL source, initial hydrogen peroxide, titanium dioxide concentration，light intensity, pH and reaction volume" --- p.38
Chapter 3.5.2 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during VL-PCO --- p.39
Chapter 3.6 --- Optimization of reaction conditions for S-PCO --- p.39
Chapter 3.6.1 --- "Effect of initial hydrogen peroxide, titanium dioxide concentration，light intensity and pH" --- p.39
Chapter 3.6.2 --- Effect of irradiation time & determination of total organic carbon (TOC) removal during S-PCO --- p.41
Chapter 3.7 --- Modification of photocatalytic oxidation --- p.41
Chapter 3.7.1 --- Buffering system --- p.41
Chapter 3.7.2 --- Immobilized titanium dioxide system --- p.41
Chapter 3.7.2.1 --- Preparation of titanium dioxide coated spiral column --- p.41
Chapter 3.7.2.2 --- Effect of flow rate for the UV-PCO (continuos- buffering/immobilized titanium dioxide) system --- p.43
Chapter 3.8 --- Estimation of pentachlorophenol degradation pathway by photocatalytic oxidation --- p.43
Chapter 3.9 --- Evaluation for the toxicity change of pentachlorophenol during the degradation process --- p.43
Chapter 3.9.1 --- Microtox® test --- p.43
Chapter 3.9.2 --- Amphipod survival test --- p.45
Chapter Chapter 4 --- Results --- p.47
Chapter 4.1 --- Determination of pentachlorophenol concentration --- p.47
Chapter 4.2 --- Optimization of reaction conditions for UV-PCO --- p.47
Chapter 4.2.1 --- Batch system --- p.47
Chapter 4.2.1.1 --- Effect of initial hydrogen peroxide concentration --- p.47
Chapter 4.2.1.2 --- Effect of initial titanium dioxide concentration --- p.54
Chapter 4.2.1.3 --- Effect of light intensity --- p.54
Chapter 4.2.1.4 --- Effect of initial pH --- p.54
Chapter 4.2.1.5 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during UV-PCO --- p.61
Chapter 4.2.2 --- Continuous system --- p.61
Chapter 4.3 --- Optimization of reaction conditions for VL-PCO --- p.69
Chapter 4.3.1 --- Effect of VL source --- p.69
Chapter 4.3.2 --- Effect of initial hydrogen peroxide concentration --- p.69
Chapter 4.3.3 --- Effect of initial titanium dioxide concentration --- p.69
Chapter 4.3.4 --- Effect of light intensity --- p.76
Chapter 4.3.5 --- Effect of initial pH --- p.76
Chapter 4.3.6 --- Effect of reaction volume --- p.76
Chapter 4.3.7 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during VL-PCO --- p.83
Chapter 4.4 --- Optimization of reaction conditions for S-PCO --- p.83
Chapter 4.4.1 --- Effect of initial hydrogen peroxide concentration --- p.83
Chapter 4.4.2 --- Effect of initial titanium dioxide concentration --- p.90
Chapter 4.4.3 --- Effect of initial pH --- p.90
Chapter 4.4.4 --- Effect of irradiation time & determination of total organic carbon (TOC) removal during S-PCO --- p.90
Chapter 4.5 --- Modification of photocatalytic oxidation --- p.96
Chapter 4.5.1 --- Buffering system --- p.96
Chapter 4.5.2 --- Immobilized titanium dioxide system --- p.104
Chapter 4.6 --- Estimation of pentachlorophenol degradation pathway by photocatalytic oxidation --- p.104
Chapter 4.7 --- Evaluation of the toxicity change of pentachlorophenol during photocatalytic oxidation --- p.104
Chapter 4.7.1 --- Microtox® test --- p.104
Chapter 4.7.2 --- Amphipod survival test --- p.112
Chapter Chapter 5 --- Discussion --- p.116
Chapter 5.1 --- Determination of pentachlorophenol concentration --- p.116
Chapter 5.2 --- Optimization of reaction conditions for UV-PCO --- p.116
Chapter 5.2.1 --- Batch system --- p.116
Chapter 5.2.1.1 --- Effect of initial hydrogen peroxide concentration --- p.116
Chapter 5.2.1.2 --- Effect of initial titanium dioxide concentration --- p.117
Chapter 5.2.1.3 --- Effect of light intensity --- p.119
Chapter 5.2.1.4 --- Effect of initial pH --- p.119
Chapter 5.2.1.5 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during UV-PCO --- p.120
Chapter 5.2.2 --- Continuous system --- p.120
Chapter 5.3 --- Optimization of reaction conditions for VL-PCO --- p.121
Chapter 5.3.1 --- Effect of visible light (VL) source --- p.121
Chapter 5.3.2 --- Effect of initial hydrogen peroxide concentration --- p.121
Chapter 5.3.3 --- Effect of initial titanium dioxide concentration --- p.122
Chapter 5.3.4 --- Effect of light intensity --- p.123
Chapter 5.3.5 --- Effect of initial pH --- p.124
Chapter 5.3.6 --- Effect of reaction volume --- p.124
Chapter 5.3.7 --- Effect of initial pentachlorophenol concentration and irradiation time & determination of total organic carbon (TOC) removal during VL-PCO --- p.124
Chapter 5.4 --- Optimization of reaction conditions for S-PCO --- p.125
Chapter 5.4.1 --- Effect of initial hydrogen peroxide concentration --- p.125
Chapter 5.4.2 --- Effect of initial titanium dioxide concentration --- p.126
Chapter 5.4.3 --- Effect of initial pH --- p.127
Chapter 5.4.4 --- Effect of irradiation time & determination of total organic carbon (TOC) removal during S-PCO --- p.127
Chapter 5.5 --- Modification of photocatalytic oxidation --- p.128
Chapter 5.5.1 --- Buffering system --- p.128
Chapter 5.5.2 --- Effect of flow rate on removal efficiency for the UV-PCO (continuos-buffering/immobilized titanium dioxide) system --- p.129
Chapter 5.6 --- Estimation of pentachlorophenol degradation pathway by photocatalytic oxidation --- p.130
Chapter 5.7 --- Evaluation for the toxicity change of pentachlorophenol during photocatalytic oxidation --- p.132
Chapter 5.7.1 --- Microtox® test --- p.132
Chapter 5.7.2 --- Amphipod survival test --- p.133
Chapter Chapter 6 --- Conclusions --- p.135
Chapter Chapter 7 --- References --- p.138
Appendix i --- p.153
Appendix ii --- p.154
Appendix iii --- p.154

The ever-increasing detection of harmful organic and inorganic compounds in habitable areas throughout the world has led to mounting research into applications and techniques for the treatment of contaminated soils, surface and groundwaters, and chemical and industrial wastewaters. Chemical oxidation technologies, in particular Fenton-based remediation systems, have exhibited considerable potential for the effective treatment and remediation of such contaminated waters and soils. The use of Fenton-based oxidation systems for the treatment of contaminated waters and wastewaters warrants the development of kinetic models capable of accurately simulating system behaviour. In this thesis, the kinetics of Fenton-mediated oxidation systems and kinetic models based on its governing reaction mechanism are investigated in order to highlight those parameters and conditions that effect Fenton chemistry and oxidation performance, and to demonstrate the application of such kinetic models to design and improve treatment systems. Experimental and simulated data describing the oxidation of formic acid by Fenton's reagent at low pH (3 to 4) and under a variety of initial conditions, operating regimes, and solution environments supports a proposed reaction mechanism that nominates the hydroxyl radical (OH) as the active oxidizing intermediate in Fenton-based oxidation systems. Laboratory experiments demonstrate that formic acid oxidation is inhibited in the presence of oxygen, and model simulations of these systems reveals that such behaviour is due to the effect organic radical intermediates and/or by-products have in assisting or hindering the redox cycling of the catalytic iron species. The critical role that iron redox cycling plays in affecting oxidation performance is further highlighted by experimental and simulated studies at alternate pHs and using different target organics, including those that react directly with iron in a redox capacity. Experiments at pH 4 reveal an increase in the redox cycling of iron and improved oxidation performance compared to pH 3 as the higher pH favours the superoxide radical, a stronger reductant than the hydroperoxyl radical that predominates at pH 3. Other laboratory and modelling studies on the Fenton-mediated oxidation of certain aromatic compounds highlight the manner in which quinone and quinone-like compounds, being added directly or generated as oxidation by-products, can improve oxidation performance via redox reactions with iron. Further simulations reveal the type of practical design and operating information kinetic models can provide for treatment processes, though it is noted an appropriate understanding of the oxidation mechanism of the target species is necessary for the accurate application of the model.

by Cheung Kit Hing.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 175-199).
Abstracts in English and Chinese.
Acknowledgements --- p.i
Abstracts --- p.ii
Table of Contents --- p.vi
List of Figures --- p.xviii
List of Plates --- p.xxii
List of Tables --- p.xxiii
Abbreviations --- p.xxv
Equations --- p.xxviii
Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- The chemistry of azo dyes --- p.1
Chapter 1.2 --- Azo dyes classification --- p.2
Chapter 1.3 --- Environmental concerns and toxicity --- p.4
Chapter 1.3.1 --- Toxicity of azo dyes --- p.5
Chapter 1.3.2 --- Carcinogenicity --- p.5
Chapter 1.3.3 --- Ecotoxicity --- p.11
Chapter 1.3.3.1 --- Toxicity to microorganisms --- p.12
Chapter 1.3.3.2 --- Toxicity towards vertebrates --- p.13
Chapter 1.4 --- Treatment of azo dyes --- p.13
Chapter 1.4.1 --- Physical treatment --- p.14
Chapter 1.4.1.1 --- Adsorption --- p.14
Chapter 1.4.1.2 --- Membrane technology --- p.15
Chapter 1.4.2 --- Chemical treatments --- p.15
Chapter 1.4.2.1 --- Chlorination --- p.16
Chapter 1.4.2.2 --- Fenton's reaction --- p.16
Chapter 1.4.2.3 --- Ozonation --- p.16
Chapter 1.4.2.4 --- Coagulation --- p.17
Chapter 1.4.3 --- Biological treatments --- p.17
Chapter 1.4.3.1 --- Activated sludge process --- p.18
Chapter 1.4.3.2 --- Biodegradation --- p.18
Chapter 1.4.3.3 --- Biosorption --- p.21
Chapter 1.4.3.3.1 --- Modeling of sorption --- p.24
Chapter 1.4.3.3.1.1 --- Langmuir sorption model --- p.24
Chapter 1.4.3.3.1.2 --- Freundlich sorption model --- p.25
Chapter 1.4.4 --- Advanced oxidation processes --- p.25
Chapter 1.4.4.1 --- Photocatalytic oxidation --- p.26
Chapter 1.4.4.2 --- Titanium dioxide (TiO2) --- p.26
Chapter 1.4.4.3 --- Mechanism of photocatalytic oxidation using photocatalyst TiO2 --- p.28
Chapter 1.4.4.4 --- Photocatalytic oxidation of s-triazine containing compounds --- p.30
Chapter 1.4.4.5 --- Photocatalytic oxidation of Procion Red MX-5B --- p.31
Chapter 1.4.4.6 --- Cyanuric acid --- p.32
Chapter 1.4.4.6.1 --- Application --- p.32
Chapter 1.4.4.6.2 --- Toxicity --- p.32
Chapter 1.4.4.6.3 --- Photocatalytic oxidation resistance --- p.34
Chapter 1.4.4.6.4 --- Biodegradation --- p.35
Chapter 1.4.4.7 --- Enhancement of photocatalytic oxidation by using sorbent immobilized with TiO2 --- p.35
Chapter 1.4.4.7.1 --- Sorption --- p.35
Chapter 1.4.4.7.2 --- Immobilization of TiO2 --- p.37
Chapter 1.4.8 --- Integration of treatment methods --- p.39
Chapter 2. --- Objectives --- p.41
Chapter 3. --- Materials and methods --- p.42
Chapter 3.1. --- Sorption --- p.42
Chapter 3.1.1 --- Chemical reagents --- p.42
Chapter 3.1.2 --- Determination of Procion Red MX-5B --- p.42
Chapter 3.1.3 --- Sampling --- p.44
Chapter 3.1.4 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.44
Chapter 3.1.5 --- Screening of Procion Red MX-5B sorption ability --- p.44
Chapter 3.1.6 --- Identification of isolated bacterium --- p.46
Chapter 3.1.7 --- Optimization of cell yield and sorption capacity --- p.47
Chapter 3.1.7.1 --- Preparation of cell culture of Vibrio sp. --- p.47
Chapter 3.1.7.2 --- Growth phase --- p.47
Chapter 3.1.7.2.1 --- Growth curve --- p.47
Chapter 3.1.7.2.2 --- Dye sorption capacity --- p.47
Chapter 3.1.7.3 --- Initial pH --- p.48
Chapter 3.1.7.3.1 --- Growth curve --- p.48
Chapter 3.1.7.3.2 --- Dye sorption capacity --- p.48
Chapter 3.1.7.4 --- Temperature --- p.49
Chapter 3.1.7.4.1 --- Growth curve --- p.49
Chapter 3.1.7.4.2 --- Dye sorption capacity --- p.49
Chapter 3.1.7.5 --- Glucose concentrations --- p.49
Chapter 3.1.7.5.1 --- Growth curve --- p.49
Chapter 3.1.7.5.2 --- Dye sorption capacity --- p.50
Chapter 3.1.8 --- Optimization of sorption process --- p.50
Chapter 3.1.8.1 --- Preparation of sorbent --- p.50
Chapter 3.1.8.2 --- Dry weight of sorbent --- p.50
Chapter 3.1.8.3 --- Temperature --- p.50
Chapter 3.1.8.4 --- Agitation rate --- p.50
Chapter 3.1.8.5 --- Salinity --- p.51
Chapter 3.1.8.6 --- Initial pH --- p.51
Chapter 3.1.8.7 --- Concentration of Procion Red MX-5B --- p.51
Chapter 3.1.8.8 --- Combination study of salinity and initial pH --- p.51
Chapter 3.2. --- Photocatalytic oxidation reaction --- p.52
Chapter 3.2.1 --- Chemical reagents --- p.52
Chapter 3.2.2 --- Photocatalytic reactor --- p.52
Chapter 3.2.3 --- Optimization of sorption and photocatalytic oxidation reactions using biomass of Vibrio sp.immobilized in calcium alginate beads --- p.54
Chapter 3.2.3.1 --- Effect of dry weight of immobilized cells of Vibrio sp. --- p.54
Chapter 3.2.3.1.1 --- Sorption --- p.55
Chapter 3.2.3.1.2 --- Photocatalytic oxidation --- p.56
Chapter 3.2.3.2 --- Effect of UV intensities --- p.57
Chapter 3.2.3.3 --- Effect of TiO2 concentrations --- p.57
Chapter 3.2.3.3.1 --- Sorption --- p.57
Chapter 3.2.3.3.2 --- Photocatalytic oxidation --- p.57
Chapter 3.2.3.4 --- Effect of H202 concentrations --- p.57
Chapter 3.2.3.5 --- Effect of the number of beads --- p.58
Chapter 3.2.3.5.1 --- Sorption --- p.58
Chapter 3.2.3.5.2 --- Photocatalytic oxidation --- p.58
Chapter 3.2.3.6 --- Effect of initial pH with and without the addition of H2O2 --- p.58
Chapter 3.2.3.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.59
Chapter 3.2.3.8 --- Combinational study of UV intensities and H2O2 concentrations --- p.59
Chapter 3.2.3.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.59
Chapter 3.2.3.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L TiO2" --- p.59
Chapter 3.3 --- Biodegradation --- p.60
Chapter 3.3.1 --- Chemical reagents --- p.60
Chapter 3.3.2 --- Sampling --- p.60
Chapter 3.3.3 --- Enrichment --- p.60
Chapter 3.3.4 --- Isolation of cyanuric acid-utilizing bacteria --- p.61
Chapter 3.3.5 --- Determination of cyanuric acid --- p.61
Chapter 3.3.6 --- Screening of Procion Red MX-5B sorption ability --- p.61
Chapter 3.3.7 --- Screening of cyanuric acid-utilizing ability --- p.61
Chapter 3.3.8 --- Bacterial identification --- p.63
Chapter 3.3.9 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.63
Chapter 3.3.10 --- Optimization of reaction conditions --- p.64
Chapter 3.3.10.1 --- Effect of salinity --- p.64
Chapter 3.3.10.2 --- Effect of cyanuric acid concentrations --- p.65
Chapter 3.3.10.3 --- Effect of temperature --- p.65
Chapter 3.3.10.4 --- Effect of agitation rate --- p.65
Chapter 3.3.10.5 --- Effect of initial pH --- p.66
Chapter 3.3.10.6 --- Effect of initial glucose concentration --- p.66
Chapter 3.3.10.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.66
Chapter 3.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.66
Chapter 3.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.67
Chapter 4. --- Results --- p.68
Chapter 4.1. --- Sorption --- p.68
Chapter 4.1.1 --- Determination of Procion Red MX-5B --- p.68
Chapter 4.1.2 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.68
Chapter 4.1.3 --- Screening of Procion Red MX-5B sorption ability --- p.68
Chapter 4.1.4 --- Identification of isolated bacterium --- p.72
Chapter 4.1.5 --- Optimization of cell yield and sorption capacity --- p.72
Chapter 4.1.5.1 --- Growth phase --- p.72
Chapter 4.1.5.1.1 --- Growth curve --- p.72
Chapter 4.1.5.1.2 --- Dye sorption capacity --- p.72
Chapter 4.1.5.2 --- Initial pH --- p.75
Chapter 4.1.5.2.1 --- Growth curve --- p.75
Chapter 4.1.5.2.2 --- Dye sorption capacity --- p.75
Chapter 4.1.5.3 --- Temperature --- p.75
Chapter 4.1.5.3.1 --- Growth curve --- p.75
Chapter 4.1.5.3.2 --- Dye sorption capacity --- p.79
Chapter 4.1.5.4 --- Glucose concentrations --- p.79
Chapter 4.1.5.4.1 --- Growth curve --- p.79
Chapter 4.1.5.4.2 --- Dye sorption capacity --- p.79
Chapter 4.1.6 --- Optimization of sorption process --- p.82
Chapter 4.1.6.1 --- Dry weight of sorbent --- p.82
Chapter 4.1.6.2 --- Temperature --- p.82
Chapter 4.1.6.3 --- Agitation rate --- p.86
Chapter 4.1.6.4 --- Salinity --- p.86
Chapter 4.1.6.5 --- Initial pH --- p.86
Chapter 4.1.6.6 --- Concentration of Procion Red MX-5B --- p.90
Chapter 4.1.6.7 --- Combination study of salinity and initial pH --- p.90
Chapter 4.2. --- Photocatalytic oxidation reaction --- p.94
Chapter 4.2.1 --- Effect of dry weight of immobilized cells of Vibrio sp. --- p.94
Chapter 4.2.1.1 --- Sorption --- p.94
Chapter 4.2.1.2 --- Photocatalytic oxidation --- p.96
Chapter 4.2.2 --- Effect of UV intensities --- p.96
Chapter 4.2.3 --- Effect of TiO2 concentrations --- p.96
Chapter 4.2.3.1 --- Sorption --- p.96
Chapter 4.2.3.2 --- Photocatalytic oxidation --- p.101
Chapter 4.2.4 --- Effect of H2O2 concentrations --- p.101
Chapter 4.2.5 --- Effect of the number of beads --- p.101
Chapter 4.2.5.1 --- Sorption --- p.105
Chapter 4.2.5.2 --- Photocatalytic oxidation --- p.105
Chapter 4.2.6 --- Effect of initial pH with and without the addition of --- p.105
Chapter 4.2.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.109
Chapter 4.2.8 --- Combinational study of UV intensities and H202 concentrations --- p.112
Chapter 4.2.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.112
Chapter 4.2.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L Ti02" --- p.112
Chapter 4.3 --- Biodegradation --- p.116
Chapter 4.3.1 --- Isolation of cyanuric acid-utilizing bacteria --- p.116
Chapter 4.3.2 --- Determination of cyanuric acid --- p.116
Chapter 4.3.3 --- Screening of Procion Red MX-5B sorption ability --- p.116
Chapter 4.3.4 --- Screening of cyanuric acid-utilizing ability --- p.116
Chapter 4.3.5 --- Bacterial identification --- p.118
Chapter 4.3.6 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.118
Chapter 4.3.7 --- Optimization of reaction conditions --- p.122
Chapter 4.3.7.1 --- Effect of salinity --- p.122
Chapter 4.3.7.2 --- Effect of cyanuric acid concentrations --- p.122
Chapter 4.3.7.3 --- Effect of temperature --- p.126
Chapter 4.3.7.4 --- Effect of agitation rate --- p.126
Chapter 4.3.7.5 --- Effect of initial pH --- p.132
Chapter 4.3.7.6 --- Effect of initial glucose concentration --- p.132
Chapter 4.3.7.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.132
Chapter 4.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.137
Chapter 4.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.137
Chapter 5. --- Discussion --- p.141
Chapter 5.1 --- Sorption --- p.141
Chapter 5.1.1 --- Isolation of Procion Red MX-5B-sorbing bacteria --- p.141
Chapter 5.1.2 --- Screening of Procion Red MX-5B sorption ability --- p.141
Chapter 5.1.3 --- Identification of isolated bacterium --- p.141
Chapter 5.1.4 --- Optimization of cell yield and sorption capacity --- p.142
Chapter 5.1.4.1 --- Growth phase --- p.142
Chapter 5.1.4.1.1 --- Growth curve --- p.142
Chapter 5.1.4.1.2 --- Dye sorption capacity --- p.143
Chapter 5.1.4.2 --- Initial pH --- p.146
Chapter 5.1.4.2.1 --- Growth curve --- p.146
Chapter 5.1.4.2.2 --- Dye sorption capacity --- p.146
Chapter 5.1.4.3 --- Temperature --- p.146
Chapter 5.1.4.3.1 --- Growth curve --- p.146
Chapter 5.1.4.3.2 --- Dye sorption capacity --- p.147
Chapter 5.1.4.4 --- Glucose concentrations --- p.147
Chapter 5.1.4.4.1 --- Growth curve --- p.147
Chapter 5.1.4.4.2 --- Dye sorption capacity --- p.147
Chapter 5.1.5 --- Optimization of sorption process --- p.148
Chapter 5.1.5.1 --- Dry weight of sorbent --- p.148
Chapter 5.1.5.2 --- Temperature --- p.148
Chapter 5.1.5.3 --- Agitation rate --- p.149
Chapter 5.1.5.4 --- Salinity --- p.149
Chapter 5.1.5.5 --- Initial pH --- p.150
Chapter 5.1.5.6 --- Concentration of Procion Red MX-5B (MX-5B) --- p.152
Chapter 5.1.5.7 --- Combination study of salinity and initial pH --- p.153
Chapter 5.2. --- Photocatalytic oxidation reaction --- p.153
Chapter 5.2.1 --- Effect of immobilized cells of Vibrio sp. --- p.153
Chapter 5.2.1.1 --- Sorption --- p.153
Chapter 5.2.1.2 --- Photocatalytic oxidation --- p.154
Chapter 5.2.2 --- Effect of UV intensities --- p.155
Chapter 5.2.3 --- Effect of TiO2 concentrations --- p.155
Chapter 5.2.3.1 --- Sorption --- p.155
Chapter 5.2.3.2 --- Photocatalytic oxidation --- p.156
Chapter 5.2.4 --- Effect of H2O2 concentrations --- p.156
Chapter 5.2.5 --- Effect of the number of beads --- p.157
Chapter 5.2.5.1 --- Sorption --- p.157
Chapter 5.2.5.2 --- Photocatalytic oxidation --- p.158
Chapter 5.2.6 --- Effect of initial pH with and without the addition of --- p.158
Chapter 5.2.7 --- Control experiments for photocatalytic oxidation of Procion Red MX-5B --- p.160
Chapter 5.2.8 --- Combinational study of UV intensities and H202 concentrations --- p.161
Chapter 5.2.9 --- Photocatalytic oxidation of Procion Red MX-5B under optimal conditions --- p.161
Chapter 5.2.10 --- "Sorption isotherms of calcium alginate beads immobilized with 70 mg Vibrio sp. and 5,000 mg/L Ti02" --- p.161
Chapter 5.3 --- Biodegradation --- p.162
Chapter 5.3.1 --- Isolation of cyanuric acid-utilizing bacteria --- p.162
Chapter 5.3.2 --- Determination of cyanuric acid --- p.163
Chapter 5.3.3 --- Screening of Procion Red MX-5B sorption ability --- p.163
Chapter 5.3.4 --- Screening of cyanuric acid-utilizing ability --- p.163
Chapter 5.3.5 --- Bacterial identification --- p.163
Chapter 5.3.6 --- Growth and cyanuric acid removal efficiency of the selected bacterium --- p.164
Chapter 5.3.7 --- Optimization of reaction conditions --- p.165
Chapter 5.3.7.1 --- Effect of salinity --- p.165
Chapter 5.3.7.2 --- Effect of cyanuric acid concentration --- p.165
Chapter 5.3.7.3 --- Effect of temperature --- p.166
Chapter 5.3.7.4 --- Effect of agitation rate --- p.167
Chapter 5.3.7.5 --- Effect of initial pH --- p.167
Chapter 5.3.7.6 --- Effect of initial glucose concentration --- p.167
Chapter 5.3.7.7 --- Combinational study of glucose and cyanuric acid concentrations --- p.168
Chapter 5.4 --- Detection of cyanuric acid formed in photocatalytic oxidation reaction --- p.170
Chapter 5.5 --- "Integration of sorption, photocatalytic oxidation and biodegradation" --- p.171
Chapter 5.6 --- Recommendations --- p.171
Chapter 6. --- Conclusions --- p.173
Chapter 7. --- References --- p.175
Appendix --- p.200