Several potential sorbent materials containing iron oxides were prepared and evaluated for potential to remove divalent metals from waste waters. These included a ferrihydrite-coated sand, maghemite incorporated in Dowex[Trademark] ion exchange resin, gothite and two thermally activated ferrihydrites. Attempts to prepare sorbents from steel shot by coating with ferrihydrite or by thermal oxidization resulted in cemented solids rather than pellets. Ferrihydrite activated at 295��C had a surface area of 113-202 m��/g, followed by gothite at 72-92 m��/g and ferrihydrite-coated sand at 0.78-1.4 m��/g. Zinc adsorption was evaluated by placing 5 g ferrihydrite-coated sand, 0.1 g maghemite in Dowex or 0.1 g gothite in batch reactors containing 40-50 mL of zinc solution, adjusting to various pH values, allowing to react for 96 hours, and analyzing the supernatant for zinc. The data fitted poorly to an ion exchange model using nonlinear regression. The adsorption site densities determined from the regression analysis were 8.0x10������ moles per gram of ferrihydrite-coated sand and 4.1x10������ moles per gram of White. Maghemite in Dowex did not provide any additonal zinc removal capacity in excess of the ion exchange capacity of the resin. Kinetic experiments showed that zinc adsorption onto ferrihydrite-coated sand was 86% complete after 96 hours. Based upon this study, the most promising sorbent appears to be gothite, although the "activated ferrihydrites" are also worthy of further study. Neither ferrihydrite-coated sand and maghemite in Dowex appear to be practical sorbents, based on their low zinc adsorption site density. Maghemite in Dowex might be useful in applications requiring magnetic sorbents. / Graduation date: 1999

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

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

published_or_final_version / Civil Engineering / Master / Master of Philosophy

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

Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2018. / Advanced oxidation processes (AOPs) have gained considerable interest in the wastewater treatment industry. Low selectivity to organic pollutants and the high oxidation potentials provided by the free radicals produced from these processes are the root of this interest. Hydroxyl radical based AOPs seemed to dominate the field but recently sulphate radical based AOPs started to become more popular due to their even higher oxidation potential. The textile industry is known to be a considerable contributor to wastewater production. Many pollutants in this wastewater are organic pollutants which are very persistent to the more traditional treatment processes such as biological treatment and membrane filtration. Numerous studies have shown the potential and success of catalytic AOPs for the degradation of organic pollutants in wastewater. One such process is the use of a cobalt oxide nano-catalyst in conjunction with a peroxymonosulfate (PMS) oxidizer (Co3O4/PMS). The shortcoming with nano-catalysts however are the difficulty of recovering the catalyst in a slurry system or the effective immobilization of the catalyst in a continuous system. To address the issue of nano-catalyst immobilization, two different methods were used in the study to effectively immobilize the catalyst in a substrate. The methods were compared by utilizing the permeable reaction barriers in a continuous flow reactor. A bench scale reactor of 2.4 L/hr was designed and used to study the effect of PMS, catalyst mass and flow rate on the degradation efficiency and to determine the residence time and catalyst per PRB cross-sectional area ratio. A scale up rationale was formulated based on a constant residence time and the catalyst mass per PRB cross-sectional area ratio. Two design correlations were developed to predict the size of the permeable barrier and the catalyst mass required for the scale up PRB system. These parameters were used to design a reactor 30 times that of the bench scale reactor. In both reactors the optimum degradation occurred within 2 minutes indicating the success for catalyst immobilization and the development of a continuous reactor utilizing the Co3O4/PMS advanced oxidation technology.

published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

The possibility of the existence of an iron-organic interaction in Harwood's Mill Reservoir contributing to a problem with floe formation after chlorinating filter-applied water was investigated. Shortened filtration-cycle times resulted when the filter-applied water contained the floc. The effects of varying pH, temperature, alum dosage, and oxidant addition on organic and meta.ls removals were examined with jar tests. Ultrafiltration analyses were performed to determine with which molecular size range of organic matter the iron may have been associated. Particle-size analysis was used to further examine the chlorination phenomenon. The low iron concentrations in the raw water were removed easily under any experimental condition. Organic removal, however, was optimized by alum coagulation ( 50 mg/L) at pH 5. 5 and a preoxidant dose of 2 mg/L. Improvements in organics removal over that of the WTP suggested that poor organic removal contributed to the floe-formation problem. / M.S.

by Chan Hiu-wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 123-133). / Text in English; abstracts in English and Chinese. / by Chan Hiu-wai. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.x / List of Tables --- p.xiii / List of Abbreviations --- p.xv / Page / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The chemical class: Phthalate esters --- p.1 / Chapter 1.2 --- Di(2-ethylhexyl)phthalate --- p.2 / Chapter 1.2.1 --- Characteristics of DEHP --- p.5 / Chapter 1.2.2 --- Production and applications --- p.5 / Chapter 1.2.3 --- Environmental releases and environmental fate --- p.8 / Chapter 1.2.4 --- Toxicity of DEHP --- p.8 / Chapter 1.2.4.1 --- Mammalian toxicity --- p.9 / Chapter 1.2.4.2 --- Toxicity to aquatic organisms --- p.10 / Chapter 1.2.5 --- Regulations --- p.10 / Chapter 1.3 --- Conventional technologies for DEHP removal --- p.11 / Chapter 1.3.1 --- Biodegradation --- p.11 / Chapter 1.3.2 --- Coagulation --- p.11 / Chapter 1.3.3 --- Adsorption --- p.11 / Chapter 1.4 --- Innovative technologies for DEHP removal --- p.12 / Chapter 1.4.1 --- Biosorption --- p.13 / Chapter 1.4.1.1 --- Definition of biosorption --- p.13 / Chapter 1.4.1.2 --- Mechanisms --- p.13 / Chapter 1.4.1.3 --- Selection of biosorbents --- p.17 / Chapter 1.4.1.4 --- Assessment of biosorption performance --- p.21 / Chapter a. --- Batch adsorption experiments --- p.21 / Chapter b. --- Modeling of biosorption --- p.21 / Chapter 1.4.1.5 --- Recovery of biosorbents --- p.23 / Chapter 1.4.1.6 --- Development of biosorption process --- p.23 / Chapter 1.4.1.7 --- Seaweeds as biosorbents --- p.24 / Chapter 1.4.2 --- Advanced oxidation processes --- p.27 / Chapter 1.4.3 --- Heterogeneous photocatalytic oxidation --- p.30 / Chapter 1.4.3.1 --- Photocatalyst --- p.30 / Chapter 1.4.3.2 --- General mechanisms --- p.31 / Chapter 1.4.3.3 --- Influencing parameters in PCO --- p.33 / Chapter 1.4.3.4 --- Enhanced performance by addition of hydrogen peroxide --- p.33 / Chapter 2 --- Objectives --- p.36 / Chapter 3 --- Materials and Methods --- p.38 / Chapter 3.1 --- Chemical reagents --- p.38 / Chapter 3.2 --- Biosorption of DEHP by seaweed biomass --- p.39 / Chapter 3.2.1 --- Biosorbents --- p.39 / Chapter 3.2.2 --- Determination method of DEHP --- p.39 / Chapter 3.2.3 --- Batch adsorption experiments --- p.44 / Chapter 3.2.3.1 --- Screening of potential biomass --- p.44 / Chapter 3.2.3.2 --- Characterization of beached seaweed and S. siliquastrum --- p.44 / Chapter a. --- Total organic carbon (TOC) content --- p.44 / Chapter b. --- Leaching of biomass components --- p.45 / Chapter 3.2.3.3 --- Combined effect of pH and biomass concentration --- p.45 / Chapter 3.2.3.4 --- Effect of retention time --- p.45 / Chapter 3.2.3.5 --- Effect of agitation rate --- p.45 / Chapter 3.2.3.6 --- Effect of temperature --- p.46 / Chapter 3.2.3.7 --- Effect of particle size --- p.46 / Chapter 3.2.3.8 --- Effect of DEHP concentration --- p.46 / Chapter 3.2.4 --- Recovery of adsorbed DEHP from seaweed biomass --- p.47 / Chapter 3.2.4.1 --- Screening for suitable desorbing agents --- p.47 / Chapter 3.2.4.2 --- Multiple adsorption-desorption cycles --- p.47 / Chapter 3.2.5 --- Statistical analysis --- p.43 / Chapter 3.3 --- Photocatalytic oxidation --- p.48 / Chapter 3.3.1 --- Photocatalytic reactor --- p.48 / Chapter 3.3.2 --- Optimization of reaction conditions --- p.48 / Chapter 3.3.2.1 --- Effect of reaction time --- p.48 / Chapter 3.3.2.2 --- Effect of initial pH --- p.51 / Chapter 3.3.2.3 --- Effect of Ti02 concentration --- p.51 / Chapter 3.3.2.4 --- Effect of UV intensity --- p.52 / Chapter 3.3.2.5 --- Effect of H202 concentration --- p.52 / Chapter 3.3.2.6 --- Effect of initial DEHP concentration and irradiation time --- p.52 / Chapter 3.3.2.7 --- Statistical analysis --- p.52 / Chapter 3.3.4 --- Determination of mineralization of DEHP by analyzing total Organic carbon (TOC) content --- p.53 / Chapter 3.3.5 --- Identification of intermediate products of DEHP --- p.53 / Chapter 3.3.6 --- Evaluation for the toxicity of DEHP and intermediate products --- p.53 / Chapter 3.3.6.1 --- Microtox® test --- p.53 / Chapter 3.3.6.2 --- Amphipod survival test --- p.55 / Chapter 3.4 --- Feasibility of combining biosorption and photocatalyic oxidation as an Integrated treatment for DEHP --- p.57 / Chapter 3.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.57 / Chapter 3.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.57 / Chapter 4 --- Results --- p.58 / Chapter 4.1 --- Determination method of DEHP --- p.58 / Chapter 4.2 --- Biosorption --- p.58 / Chapter 4.2.1 --- Batch adsorption experiments --- p.58 / Chapter 4.2.1.1 --- Screening of potential biomass --- p.58 / Chapter 4.2.1.2 --- Characterization of beached seaweed and S. siliquastrum --- p.61 / Chapter a. --- Total organic carbon (TOC) content --- p.61 / Chapter b. --- Leaching properties --- p.61 / Chapter 4.2.1.3 --- Combined effect of pH and biomass concentration --- p.61 / Chapter 4.2.1.4 --- Effect of retention time --- p.74 / Chapter 4.2.1.5 --- Effect of agitation rate --- p.74 / Chapter 4.2.1.6 --- Effect of temperature --- p.74 / Chapter 4.2.1.7 --- Effect of particle size --- p.74 / Chapter 4.2.1.8 --- Effect of initial DEHP concentration: Modeling by Langmuir and Freundlich adsorptin isotherm --- p.79 / Chapter 4.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.84 / Chapter 4.2.2.1 --- Screening for suitable desorbing agents --- p.84 / Chapter 4.2.2.2 --- Multiple adsorption-desorption cycles --- p.84 / Chapter 4.3 --- Photocatalytic oxidation --- p.90 / Chapter 4.3.1 --- Optimization of reaction conditions --- p.90 / Chapter 4.3.1.1 --- Effect of reaction time --- p.90 / Chapter 4.3.1.2 --- Effect of initial pH --- p.90 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.90 / Chapter 4.3.1.4 --- Effect of UV intensity --- p.90 / Chapter 4.3.1.5 --- Effect of H2O2 concentration --- p.95 / Chapter 4.3.1.6 --- Effect of initial DEHP and irradiation time --- p.95 / Chapter 4.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.95 / Chapter 4.3.3 --- Identification of intermediate products of DEHP --- p.95 / Chapter 4.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.102 / Chapter 4.3.4.1 --- Microtox® test --- p.102 / Chapter 4.3.4.2 --- Amphipod survival test --- p.102 / Chapter 4.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.102 / Chapter 4.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.102 / Chapter 4.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.103 / Chapter 5 --- Discussion --- p.108 / Chapter 5.1 --- Determination method of DEHP --- p.108 / Chapter 5.2 --- Biosorption --- p.108 / Chapter 5.2.1 --- Batch adsorption experiments --- p.108 / Chapter 5.2.1.1 --- Screening of potential biomass --- p.108 / Chapter 5.2.1.2 --- Characteristic of S. siliquastrum and beached seaweed --- p.109 / Chapter 5.2.1.3 --- Combined effect of pH and biomass concentration --- p.109 / Chapter 5.2.1.4 --- Effect of retention time --- p.111 / Chapter 5.2.1.5 --- Effect of agitation rate --- p.111 / Chapter 5.2.1.6 --- Effect of temperature --- p.111 / Chapter 5.2.1.7 --- Effect of particle size --- p.112 / Chapter 5.2.1.8 --- Effect of initial DEHP concentration: Modeling of Langmuir and Freundlich adsorption isotherms --- p.112 / Chapter 5.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.114 / Chapter 5.2.2.1 --- Screening for suitable desorbing agents --- p.114 / Chapter 5.2.2.2 --- Multiple adsorption-desorption cycles --- p.115 / Chapter 5.3 --- Photocatalytic oxidation --- p.115 / Chapter 5.3.1 --- Optimization of reaction conditions --- p.115 / Chapter 5.3.1.1 --- Effect of reaction time --- p.115 / Chapter 5.3.1.2 --- Effect of pH --- p.116 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.116 / Chapter 5.3.1.4 --- Effect of UV intensity --- p.116 / Chapter 5.3.1.5 --- Effect of H2O2 concentration --- p.117 / Chapter 5.3.1.6 --- Effect of DEHP concentration and irradiation time --- p.117 / Chapter 5.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.117 / Chapter 5.3.3 --- Identification of intermediate products of DEHP --- p.118 / Chapter 5.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.119 / Chapter 5.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.119 / Chapter 6 --- Conclusions --- p.121 / Chapter 7 --- References --- p.123

Dentre as tecnologias para tratamento de efluentes, este trabalho abordou processos de oxidação avançada fundamentados no uso de catalisadores heterogêneos, sendo este processo também conhecido por fotocatálise heterogênea. A eficiência desse tipo de processo já é bastante conhecida e reportada na literatura, no entanto, sua aplicação conta com gastos de energia artificial para ativação do catalisador responsável pela degradação de contaminantes. Neste sentido, novos materiais têm sido desenvolvidos para promoverem a fotossensibilização de catalisadores como TiO2, o que viabiliza ativação pela luz visível e aplicações com energia renovável solar. No desenvolvimento de novos catalisadores, os materiais nanoestruturados compósitos, formados por duas ou mais substâncias em contato íntimo, destacam-se pelo sinergismo que confere propriedades singulares ao material. Este trabalho teve como objetivo a síntese, caracterização e aplicação de nanocompósitos formados por polianilina (PANI), TiO2-P25 e NTCs como catalisadores na degradação do fármaco sulfametoxazol sob luz solar simulada. A síntese do catalisador consistiu na polimerização interfacial (água/tolueno) da anilina, contento fase orgânica com NTCs e anilina, e dióxido de titânio na fase aquosa. Diferentes associações dos materiais e concentrações de TiO2 foram testadas e resultaram nos seguintes catalisadores PANI:TiO2, PANI:TiO2-conc, NTC:PANI:TiO2 e NTC:PANI:TiO2-conc. Os materiais foram caracterizados por espectroscopia Raman, difração de raios X, microscopias eletrônicas de varredura e transmissão e análise termogravimétrica. O potencial desses materiais em fotocatálise de sulfametoxazol foi avaliado por um sistema de luz solar simulada. A síntese interfacial resultou em compósitos verdes, cor característica da polianilina. As técnicas de caracterização indicaram a formação de polianilina como uma massa polimérica contendo NTCs e/ou TiO2. O polímero nos compósitos mostrou, por espectroscopia Raman, ser mais polariônico, planar e menos reticulado. Análises termogravimétricas revelaram que os compósitos foram constituídos por cerca de ~ 85 % de TiO2 nas amostras com NTCs e ~ 95 % de óxido nas amostras formadas apenas por polianilina e óxido de titânio. Foi discutido condições fundamentais sobre a determinação da fotossensibilização do TiO 2-P25 por polianilina e NTCs, através de um sistema solar simulado. O catalisador PANI:TiO2-conc mostrou maior capacidade de fotodegradação de sulfametoxazol sob luz solar simulada em relação ao TiO2-P25. Diante disso, o compósito formado por polianilina e TiO2 com baixo percentual de polímero, resultou em um material com maior potencial para aplicações em sistemas solares. / Among the technologies for wastewater treatment, this work addressed advanced oxidation processes based on the use of heterogeneous catalysts, this process is also known as heterogeneous photocatalysis. The efficiency of this type of process is already well known and reported in the literature, however, its application has artificial energy costs for activation of the catalyst responsible for the degradation of contaminants. In this sense, new materials have been developed to promote the photosensitizing catalysts such as TiO2, which enables activation by visible light and solar renewable energy applications. In the development of new catalysts the nanostructured composite materials formed of two or more substances in close contact, stand out due to synergism which confers unique properties to the material. This study aimed to the synthesis, characterization and application of nanocomposites formed by polyaniline (PANI), TiO2-P25 and CNTs as catalysts in the degradation of the drug sulfamethoxazole under simulated sunlight. The catalyst synthesis was the interfacial polymerization (water / toluene) of aniline, containing organic phase with CNTs and aniline, and titanium dioxide in the aqueous phase. Different associations of materials and TiO2 concentrations were tested and resulted in the following catalysts PANI:TiO2, PANI:TiO2-conc, NTC:PANI:TiO2 and NTC:PANI:TiO2-conc. The materials were characterized by Raman spectroscopy, X- ray diffraction, electronic microscopy of scanning and transmission, and thermogravimetric. The potential for these materials in photocatalysis of sulfamethoxazole was evaluated by a simulated solar light system. The interfacial synthesis resulted in a green composite color, characteristic of polyaniline. The characterization techniques indicated the formation of polyaniline as a polymeric mass containing CNTs and / or TiO2. The polymer in the composite showed by Raman spectroscopy, to be more polaronic form, planar, an less reticulation. Thermogravimetric analysis showed that the composite consisted of approximately ~ 85 % TiO2 on samples with CNTs and ~ 95 % oxide in the samples formed only polyaniline and titanium oxide. Was discussed fundamental conditions on determining the photosensitivity of TiO2-P25 by polyaniline and CNTs, through a simulated solar system. The catalyst PANI:TiO2-conc showed higher photodegradation ability to sulfamethoxazole under simulated sunlight compared to TiO2-P25. Thus, the composite formed by polyaniline and TiO 2 with low percentage of polymer, resulted in a material with the greatest potential for applications in solar systems.