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1
Tikoo, Vidya. "Microalgal biodegradation of pentachlorophenol". Thesis, University of the West of England, Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319256.
Testo completoAbstract (sommario):
Pentachlorophenol (PCP) is a chlorophenol with a pronounced biocidal activity that has led to its use in a number of applications. It was introduced in the 1930s as a preservative for timber and lumber and since then has found wide use as a biocide in agricultural and industrial applications. Many different physical, chemical and biological methods have been tried for the removal of PCP from wastewater. However, using microalgae for the removal of PCP and other organochlorine compounds from water may prove to be a cheaper alternative and give complete degradation of the compounds. The aim of this project was to study the efficiency of microalgae to degrade PCP. An algal strain named VT -1 and a bacterial strain named AT -14 were isolated from PCP containing conditions in the laboratory. The growth of VT -1 in the presence of PCP was compared with Chlorella emersonii and Chlorella vulgaris in two different autotrophic media. It was observed that VT-1 had the highest IC50 value of 25-26mg }-l PCP and EC50 value of 11.3mg }-1 PCP in S&K medium. With glucose as an additional carbon source the IC50 value for VT-1 in S&K medium was 29-30mg t 1 PCP. Bacterium AT-14 could grow in the presence of PCP, only with glucose as a carbon source. Mineralization of PCP by VT -1 and the two Chlorella strains was compared by using 14C_PCp. With all the three algae exposed to 14C_PCp, only VT-1 showed release of 14C02, which was evidence of mineralization of PCP by VT-1 which occurred only in the presence of light. Bacterium AT-14 did not produce 14C02. However, the consortium of VT-1 and AT-14 showed enhanced 14C02 evolution in the presence of glucose. The release of chloride ions from PCP can also indicate PCP dehalogenation and degradation. The evolution of 14C02 lagged behind chloride release (90 %) indicating that dechlorination of PCP could be the first step in its biodegradation. Breakdown of PCP was also followed by its extraction from the cells and medium. Normally dichloromethane (DCM) was used to extract PCP. The changes in the label extracted in DCM and iso-butanol were studied under different light condjtions, which showed that the 14C counts in DCM reduced and those in iso-butanol extract increased with time. The 14C counts in the iso-butanol extract could be a metabolite of PCP which is more hydrophilic. VT-1 appeared not to degrade PCP completely, since only 15% of 14C was recovered as 14C02. It appears that intermediates are formed which are distributed in the growth medium and in the biomass. It can thus be concluded that VT -1 is tolerant of PCP, appears to dechlorinate PCP and then releases some part of it as CO2.
2
Magar, Victor S. "Fate and biotransformation of PCP in anaerobic fluidized-bed reactors and anaerobic digesters /". Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/10185.
Testo completo
3
Shaw, Kerry W. "Pentachlorophenol degradation by Pseudomonas sp. UG30". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0015/MQ27543.pdf.
Testo completo
4
Ullah, Millie Ann. "Biotreatment of pentachlorophenol using wood rotting funghi". Thesis, University of Westminster, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322996.
Testo completo
5
Baranow, Steven A. "Degradation of pentachlorophenol by anaerobic subsurface microorganisms". Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54376.
Testo completoAbstract (sommario):
Microbial populations from subsurface soil collected from a hydrocarbon contaminated site and a pristine site with no history of contamination had the ability to degrade pentachlorophenol (PCP) in anaerobic enrichment cultures. Increasing concentrations of PCP in nitrate, sulfate and yeast extract-mineral salts media were used to acclimate the cultures. Nitrate enrichments, previously incubated in an anaerobic phenol-mineral salts medium, showed 23% degradation in medium containing 40 μg ml⁻¹ PCP during a 32 d incubation period. Cultures not adapted to phenol degradation did not degrade PCP at concentrations over 20 μg ml⁻¹. Enrichment cultures grown in the anaerobic yeast extract-mineral salts medium did not degrade PCP at concentrations over 20 μg ml⁻¹ and phenol adaptation did not enhance PCP degradation. The sulfate reducing enrichment containing 1 μg ml⁻¹ PCP showed 71.3% degradation after 32 d incubation. No degradation occurred at or above 5 μg ml⁻¹ PCP. PCP intermediates, 2,4,6-trichlorophenol (TCP) and 3,4,5 TCP were found in the spent culture of the nitrate reducing enrichment. In the spent culture of the sulfate reducing enrichment, 3,4,5 TCP and 2,3,4,5-tetrachlorophenol were found. Attempts to obtain a pure culture of an anaerobic PCP degrading bacterium were unsuccessful.Master of Science
6
FRONTIN, PHILIPPE. "Le pentachlorophenol : a propos d'un cas grave d'intoxication". Toulouse 3, 1990. http://www.theses.fr/1990TOU31197.
Testo completo
7
Duncombe, Tracey Elizabeth. "The bioremediation of contaminated soils with mushroom compost". Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366888.
Testo completo
8
Webb, Martin Darren. "Biotransformation of pentachlorophenol by actinomycetes isolated from compost". Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243205.
Testo completo
9
Carvalho, Mariana Boavida Lopes. "The Biotransformation of Pentachlorophenol by Mucor plumbeus: Mechanistic Insights". Doctoral thesis, Universidade Nova de Lisboa. Instituto de Tecnologia Química e Biológica, 2013. http://hdl.handle.net/10362/11943.
Testo completoAbstract (sommario):
Dissertation presented to obtain the Ph.D degree in BiochemistryPentachlorophenol (PCP) is a synthetic compound introduced as a wood preservative and used for decades in agricultural and industrial applications. Today, the production and use of PCP is restricted due to its toxicity and environmental impact. However, extensive use in the past and its environmental persistence has resulted in substantial contamination of PCP worldwide. The detection of PCP in the human population and in remote environments, such as the Arctic, is still being reported.(...)
10
Brown, William Charles. "Mechanisms of pentachlorophenol induced charge transport in lipid membranes". PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/1257.
Testo completoAbstract (sommario):
Pentachlorophenol (PCP) is one of the prominent environmental pollutant that has penetrated into food chain and is present in humans. Health concerns have been raised since daily intake of PCP by the US population is estimated to be 16-19 µg. PCP facilitates dissipation of electrochemical potential gradients of hydrogen ions across energy transducing membranes, which are the energy sources for the conversion of adenosine diphosphate into adenosine triphosphate. Closely linked to these dissipative effects is the development of electrical conductivity in lipid membranes, induced by the presence of PCP. Three modes of PCP - induced membrane electrical conductivity were theoretically analyzed and experimentally verifiable formulations of each models were developed. Experimental studies using the charge - pulse method involved characterization of the time dependent transmembrane voltage over a wide pH range, from 1.8 to 9.5, for 30 µM concentrations of PCP. Lipid membranes were prepared from dioleoyl phosphatidylcholine. It was shown that three PCP molecular species were determining the transmembrane transfer of hydrogen ions: electrically neutral PCP molecules (HA), negatively charged pentachlorophenolate ions (A⁻) and negatively charged heterodimers (AHA⁻). It was found that at pH>9 the membrane electrical conductivity was determined by the transmembrane movement of A⁻ ions, whenever pHAHA⁻ species. Two new membrane surface reactions were proposed as supplementary mechanisms for the generation of AHA⁻ in addition to the formation of AHA⁻ by the recombination of HA and A⁻, HA + A⁻→ AHA⁻. These new reactions are, (i) 2HA → H⁺ + AHA⁻, and (ii) H20 + 2A⁻ → OH' + AHA⁻. Reaction (i) provides formation of membrane permeable heterodimers AHA⁻ at pH < < 5.5 and reaction (ii) at pH> > 5.5. The maximum surface density of AHA" heterodimers was 0.09 pmol/cm² • The rate constant of formation of AHA' by recombination, HA + A⁻ → AHA' was estimated to be k[subscript f] = 2.6xl0⁹ cm² mol⁻¹ s⁻¹ and the dissociation rate constant for AHA⁻ Further, it was possible to determine the rate constants of transmembrane translocation for A' and AHA⁻ ions to be k[subscript a] = 6.6x10⁻⁵ s⁻¹ and k[subscript aha] = 1200 S⁻¹, respectively.
11
Masson, Catherine. "Le pentachlorophenol : le lindane ; atteintes hematologiques a propos d'un cas". Limoges, 1988. http://www.theses.fr/1988LIMO0120.
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12
King, J. M. H. "Effect of pentachlorophenol on the microbial ecosystem of activated sludge". Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379496.
Testo completo
13
Pu, Xunchi. "EFFECTS OF SOIL PROPERTIES AND MICROBIAL SOURCE ON PENTACHLOROPHENOL BIOREMEDIATION". University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133189415.
Testo completo
14
Alleman, Bruce Charles. "Degradation of pentachlorophenol by selected species of white rot fungi". Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185547.
Testo completoAbstract (sommario):
The focus of this research was to examine the potential for using white rot fungi to degrade pentachlorophenol (PCP) in water. Experiments were designed to determine the optimum growth conditions for 4 species of fungi, quantify toxicity of PCP to 18 species, and examine PCP degradation by both extracellular enzymes and whole cultures of 4 species. Optimum growth temperatures ranged from 25°C for G. oregonense to 40°C from P. chrysosporium with I. dryophilus and T. versicolor at approximately 30°C. Optimum growth pH were 4.5 for Phanerochaete chrysosporium and 6.0 for the other 3 species. Eighteen species tested for PCP sensitivity were inhibited by 10 mg-PCP/L when grown on agar plates. Within 2 weeks, 17 of the 18 species grew in the inhibition zones. In liquid phase toxicity experiments, all 18 species were killed by 5 mg-PCP /L. Further liquid testing showed that P. chrysosporium and G. oregonense were among the most sensitive species while I. dryophilus and T. versicolor were more tolerant species, having lethal dosages of 17-34, 25-50, >41, and >85 μg-PCP/mg-biomass, respectively. Extracellular enzymes produced in shallow batch cultures by P. chrysosporium and T. versicolor, degraded up to 50% and 75% of the PCP, respectively, when 40 mg-PCP/L was added to mycelia free culture broth. The pattern of chloride ion release resulting from dehalogenation of PCP was bimodal for both species. PCP was degraded by 10 species when PCP was added to whole cultures. Further testing with 4 species showed P. chrysosporium and T. versicolor were the more efficient at reducing aqueous organic chlorine concentrations. Trametes versicolor consistently dehalogenated the most PCP with over 60% of the chlorine being released as chloride ion in 8 days. Comparisons of PCP degradation between species growing as fixed films in rotating tube reactors (RTRs) verified this observation. Degradation in RTRs was superior to degradation in shallow batch reactors on the basis of PCP removal, organic chlorine reductions, and dehalogenation.
15
Crane, Cynthia E. "Sorption of pentachlorophenol to humic acids and subsequent effects on biodegradation and solvent extraction". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-03172010-020652/.
Testo completo
16
Entezami, Azam A. (Azam Alsadat). "Aquatic Heterotrophic Bacteria Active in the Biotransformation of Anthracene and Pentachlorophenol". Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc504319/.
Testo completoAbstract (sommario):
Dominant genera of bacteria were isolated from three river waters during anthracene and pentachlorophenol biotransformation studies. The genera Pseudomonas, Acinetobacter, Micrococcus, Chromobacterium, Alcaligenes, Azomonos, Bacillus, and Flavobacterium were capable of biotransforming one or both of these compounds. These isolates were subjected to further biotransformation tests, including river water and a basal salt medium with and without additional glucose. The results of these experiments were evaluated statistically. It was concluded that only a limited number of the bacteria identified were able to transform these chemicals in river water. The addition of glucose to the growth medium significantly affected the biotransformation of these chemicals. It was also determined that the size of the initial bacterial population is not a factor in determining whether biotransformation of anthracene or pentachlorophenol can occur.
17
Nensala, Ngudiankama. "Photocatalytic reactions of metal diphthalocyanine complexes". Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1004989.
Testo completoAbstract (sommario):
Photocatalytic reactions of tin diphthalocyanine, Sn ^IVPc₂ and anionic form of Nd^III, Dy^III, Eu^III, Tm^III and Lu^III diphthalocyanine complexes ( [Pc(-2)Nd^IIIpc(-2)]⁻ , [Pc(-2)Dy^IIIPc(-2)]⁻ , [Pc(-2)Eu^IIIPc(-2)⁻, [Pc(-2)Tm^IIlPc(-2)r and [Pc(-2)LuIIIpc(-2)]⁻ respectively) in the presence of CH₂CI₂, S0₂, pentachlorophenol (PCP), 4-chlorophenol (4-Cp) and thionyl chloride have been studied. Photoreactions involving lanthanide diphthalocyanines, filtered and unfiltered radiations were employed, whereas for photoreactions involving tin diphthalocyanine, only unfiltered radiation was employed. For lanthanide diphthalocyanine complexes, LnPce-, the photosensitization power increases with the decrease of the lanthanide ionic radii, implying that the photocatalytic activity of LnPc₂⁻ complexes is associated with the π-π interaction between both phthalocyanine rings. Thus, LuPc₂⁻ is a better photocatalyst than other lanthanide diphthalocyanine complexes. Photolysis ofSnPc₂ in an acetonitrile/dichloromethane solvent mixture, using unfiltered radiation from a tungsten lamp, results in the one-electron oxidation of this species to [Pc( -2 )Sn(IV)Pc(-1)]⁻. The relative quantum yields for the disappearance of SnPc₂ are in the order of 10⁻¹. The photoreaction of SnPc₂ is preceded by excitation to nπ* excited states, before been ,quenched by CH₂CI₂. The one-electron oxidation species, [Pc(-2)Sn(lV)pc(-1)]⁻ was also formed during the photolysis of SnPc₂ in dichloromethane containing S0₂, and with quantum yields of order of 10⁻³. Visible photolysis of [Pc( -2)Nd^IIIpc(-2)]⁻, [Pc(-2)Dy^IIIPc(-2)]⁻ and [Pc(-2)Lu^IIIpc(-2)]⁻ in N,N. dimethylformamide (DMF)/dichloromethane solvent mixture containing SO₂, results in the formation of the one-electron oxidation species, Pc(-2 )Nd^IIIpc(-1), Pc( -2) Dyi^IIIPc(-1) and Pc(-2)Lu^IIIpc(-1), respectively. The relative quantum yields are in the order of 10². The photoreactions are preceded by population of the excited triplet state,³π-π* [ LnPc₂]⁻ complex, before exchanging an electron with S0₂. The one-electron oxidation species of Dy^III and Lu^III diphthalocyanine complexes have also been formed from visible photolysis of [Pc(-2 )Dy^IIIPc(-2)]⁻and [Pc(-2)Lu^IIIpc(-2)]⁻in acetonitrile containing PCP. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are in the order of 1 0⁻. Photolysis, using visible radiation from 220 W Quartzline lamp, of an aqueous solution of 4-Cp, saturated with oxygen and containing a suspension of solid [Pc(-2)Nd^IIIpc(-2)]⁻, results in the formation of benzoquinone, hydro quinone and 4-chlorocatechol. The quantum yields for the degradation of 4-Cp are in the order of 10⁻. Langmuir-Hinshelwood kinetic model shows the adsorption of 4-chlorophenol onto solid [Pc(-2)Nd^IIIpc(-2)]⁻. Lanthanide diphthalocyanine complexes ([Pc-2)Nd^IIIpc(-2)]⁻. [Pc(-2)Eu^IIIpc(-2)]⁻, (Pc(-2)Tm^IIIpc( -2)]⁻ and (Pc(-2)Lu^IIIpc(-2)]⁻) undergo one or two-electron oxidation in the presence of thionyl chloride. At low concentrations of SOCI₂(<10⁻⁴ mol dm⁻³) the visible yhotolysis of [Pc(-2 )LnPc(-2)]⁻ complexes result in the one-electron oxidation, giving neutral lanthanide diphthalocyanine species, Pc(-2)Ln^IIIpc(-1). The Pc(-2 )LnPc(-I) species undergoes one-electron photooxidation to [Pc(-I )LnPc( -I)]⁻ in dichloromethane and in the presence of SOC₁₂. At large concentrations of SOC₁₂ (>10⁻² mol dm⁻³), direct two-electron oxidation of the (Pc(-2 )LnPc - 2)]⁻ species to (Pc(-1)LnPc(-1)]⁻ occurs. Spectroelectrochemical behaviours of Sn^IVPc₂ have been also studied. The cyclic voltammetry ofSnPc₂ in CH₂CI₂/TBAP show two reduction couples at -0.56 V and -0.89 V versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE. In DMFITEAP system, the reduction couples are observed at -0.44 V and -0.81 V versus SCE whereas the oxidation couple occurred at 0.43 V versus SCE. The oxidation couple corresponds to [Pc(-2 )Sn^IVPc(-2 )]/[Pc(-2)Sn^IVPc( -I)] . and the reduction couples to [Pc(-2)Sn^IVPc( -2 )]/[Pc(-2 )Sn^IVPc( -3 )]⁻ and [Pc(-2)Snl^IVPc( -3)] ⁻/[Pc(-3 )Sn^IVPc(-3)]²⁻, respectively. The electronic absorption spectra of these reduced and oxidized species are reported.
18
ABAHAMID, ABDELOUAHAB. "Adaptation de cellules d'euglena gracilis au pentachlorophenol et au cadmium : modulations de l'expression de proteines de stress et d'enzymes de detoxication apparentees aux cytochromes p-450 (doctorat : structure et fonctionnement des systemes biologiques integres)". Paris 11, 1998. http://www.theses.fr/1998PA114825.
Testo completo
19
Seech, Alan G. "Bioremediation of soil containing pentachlorophenol and polycyclic aromatic hydrocarbons using organic amendments". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27468.pdf.
Testo completo
20
Morante, Susan Janet. "The uptake of pentachlorophenol, chromated copper arsenate and copper naphthenate by soils". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34980.pdf.
Testo completo
21
Bethune, Kristie Joyce Chamber Robert P. "Bioremediation of pentachlorophenol and bleach plant effluent by Trametes versicolor and its extracellular fluid, focused on intermediates and products formed and the role of protein binding of chlorinated compounds in a two-stage reactor system". Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/doctoral/BETHUNE_KRISTIE_56.pdf.
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22
McKinzi, Adonia. "A microbially-driven Fenton reaction for oxidative dechlorination of pentachlorophenol by shewanella putrefaciens". Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/30637.
Testo completo
23
Lear, Gavin. "Using electrokinetics and bioaugmentation to optimise the remediation of a pentachlorophenol contaminated soil". Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404173.
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24
Song, Myoungsuk. "Surfactants effects on microbial activity during pentachlorophenol degradation by Sphingomonas chlorophenolicum strain RA2". Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3303819.
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25
WILSON, GREGORY. "ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIZED BED BIOREACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1018531262.
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26
Don-Pedro, Esther A. "The effects of soil properties and clay minerals on the bioremediation of soils contaminated with pentachlorophenol". Akron, OH : University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1126632988.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Akron, Dept. of Geology, 2005."August, 2005." Title from electronic thesis title page (viewed 11/29/2005) Advisor, Annabelle Foss; Committee members, Teresa Cutright, Ira Sasowsky; Department Chair, John Szabo; Dean of the College, Charles B. Monroe; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
27
Don-Pedro, Esther. "THE EFECTS OF SOIL PROPERTIES AND CLAY MINERALS ON THE BIOREMEDIATION OF SOILS CONTAMINATED WITH PENTACHLOROPHENOL". University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1126632988.
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28
Kabir, Anwar. "Dechlorination of chlorinated organic compounds by zero-valent and bimetallic mixture". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31246.
Testo completoAbstract (sommario):
Organochlorine (OC) compounds that include several pesticides as well as an array of industrial chemicals were very efficacious for their intended use but were also characterized by deleterious environmental impacts when released either intentionally or inadvertently. Their lipophilic nature, long persistence in the environment and threat to human health caused all the developed countries to ban the production of these chemicals as well as restricted the use of formulations containing these material for food production.A number of scientists have become involved in the development of intentional degradation methods/techniques for these compounds using zero-valent metals or bimetallic mixtures. To date, there is no single, simple and continuous procedure available to completely dechlorinate lindane or pentachlorophenol (PCP). This work describes the complete dechlorination of lindane and pentachlorophenol by zero-valent Zn, Fe and Fe/Ag bimetallic mixture as well as a supercritical fluid extraction technique for a more efficient mass transfer of the substrates to the surfaces of the metal catalyst. The dechlorination reaction occurs on the surface of metal particles with the removal of all the chlorine atoms from lindane and PCP in a matter of minute, and yields completely dechlorinated hydrocarbon molecules and chloride as products. (Abstract shortened by UMI.)
29
Cooper, Dunstan W. "An investigation into the binding of pentachlorophenol into natural and synthetic organic macromolecules using pyrolysis techniques". Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260688.
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30
Jenkins, Erica Helen. "A method for the quantitative determination of pentachlorophenol in environmental samples utilising gas chromatography/mass spectrometry". Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238787.
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31
Sembiring, Brahmana Simon. "Incorporation et effets du pentachlorophenol chez les macrophytes flottantes (Lemna minor L et Salvinia Natans L)". Chambéry, 1991. http://www.theses.fr/1991CHAMS014.
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32
Chan, Tsz Chung. "Toxicokinetics of pentachlorophenol, 2,3,4,6-tetrachlorophenol and 2,4,6-trichlorophenol in the golden apple snail (pomacea lineata wagner)". HKBU Institutional Repository, 1994. http://repository.hkbu.edu.hk/etd_ra/31.
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Silva, Marcio Wagner da. "Efeitos da adição de metais básicos aos catalisadores à base de Pd e Ru para a hidrodescloração do pentaclorofenol". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266936.
Testo completoAbstract (sommario):
Orientadores: Antonio José Gomez Cobo, Antonio Guerrero RuizTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Alguns compostos organoclorados são motivo de grande preocupação, em razão da elevada toxicidade e persistência, tanto no meio ambiente quanto em organismos vivos. Dentre tais compostos, encontra-se o pentaclorofenol, utilizado para a conservação de madeira e na proteção de lavouras. Uma das tecnologias mais promissoras para o tratamento dessa classe de compostos tóxicos é a hidrodescloração catalítica, através da qual é possível recuperar a matéria-prima utilizada na síntese do contaminante. Embora diferentes catalisadores possam ser utilizados nesta reação, destacam-se os sólidos à base de Pd e Ru, notadamente devido à maior atividade catalítica. No entanto, os elevados preços destes metais nobres podem aumentar significativamente os custos do processo. Nesse contexto, o objetivo do presente trabalho é estudar os efeitos da presença dos metais básicos Fe e Ni em catalisadores à base de Pd e Ru, destinados à hidrodescloração do pentaclorofenol em fase líquida. Para tanto, catalisadores monometálicos e bimetálicos, suportados em alumina (Al2O3) ou titânia (TiO2), foram preparados a partir dos precursores clorados, através do método de co-impregnação a seco. Os sólidos obtidos foram caracterizados por meio das técnicas de adsorção de N2 (método BET), microscopia eletrônica de varredura com espectrometria de energia dispersiva de raios-X (MEV-EDX), espectroscopia fotoeletrônica de raios-X (XPS), redução à temperatura programada (TPR) e microscopia eletrônica de transmissão (MET). A hidrodescloração do pentaclorofenol foi conduzida num reator Parr® do tipo "slurry", à temperatura de 383 K e sob pressão de H2 de 0,5 MPa. Na reação de interesse, a adição de Ni ao catalisador de Ru/TiO2 diminui a atividade catalítica, porém mantém a elevada seletividade de cicloexanol, possibilitando, portanto, uma diminuição do custo do catalisador, sem perda de seletividade. Já para o catalisador de Pd/TiO2, a presença de Ni também diminui a atividade catalítica, assim como observado no caso do catalisador de Ru/TiO2, mas verifica-se uma diminuição da seletividade de fenol. Por sua vez, a adição de Fe ao catalisador de Pd/TiO2 tem pouca influência sobre a atividade e a seletividade, possibilitando, assim, uma significativa diminuição do custo do catalisador, sem prejuízo do desempenho catalítico. Os comportamentos catalíticos observados são analisados e interpretados à luz dos resultados obtidos através das caracterizações dos sólidos, assim como das informações disponíveis na literatura
Abstract: Some organic chlorine compounds are of great concern, because of high toxicity and persistence, both the environment and in living organisms. Among these compounds, is the pentachlorophenol, which is used to Wood conservation and for the protection of crops. A very promising technology to treating this class of toxic compounds is the catalytic hydrodechlorination, through which it is possible the recovery of raw material used in the synthesis of the contaminant. Although various catalysts may be used in this reaction, we highlight the solids Pd and Ru, mainly due to higher catalytic activity. However, the high prices of these noble etals can increase significantly the process costs. In this context, the objective of this work is to study the effects of base metals addition, Fe and Ni, in the catalysts based on Pd and Ru, for the pentachlorophenol hydrodechlorination in liquid phase. For this, monometallic and bimetallic catalysts, supported in alumina (Al2O3) or titanium oxide (TiO2), were prepared from chlorinated precursors by the incipient impregnation method. The obtained solids were characterized by techniques of N2 adsorption (BET method), scanning electronic microscopy with X-ray spectrometry analysis (EDX), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and transmission electronic microscopy. The pentachlorophenol hydrodechlorination was carried out in a "slurry" Parr® reactor, at the temperature of 373 K under the hydrogen pressure of 0,5 MPa. In the interest reaction, the addition of Ni to the Ru/TiO2 catalysts reduces the catalytic activity, but the high cyclohexanol selectivity is maintained, enabling thus, decrease the catalyst cost, without loss of selectivity. To the Pd/TiO2 catalyst, the i presence reduce the catalytic activity, like to the observed to the Ru/TiO2 case, but is verified the decreasing of phenol selectivity. In turn, the Fe addition to the Pd/TiO2 catalyst has little influence on the activity and selectivity, leading thus to a significant decrease in the catalyst cost, without prejudice to the catalytic performance. The observed catalytic behaviors are analyzed and interpreted based in the results obtained through the characterization of solids, as well as information available in the literature
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
34
Nguyen, Thanh Dien. "Atmospheric behaviors and control measures of persistent organic pollutants: case studies on polybrominated diphenyl ethers and pentachlorophenol". 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217161.
Testo completo
35
Cassidy, Michael B. "Encapsulation of bacterial cells in a novel k-carrageenan formulation for enhanced mineralization of pentachlorophenol in soil". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24400.pdf.
Testo completo
36
Chen, Shin-Ling, e 陳欣伶. "Microwave Heating Desorption Pentachlorophenol". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/26034175147354532341.
Testo completoAbstract (sommario):
碩士國立屏東科技大學
環境工程與科學系
92
Abstract The principle of organoclay formction is that organ cation organic compounds proceed a isomorphism ion exchange of sorbed metal of soil to enter the structure of soil matrix.The characteristics of surfactant modifed clay surface would make the hydrophilic hydrophobic.Because of the increase of iner-sapace makes smectite adsorbtion ability of nonpolar mimerals be raised.One of the treatment used in soil contamination desorption not to dehydrate is called the microwave heating.And it has better efficiency in dealing with high organic and clay content soils . Generally, microwave heating is very high temperature to remove contaminants in soil.In this study the catalytic wet air oxidation（CWAO）was used to decrease oxidation reaction temperature and reaction rates,therefore the reaction times would be shorten. The authors used carboxydecyl triethyl ammonium cation（CDTEA）, hexadecyl trimethyl ammonium cation（HDTMA）for a modification of clays purified from Wu-Kan and San-Tai series of Taiwan soil and Smectite(Wyoming bentonite), and called as organoclay.The organoclays were used as adsorbent for pentachlorophenol（PCP）,and the effects of studied its adsorption mechanism.Regarding the decorption of PCP,addition of catalysts（Pd,Ni）and heated by microwave were compared After microwave heating ,the changes of organoclay structure and adsorption ability were investigated,and the recyclability was also discucsed. The order of isotherm adsorption capacity of six serices of organoclay for PCP was resulted as=Sm-HDTMA＞Wk-HDTMA＞St-HDTMA,the structure or length of alkylamine chains both affected the recults . HDTMA has a 16 carbon aliphatic chain,but CDTEA only has a 10 carbon chain. The most important part in compositing a hydrophobic chain is its amino group.So the adsorption of PCP in HDTMA was better in CDTEA. The effect of microwave deaorption on catalyst（Pd,Ni） showed that PCP concentration to be decreased of 200-300 mg/kg by adding Pd catalyst for heating 1-2min.All PCP could be removed from all of six serices of organoclay after 5min heating by microwave,but it was than 5min in the case of addition of Ni catalyst. The reaction rate of catalysis was Pd＞Ni. After microwave heating for 5min,all PCP already destructed and can not be detected by GC/MSD. FT-IR spectrum of six serices of organoclay after microwave heating showed bands of carboxylic group, quaternary ammonium groups（CDTEA）,C-N, and alkyl chain（HDTMA）.
37
Tasi, Chi-Tang, e 蔡啟堂. "Characterization of bacteria degrading pentachlorophenol". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/93551344763132060231.
Testo completoAbstract (sommario):
碩士國立中山大學
生物科學系研究所
90
Pentachlorophenol (PCP) is a chloride-containing aromatic compound which is mostly used for preserving wood and leather, but still one can easily detect this compound present in the waste water generated by various industries such as petrifaction, oil-refining, and etc. PCP, due to its chemical property of being stable and highly toxic, would cause severe and irreparable environmental pollution once exposed to open air. This study is intended to explore the feasibility of dealing the problem of PCP with biodegradation. The examination results showed that, except for absorption, the suspension of contaminated soil (aerobic incubation), nonetheless, could effectively degrade PCP during a period of 90 days without the aid of any extra carbon source. (0.62 mg/L/day). The degradation rate was further greatly improved by adding sodium acetate, molasses, and sludge cake (sodium acetate added: 4.15 mg/L/day; molasses added: 1.05 mg/L/day; sludge cake added:0.83 mg /L/day). None of four experimental groups of aerobic sludge, anaerobic sludge, contaminated soil (anaerobic incubation), and Fe3+reaction could degrade PCP after 135 days, 174 days, 250 days, and 124 days, respectively, regardless of whether any sources of carbon were added or not. A bacterium which used PCP as the sole carbon source was isolated from the contaminated soil. After 16s rDNA sequence analysis, it had 98% degree of similarity to Pseudomonas mendocina and was designated as Pseudomonas mendocina NSYSU. The PCP (40 mg/L) degradation rate of Pseudomonas mendocina NSYSU was 9.33 mg/L/day, and the degradation rate would slow down as PCP concentration increased. At a PCP concentration of 320 mg/L, PCP degradation was completely inhibited, although an active population of Pseudomonas mendocina NSYSU was still present in these cultures. The study also indicated that the addition of various carbon sources such as sodium acetate and glucose did not facilitate the degradation of PCP with the degradation rate of 8.11 mg/L/day for sodium acetate, and that of 7.55 mg/L/day for glucose. Analysis from examining several environmental factors showed that the optimal condition for PCP degradation is that of 30℃, pH6, and in the presence of oxygen. The end products of PCP degradation were detected by GC-MS. After 6 days of incubation, PCP was gradually disappeared and the metabolic intermediate product, acetic acid was detected. The chloride ion concentration also increased by 21.8 mg/L, which is approximately equal to the original total chloride content in PCP (66% of chloride content). In conclusion, PCP could be effectively and completely degraded by Pseudomonas mendocina NSYSU.
38
Chan, Hui-ling, e 詹惠齡. "Degradation of pentachlorophenol by ozoneation". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/h99fts.
Testo completoAbstract (sommario):
碩士嘉南藥理科技大學
環境工程與科學系暨研究所
93
Pentachlorophenol (PCP) is a highly toxicity material. Owing to its chemical property, it is difficult to dissolve in water and is recalcitrant to biological degradation. It can accumulate in the environment and can cause serious soil and groundwater contaminations. The objective of this study focused on the oxidation of PCP by ozone. Parameters studied in this investigation include ozone concentration, solution pH, and radical scavenger. It was found that under higher ozone concentration, the degradation of PCP will lead to three intermediates: tetrachloro-p- hydroquinone, tetrachloro-p-benzoquinon, and tetrachlorocatechol. Within 2 minutes of reaction at pH 6, the degradation of PCP were around 95%. From the experimental data, it was found that the reaction followed second-order kinetics and its initial rate was 4.98 ×10-2 S-1. On the other hand, at 2 minutes of reaction at pH 3 the degradation of PCP was only 30%. The degradation of PCP by ozone without the addition of the scanvenger, under different ozone concentrations at 0.08 min of reaction, reached a steady concentration. Under higher ozone concentrations, the degradation of PCP was around 90%. Under these conditions, PCP degradation also produce two intermediates: tetrachlorocatechol and tetrachloro-p-hydroquinone and its initial rate was 1.82 × 10-1 S-1.
39
Huang, Chung-Cheng, e 黃忠政. "Study on Removable Methods of Pentachlorophenol". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/17451347552947621913.
Testo completo
40
Huang, Chia-Chen, e 黃嘉貞. "Pentachlorophenol Humification and Adsorption in a Latosol". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/46895160288308373042.
Testo completoAbstract (sommario):
碩士國立屏東科技大學
環境工程與科學系
90
Abstract In this study, phenolic compounds and commercial humic soil are mixed with latosol, heterogeneous oxidation catalysts, that may accelerate the ploymerization of humic substances. We expect those phenolic compounds can be oxidized and catalyzed by latosol, simultaneously, pentachlorophenol could become complexation. We found latosol couldn’t oxidize and polymerize pentachlorophenol to form humic substances no matter how much the phenolic compounds and commercial humic soil or changed the concentration of penatchlorophenol we add in the short time. Furthermore, the analysis of FTIR confirmed that the matter from the polymerized substances were not humus. Then, we proceed the second experiment. In the second test, we add catechol and pyrogallol in latosol contaminated by pentachlorophenol. After 21 days, we found phenolic compounds could deal oxidation and polymerization with ozone. However, the E4/E6 of substances dealt with ozone are lower than 3, which mean they are humidified undecomposition enough. These study confirmed phenolic componuds and pentachlorophenol couldn’t oxidize and polymerize with each other in the natural environment. Ozone may strongly accelerate the ploymerization of phenolic compountds and pentachlorophenol.
41
Yeh, Li-Chi, e 葉力綺. "Biodegradation Enhancement by Screened Pentachlorophenol Degradating Bacteria". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/18937456832357902760.
Testo completoAbstract (sommario):
碩士國立屏東科技大學
環境工程與科學系
92
The widespread use of the pentachlorophenol (PCP) has caused certain pollutions in the soil, water, and air. However, Bioremediation is an economical and feasible disposing way that helps to reduce the damage to the environment. This study isolated the PCP degradating bacteria from three different PCP degradation microbial consortia in compost-soil that we have been climated for 150 days, and to find the most suitable environmental parameter on degradation. Then we used bioaugmentation to add screened bcteria into microbial consortia for enhancing PCP degradation activity. The diversity of the three microbial consortia analysis by denaturant gradient gel electrophoresis (DGGE) showed the same structure in mature hog manure and bark compost-soils and they were more diversity than the structure of contaminated-soil only. Enriched more times with PCP added, the diversity of PCP degradation microbial consortia became simpler. Pseudomonas citronellolis NPUED001 was isolated from bark compost soil and it showed 24.3 % PCP degradation ratio in the 75 mg/L concentration of PCP. The most suitable degradation pH for PCP degradation by NPUEM001 is 7.88~8.99 under the temperature of 30~35℃ with 75 mg/L initial concentration of PCP. The higher inoculum density of NPUEM001 will increase the PCP degradation ratio. The most efficient degradation ability is 51.41 % when the inoculum density is 2.8×106 cell/mL in 75 mg/L PCP-concentration. The initial concentration needs to reach the rang within 1.4×106~2.8×106 cell/mL of inoculum density for the effectiveness. When added with glucose as the second carbon source the PCP degradation ratio was raised up 17.3 % with 75 mg/L initial concentration of PCP but there was no obvious increase for citric acid addition. The bioaugmentation by added proliferation NPUEM001 into PCP degradation microbial consortia can effectively increase PCP degradation ratio to 50.7 %. The toxicity analysis of culture medium by Microtox showed the toxicity of PCP didn''t descend after the degradation of NPUEM001. The Pseudomonas citronellolis NPUEM001 and microbial consortia from bark compost-soil could be the inoculum for PCP contaminated site in Taiwan in the future.
42
"Inhibition by pentachlorophenol on anaerobic acidogenic systems". Tulane University, 1995.
Cerca il testo completoAbstract (sommario):
Pentachlorophenol (PCP) is a biocide which is widely used for its toxicity to microorganisms. Its major application is in wood preservation, and PCP at abandoned wood preserving sites is a major source of environmental pollution. Although much of the literature documents aerobic treatment for PCP, research indicates that there is great potential for anaerobic dechlorination of these compounds. The objectives of this investigation were to study the acidogenesis phase of the anaerobic biodegradation process; how acidogenesis is affected by PCP toxicity alone and in the presence of zinc; what role acidogenesis plays in the biodegradation of PCP; and how operating parameters, such as organic loading rate (OLR) and solids retention time (SRT) affect the degradation of PCP during acidogenesis. Batch anaerobic toxicity assays (ATAs) were performed to quantify the toxicity threshold for PCP and zinc, and to study the effect of these toxicants on volatile acids production. Continuous reactors (chemostats) were operated at SRTs of 0.25-0.61 day to kinetically exclude methanogenesis from acetate, so that the effects of the toxicants on acidogenesis could be evaluated PCP was found to have a toxicity threshold of 2.7-3.0 mg/L and zinc 23-27 mg/L in batch systems. Acetate utilizers showed the first signs of inhibition in PCP spiked systems, whereas hydrogen utilizers were the first organisms affected in response to a zinc spike. In the continuous systems, PCP in spike concentrations of 7.0 mg/L did not affect the quantity or composition of volatile acids produced in the chemostats. A rise in headspace hydrogen at 30 mg/L zinc indicated that hydrogen utilizers became inhibited in the presence of high zinc concentrations PCP was degraded, with approximately half of the degradation occurring during acidogenesis. GC/MS analysis detected no intermediate chlorophenols in the effluent. The efficiency of degradation varied indirectly with spike concentration and directly with SRTacase@tulane.edu
43
"Integrated treatment of pentachlorophenol by adsorption using magnetite-immobilized chitin and photocatalytic oxidation". Thesis, 2007. http://library.cuhk.edu.hk/record=b6074514.
Testo completoAbstract (sommario):
Chitin is known as an effective biosorbent, which is used to preconcentrate PCP for further treatment. In order to reuse and recover the biosorbent, magnetic separation is a cost-effective alternative to separate the PCP-adsorbed biosorbent (i.e. chitin) from the treated water. Therefore, chitin is immobilized by magnetite prior PCP adsorption. From the immobilization results, the solution pH, temperature, agitation rate do not show great effect on the immobilization of chitin and magnetite. Second, magnetite-immobilized chitin can be formed as quickly as 5 min. Moreover, the interaction of chitin and magnetite is very strong since it is not easy to separate by vigorous shaking, high temperature and changing pH. Although the underlying mechanism of magnetite and chitin is still obscure, the biosorbent is proved to have high stability and reusability. In addition, both Langmuir and Freundlich models indicate that immobilization of chitin by magnetite is favorable with the Langmuir model being the major one.For PCP adsorption study, it is found that magnetite-immobilized chitin can retain the PCP adsorption ability as free chitin. In accordance with the results, the PCP adsorption of magnetite-immobilized chitin is influenced by altering the parameters of biosorbent concentration, solution pH, temperature, agitation rate, contact time and initial PCP concentration. In general, higher amount of biosorbent gives higher removal efficiency (RE) but lower removal capacity (RC) as more binding sites are available for PCP. The PCP removal is enhanced by lowering pH since uncharged PCP is favorable for adsorption. It is speculated that hydrophobic interaction, hydrogen bonding and electrostatic interaction are involved. In addition, the biosorption efficiency is impeded by high temperature. Evidence shows that the adsorption might be due to the exothermic force such as hydrogen bonding. The biosorption is described as biphasic mechanism with the fast initial phase followed by slow equilibrium phase. For the PCP (10 mg/L) adsorption, the optimized conditions are: 1,500 mg/L of magnetite-immobilized chitin, initial pH 6, 25°C, 200 rpm and 60 min. The RE is 57.9% and RC is 5.4 mg/g. However, the increase in the amount of immobilized chitin (24,000 mg/L) can increase the RE up to 98%. By considering the Langmuir and Freundlich isotherms, the adsorption might be heterogenous, as the correlation coefficient from Freundlich model is higher.
Pentachlorophenol (PCP), a highly chlorinated aromatic organic compound, was widely used as a biocide and is now restrictly used as a wood preservative. PCP is toxic and ubiquitous environmental pollutant. In the present study, integrated treatment of biosorption and photocatalytic oxidation (PCO) using magnetite-immobilized chitin is employed to completely degrade PCP.
To thoroughly remove PCP, PCO is also employed after the biosorption. One hundred % of PCP removal is achieved after 5 h irradiation time, in 100 mL solution at initial pH 9 with 20 mM of H2O2 and 200 mg/L of TiO2. The intermediates of PCP are identified as 2,3,5,6-tetrachlorohydroquinone (TeHQ) and 2,3,5,6-tetrachlorophenol (TeCP) by GC/MS analysis. In addition, the toxicity of sample is monitored by the solid-phase and aqueous-phase Microtox RTM tests, which the toxicity increases and then decreases along the irradiation time. The biosorbent shows no great changes on chitin content and functional groups after PCO. In addition, the results imply that magnetite-immobilized chitin has a good potential to be reused at least for four cycles with high RE and DE. Therefore, the combination of biosorption and PCO treatment was feasible for PCP removal and the system is economic and convenient for repeated use.
by Pang, King Man.
"Oct 2007."
Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4636.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2007.
Includes bibliographical references (p. 186-212).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
44
Deng, Li-Hao, e 鄧禮浩. "Surfactant-enhanced Electrokinetic Remediation of Pentachlorophenol from Soil". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/33065757969093713124.
Testo completoAbstract (sommario):
碩士國立中興大學
環境工程學系所
99
Pentachlorophenol (PCP) is a highly chlorinated organic compound that has been extensively used as a pesticide, particularly in the wood preservation industry. Due to its stable aromatic ring structure and high chlorine content, PCP is persistent in the environment, and it has become one of the most widespread contaminants in soil and water. The objective of this study was to investigate the removal of PCP from the kaolinite using electrokinetic method in the presence of surfactants. An anionic surfactant, Sodium dodecylbenzene sulfonate (SDBS) was used to enhance the solubility of PCP. It was found that the removal of PCP was limited in the electrokinetic remediation when SDBS was used as the anodic electrolyte solution. This was attributed to that PCP transport toward the anode overcame the opposite electrosmotic flows. On the other hand, using SDBS as the cathodic electrolyte solution removed 23.37% of PCP from kaolinite. This was attributed to PCP transport toward the anode within the negatively charged micelles.
45
Roberts, David Bradley. "Down-borehole permeable barrier reactor : verification of complete mineralization of pentachlorophenol in a sequential anaerobic-aerobic process". Thesis, 1997. http://hdl.handle.net/1957/33714.
Testo completo
46
Kaslik, Peter J. "Down-borehole permeable barrier reactor : primary substrate selection for aerobic dichlorophenol degradation". Thesis, 1996. http://hdl.handle.net/1957/34705.
Testo completoAbstract (sommario):
In situ bioremediation of pentachlorophenol-contaminated ground water in a sequential
anaerobic-aerobic down borehole permeable barrier reactor requires a non-toxic primary
substrate for dichlorophenol cometabolism. Serum bottle tests comparing the
effectiveness of eight primary substrates for aerobic dichlorophenol degradation showed
phenol to be the most effective followed by imitation vanilla flavoring, guaiacol, sodium
benzoate, molasses, acetic acid, propylene glycol and ethyl vanillin in propylene glycol.
As phenol is a pollutant, imitation vanilla flavoring is the recommended primary substrate
for field use. In a second bottle test, 3,4,5-trichlorophenol was not sufficiently
biotransformed, emphasizing the need for biotransformation to occur in the anaerobic
zone of the reactor.Graduation date: 1996
47
Stuart, Sheryl L. "The effect of environmental conditions on the reductive dechlorination of pentachlorophenol by a mixed, methanogenic culture". Thesis, 1996. http://hdl.handle.net/1957/34451.
Testo completo
48
Liu, Chia-Fu, e 劉家福. "Study on Remediation Technologies for Pentachlorophenol Pollutant in Groundwater". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/04622806922007424039.
Testo completoAbstract (sommario):
碩士朝陽科技大學
環境工程與管理系碩士班
97
Chlorophenols are a type of organic compound difficult to decompose in the natural environment. Pentachlorophenol, among which, is a hydrophobic ionizable organic pollutant. Once the environment is polluted by adsorption in the soil, it affects the groundwater sources, causing soil and groundwater pollution. Supercritical carbon dioxide has the characteristics of being inactive, non-toxic, safe, relatively low in price, and easy to obtain. Therefore, the main objective of this research was using the green technology of supercritical fluid with methanol modifier to extract the pentachlorophenol pollutant in groundwater. The best extraction efficiency was then determined, followed by chemical oxidation experiments to destroy pentachlorophenol. First, pentachlorophenol was added to non-contaminated groundwater to make unsaturated, saturated and oversaturated groundwater samples, of which, the groundwater pH value is neutral with its electrical conductivity and oxidation reduction potential similar to common groundwater. Therefore, it can be used as a reference for general groundwater remediation. While conducting supercritical fluid extraction, in order to determine the optimal conditions and individual efficiencies, this study investigated different temperatures, pressure and the addition ratio of methanol modifier. During the extraction for unsaturated, saturated and oversaturated pentachlorophenol in groundwater, the extraction efficiency was found above 96% without adding modifier. However, the extraction efficiency was determined above 97% when 2.5% and 5% v/v methanol modifier was introduced. In the chemical experiment, this research applied the Fenton oxidation reaction, Persulfate oxidation reaction and TiO2 photocatalysis with UV light to removal the pentachlorophenol pollutant in groundwater. In the Fenton oxidation reaction, hydrogen peroxide solution of 206 mM and ferrous iron of 14.4 mM were prepared for the reaction. As for the persulfate oxidation reaction, sodium persulfate solution of 16.8 mM and ferrous iron of 14.4 mM were prepared for the reaction, the removal efficiencies were determined above 94% for both chemical oxidation reactions. Using the two chemical oxidation methods accompanied by appropriate chemical reagents, optimal removal efficiency can be achieved. In the TiO2 photocatalyst reaction, addition of 0.1% TiO2 provided the best pentachlorophenol removal efficiency in the UV light. However, when adding higher concentration of TiO2, due to the shadowing effect, the removal efficiency of pentachlorophenol was reduced. After using the supercritical fluid to extract pentachlorophenol from the groundwater followed the chemical oxidation experiment, the amount of chemical reagents can be reduced and so will the environmental secondary pollution.
49
Su, I.-Min, e 蘇益民. "Study on Remediation Technologies for Pentachlorophenol Pollutant in Soil". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/20706088078866706112.
Testo completoAbstract (sommario):
碩士朝陽科技大學
環境工程與管理系碩士班
97
Chlorophenol compounds are difficult to break down naturally in the environment. This study was to use Fenton oxidation, TiO2 photocatalytic degradation, biological surfactants cyclodextrins washing, supercritical carbon dioxide extraction to remove or destroy pentachlorophenol in soils, it has reached in the environment PCP reduction purposes. Soil samples used in this study were obtained from the central region of Taiwan, and were the common red and alluvial soils. The characteristics of soils was analyzed and discussed, herein the contaminated soil was prepared by spiking PCP in soil. The result of Fenton oxidation indicated that H2O2 concentration 206 mM and Fe2+ concentration 57.6 mM were the optimal concentrations for the red soil experiment, the removal efficiency of PCP reached to 75%, however the concentration of H2O2 required to upgrade to 825 mM for alluvial soil in order to obtain 70% removal efficiency. Using 1 mM Cyclodextrin solution to wash PCP from soil, the removal efficiency was 60% for red soil while reach to 80% for alluvial soil. Various temperature, pressure and modifier ratio were conducted in supercritical carbon dioxide extraction experiments. The extraction efficiency reached to 60% in the condition of 100 bar and 70˚C for both soils, moreover the extraction efficiency increased about 10% while 5% (v/v) methanol modifier was introduced, however the extraction efficiency decreased when 10% modifier was overdosed. The extracted PCP was concentrated in the methanol with 2 mL volume, was then examined with Fenton reaction. The data showed the PCP was completely destructed by using significantly lower amount of Fenton’s reagent compared to directly addition of Fenton’s reagent to soil. Keywords: Supercritical fluid extraction, Soil, Pentachlorophenol, Fenton oxidation, Cyclodextrin.
50
Wang, Jr-Wei, e 王志偉. "Removal of Pentachlorophenol in Water by Electrochemical Treatment Process". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/wz283e.
Testo completoAbstract (sommario):
碩士崑山科技大學
環境工程研究所
96
This study addressed the application of electrochemical technology on the detection of chlorophenols and the removal of pentachlorophenol in water. The reactor used in this study is a 50 mL double-jacketed glassware , which is established a Pt electrode as working electrode, a Pt wire as counter electrode, and an Ag/AgCl electrode as reference electrode. The electrochemical analyzer is employed to precisely control a constant potential during the experiments, and the currency passing through the electrodes in the reactor was recorded by the 61/2 multimeter. In the detection experiments, the scan rate is set at 0.3 V/s under the analysis of linear sweep voltammetry (LSV). On the cyclic voltammetry (CV) plot, each pair of clear redox peaks was observed for 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), and penta- chlorophenol (PCP). The potentials of the redox pairs were 1.218 and -0.460 V for 4-CP, 1.128 and -0.448 V for 2,4-DCP, and 1.037 and -0.473 V for PCP. Based on the liner relationship between the concentrations of chlorophenols and the corresponding peak current, the suitable quantification ranges were 0.2~1 mg/L for 4-CP, 0.3~2 mg/L for 2,4-DCP, and 0.1~4 mg/L for PCP by the LSV analysis. The detection experiments demonstrated a quick measurement method to quantify the trace levels of chlorophenols in water by the electrochemical analyzer. As using 1.00 M KI as electrolyte in the degradation experiments, a complete removal of PCP was achieved by the electrolysis at 500 mV. However, the same controls of degradation experiments did not result in a similar result as using 1.00 M KCl or Na2SO4. A possible contribution is ascribed to the formation of the redox couple I3-/I-, which might play the role of mediator to initiate indirect oxidation. On the contrary, PCP can be completely removed for 1.00 M KI, KCl, or Na2SO4 by the electrolysis at -1200 mV. The possible mechanism is that the forming H atoms from water electrolysis might dechlorinate the adsorbed PCP on the electrode surface. Thus, the degradation of PCP synchronized with the dechlorination of PCP. As using 0.50 M KCl as electrolyte in the degradation experiments, a complete removal of PCP was achieved by the electrolysis at -1500 mV. The same controls of experiment conditions did not result in a similar result as using NaNO3 or CaCO3. The removal of PCP is only 88% under the initial pH 9.97, while the removal efficiency is over 99% under the initial pH 3.86. As a consequence, the strong basic condition of initial pH is not favorable for the electrochemical degradation of PCP. Based on the analysis of GC/MS, the intermediates of PCP degradation are determined as 1,2-dichloro-cyclohexane, trans-2-chloro-cyclohexamol, and 3-hexen- 1-yne. Accordingly, PCP can be successfully dechlorinated by a proper control of electrochemical treatment process.