Dissertations / Theses on the topic 'Persulfate'

Ce travail de thèse a porté sur l'élimination d'un pesticide, l'imazalil, en phase aqueuse par trois procédés de dégradation (UV/TiO2, UV/TiO2/K2S2O8 et UV/K2S2O8) en mettant en oeuvre les outils analytiques nécessaires pour identifier les photoproduits de dégradation, suivre leur cinétique de formation et la minéralisation. L'ajout de K2S2O8 est bénéfique pour la dégradation et la minéralisation car il produit des radicaux sulfates qui sont des espèces oxydantes puissantes. Par ailleurs, le rôle des espèces radicalaires a été mis en évidence dans les trois systèmes de dégradation par des inhibiteurs de radicaux tels que les alcools (inhibiteurs des radicaux OH•). Dans une première partie, la dégradation de l'imazalil a été réalisée dans le système UV/TiO2 et les principaux photoproduits ont été identifiés par LC/MS/MS, leurs cinétiques ont été tracées. La minéralisation a été suivie et un mécanisme de dégradation a été proposé. La dégradation se déroule selon deux voies, par l'attaque des radicaux OH• ou par les trous. Dans une deuxième partie, la méthodologie de plans d'expériences a été établie dans le système UV/TiO2/K2S2O8 afin i) d'identifier les paramètres les plus influents et leurs interactions et ii) de déterminer les conditions expérimentales les plus favorables à la dégradation. Enfin, la dégradation de l'imazalil a été comparée dans les trois systèmes de dégradation en utilisant différentes concentrations de persulfate et différents pH. Il est apparu que la dégradation dans UV/TiO2, est plus efficace en milieu basique alors le pH acide est plus favorable à la dégradation de l'imazalil dans le système UV/TiO2/K2S2O8. Par contre, le pH ne joue pas un rôle important dans le système UV/K2S2O8
The aim of this thesis was the degradation of the pesticide imazalil in water in three different systems of degradation (UV/TiO2, UV/TiO2/K2S2O8 and UV/K2S2O8). Analytical techniques were used to identify photoproducts, to follow their kinetics and mineralization. The addition of K2S2O8 is beneficial for the degradation and mineralization because it produces sulfate radicals that are powerful oxidizing species. In addition, the role of radical species has been highlighted in the three systems of degradation by using scavengers of these radicals such as alcohols (hydroxyl radical scavenger). In the first part, the degradation of imazalil was performed in the system UV/TiO2 and the main photoproducts were identified by LC/MS/MS also their kinetics were plotted. Furthermore, mineralization was followed and degradation mechanism was proposed. The degradation of imazalil could happen in two ways, by the attack of OH• radicals or by holes. In the second part, the methodology of experimental design was established in the system UV/TiO2/K2S2O8 to identify the most influential parameters also their interactions and to determine the experimental conditions that are most favorable to the degradation. Finally, the degradation of imazalil was compared in the three degradation systems using different concentrations of persulfate and different pH. It appears that the degradation in UV/TiO2 is more efficient in alkaline medium while the acidic pH is more favorable to the degradation of imazalil in the system UV/TiO2/K2S2O8. On the other hand, the pH does not play an important role in the system UV/K2S2O8

Thesis (Ph. D.)--Washington State University, August 2009.
Title from PDF title page (viewed on Sept. 9, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references.

Dans ce travail, nous avons étudié la dégradation de la sulfaclozine, un antibiotique, dans des solutions aqueuses par photocatalyse (TiO2 en suspensions) ainsi que par oxydation par les ions persulfate. L'utilisation d'inhibiteurs spécifiques (KI et alcools) nous a permis de comprendre l'intervention de chacune des espèces réactives (électrons, trous, radicaux •OH) dans la dégradation de la sulfaclozine. En outre, l'identifications des produits de dégradation par LC-MS/MS et le suivi de leur cinétique d'apparition et de disparition avec et sans alcool nous a permis de proposer un mécanisme de dégradation photocatalytique faisant intervenir les trous, les radicaux •OH, les électrons, et les radicaux O2•–. Nous avons également évalués plusieurs méthodes d'activation du persulfate (UV, irradiation solaire, UV/TiO2 et Fe(II)) afin de générer des radicaux SO4•– pour dégrader la sulfaclozine. Nous avons montré qu'à pH 7, le système présentant la plus grande efficacité quelque soit la concentration de persulfate, était le système UV/TiO2/K2S2O8. L'utilisation des inhibiteurs spécifiques des radicaux •OH et SO4•– a permis de constater que le pH a un effet important sur le rôle de chacun de ces radicaux dans la dégradation de la sulfaclozine. Les constantes de vitesse de la réaction de la sulfaclozine avec les radicaux •OH et SO4•– ont été déterminées et des valeurs proches ont été trouvées (?109 M-1s-1). Nous avons également étudié l'effet des principaux ions constituants de l'eau sur la dégradation de la sulfaclozine dans les trois systèmes suivants: UV/TiO2, UV/TiO2/K2S2O8 et UV/K2S2O8. Cette étude a montré que les bicarbonates et les phosphates accélèrent la dégradation photocatalytique alors qu'aucun effet n'a été observé dans le système UV/K2S2O8. En ce qui concerne les ions chlorures et nitrates nous avons montré qu'ils augmentaient l'adsorption de la sulfaclozine à la surface de TiO2 mais n'accéléraient pas significativement la réaction de dégradation
In this work, we studied the degradation of the antibiotic sulfaclozine in aqueous solutions by photocatalysis (on TiO2 suspensions) as well as by persulfate ions. The use of specific inhibitors (KI and alcohols) allowed us to understand the intervention of each of the reactive species (electrons, holes, radicals •OH) in the degradation of sulfaclozine. In addition, the identification of the by-products by LC-MS / MS and the monitoring of their appearance and disappearance kinetics, allowed us to propose a photocatalytic degradation mechanism involving TiO2 holes, •OH radicals, electrons, and O2•– radicals. We also evaluated several methods for persulfate activation (UV, sunlight, UV / TiO2 and Fe (II)) to generate SO4•–. We have shown that at pH 7, the system having the highest efficiency, regardless of persulfate concentration, was the UV/TiO2/K2S2O8 system. The use of specific inhibitors of •OH and SO4•– radicals showed that pH has a significant effect on the role of each of these radicals in the sulfaclozine degradation. Moreover, the reaction rate constants of sulfaclozine with •OH radicals and with SO4•– radicals were determined and close values were found (?109 M-1s-1). We also studied the effect of the main water constituents on the degradation of sulfaclozine in the following three systems: UV/TiO2, UV/TiO2/K2S2O8 and UV/K2S2O8. This study showed that bicarbonate and phosphate accelerated the photocatalytic degradation of sulfaclozine while no effect was observed in the UV/K2S2O8 system. Regarding chloride and nitrate ions, we obtained an enhancement in sulfaclozine adsorption on the surface of TiO2 but no significant enhancement of the degradation rate was observed

Thesis (M.S. in environmental engineering)--Washington State University, December 2008.
Title from PDF title page (viewed on Apr. 17, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 15-18).

Thesis (M.S. in civil engineering)--Washington State University, August 2010.
Title from PDF title page (viewed on July 23, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 15-17).

Thesis (M.S. in environmental engineering)--Washington State University, August 2010.
Title from PDF title page (viewed on July 30, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 13-14).

El asma relacionada con el trabajo se define como el asma causada por la exposición a agentes que se encuentran en el lugar de trabajo, y es responsable de hasta un 25% de los casos de asma de inicio en la edad adulta. En los países industrializados es una de las causas más comunes de enfermedad respiratoria ocupacional. Concretamente, el asma ocupacional (AO) se atribuye a exposiciones en un particular ambiente ocupacional y no a estímulos fuera del lugar de trabajo, y puede estar inducido tanto por la sensibilización a un agente específico (AO inmunológico) como por exposición a sustancias irritantes (AO no inmunológico). Se han descrito más de 400 agentes causantes de AO y se dividen en agentes biológicos de alto peso molecular (APM) como proteínas, glicoproteínas y polisacáridos, y agentes químicos de bajo peso molecular (BPM) como sustancias químicas sintéticas, compuestos naturales, fármacos y metales. Las sales de persulfato son agentes químicos de BPM presentes en los productos decolorantes del cabello a concentraciones superiores al 60%. Estas sustancias son capaces de producir una sensibilización inmunológica y posterior enfermedad alérgica (dermatitis de contacto y asma bronquial), y son reconocidas como la principal causa de AO entre los profesionales de peluquería. Sin embargo, los detalles de la respuesta inmune implicada en el AO inducido por sales de persulfato no son bien conocidos, ya que parecen diferir de la respuesta típicamente alérgica de tipo 2. En algunos casos, se ha propuesto un mecanismo inmunológico mediado por inmunoglobulina-E (IgE) a pesar de las evidencias de una respuesta inmune tipo 1. En este sentido, un modelo murino de asma inducido por sales de persulfato, previamente validado, ha permitido ampliar el conocimiento de la fisiopatología implicada en este tipo de AO. La primera parte de la presente tesis se centra en el estudio de la persistencia de la respuesta asmática a sales de persulfato tras la sensibilización dérmica y tras una inhalación intranasal de persulfato amónico en ratones sensibilizados. Estos estudios mostraron una progresiva disminución de la respuesta asmática con el tiempo y los síntomas asmáticos llegaron incluso a desparecer, de forma parecida a lo que puede ocurrir en los pacientes con AO cuando cesa la exposición al agente causal. Sin embargo, no está claro que la completa eliminación de la exposición al agente sensibilizante sea la medida más eficiente ya que muchos pacientes permanecen sintomáticos. En este sentido, los ratones sensibilizados mostraron signos de sensibilización sistémica a largo plazo que les haría susceptibles a desarrollar una nueva respuesta asmática en el caso de una posible re-exposición al agente causal. El objetivo de la segunda parte de la tesis es evaluar el papel de la IgE y los mecanismos implicados en el desarrollo de la respuesta inmune en el AO causado por agentes de BPM, ya que el rol que desarrolla la IgE en este tipo de asma no está bien dilucidado. Mediante el bloqueo de la IgE, se pudieron estudiar los efectos del tratamiento con el anticuerpo monoclonal (AcM) anti-IgE en el modelo murino de AO inducido por sales de persulfato. La administración del AcM anti-IgE neutralizó completamente los niveles de IgE en suero y mejoró los síntomas asmáticos como la hiperrespuesta bronquial y los parámetros inflamatorios. Estos hallazgos sugieren la implicación de un mecanismo inmunológico donde la IgE puede tener un papel relevante para la fisiopatología del asma causada por agentes de BPM. En conclusión, los estudios de esta tesis arrojan conocimientos en la fisiopatología del AO a sales de persulfato y proponen una compleja interacción entre la respuesta inmune innata y una respuesta adaptativa mixta tipo1-tipo2.
The exposure to specific agents present in the workplace is thought to account for up to 25% of all cases of adult-onset asthma leading to work-related asthma, which is a common cause of work-related lung disease in the industrial world. Specifically, occupational asthma (OA) is attributable to exposure in a particular work environment and not to stimuli outside the workplace, induced by either sensitization to a specific substance (sensitizer-induced OA) or by exposure to an inhaled irritant at work (irritant-induced OA). More than 400 agents are reported to cause OA. They can be divided into biological agents of high molecular weight (HMW) (>5 KDa), such as proteins, glycoproteins and polysaccharides, and chemical agents of low molecular weight (LMW) (< 5 KDa) such as synthetic chemicals, natural compounds, drugs and metals. Persulfate salts are LMW chemical compounds present in hair bleaching products at concentrations up to 60%. They are capable of causing immunological sensitization and subsequent allergic disease (such as contact dermatitis and bronchial asthma), and are the main cause of OA among hairdressers. Nevertheless, no consensus has been reached regarding the details of the immune response involved in persulfate-induced OA, as it seems to differ from the typical allergic type2 immune response. In some cases, an IgE-mediated mechanism has been proposed despite evidence of a type 1 immune response. In this connection, a validated mouse model of persulfate-induced asthma has provided valuable knowledge about the physiopathology involved in this type of OA. The first part of this thesis focuses on the study of the persistence of the asthmatic response to persulfate salts after dermal sensitization (Chapter 1) and after specific persulfate challenge in sensitized mice (Chapter 2) in the mouse model of persulfate-induced asthma. These studies showed a progressive decrease in the asthmatic response over time and even found that the asthma symptoms may disappear, perhaps mirroring what happens in patients when the exposure to the causal agent ceases. Nevertheless, it is not clear that complete removal from the exposure to the sensitizing agent is the most efficient therapeutic approach, as many patients remain symptomatic despite avoidance of the causal agent. In this context, sensitized mice exhibited signs of long-term sensitization which would make them susceptible to developing a new asthmatic response when re-exposed to the sensitizing agent. The aim of the second part of this thesis was to explore the role of IgE and the mechanisms involved in the development of the immune response in this type of OA due to LMW agents. By neutralizing the IgE, we wanted to study the effects of anti-IgE monoclonal antibody (mAb) treatment in the established mouse model of persulfate-induced OA (Chapter 3). The administration of anti-IgE mAb completely neutralized serum IgE and improved asthma symptoms such as airway hyperresponsiveness (AHR) and inflammation patterns in the mouse model of OA, suggesting that an immunological mechanism is involved and that IgE may play an important role in the pathophysiology of the chemical-induced asthma. In conclusion, the studies included in his doctoral thesis shed light on the pathophysiology of OA due to persulfate salts and propose a complex interaction of innate and a mixed type1-type2 adaptative immune response.

PFAS are a group of relatively newly discovered man-made pollutants. PFAS contains a C-F bond which is one of the strongest bonds in organic chemistry. Therefore, PFAS are not easily degradable and, once release into nature, are very persistent. PFAS are also labile in natural environments and therefore, they can sometimes be found far from the source of pollution. Their persistent and labile nature, in combination with their bioaccumulation ability and human health effects make of this compounds an important contaminant to take care of. Currently there are not stablish, wellfunctioning methods to treat contaminated soils and waters. A lot of research is performed at the moment to find good treatment options. In this work a test to chemically degraded spiked samples of PFOA, PFOS and PFBA was performed. By means of experimental design tools, we aim to evaluate which operational factors are relevant for this treatment. Best results when using hydrogen peroxide as a reactant was 70% degradation for PFOS and 42% degradation for PFOA. When persulfate was used as a reactant, a 57% degradation of PFOS, 99% degradation of PFOA and 99% degradation of PFBA was achieved.

Polyfluorinated compounds (PFCs) are a class of anthropogenic chemicals that have been found in groundwater and wastewater around the world. Perfluoroctane sulfonate (PFOS) and perfluoroctanoic acid (PFOA) are primarily used for industrial surfactants, and aqueous film forming foams (AFFFs). These PFCs and many of their constituents have been found to be carcinogenic to humans and other animals. A simple method for defluorination of these compounds is needed. Advanced oxidation of PFOS, PFHxS, and PFBS-k was carried out using activated sodium persulfate through ultrasonic irradiation with the following condition; [PFC] = 20 millimolar (mM), [Na2S2O8] = 25 mM, pH = 7, and 25°C. Fluoride concentrations were quantified by ion chromatography (IC). In laboratory experiments, batch reactions of PFBS solutions were conducted in purified water at different pH conditions and N2S¬2O8: PFBS molar ratios of 1:1, 2:1, 10:1, and 100:1 respectively. Solution pH was maintained at 7 using HNO3. Of the three compounds, PFHxS had the greatest defluorination (11%) after 120 minutes reaction time. However, PFBS-K had the greatest increase in defluorination (115%) between the control ultrasound (US) experiment and the combination experiment. When Na2S2O8 was increased, the defluorination ratio of PFBS decreased. This decrease was partly attributed to scavenging reactions between SO4¯• and S2O8²¯. These results show a synergism between ultrasonic irradiation and activated sodium persulfate as a form of advanced oxidation. Recommendations for further research into defluorination of PFOS and its constituents by ultrasonic degradation include: the use of high performance liquid chromatograph with accompanying mass spectrometry (HPLC/MS), the use of an ultrasonic probe with alternate frequencies, and the effects of surface tension on defluorination.

Perfluorinated compounds (PFCs) are a class emerging contaminants that have been implicated in bladder cancer and other human health problems. Due to the widespread exposure to humans, persistence in the environment, and their negative effects on human health, we need to develop a treatment method to degrade these chemicals into harmless species. Perfluorooctanoic acid (PFOA, C₈HF₁₅O₂) is one of the top representatives of PFCs commonly reported to be found in water sources, hence it was chosen as the model compound and focus in this project. We examined an iron-activated persulfate oxidation (IAPO) method to decompose aqueous PFOA, and tested the reaction under various conditions, including: oxic, anoxic, and anoxic/dark conditions. We observed 𝑐𝑎. 64% of PFOA (beginning with solution phase concentration fo 𝑐𝑎. 1.64*10⁻⁶ mol L⁻¹) was transformed after four hours under anoxic conditions. This was about seven times higher than measured under oxic conditions, and about five times higher than anoxic/dark conditions. Therefore, we concluded that IAPO can decompose PFOA at 25 °C, the ambient condition temperature. This method can potentially be used as an inexpensive and environmentally-friendly PFOA remediation method, with potential application to other PFCs in groundwater and soil. In addition, this method may be applicable for surface water sources such as potable water reservoirs, waste water effluent, and extracted groundwater.

Thesis (M.S. in Environmental Engineering)--Washington State University, May 2009.
Title from PDF title page (viewed on May 21, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 14-15).

As técnicas de remediação para solos contaminados como os processos de oxidação avançados \"in situ\" visam essencialmente a mineralização dos contaminantes, reduzindo-os, em última instância, a CO2 e H2O. O objetivo deste estudo é apresentar os resultados de experimentos conduzidos para investigar como as características do solo, tais como a granulação, o teor e a natureza dos minerais argilosos, e o teor da matéria orgânica influem no desempenho da mineralização do contaminante linar alquilbenzeno no solo. Em várias partes da cidade de São Paulo há locais contaminados por esse e outros tipos de vazamentos e os responsáveis e as autoridades estão interessadas em possíveis soluções. Uma possível solução seria o tratamento in situ através dos processos de oxidação avançada. Porém, não há como decidir a priori sobre a melhor técnica, pois ela dependerá tanto do reagente empregado como do tipo de solo contaminado. Essa resposta poderá ser cientificamente fundamentada a partir de ensaios no laboratório desenhados para investigar os fatores que controlam a eficácia do processo. Os experimentos em laboratório foram conduzidos com dois tipos de solo da região metropolitana de São Paulo contaminados com linear alquilbenzeno, composto utilizado como óleo térmico em revestimentos de cabos subterrâneos de alta voltagem. Os desempenhos da mineralização com o Reagente de Fenton e Persulfato de Sódio foram avaliados na oxidação do composto linear alquilbenzeno com uma concentração inicial de 10 mg/grama de solo contaminado. Os resultados mostram uma redução considerável em massa de 82% a 85% do contaminante nos dois solos com a utilização de Persulfato de Sódio ativado termicamente e através de metal de transição \'Fe POT.2+\' disponível naturalmente no solo . O reagente de Fenton nas mesmas condições do experimento mostrou um desempenho mais limitado entre 10 % a 30% de redução em massa do contaminante. O conhecimento prévio das características do solo como o teor de argila , teor de carbono orgânico que influem fortemente os fenômenos de sorção e desorção e a composição mineralógica são variáveis importantes na definição dos reagentes e nas condições de reação de oxidação dos poluentes e contribuem na escolha mais acertada da tecnologia de remediação \'in situ\".
The remediation techniques used in contaminated soils such as \"in situ\" chemical oxidation aim essentially the mineralization of contaminants, reducing it to CO2 and H2O. The objective of this study is pointing out the results of experiments conducted to investigate how the soil characteristics such as granulometry, assay and nature of clay minerals as well as organic matter can influence in the mineralization performance of linear alkylbenzene in the soil. In some areas of São Paulo city there are contaminated sites by leakage of linear alkylbenzene and many other chemical leakages and site\'s responsible and local authorities are interested in possible technical solutions to clean it. One possible solution would be in situ treatment through advanced oxidation process; however there is no way how to decide about the best technique because it depends on contaminant substance, reagents used as well as the contaminated soil characteristics. The answer could be scientifically based on bench laboratory experiments properly designed to investigate the factors that control the process performance. The bench lab experiments were conducted with two soils sampled from metropolitan region of São Paulo and contaminated with linear alkyl benzene, used in high and medium voltage underground electrical cables. The mineralization performance was evaluated in soils contaminated with an initial concentration of 10 mg / gr of contaminated soil by oxidation of linear alkyl benzene with Fenton reagent and sodium persulfate. The final results pointed out a considerable mass reduction from 82% to 85% in both soils tested with sodium persulfate thermally activated and by naturally available transition metal \'Fe pot.2+\' in the soil. The Fenton reagent in the same experiment conditions pointed out a more limited mass reduction performance between 10% and 30%. The previous knowledge of soil characteristics such as clay assay , natural carbon content in the soil which influence the sorption / desorption phenomenon as well as the mineral composition of the soil are the key variables to define reagents and the oxidation reaction conditions which contribute to select a proper in situ chemical oxidation technology.

Trichloroethylene (TCE) is one of the most common groundwater pollutants in the United States and is a suspected carcinogen. The United States Environmental Protection Agency (EPA) estimated that between 9% and 34% of the drinking water sources in the United States may contain TCE, and have set a maximum contaminant level of 5 ìg/L for drinking water. Traditional treatment technologies such as granular activated carbon and air stripping have only had marginal success at removing TCE from contaminated sites. Chemical oxidation processes have provided a promising alternative to traditional treatment methods. The objective of this research was to examine the conditions under which zero valent iron (Fe0) activates persulfate anions to produce sulfate free radicals, a powerful oxidant used for destroying organic contaminants in water. With batch experiments, it was found that persulfate activated by zero valent iron removed TCE more effectively than persulfate oxidation activated by ferrous iron. This laboratory study also investigated the influence of pH (from 2 to 10) on TCE removal. TCE was prepared in purified water and a fixed persulfate/TCE molar ratio was employed in all tests. The results indicated that this reaction occurred over a wide range of pH values. The production and destruction of daughter products cis 1,2 dichloroethylene and vinyl chloride were observed. The effect of persulfate dose on this reaction was also studied. Results showed that a molar ratio of 10/1/1 (persulfate/ZVI/TCE) yielded over 95 percent TCE destruction. Increasing the persulfate dose resulted in greater TCE destruction as well as destruction of the daughter products. Kinetic experiments at a molar ratio of 10/1/1 (persulfate/ZVI/TCE) show that approximately 90 percent of the TCE was destroyed in less than 15 minutes.

碩士
明新科技大學
化學工程研究所
96
Sodium persulfate, a ultra-strong oxidant, is used in the preparation of copper micro-etching solution for the production of printed-circuit boards. By studying the major steps for the synthesis and purification of sodium persulfate including anodic oxidation with membrane separating anode and cathode, degassing ammonia by neutralization (alkalization), ammonia absorption, vacuum evaporation, and cooling crystallization, a process that can be commercialized is suggested.

碩士
靜宜大學
化粧品科學系
102
Hair coloring is a symbol of modern fashion. However, these decolorant agents may have effects on the production of melanin in melanocytes. In this study, we focus on the effects of commonly used hair dyes , such as ammonium persulfate, sodium persulfate, resorcinol and lawsone on melanogenesis in B16-F10 cells. Firstly, we use MTT assay to confirm the non-cytotoxic concentrations of these agents. Subsequently, these agents were used to test the effects on melanin production, tyrosinase activity and the expressions of microphthalmia-associated transcription factor (MITF) and tyrosinase Our results indicated that ammonium persulfate, resorcinol and lawsone have abilities to reduce the melanin productions of 10.4 %, 31.7 % and 9.7 %. Resorcinol and lawsone have ability to reduce the tyrosinase activity 34.7 % and 18.6 %. In mushroom tyrosinase activity assay, these agents can decreases 94.3 and 11.0% tyrosinase activity. Besides resorcinol and lawsone has ability to reduce tyrosinase activity approximately 0.35 and 0.54 fold of control in tyrosinase zymography and also protein levels of MITF and tyrosinase. Therefore, Resorcinol and Lawsone can evidently inhibit the production of melanin.

Petroleum hydrocarbons (PHCs) such as gasoline are ubiquitous organic compounds present at contaminated sites throughout the world. Accidental spills and leakage from underground storage tanks results in the formation of PHC source zones that release hundreds of organic compounds, including the high impact, acutely toxic and highly persistent aromatics (e.g., benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) into groundwater. Contamination by these compounds continues to persist until the PHC source zone is treated in place or removed. In situ chemical oxidation (ISCO) employing persulfate was identified as a potentially viable technology for the treatment of PHC source zones. The effectiveness and efficiency and, therefore, the overall economic feasibility of a persulfate-based ISCO treatment system depend upon the reactivity of the target organic compounds and the interaction of persulfate with aquifer media. The objective of this research was to investigate the persistence of unactivated and activated persulfate in the presence of aquifer materials, and to examine persulfate oxidation of PHC compounds at both the bench- and pilot-scales. A series of bench-scale studies were performed to estimate persulfate degradation kinetic parameters in the presence of seven well-characterized, uncontaminated aquifer materials and to quantify the changes in specific properties of these materials. Batch experiments were conducted in an experimental system containing 100 g of solids and 100 mL of persulfate solution at 1 or 20 g/L. Column experiments were designed to mimic in situ conditions with respect to oxidant to solids mass ratio and were performed in a stop-flow mode using a 1 g/L persulfate solution. The degradation of persulfate followed a first-order rate law for all aquifer materials investigated. An order of magnitude decrease in reaction rate coefficients was observed for systems that used a persulfate concentration of 20 g/L as compared to those that used 1 g/L due to ionic strength effects. As expected, the column experiments yielded higher reaction rate coefficients than batch experiments for the same persulfate concentration due to the lower oxidant to solids mass ratio. Bench-scale data was used to develop a kinetic model to estimate the kinetic response of persulfate degradation during these tests. The push-pull tests involved the injection of persulfate (1 or 20 g/L) and a conservative tracer into a hydraulically isolated portion of the sandy aquifer at CFB Borden, Canada. The kinetic model developed from the bench-scale data was able to reproduce the observed persulfate temporal profiles from these push-pull tests. This implies that persulfate degradation kinetics is scalable from bench-scale to in situ scale, and bench tests can be employed to anticipate in situ degradation. The estimated reaction rate coefficients indicate that persulfate is a persistent oxidant for the range of aquifer materials explored with half lives ranging from 2 to 600 days, and therefore in situ longevity of persulfate will permit advective and diffusive transport in the subsurface. This is critical for successful delivery of oxidant to dispersed residuals in the subsurface. Activation of persulfate is generally recommended to enhance its oxidation potential and reactivity towards organic compounds. This approach may influence the stability of persulfate-activator system in the presence of aquifer materials. A series of batch tests were performed to investigate persistence of persulfate at two concentrations (1 or 20 g/L) using three contemporary activation strategies (citric acid chelated-ferrous, peroxide and high pH ) in the presence of 4 well-characterized, uncontaminated aquifer materials. Chelation by citric acid was ineffective in controlling the interaction between persulfate and Fe(II) and a rapid loss in persulfate concentration was observed. Higher Fe(II) concentration (600 mg/L) led to greater destabilization of persulfate than lower Fe(II) concentration (150 mg/L) and the persulfate loss was stoichiometrically equivalent to the Fe(II) concentration employed. Subsequent to this rapid loss of persulfate, first-order degradation rate coefficients (kobs) were estimated which were up to 4 times higher than the unactivated case due to the interaction with Fe(III) and CA. Total oxidation strength (TOS) was measured for peroxide activation experiments and was observed to decrease rapidly at early time due peroxide degradation. This was followed by slow degradation kinetics similar to that of unactivated persulfate implying that the initial TOS degradation was peroxide dominated and the long-term kinetics were dominated by persulfate degradation. The kobs used to capture TOS degradation for later time were shown to depend upon unactivated persulfate and peroxide degradation rate coefficients, and peroxide concentration. Either a slow peroxide degradation rate and/or higher peroxide concentration allow a longer time for peroxide and persulfate to interact which led to kobs ~1 to 100 times higher than kobs for unactivated persulfate. For alkaline activation, kobs were only 1 to 4 times higher than unactivated persulfate and therefore alkaline conditions demonstrated the least impact on persulfate degradation among the various activation strategies used. For all activation trials, lower stability of persulfate was observed at 1 g/L as compared to 20 g/L due to insufficient persulfate and/or ionic strength effects. A series of batch reactor trials were designed to observe the behavior of the nine high impact gasoline compounds and the bulk PHC fraction measures subjected to various persulfate activation strategies over a 28-day period. This bench-scale treatability used unactivated persulfate (1 or 20 g/L) and activated persulfate (20 g/L). Activation employed chelated-Fe(II), peroxide, high pH or two aquifer materials as activators. No significant oxidation of the monitored compounds was observed for unactivated persulfate at 1 g/L, but 20 g/L persulfate concentration resulted in their near-complete oxidation. Oxidation rates were enhanced by 2 to 18 times by activation with peroxide or chelated-Fe(II). For alkaline activation, pH 11 trials demonstrated ~2 times higher oxidation rates than the unactivated results. For pH 13 activation the oxidation rates of benzene, toluene and ethylbenzene were reduced by 50% while for the remaining monitored compounds they were enhanced by 5 to 100%. Natural activation by both aquifer materials produced oxidation rates similar to the unactivated results, implying that either activation by minerals associated with aquifer material was not significant or that any potential activation was offset by radical scavenging from aquifer material constituents. Acid-catalyzation at pH <3 may enhance oxidation rates in weakly buffered systems. Oxidation of the monitored compounds followed first-order reaction kinetics and rate coefficients were estimated for all the trials. Overall, activated and unactivated persulfate appear to be suitable for in situ treatment of gasoline. Persulfate under unactivated or naturally activated conditions demonstrated significant destruction of gasoline compounds and showed higher persulfate persistence when in contact with aquifer solids as compared to chelated-Fe(II) or peroxide-activated persulfate systems. This observation was used as the basis for selecting unactivated sodium persulfate for a pilot-scale treatment of gasoline-contaminated source zone at CFB Borden, Canada where a ~2000 L solution of persulfate (20 g/L) was injected into a PHC source zone. Concentration of organics and inorganics were frequently monitored over a 4 month period across a 90 point monitoring fence line installed down-gradient. Treatment performance was measured by estimating organic and inorganic mass loading across the monitoring fence. Increased mass loading for sodium was observed over time as the treatment volume moved across the fence-line indicating transport of the inorganic slug created upon oxidant injection. The mass loading also increased for sulfate which is a by-product generated either due to persulfate degradation during oxidation of organic compounds or during its interaction with aquifer materials. Oxidation of organic compounds was evident from the enhanced mass loading of dissolved carbon dioxide. More importantly, a significant (45 to 86%) decrease in mass loading of monitored compounds was observed due to oxidation by injected persulfate. The cumulative mass crossing the monitoring fence-line was 20 to 50% lower than that expected without persulfate treatment. As the inorganic slug was flushed through the source zone and beyond the monitoring fence, the mass loading rate of sodium, sulfate and carbon dioxide decreased and approached background condition. Mass loading of the monitored compounds increased to within 40 to 80% of the pre-treatment conditions, suggesting partial rebound. These investigations assessed the impact of activation on persulfate persistence and treatability of gasoline and served to establish guidelines for anticipating field-scale persulfate behavior under similar conditions. In summary, unactivated persulfate is a stable oxidant in the presence of aquifer materials and its persistence depends upon TOC and Fe(Am) content of the materials, ionic strength, and aquifer to solids mass ratio. Persulfate exhibits significant destruction of gasoline compounds and can be employed for the remediation of gasoline-contaminated sites. Peroxide and chelated-Fe(II) enhance oxidation rates of these compounds, but reduce stability of the persulfate-activator system. Persulfate activation using high pH conditions does not significantly impact persulfate persistence but reduces the overall destruction of gasoline compounds. Therefore, activation imposes a trade-off between enhanced oxidation rates and reduced persulfate persistence. Kinetic model is representative of persulfate degradation at bench- and pilot-scales and can be used for estimation of in situ degradation. The quantification of oxidation rates for gasoline compounds under activated and unactivated persulfate conditions will assist decision-making for identification of appropriate remediation options when targeting contamination by gasoline or by specific high impact gasoline compounds. While persulfate oxidation resulted in partial treatment of a small gasoline source zone, aggressive persulfate load will be required during injection for a complete clean-up. Overall, persulfate-based in situ chemical oxidation was demonstrated to be an effective and a viable technology for the remediation of contaminated soil and groundwater.

碩士
中興大學
環境工程學系所
99
In situ chemical oxidation (ISCO) mainly by the injection of a chemical reagent into the subsurface environment to reduce contaminant mass by oxidation processes. Persulfate as an emerging oxidant for soil and groundwater contaminants, and it has several advantages. First, persulfate is more stable than hydrogen peroxide and thus able to transport greater distances in the sub-surface. Second, persulfate has less affinity and is thus more efficient in high organic soils. Few studies to date have investigated simulation for the transport of persulfate in porous media. Therefore, the objective of this study was to investigate the transport mechanism of persulfate in the aquifer through one-dimensional system. The results of this research demonstrate that the one-dimensional Convective-Dispersive-Degradative equation can appropriately describe the process of persulfate in silica sand and sandy soil, and in the same dimension, the dispersivity coefficient for these two soils packed column was the same; persulfate mass loss increases with a slower flow rate. In addition, different permeant water for testing at a constant head presents different flow rate. Mineral water used as a permeant can reduce clay minerals swelling more than distilled water. Furthermore, only little clay soils may cause expansion of the double layer and lead to the generation of preferential flow.

Dissertação de Mestrado Integrado em Engenharia Química apresentada à Faculdade de Ciências e Tecnologia
Wastewaters from the olive oil industry are considered a regional environmental problem, given their rich composition of phenolic compounds and their inherent toxicity. Despite the research done in advanced oxidation processes (AOP), these technologies are not yet applied on a large scale, due to the high associated cost. Specifically, in the case of Fenton process, there is also associated the drawback related to iron sludge formation and management. Thus, this study focusses on Sulfate Radical based Advanced Oxidation Process (SRbAOP) as an alternative to Fenton process in wastewater treatment. The SRbAOP applied is based on the metal activated persulfate using homogeneous and heterogenous catalysis, applying manganese, iron and copper as the main metals. This method was tested to treat a synthetic wastewater from the olive oil industry composed of 5 phenolic acids usually found on the real agro-effluents. Synthetic olive mill wastewaters were submitted to homogeneous SRbAOP using iron sulfate, as the source of iron (II). This process was optimized by testing different pH values, as well as iron and persulfate loads. With the optimization, it was possible to achieve a 39%, 63% and 37% of COD, phenolic compounds and TOC removal, by using a pH of 5, 300 mg/L of iron and 600 mg/L of persulfate. Toxicity tests using A. fischeri and L. sativum showed that the untreated and the treated wastewater presented the same toxicity, the reason possibly being the formation of hydroquinone as an intermediate compound. The synthetic wastewater was also submitted to heterogenous SRbAOP using red mud and Fe-Ce-O, as a source of iron (III), and commercial catalysts, as a source of manganese and copper. The best catalyst was Fe-Ce-O with an optimal load of 1600 mg/L. At these conditions, 27%, 55% and 5% of COD, phenolic compounds and TOC removal were achieved. Toxicity tests on A. fischeri and L. sativum showed a rise in toxicity from the treated solutions, when compared with the original one.
Os efluentes da indústria do azeite são considerados um problema ambiental regional, tendo em conta a sua composição rica em composto fenólicos e a sua toxicidade inerente. Apesar da investigação realizada em processos de oxidação avançada (AOP), devido ao seu elevado custo associado, estas tecnologias ainda não aplicadas em grande escala. Especificamente, no caso do processo de Fenton, há ainda associada a desvantagem da formação de lamas ferrosas e a sua gestão. Assim, este estudo foca-se nos Processos de Oxidação Avançada baseados em Radicais de Sulfato (SRbAOP) como uma alternativa ao processo de Fenton no tratamento de efluentes. O SRbAOP aplicado baseia-se na ativação de persulfato por metais, recorrendo tanto à catálise homogénea como à heterógena, usando manganês, ferro e cobre como os principais metais. Este método foi testado quanto à sua eficácia para tratar um efluente sintético da indústria do azeite composto por cinco ácidos fenólicos, usualmente encontrados em agro- efluentes reais. O efluente sintético foi submetido ao SRbAOP homogéneo no qual foi usado sulfato de ferro, como fonte de ferro (II). Este processo foi otimizado por testagem de diferentes valores de pH e diferentes concentrações de ferro e persulfato. Com esta otimização, foi possível alcançar-se uma remoção de 39%, 63% e 37% de COD, compostos fenólicos e TOC, respetivamente, usando um pH de 5, 300 mg/L de ferro e 600 mg/L de persulfato. Os testes de toxicidade recorrendo a A. fischeri e L. sativum mostraram que o efluente não tratado e o tratado apresentam a mesma toxicidade, o que se pode dever à formação de hidroquinona, como um composto intermediário. O efluente sintético foi ainda submetido ao SRbAOP heterogéneo usando lamas vermelhas e Fe–Ce–O, como fontes de ferro (III), e a catalisadores comerciais, como fonte de manganês e cobre. O melhor catalisador foi o Fe–Ce–O com uma concentração ótima de 1600 mg/L. Nestas condições, alcança-se uma remoção de 27%, 55% e 5% de COD, compostos fenólicos e TOC, respetivamente. Os testes de toxicidade com A. fischeri e L. sativum mostram que a toxicidade no efluente tratado é superior a do efluente não tratado.

碩士
國立雲林科技大學
化學工程與材料工程研究所
99
The objective of this study is to handle organic compounds of waste water from TNT manufacturing process by US/Persulfate. The experiment content is remove organic compounds by use sonicator and persulfate. Experiment with the sound intensity, pH, temperature, concentration, cavitation enhance to explore. The results show that removing organic compounds , increasing intensity of ultrasound can help removal of organic compounds, However, it must have an optimum value. Excessive energy will cause the opposite result and restrain the effect of removal. Because of the acid-catalyzed happen, so at different pH affect the removal. As the temperature increases can help SO4– decompose organic reaction rate. in test H2O2 , we found decomposition of organic have OH and SO4– ,but the most important to decompose organic that is SO4–. So adding more and more persulfate will be very obvious benefit. Experiments also found that adding other salts, activated carbon, TiO2 are generated will help cavity, and thus enhance the removal of organic compounds ; To test different sizes of activated carbon , the results show that add different sizes are generated similar cavity ; The TiO2 because have electron-hole pairs Creating a high degree of removal.

碩士
國立雲林科技大學
化學工程與材料工程系碩士班
100
The objective of this study is to removal of aqueous solution of phenol in wastewater by ultrasound/persulfate at variety of sound intensity, solution temperature, pH value, oxygen flow rate, salt concentration to explore the impact of phenol mineralization. Using spectrophotometer to detect hydrogen peroxide production on changing solution of sound intensity, temperature, pH value, oxygen flow rate, salt concentration. The results show that removing organic compound, increasing sound intensity can enhance removal value , However, it must have an optimum value. Excessive energy will cause the opposite result and restrain the effect of removal. Increasing the temperature of solution system will reduce the maximum temperature and pressure of collapse of cavity, so that difficult the degradation. Adding the oxygen can help removal of organic compounds, because of affording large bubbles and hydroxyl radicals. The mineralization of phenol is productive for experiments conducted in acidic solution than those conducted in basic solutions. This is probably because of the predominance of molecular phenols in acidic solution, which are more hydrophobic ionic phenols, and more easily decomposed by pyrolysis and by hydroxyl radicals. In addition, in the blank test of hydrogen peroxide, shows the effect of sound intensity,the highest hydrogen peroxide generation is not proportional to the sound intensity.When the solution containing saturated oxygen, help to the generation of hydroxyl radicals after ultrasound exposure.Adding salt in solutions help generation hydrogen peroxide that is true of salt concentration effect under high salt concentration.

碩士
國立臺灣大學
環境工程學研究所
107
With the development of high-tech industries in Taiwan, significantly increasing of wastewater was discharged for various organics. Isopropanol (IPA) is one of volatile organic compounds (VOCs), which is widely adopted in the semiconductor industry as a cleaning agent at diverse stages of wafer surface washing and cleaning processes. It is also used as a solvent in paint, lithography, pharmaceutical, and rubber manufacture industries. The IPA-containing wastewater may cause adverse effect on water quality and human health. Therefore, it is necessary and stringent to find an applicable treatment technology to remove IPA from water. The use of ultrasonic (US) processes for wastewater treatment is technically feasible by many reports, which can oxidize various pollutants by using cavitation phenomenon and radicals generated during the reaction. This study aims to evaluate the effects of US, persulfate (PS), and US+PS on IPA removal in aqueous solutions, respectively. To understand the effects of operating parameters for implementing sonochemical degradation of IPA at an effective level. The effects of initial IPA concentration, PS concentration, ultrasonic power, and initial pH were studied and discussed. The degradation of IPA and its major degradation intermediates were also be investigated by using a purge and trap gas chromatograph (GC) with flame ionization detection (FID) system and high performance liquid chromatography (HPLC). The results show that PS process was significantly enhanced in the presence of ultrasound. PS process in the presence of US can reach about 80.2 % of IPA decomposition in 120 minutes with the US power of 500 W at pH 5.0, with an initial IPA concentration of 250 ppm and a PS/IPA ratio of 5:1. The identified predominant radical is hydroxyl radical. Therefore, US/PS process is an effective method for degrading IPA in aqueous solutions.

碩士
國立中興大學
環境工程學系所
98
UV activated persulfate can produce highly reactive sulfate free radicals (SO4-․). At alkaline condition, SO4-․can react with hydroxyl ions and undergo radical interconversion to form hydroxyl radicals (OH․). This study investigated feasibility of 254 nm UV activated persulfate oxidation of phenol and focused on effects of pH and persulfate/phenol molar ratios on the degradation of phenol. The results of this study show that un-activated persulfate was not able to effectively degrade phenol within an hour. However, UV can efficiently activate persulfate to produce SO4-․ in degrading phenol. When initial phenol concentration was 0.5 mM, 99% of phenol degradation and 63% of mineralization were achieved within an hour of oxidation reaction while 3% of persulfate was decomposed. Moreover, the results obtained from the oxidation reaction under different pHs exhibited effects of pH conditions on phenol degradations were minor. However, initial phenol and persulfate concentrations significantly influenced the phenol degradation.

碩士
國立中興大學
環境工程學系所
97
Leaking underground storage tanks are a serious threat and the associated soil and groundwater pollution is a serious problem in Taiwan. Gasoline hydrocarbons including benzene, toluene, ethylbenzene, and xylene (BTEX) can create a hazard to public health. In situ chemical oxidation (ISCO) uses oxidants to destroy pollution in soil and groundwater. This technique does not involve digging up polluted soil and the oxidant undergoes oxidation to convert harmful chemicals into harmless compounds. The most recent ISCO oxidant to clean up pollution is persulfate anion, which can be activated to produce a more aggressive oxidant know as sulfate radicals. Therefore, this present study explored effects of various activation processes on the efficiency of persulfate oxidation of benzene in an aqueous phase. The results indicated that benzene was effectively oxidized by persulfate at ambient temperature with extended reaction time (days to months). Also, the benzene degradation rate increased with increases in persulfate concentrations. Ferrous ion activated persulfate process can accelerate the degradation of benzene (within minutes), but benzene was only partially degraded. However, when ferrous ion was gradually added, instead of a single dose, benzene can be completely degraded. The use of citric acid chelated ferrous can also enhance the ferrous ion activation process in degrading benzene. It is speculated that the more complete and effective benzene degradation was due to successful regulation of ferrous ion, via the way of dosing ferrous ion and the use of chelating agent.

碩士
國立雲林科技大學
化學工程與材料工程系
102
Phenolic compounds are often presence in industrial effluents. Discharging such wastewater without treatment is a serious pollution problem to the whole environment. In this work, we carry out the oxidative degradation experiment of phenol in aqueous solution using titanium dioxide photocatalyst, persulfate treatment by UV irradiate. This system has the ability to convert phenol to CO2 and H2O with the help of appropriate amounts of light, TiO2 and persulfate. Hopefully, this system could meet the standards of effluent discharge. In this work, phenol was degraded using mercury light (253nm). The process at variety of temperature, pH value, concentration of TiO2, concentration of persulfate and intensity of UV light to explore the impact of phenol mineralization. And using spectrophotometer to detect hydrogen peroxide production. The result shows that high temperature could enhance the generation rate of sulfate radical(〖SO〗_4^-∙), so it has optimal value at 45℃. The more high-energy ultraviolet light, the more degradation rate of phenol. There’s are optimal value in titanium dioxide and persulfate, excess or less could affect the final results. pH value is the important factor in the system, the lower pH value, the better phenol degradation. Exploitation spectrophotometer determination of hydrogen peroxide formation experiments by use deionized water simulate the wastewater. According to generation of hydrogen peroxide, it’s consistent with the previous results. So the removal of phenol in wastewater is feasibility by using UV/persulfate/TiO2 process.

碩士
國立雲林科技大學
化學工程與材料工程系
102
In the chemical products made from them, discharged wastewater containing phenolic compounds accounted for a large proportion, if not handled properly and this wastewater discharge treatment system will have impact on the environment, and have a great impact on the ecology. In recent years, often using advanced oxidation process (Advanced Oxidation Process, AOPs) approach to wastewater treatment, is by generating stronger oxidizing power of hydroxyl radicals (OH･) to destroy organic pollutants in water, and decomposition carbon dioxide and water, procedural methods include ultrasonic oxidation, ozone oxidation, electrochemical reaction, UV / photocatalyst, Fenton method ... and so on. This study attempts to combine electrochemical oxidation method persulfate oxidation for the degradation of phenol, by changing the electrolysis potential, the reaction temperature, persulfate concentration, and pH values to investigate the effect of the degradation of organic pollutants, H2O2 generation rate and possible reaction pathway. Its organic phenol solution concentration of approximately 200 mg / L. The results showed that a combination of chemical oxidation process when persulfate oxidation of organic matter removal, electrolysis potential 6 volt, reaction temperature 45 ℃, pH value of 1, sodium persulfate dosage under 3 wt% of operating conditions, after reaction 6 hours, the effect of oxidative degradation of organic matter 91%. Substituted phenol in aqueous solution with ultra pure water was measured by a spectrophotometer to generate the amount of hydrogen peroxide, which can be found the amount of hydrogen peroxide generated is consistent with the above results, it can be proved by electrochemical / persulfate oxidation process can remove phenolic wastewater.

碩士
國立成功大學
環境工程學系碩博士班
97
Persulfate is one of the oxidants used in of in-situ chemical oxidation (ISCO) of groundwater contamaintion. The oxidant may produce sulfate radical (SO4–•) and hydroxyl radical (OH•) with high oxidation potential in the remediation techniques. Although the oxidation potential for the chemical is high, the kinetics is very slow under typical environmental conditions. Therefore, the objective of this work was to investigate the feasibility of enhancing the reaction rates of persulfate for the oxidation of methyl tert-isobutyl ether using ultraviolet (UV) light. In this study, 254 nm and 365 nm UV were used to activate persulfate for oxidizing MTBE at different pH values. MTBE was easily degraded by the persulfate/UV254 system. Within 50 mins, 53% of MTBE was mineralized in the persulfate/UV254 system. The concentration of persulfate was decreased by 40 %, while that of MTBE was reduced by 99.5% within 1 hour in the 254 nm UV system. A second-order kinetic model well described the reduction of MTBE in aqueous solution. At lower pH, higher kinetic rate was observed for MTBE reduction. For the persufate/UV365system, MTBE was resistant to degrade. Within 1 hr of reaction, very minor amount of persulfate decomposed, and only 25% and 17% of MTBE was degraded and mineralized, respectively. Unlike that in the persulfate/UV254 system, the degradation of MTBE for this case followed a pseudo-first-order reaction.

碩士
國立暨南國際大學
土木工程學系
103
Persulfate possess oxidation ability, high solubility, long-time presence, good transmission capacity and regulation applicable to a wider range of features. In this study, the biodegradable hydroxypropyl methyl cellulose as a coating material, development of a sustained-release persulfate of green remediation tablets in groundwater. Through batch and column experiment assess release efficiency of persulfate about sustained-release presulfate tablet, with the type of cement persulfate release material were compared. This study aim is as follows: (1) assess release efficiency of persulfate about sustained-release persulfate tablet; (2) to obtain the best proportion of sustained-release persulfate tablet; (3) assess the coating material the impact to in situ environment. The result show, through difference of pressure, hydroxypropyl methyl cellulose proportion, persulfate content on batch release experiment, type of hydropropyl methyl cellulose sustained-release persulfate tablet release time can be accumulated about 10 days. With type of cement persulfate release material were compared, persulfate not only can preserve sustainability release efficiency, but also decrease doubt about secondary pollution in type of hydroxypropyl methyl cellulose sustained-release persulfate tablet. Because hydropropyl methyl cellulose can consume to persulfate that loss of certain degree. When persulfate release from the tablet, that destroy structure of gel. On column release experiment of simulation groundwater environment, mobility of water have obvious effect about persulfate release efficiency, that also decrease degree of consume persulfate with hydropropyl methyl cellulose. These result support hydropropyl methyl cellulose as coating material to sustained-release persulfate tablet was a feasible and apply to remediation on in situ environment.

碩士
嘉南藥理科技大學
環境工程與科學系碩士班
96
In Situ Chemical Oxidation (ISCO) involves the injection or application of an oxidant into the subsurface to transform organic contaminants into less toxic byproducts. An accelerated reaction using persulfate (S2O82-) to destroy trichloroethylene (TCE) and aniline can be achieved via chemical activation with ferrous ions and energy to generate sulfate radicals (SO4-.) (E0 = 2.6V). The test result showed that the addition of ferrous accelerates the degeneration of aniline by persulfate. For the thermally activated persulfate oxidation experiment, the optimum persulfate/aniline concentration at 30℃ was at 5.4mM or 20/1. This ratio had given the highest aniline removal which is 45%. For the ferrous ion activated persulfate oxidation experiment, there is marginal difference in the result for the 30 min. experiment for the various ferrous/oxidant molar ratio. Thus, another series of experiment was conducted to determine the optimum ratio. A ferrous/persulfate molar ratio of 1.25 was observed to give the best degeneration efficiency. For the iron oxide-coated sand catalysis, 1g, 0.5g and 0.25g of iron oxide-coated sands were added to conduct the oxidation experiment at 25℃. Addition of iron oxide-coated sand accelerated the degradation of TCE by persulfate; the removal was 25%, 15% and 10%, respectively. During the reaction, ferrous ions were dissolved from the iron oxide surface in the range of 0.08~0.25 mg/l. Under this concentration range, the catalytic ability can be ignored according to the observation from the control experiment. Therefore, the major catalytic reaction came from the iron oxide-coated sand surface. However, the dissolved ferrous ions were recrystalized on the iron oxide surface. For the result of column study, the chloride ions affect persulfate oxidation. The reaction rate of degradation of TCE was increased when hydration was increased between TCE and iron oxide-coated sand.

碩士
中興大學
環境工程學系所
94
Cyclodextrins (CDs) can be used to simultaneously complex chlorinated solvents such as trichloroethylene (TCE) and perchloroethylene (PCE) and transitional metals (e.g., ferrous ion, Fe2+). Therefore, the use of CD in conjunction with chemical oxidation with persulfate anion (S2O82-) poses several advantages. For example, CD will increase the contaminant water solubility via complexation and the simultaneous complexed Fe2+ can be used to activate persulfate to generate a strong oxidant known as sulfate free radicals (SO4-．) (Eo = 2.4 V). Chemical oxidation methods are usually most successful to dissolved phase chlorinated solvents. Therefore, it is likely to increase mass transfer from non-aqueous to aqueous phase for effective oxidation reaction to occur. Experimental results revealed that β-CD can increase TCE and PCE solubilization. However, increases in hydroxypropyl-β-CD (HP-β-CD) concentrations resulted in increases in relative solubilization (St/So) of TCE and PCE. The increases were linear and indicated formation of a 1:1 binding complex. Moreover, the existence of Fe2+ did not affect the contaminant solubilization. The comparison of the results with respect to the ferrous ion activated persulfate with and without HP-β-CD demonstrated that the HP-β-CD can regulate the presence of Fe2+ and resulted in gradual persulfate decomposition. In contrast, in the presence of Fe2+ alone persulfate was decomposed to a certain level and halted depending on the concentrations of ferrous ion added. Furthermore, in the presence of HP-β-CD /Fe2+ or only Fe2+ persulfate can rapidly destroyed TCE and PCE (60 mg/L). However, the contaminant degradations thereafter were in slow rates. On the other hand, when the TCE and PCE solubilities increased to 1,400 and 330 mg/L, respectively, with HP-β-CD the contaminants can be degraded with persulfate activated by continuously providing Fe2+ activator.

碩士
國立雲林科技大學
化學工程與材料工程系碩士班
100
The objective of this study is to handle organic compounds of waste water from TNT manufacturing process by Ultrasound/Persulfate and add titanium dioxide to enhance the oxidative degradation effect of the nitro compound. Experiments with ultrasonic sound intensity, the concentration of titanium dioxide, temperature, persulfate concentration, pH. The experimental results show that removing organic compounds ,increasing intensity of ultrasound can help removal of organic compounds, however, it must havean optimum value. Excessive energy will cause the opposite result and restrain the effect of value. The TiO2 catalyst on the sonocatalytic degradation of organic compounds were considered in the case: Increasing the amount of TiO2 catalyst will enhance the degradation.Increasing the temperature of solution system will reduce the greatest temperature and greatest pressure of collapse of cavity, the factors relatively to effect to difficultly produce hydroxyl radicals. When it is pH 2 in the wastewater, organic compounds will become ions in solution.The most important to decompose organic in solution by SO4- . Adding an excess over the sulfate, organics removal rate will be lowered, this may be due to cavitation generated by ultrasound is limited, not enough vacuoles activated persulfate. By adjusted water to the nature of the wastewater, and detection of ultrasound / persulfate / TiO2 oxidation processes,we found decomposition of organic have OH．and SO4- .The most important to decompose organic that is SO4- . Hydrogen peroxide experiment result is consistent with previous experimental and confirmed that the organics degraded in aqueous solution.Experiment also found that adding TiO2 to increase the concentration of hydrogen peroxide is right.

碩士
國立雲林科技大學
化學工程與材料工程系碩士班
101
In this study, the electrochemical / persulfate oxidation procedure of organic substances contained in the TNT wastewater system removal study was diluted with deionized water to 20 times the processing of waste acid trinitrotoluene, the organic matter concentration of about 180mg / L。Studies have shown that the electrochemical / persulfate oxidation process to remove organic matter in wastewater trinitrotoluene process when the electrode potential 6 volt, the reaction temperature is 45 ℃, persulfate concentration of 1.7wt%, pH of 0.5 under operating conditions, experience 21hr after the removal of organics can reach about 90%. Further , the operation of the electrochemical oxidation process the pH effect, persulfate oxidation process to compare the effect of temperature in the electrochemical / persulfate oxidation process with the additive。In the electrochemical oxidation process, the electrode potential 6 volt, reaction temperature 45 ℃, pH = 0.5, after 7hr reaction, in the absence of any oxidants , the mineralization rate can achieve to 33.1%, suggesting oxidizing power of the water from the wastewater, electrolysis into oxygen, thereby generating hydrogen peroxide. The electrochemical / persulfate oxidation process at potentials 6 volt, reaction temperature 45 ℃, pH = 0.5, persulfate concentration of 1.7wt%, after a 7hr, the reaction rate of 66.44% obtained mineralization, and electrochemical / persulfate oxidation process, electrochemical oxidation process that is, for a difference of 33.34% sulfate radical generated effect. This study shows that hydrogen peroxide (H2O2) generation experiments,electrochemical / persulfate oxidation process, the program can generate electrochemical oxidation of hydrogen peroxide (H2O2), generated by hydrogen peroxide to explain the mineralization of organic matter pathways . And electrochemistry / persulfate oxidation process made the experimental results into the Design-Exper this software, the display of this study is a significant effect, in which electrolysis potential, persulfate concentration, pH value of wastewater is also a significant effect.

碩士
國立中興大學
環境工程學系所
106
Application of in situ chemical oxidation (ISCO) remediation technology using sodium persulfate (SPS) could be affected by geological heterogeneity of an aquifer to result in ineffective oxidant delivery. Therefore, this study attempted to utilize passive oxidant delivery as an alternative ISCO injection method. Sustained-release oxidant gel was prepared, and the oxidant release behavior was investigated. Initial experiments focused on evaluating oxidant compatibility with various gel materials, including sodium alginate, xanthan gum/sodium aluminate, aluminosilicate and xanthan gum/gelatin and the xanthan gum/gelatin was selected as a suitable material, which resulted in gelation time over 8 hours and initial viscosity below 15 cP. 　　Oxidant release behavior exhibited that trichloroethylene (TCE) wouldn’t affect the oxidant release rate. Oxidant release was simulated with different models, First-order equation appeared well fitted (R2 >0.9), and 80 – 100 days were required for oxidant release over 90% in the soil or silica sand medium with a first-order release rate constant between 0.021 d-1 to 0.031 d-1. Control test with pure TCE liquid alone, with or without the presence of SPS or gel, the mass transfer coefficient (kLa) of TCE dissolution in aqueous solution is between 0.00004 d-1 and 0.0066 d-1 in the silica sand and between 0.0009 d-1 and 0.0061 d-1 in the soil. By comparison of kLa values, the gel without SPS could inhibit TCE release in the silica sand. However, gel may promote TCE release in the soil, possibly due to interaction between gel and soil organic matter. TCE degradation rate in the conventional persulfate oxidation system (without SPS/gel) was higher than that in the sustained-release oxidant gel system, due to that the TCE oxidation rate was greater than the TCE release rate under the condition with higher initial SPS concentration in the aqueous phase, while initial SPS concentration was low and its concentration was gradually increased with time. Nevertheless, when both gel and SPS was simultaneously present, TCE release was successfully constrained in the aqueous phase due to the function of gelation and sustained SPS release.

碩士
國立臺灣大學
環境工程學研究所
107
4-Methylbenzylidene camphor (4-MBC), a widely used UV filter, has been reported to show estrogenic activity. Owing to insufficient removal in conventional wastewater treatment plants, 4-MBC has been widely detected at the level of ng/L to µg/L in the aquatic environment, The UV-activated persulfate (UV/persulfate) process is a promising and efficient technology that has the potential to remove many recalcitrant organic contaminants. Thus, using the UV/persulfate process to degrade 4-MBC was first evaluated in the present study. The goals of this work were to determine the reaction mechanism, reactive species, transformation byproducts formation and pathways, and change in toxicity and to apply process in an actual water matrix. 4-MBC degradation can be well fitted by pseudo-first-order kinetics; the rate constant and the persulfate dosage have a linear relationship in the persulfate dosage range of 4.2 µM to 42 µM. Under the conditions of [4-MBC]0 = 0.39 µM, [persulfate]0 = 42 µM and initial pH = 7, up to 90% of 4-MBC was decomposed within 6 min by the UV/persulfate process, which is advantageous compared to the results obtained using UV irradiation alone and persulfate dark oxidation. Upon UV photolysis alone, 4-MBC experienced only photoisomerization between (E)- and (Z)-4-MBC. The rate constant remained similar, ranging from 11.8 × 10−2 min−1 to 11.0 × 10−2 min−1, in acidic (pH 5) and neutral pH, whereas it significantly decreased to 6.8 × 10−2 min−1 in basic conditions (pH 9). Radical scavenging and competition kinetics experiments indicated that SO4−• exhibited much higher reactivity toward 4-MBC than that of HO•, and the second-order rate constant of SO4−• with 4-MBC was estimated to be (2.95 ± 0.05) × 109 M−1 s−1. Moreover, after 10 min of reaction time, all the added persulfate was completely transformed into sulfate anion. 4-MBC followed transformation pathways including hydroxylation and demethylation, resulting in the generation of the transformation products P1 (C18H22O2, m/z = 271.1587) and P2 (C17H22O, m/z = 242.2030), respectively. Microtox® acute toxicity tests with Vibrio fischeri indicated that the inhibitory effect continuously increased in the first 20 mins and then remained at the same level for a certain time before starting to decrease. The rising toxicity indicated the formation of unknown transformation products that are more toxic and photolabile than 4-MBC itself, and 4-MBC was not completely mineralized at the end of the reaction. In contrast, the 4-MBC degradation rate was significantly attenuated in outdoor swimming pool water (the removal efficiency decreased from 93% to 48%), which resulted from the high concentration of Cl−. Consequently, removing inorganic anions would be an important pretreatment step if this UV/persulfate process were to be used in real wastewater environments.

碩士
國立中興大學
環境工程學系所
99
According to soil and groundwater contaminant control standards, organic contaminants can be classified as monocyclic aromatic hydrocarbons(MAHs), polycyclic aromatic hydrocarbons(PAHs), chlorinated hydrocarbons(CHs), pesticides and total petroleum hydrocarbons(TPHs), etc., which are persistent substances and resistant to degradation under natural environmental conditions. Therefore, this study focused on the treatability of 53 mixed organics including MAHs(benzene, toluene, ethylbenzene, and xylenes), PAHs(naphthalene), HHCs(halogenated alkanes, halogenated alkenes, halogenated aromatics) and 6 phenolic compounds with various persulfate activations. Furthemore, based on the selected most suitable persulfate activation process, optimum operating conditions including dosages of persulfate and activator and reaction time for treating chloroform were investigated. In addition, the chemical probe technique was applied to identify the radical species produced in the persulfate activation system. The results of persulfate activation feasibility study revealed that thermal and base activated persulfate were capable of effectively degrading 53 mixed organic compounds and 6 phenolic compounds. When comparing these two activation systems, the lower persulfate consumption during base activated persulfate was observed and hence this process exhibited a great potential for remediating persistent organics contamination. Moreover, it was found that the dosage of base revealed no noticeable effects on chloroform degradation. However, the increase of persulfate concentration resulted in the increase in chloroform degradation efficiency. The results of radical identification experiments revealed that under base-activated persulfate process HO‧ is the major radical oxidizing species.

碩士
國立中興大學
環境工程學系所
99
This study was to evaluate the feasibility of treating diesel contaminated soils with base and iron activated sodium persulfate (SPS) and dual oxidation system (H2O2/SPS). The alkaline source, lime (CaO) and sodium hydroxide (NaOH) and various factors including soil type, heat, reagent addition sequence and reaction time were also investigated in base activation system. Batch experiments were conducted using two soils (silica sand and sandy soil) spiked with diesel. Initial results showed that best diesel degradation was approximate 20% of diesel removal after 7 days of reaction time in the presence of either soil samples. Besides, no significant improvement on degradation of diesel was noted in the single or two-stage addition of SPS. The desorption of diesel from silica sand to aqueous phase was observed with addition of NaOH, but the observation did not occur with addition of CaO. In addition, it can be seen that diesel was mainly present as sorbed phase in the sandy soil system. Further experiments were carried out with elevated concentration of persulfate (from 0.1 M to 0.5 M) and extended reaction time (from 7 days to 14 and 28 days). Results revealed that about 30% of diesel removal observed after 28 days of reaction time. In summary, due to a low water solubility of diesel, the removal efficiency of diesel was not significant under all experimental conditions. Furthermore, the addition of surfactant (Tween 80) for increasing the solubility of diesel to enhance the treatment of diesel contaminated soil was evaluated. The optimal removal efficiency of 35% was achieved with 1.0% Tween and NaOH/SPS mole ration of 2.0/0.5. The results indicated that it was incapable to substantially increase the overall degradation efficiency of contaminants with addition of surfactant. The reason was due to competition between surfactant and diesel for oxidation. Pyrite as a ferrous source for activating persulfate was applied and 40% removal of diesel was reached with 0.5 M SPS and 6 g/L FeS2 for 3 days of reaction. However, since diesel can’t be effectively released to the aqueous phase, complete degradation of diesel was not achieved. Moreover, the best removal of diesel (about 56%) was achieved in dual oxidation system. Because of two strong oxidants involved in dual oxidation system, various radical oxidant species participated in degradation of diesel and resulted superior performance than other experimental conditions evaluated in this study.

碩士
國立中興大學
環境工程學系所
100
Polycyclic aromatic hydrocarbons (PAHs) have the characteristics such as low solubility and low volatilization. This study was conducted to develop an oxidative foam flushing technology, which combines the benefits of alkaline activated persulfate and surfactant foam flushing for the treatment of PAHs (e.g., naphthalene) contaminated soils. The feasibility of producing alkaline activated persulfate foam with the mixed solution which contains surfactant (Sodium dodecylsulfate, SDS, at various concentration levels) and oxidant (Sodium persulfate, SPS, at one concentration level) and their characteristics were examined. The results showed 1.5% SDS/0.1 M SPS/0.1 M NaOH mixed solution can be employed to generate stable oxidative foam, with characteristics of foam quality of 99.8% and stability of 0.8 hr. In the solubilization test, the solubility of naphthalene increased about 16.6 folds in solution with the above mentioned composition than the naphthalene aqueous saturated solubility. Furthermore, it was observed that the solubilization of naphthalene was not affected by addition of SPS or NaOH. Naphthalene in the aqueous phase (26.3 mg/L) can be completely degraded in 24 hr with alkaline activated persulfate system. However, the presence of SDS would decrease the degradation rate of naphthalene. The results of soil column experiments showed that the removal of naphthalene was about 94.0% by oxidative foam flushing. 41.4% of naphthalene was removed by liquid while the remaining portion of naphthalene removal was induced in gaseous phase. Additional soil column experiments spiked with anthracene, which has a lower volatility was conducted. Experimental results showed the removal of anthracene was about 68.0% in which the percentages of anthracene removal in liquid and suspension/sediments were 38.4% and 14.9%, respectively. In addition, through mass balance calculation, it was found that 14.6% of anthracene was destroyed by oxidation. In conclusion, the oxidative foam flushing would function both physical removal and chemically destroy PAHs and therefore, exhibits the potential for remediating PAHs contaminated soils.

碩士
國立中興大學
環境工程學系所
101
Tetramethylammonium hydroxide (TMAH) is widely used in the hightech industry as a developing agent of the circuit board or an alkali washing liquid. Due to its characteristics of alkaline pH, neuronal toxicity, and chemical stability, TMAH might not be effectively removed by conventional wastewater treatment processes; therefore it may pose threat to the ecological system if TMAH solution is not properly treated. In this study, the degradation of TMAH by UV activated persulfate was investigated, in which process hydroxyl or sulfate radicals can be generated for destroying target contaminants. Influences of pH, persulfate concentration, UV strength, and temperature on the oxidation system were examined. Furthermore, acute toxicities of TMAH and species involved in the oxidation system were also analyzed. Based on the experimental results, operating conditions in this oxidation system of pH = 2, UV = 15 W, persulfate dose = 50 mM, and 30oC were recommended. Under these operating conditions, complete degradation of 1.1 mM TMAH was achieved after 70 minutes of reaction by the UV/persulfate oxidation process with the pseudo-first-order rate constant for TMAH degradation (kobs, TMAH) of 0.0605 min-1. Additionally, 85% of total organic carbon removal was achieved at the end of the reaction (130 minutes). The result of biological acute toxicity analysis showed that the toxicity of TMAH is mainly caused by alkaline pH, and if pH effect was excluded, low TMAH concentration still exhibited acute toxicity. Moreover, the acute toxicity of persulfate depends on the degree of persulfate decomposed and when persulfate is completely decomposed to sulfate ions, the acute toxicity would be significantly reduced. Additionally, the solution pH variation during the course of reaction is also an important factor than influences toxicity. In conclusion, UV photolytic persulfate activation can effectively degrade TMAH in water and the results of toxicity analysis give information clarifying relationship between TMAH and oxidation system. The results of this study may serve as a reference for wastewater treatment in the high-tech industry using persulfate oxidation processes.

碩士
國立雲林科技大學
化學工程與材料工程系
105
Removal of p-Nitrophenol in wastewater performed using sono-activated persulfate/PbO oxidation. 　　Experiments were carried out under batch-wise mode to investigate the influence of various operation variables on the sono-activated behavior, such as ultrasonic power intensity, sono-activated temperature, persulfate concentration, acidity of wastewater and PbO concentration of degradation efficiency and using TOC to investigate. 　　Its organic p-Nitrophenol solution concentration of approximately 100 mg / L. Experiments were added to persulfate and PbO combine with ultrasonic process.However, it is remarkable that p-Nitrophenol pollutants into the reaction time of 6 hours could be nearly thoroughly 31.03% removed under the conditions of persulfate = 3wt%, ultrasonic power = 189 W/cm2, T = 318 K, pH =7.But when add additional PbO concentation=4.480mM and persulfate concentration increase to 5wt%, ultrasonic power = 189 W/cm2, T=318K, pH=7,reaction time of 6 hours that organic pollutants could be removed nearly 91.92%. 　　Because more persulfate can provide more sulfate radicals(SO4-•) and additional PbO can provide more free electrons to degrade organic pollutants by persulfate. 　　Methanol and Ethanol were used as scavengers to clarify the reactive radicals.

碩士
國立雲林科技大學
化學工程與材料工程系
105
Bisphenol A is a common water pollutant which can not be easily degraded. Recently, often using advanced oxidation process (Advanced Oxidation Technology, AOTs) approach to wastewater treatment. The principal active species in such systems are the hydroxyl radical (OH•) and sulfate radicals(SO4• –),both of them are highly oxidizing agent of organic contaminants. In this work, Bisphenol A was degraded using mercury light (253nm). The process at variety of temperature, PH value, concentration of Cu2O, concentration of persulfate and intensity of UV light to explore the impact of Bisphenol A mineralization. And using total organic carbon analyzer to detect hydrogen peroxide production. Each operating parameter would be discovered using the Taguchi's orthogon alarrays Methods the optimal operating conditions would be established. The concentration of Bisphenol A solution is 100 mg / L. The result shows that high temperature could enhance the generation rate of sulfate radical(SO4• –), so it has optimal value at 45℃. The more high-energy ultraviolet light, the more degradation rate of Bisphenol A. There's are optimal value in cuprous oxide and persulfate, excess or less could affect the final results. PH value is the important factor in the system, the PH value is neutral. The scavenging effect was examined by using methanol (MeOH) and ethyl alcohol (EtOH) to identify the reactive radicals in UV/PDS process.The removal of Bisphenol A from water was investigated by the UV/PDS using hydroxyl radicals(OH•) and sulfate radicals(SO4–•) which leads to the oxidative degradation of Bisphenol A. Keywords: Bisphenol A, sulfate radicals, persulfate, ultraviolet light, cuprous oxide

碩士
國立暨南國際大學
土木工程學系
101
Methyl tert-butyl ether (MTBE) and 1,2-dichloroethane (1,2-DCA) are common groundwater pollutants. MTBE is widely used as a gasoline additive while 1,2-DCA is used for the production of vinyl chloride (VC). Both pollutants are difficult to be remediated and may cause cancer. In this study, alkaline-activated persulfate was used to treat MTBE- and 1,2-DCA-contaminated groundwater. Batch experiments were conducted under different pH to determine the required pH for alkaline-activated persulfate reaction. Furthermore, the potential of alkaline-activated persulfate by industrial waste was also evaluated. The main objectives were to: (1) investigate the required pH for alkaline-activated persulfate; (2) evaluate the degradation efficiency of MTBE and 1,2-DCA by alkaline-activated persulfate; and (3) evaluate the potential of industrial waste to drive alkaline-activated persulfate process. Results show that alkaline-activated persulfate can effectively accelerate the degradation of 1,2-DCA. The byproduct of 1,2-DCA degradation, VC, was observed during the experiments. Alkaline-activated persulfate reduced the degradation rate of MTBE and inhibited the production of MTBE-degrading byproducts, tert-butyl alcohol (TBA) and tert-butyl formate (TBF). Persulfate activated by industrial waste basic oxygen furnace slag (BOF Slag) enhanced the degradation of 1,2-DCA and the production of VC was also observed. No heavy metals were released from BOF slag during the experiments. Results of this study would be helpful to design a practical system for the treatment of contaminated sites. Since the mechanisms of contaminant removal by alkaline-activated persulfate are complicated, feasibility study is necessary before alkaline-activated persulfate is applied to other target compounds to avoid the retardation of contaminant degradation.

碩士
國立中興大學
環境工程學系所
104
Pharmaceuticals and personal care products are emerging contaminants. Due to advances in medicine, people develop the habit of abuse and disposal of its residual material, which will go into the environment, enventually causing environmental and ecological pollution as well. Among them, acetaminophen (ACE) has a higher appearance rate in the wastewater. Advanced oxidation process (AOPs) is a kind of oxidation treatment which is often used to treat the organic pollutants, such as persulfate and Fenton process. They can be activated by light, heat, electricity, transition metals, ultrasound and others. This study tried to use electrolysis to activate the sodium persulfate (SPS), that can produce sulfate radical (SO4-‧) to degrade the ACE. These five programs (E-A, S-A, ES-A, ESH-A, ESF- A) are designed to explore the effects and differences. In order to investigate the effects of ACE degradation efficiency, and to find the optimum operating condition, types of acid, pH, voltage, and SPS concentration are the main parameters under consideration. Among all the processes, ESF-A system achieved the best ACE removal, based on the optimal operating conditions (pH = 3, sulfuric acid, [SPS] = 9.9 mM, 5 V). The ACE removal rate reached 100% in 20 min by adding 1 mM of Fe2 + to ESF-A system. However, the results of the other programs show that: under E-A process, the removal rate of ACE was 31.08% after 180 min. In case of S-A process, ACE could not been degraded but turned into other substances. ES-A oxidation process’s removal rate was 63.17%, if extention of time to 12 hr. But for ESH-A system, the more H2O2 added, the less removal got.

博士
國立雲林科技大學
化學工程與材料工程系
104
Mineralization of aniline in wastewater was performed using electro-activated persulfate/peroxymonosulfate oxidation assisted with ultrasonic irradiation. Experiments were carried out under batch-wise mode to investigate the influence of various operation variables on the sonoelectrolytic behavior, such as ultrasonic power intensity, electrode potential employed, sonoelectrolytic temperature, persulfate anion concentration, acidity of wastewater and nitrogen/oxygen gas dosage. Discussion on the organic pollutants of degradation efficiency, hydrogen peroxide (H2O2) generation amount and the plausible degradation pathway. Moreover, it is remarkable that aniline pollutants into the reaction time of 12 hours could be nearly thoroughly 96% removed under the optimal conditions of ultrasonic power = 7U, E.P. = 6 V, T = 318 K, persulfate/peroxymonosulfate anion concentration = 2.5 wt%, pH = 3.0 and N2/O2 = 150 mL min-1. It is notable that the aniline contaminants could be almost entirely eliminated by means of sonoelectro-activated persulfate/peroxymonosulfate oxidation, in which sulfate radicals served as principal oxidizing agents, of which amounts were significantly elevated with assistance of acoustic streams. Ethanol and tert-butyl alcohol were used as scavengers to clarify the reactive radicals. Based on the results given by gas chromatograph–mass spectrometer (GC–MS), it was postulated that aniline preliminarily underwent oxidation to form iminobenzene radicals, followed to convert into azobenzene, nitrobenzene and nitrosobenzene respectively. Hydroquinone and p-benzoquinone were also detected as reaction intermediates.

碩士
中興大學
環境工程學系所
94
In-situ chemical oxidation (ISCO) is a technology used for groundwater remediation. Persulfate (S2O82-, E° = 2.01 V) is an oxidant for application of ISCO. S2O82- can be thermally or chemically activated to produce a powerful oxidant sulfate free radical (SO4-•, E° ~ 2.6 V) which can potentially destroy many organic contaminants such as trichloroethylene (TCE). However, althought activation process can increase oxidation rate but it also caused more oxidant consumption. This laboratory study investigated the efficiency on the persulfate oxidation of TCE at near ambient temperature (10, 20 and 30 °C) and the influence of pH and radical scavengers such as chloride ion (Cl-) and alkanility species (i.e., HCO3-/CO32-) on the oxidation.. Under the range of temperatures tested, the maximum rate of TCE degradation occurred at near neutral pH (i.e., pH 7). Increases and decreases in pH resulted in decreases in TCE degradation rates. Radical scavenging tests used to identify predominant radical species suggested that SO4-• predominates under acidic conditions and the hydroxyl radical (•OH) predominates under basic conditions. It was found that TCE degradation by persulfate was not affected by the presence of HCO3-/CO32- for concentrations within the range of 0 ~ 9.2 mM at 20°C and pH 7. The presence of Cl- concentration below 0.2 M revealed no effect on TCE degradation rate. However, at Cl- levels greater then 0.2 M, TCE degradation rate was seen to reduce with increases in Cl- concentration. In a side by side comparison of groundwater vs. unbuffered RO water tests, it was seen that when the pH is buffered due to the presence of groundwater constituents the observed TCE degradation rate is higher than that in RO water where pH dropped from neutral to acidic.

碩士
義守大學
生物技術與化學工程研究所
100
Peroxide is generally used as oxidant in chemical reaction. Hydrogen peroxide is the one most widely used in these peroxides. It could oxidize iodide, but it also could be oxidized by iodine to produce oxygen. In this work, kinetics of the oxidation of iodine by persulfate is investigated. The reactions were studied in pseudo-first-order condition with persulfate in excess at μ 2.0 M. The reaction is first-order dependence of persulfate and iodine, the rate law of this reaction is: -d[I_2 ]/dt=(k_0+k[S_2 O_8^(2-)])[I_2] The rate constant, thermodynamic activation parameters, the characterization of final products and the stoichiometry of the reaction are reported.

碩士
國立臺灣大學
環境工程學研究所
100
This research is to decomposition of persistant and bioaccumulative perfluorooctanoic acid(PFOA) in water with activated-carbon catalyzed persulfate (S2O82-) under ambient temperatures. The main objective of the usearch was of investigat the effect of temperatures (25, 35 and 45oC), initial pH (2.5, 7.0 and 11.0), and the persulfate doses and activated-carbon doses on the PFOA decomposition study. Three different system were studied: Persulfate (PS) only system and active-carbon (Ac) only system and PS+AC system. The result showed that the PS+AC system has a better decompostion capability than that of PS only system. But the AC only system could remove more perfluorooctanoic acid from water, it did not decompose perfluorooctanoic acid. The best operation for the PS+AC system is high temperature coupled with low pH, which can accelerated the free radical (SO4-˙) generation, to decompose PFOA. At pH of 2.5, temperature of 45 oC, PS dose of 60.25 mM, AC dose of 1g/L, and shake rate of 100 rpm, 85% PFOA were decomposes and 79% of fluoride-ions were released to the water. Experimental of the PS only system could be simulated with pseudo first-order kinetics of the PFOA degradation; while those of the PS+AC system and the AC only system could be well simulated with pseudo second-order kinetics.