Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Os Processos Oxidativos Avançados (POA) surgem como uma tecnologia eficiente para a remediação de áreas contaminadas com óleos, permitindo em muitos casos a completa degradação de uma grande variedade de compostos orgânicos recalcitrantes. Dentre os POA, o reagente de Fenton se destaca por sua simplicidade operacional e tecnologia eficiente para grande carga orgânica, assim como, envolve tempo e custo de processos reduzidos. A literatura reporta uma variedade de trabalhos envolvendo remediação de solos arenosos por POA. Estes resultados não devem ser aplicados diretamente para remediar solos brasileiros devido à variedade dos tipos de petróleo e à grande extensão do território brasileiro rico em diferentes tipos de solos predominantemente argilosos. Dessa forma, é de extrema importância o profundo conhecimento de avaliação e indicação de uma forma de se remediar o solo com condições menos agressivas evitando assim a sua desertificação. Dessa forma, este trabalho tem como objetivo avaliar a eficiência do teor e da forma do ferro endógeno na remediação do tipo Fenton em diferentes amostras de solos brasileiros contaminados com óleo diesel. Dez diferentes tipos de solos brasileiros: argissolo (Arg), chernossolo (Che), latossolo vermelho (LV), latossolo amarelo (LA), latossolo vermelho e amarelo (LVA), latossolo férrico (LE), neossolo (NeQ), organossolo (Org), solonchak (Soc), vertissolo (Ver). Os teores das diferentes formas de ferro endógenos (amorfo, cristalino, biodisponível e total) foram determinados pela extração por ditionito-citrato-bicarbonato de sódio (Fe-CDB), extração com oxalato ácido de amônio (Fe-oxalato), extração com ácido sulfúrico (Fe2O3-AS) e extração com solução de ácido dietileno triamino pentacético (Fe-DTPA), respectivamente. A avaliação da eficiência de oxidação pela dosagem de H2O2 e a forma de ferro disponível, assim como a sua quantidade, foi avaliada segundo correlação de Pearson. Verificou-se que a maioria dos solos argilosos tropicais (LV, LE, LA), mesmo apresentando uma grande quantidade de óxido de ferro cristalino (Fe-DCB) comparados aos solos tipo arenosos (NeQ, Org, Soc), apresentaram resultados de remediação semelhantes aos solos arenosos. Além disso, não foi observada uma correlação linear entre a quantidade de óxido de ferro cristalino e a eficiência da remediação, porém sugere-se que a elevada quantidade de óxido de ferro cristalino (Fe-DCB) adsorva os íons ferro da solução. O LVA foi o solo que apresentou a maior eficiência de remediação, independente da adição ou não de ferro. Este resultado foi atribuído à sua maior quantidade de ferro amorfo (Fe-oxalato). A tentativa de se correlacionar a remediação com algumas propriedades dos solos demonstrou que a correlação com pH, sem considerar o solonchack (Soc) é a que apresenta maior significância, ou seja, é o pH do solo que parece influenciar o grau de diferenciação das remediações com ou sem adição de ferro. Em solos mais arenosos, a eficiência da remediação com a adição de ferro exógeno foi mais significativa do que a observada para os solos argilosos.

Submitted by Ana Caroline Costa (ana_caroline212@hotmail.com) on 2018-11-21T16:41:37Z No. of bitstreams: 2 Tese - Neemias Cintra Fernandes - 2018.pdf: 4113836 bytes, checksum: bff379029847f46880350ed814f5048d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-11-26T14:06:45Z (GMT) No. of bitstreams: 2 Tese - Neemias Cintra Fernandes - 2018.pdf: 4113836 bytes, checksum: bff379029847f46880350ed814f5048d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-11-26T14:06:45Z (GMT). No. of bitstreams: 2 Tese - Neemias Cintra Fernandes - 2018.pdf: 4113836 bytes, checksum: bff379029847f46880350ed814f5048d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-06-18 / Azo dyes represent the most important class of textile dyes, being widely used in the pharmaceutical and food industry. These molecules are present in domestic and industrial wastewater, and are resistant to conventional effluent treatment eventually producing more toxic products than the original dyes. Advanced oxidative processes (AOPs) have been implemented in order to decompose or mineralize substances that are difficult to treat, reducing their toxicity and the inherent risks of releasing pollutants into the environment. Objective: To study the ecotoxicity and optimize the operational conditions in the decomposition of textile azo dye DR343 using Fenton and Fenton-like reactions. Method: Oxidative processes were studied using the factorial design Box-Behnken Design (BBD), and the optimization of the reaction conditions was performed by applying the desirability function. The pH of the medium, the reaction time, the concentrations of iron [Fe 2+ ] (Fenton) and [Fe 3+ ] (Fenton-like) as well as the oxidizing agent [H 2 O 2 ] were used as independent variables in the planning. The responses studied were the removal of DR343, the concentration of residual hydrogen peroxide [H 2 O 2residual ] and the mortality of Artemia salina. The toxicity of the untreated dye was evaluated in different organisms (lettuce seeds, Artemia salina and zebrafish embryos). Samples treated under optimal conditions were submitted to the same protocols. Results: The dye removal was in the range of 5.8% to 100%, being affected only by the concentration of catalyst [Fe 2+ /Fe 3+ ] in both processes. On the other hand, the process time had a significant effect on the mortality of A. salina in samples submitted to the Fenton process, which suggests formation of toxic oxidation byproducts at the beginning of the process, followed by the mineralization of the samples. Optimum conditions for the Fenton reaction included [Fe 2+ ] of 0.33 mmol.L -1 and [H 2 O 2 ] of 4.50 mmol.L -1 . Under these conditions, 100% of the dye decomposition was observed in 16.1 minutes. On the other hand, the optimal conditions of the Fenton-like process included [Fe 3 + ] of 0.25 mmol.L -1 and [H 2 O 2 ] of 0.54 mmol.L -1 . Under these conditions total dye decomposition was observed in only 9.2 minutes. No [H 2 O 2residual ] was detected in both optimized processes. No significant phytotoxic effects were observed on the untreated dye dispersions, nor after treatment in both procedures. In the case of the A. salina assays, differences between the two processes were observed. Samples treated by Fenton-like did not show significant toxicity, whereas the Fenton process induced significant mortality for this organism. Samples treated under optimal conditions, from both methods, did not induce lethal or sublethal effects on zebrafish embryos. Total organic carbon reduction of 52.0% and 34.8% was observed for Fenton and Fenton-like, respectively. Conclusion: Both the studied processes can be successfully used to decompose the DR343 dye in water, however, the Fenton reaction, despite obtaining better mineralization rates, produced more toxic by-products when compared to the Fenton-like process. The untreated dye did not show phytotoxicity, nor did it generate significant effects on zebrafish embryos. / Os azo corantes, como o Disperse Red 343 (DR343) representam a mais importante classe de corantes têxteis, além de serem amplamente utilizados na indústria farmacêutica e alimentícia. Presentes em águas residuárias industriais e domésticas, estas moléculas são resistentes aos tratamentos convencionais de efluentes e podem, eventualmente, gerar produtos ainda mais tóxicos que os corantes originais. Os processos oxidativos avançados (POAs) têm sido empregados a fim de aumentar a biodegradabilidade ou mineralizar substâncias de difícil tratamento, reduzindo sua toxicidade e os riscos inerentes ao lançamento de poluentes no meio ambiente. Objetivo: Avaliar a ecotoxicidade e otimizar as condições de decomposição do azo corante têxtil DR343 utilizando reações do tipo Fenton e Fenton-like. Metodologia: Os processos oxidativos foram estudados utilizando planejamento fatorial do tipo Box Behnken Design (BBD), e a otimização das condições de reação foi realizada pela aplicação da função de desejabilidade. O pH do meio, o tempo de reação, as concentrações de ferro [Fe 2+ ] (Fenton) e [Fe 3+ ] (Fenton-like), assim como de agente oxidante [H 2 O 2 ] foram utilizadas como variáveis independentes no planejamento. As respostas estudadas foram a remoção do DR343, a concentração de peróxido de hidrogênio residual [H 2 O 2residual ] e a mortalidade de Artemia salina. A toxicidade do corante não-tratado foi avaliada em diferentes organismos (sementes de alface, Artemia salina e embriões de zebrafish). As amostras tratadas sob condições ótimas foram submetidas aos mesmos protocolos. Resultados: A remoção do azo corante esteve na faixa de 5,8% a 100%, sendo afetada somente pela concentração de catalisador [Fe 2+ /Fe 3+ ] em ambos os processos. Por outro lado, o tempo de processo teve efeito significativo na mortalidade de A. salina em amostras submetidas ao processo Fenton, o que sugere formação de subprodutos de oxidação tóxicos no começo do processo, seguido pela mineralização das amostras. Condições ótimas para a reação de Fenton incluíram [Fe 2+ ] de 0,33 mmol.L -1 e [H 2 O 2 ] de 4,50 mmol.L -1 . Nessas condições, observou-se decomposição de 100% do corante em 16,1 minutos. Por outro lado, as condições ótimas do processo Fenton-like incluíram [Fe 3+ ] de 0,25 mmol.L -1 e [H 2 O 2 ] de 0,54 mmol.L -1 . Sob essas condições observou-se a decomposição total do corante em apenas 9,2 minutos. Não foi detectada [H 2 O 2residual ] em ambos os processos otimizados. Nenhum efeito fitotóxico significativo foi observado nas dispersões do corante não-tratado, tampouco após o tratamento em ambos os processos. No caso dos ensaios com A. salina, observou-se diferenças entre os dois processos. As amostras tratadas por Fenton-like não apresentaram toxicidade significativa, enquanto que o processo Fenton induziu mortalidade significativa para esse organismo. Amostras tratadas sob condições ótimas, oriundas de ambos os métodos, não induziram efeitos letais ou subletais aos embriões e larvas de zebrafish. Foi observada redução de carbono orgânico total de 52,0% e 34,8% para Fenton e Fenton-like, respectivamente. Conclusões: O corante não-tratado não apresentou fitotoxicidade, assim como não gerou efeitos tóxicos significativos nos embriões de zebrafish. Ambos os processos estudados podem ser utilizados com sucesso para decompor o corante DR343 em água, entretanto, a reação de Fenton, apesar de obter melhores índices de mineralização, produziu subprodutos mais tóxicos quando comparado ao processo Fenton-like.

Orientador: Wilson de Figueiredo Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T10:39:52Z (GMT). No. of bitstreams: 1 Andrade_JulianodeAlmeida_M.pdf: 3254677 bytes, checksum: 72d1e108844df115bda11c77f7fd1337 (MD5) Previous issue date: 2005 / Mestrado / Quimica Analitica / Mestre em Química

Orientador: Rodnei Bertazzoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T06:34:47Z (GMT). No. of bitstreams: 1 Badellino_Carla_M.pdf: 4439168 bytes, checksum: 0e434b627394c712d54234bcc01ad717 (MD5) Previous issue date: 2006 / Resumo: Nest trabalho foi investigada a desempenho do peróxido de hidrogênio eletrogerado a partir de redução do oxigênio na superfície de um catodo de carbono vítreo reticulado para a oxidação do herbicida ácido 2,4-diclorofenoxiacético. Inicialmente, foram feitas voltametrias cíclicas para verificar se o 2,4-D para verificar a existência de pares redox. O eletrólito suporte usado foi o K2SO4 0,3 mol L-1, pH 10, em meio saturado de N2. Após a verificação da ausência de reação redox para o 2,4-D, fez-se a otimização da eletrogeração de peróxido de hidrogênio. Usando como catodo um eletrodo rotatório cilíndrico de carbono vítreo reticulado de 60 ppi e um anodo de platina, em meio de K2SO4 0,3 mol L-1, pH 10, saturado com O2 e 900 rpm, determinou-se que o melhor potencial para eletrogeração de H2O2 foi de ¿ 1,6 V vs. ECS a uma temperatura de 8 0C. Em etapa subseqüente, verificou-se a degradação do herbicida 2,4-D em solução, na concentração de 100 mg L-1 por diferentes três processos: H2O2 eletrogerado, UV/H2O2, e fotoeletro-Fenton, este último realizado em pH 2,5. Para tanto foram feitas injeções no Cromatógrafo Líquido de Alta Eficiência, além de análise de Carbono Orgânico Total e Demanda Química de Oxigênio. Dos processos estudados, o mais vantajoso foi o catalisado com radiação UV e sais de Fe2+ (Reagente de Fenton), com uma redução do COT de 69 % do valor inicial. Dando continuidade os estudos, foi construído um reator em escala piloto do tipo filtro prensa com fluxo transversal para eletrogeração de peróxido de hidrogênio. Composto por dois compartimentos anódicos e um catódico, separado por membranas catiônicas Nafion ®N242, o reator foi otimizado em três diferentes parâmetros: o potencial de trabalho, a velocidade de vazão do fluido e a vazão de oxigênio. Os valores ótimos encontrados para eletrogeração de H2O2 em eletrólito suporte de K2SO4 0,3 mol L-1 foram: potencial de -1,6 V vs. Pt, velocidade do fluido de 500 L h-1 e vazão de oxigênio de 6 L s-1. Com o reator otimizado e acumulando cerca de 1100 mg L-1 de H2O2 em 5 horas de processo, foram feitos ensaios de degradação do 2,4-D em seis deferentes métodos: dois ensaios em meio básico com e sem incidência de radiação ultravioleta, e em seguida, mais quatro ensaios em meio ácido, também com e sem a incidência de radiação ultravioleta, na presença do reagente de Fenton, e por fim, um ensaio catalisado com radiação ultravioleta e na presença do reagente de Fenton. Os ensaios em meio ácido e catalisado, mais uma vez se mostraram mais eficientes e a remoção do COT seguiu uma cinética de pseudo-primeira ordem. Mesmo não havendo muita variação no tempo de degradação o gráfico de ln[C(t)/C(0)] vs. tempo, mostra que o processo mais vantajoso é aquele catalisado com UV/Fenton, com uma constante de redução do COT uma ordem de grandeza maior do que para o processo apenas com incidência de radiação UV. Os valores foram, respectivamente, 9,4x10-5 s-1 e 1,75x10-4 s / Abstract: In this work, the performance of the H2O2 electrogeneration process from O2 reduction on a reticulated vitreous carbon cathode was investigated. The process was also use for the oxidation of the herbicide 2,4-dichlorophenoxyacetic acid. Firstly, cyclic voltammetries were used for the identification of possible reduction reactions of the herbicide. The supporting electrolyte used was a 0,3 mol L-1 K2SO4, pH 10, nitrogen saturated solution. Then, the optimization of hydrogen peroxide electrogeneration it was carried out. As a cathode, a reticulated vitreous carbon-rotating cylinder, shaped from a 60 ppi RCV plate was used. A platinum foil was used as anode and a saturated calomel electrode was used as reference. Supporting electrolyte was always K2SO4 0,3 mol L-1, in an O2 saturated solution. The experiments were run in a 150 mL electrode cell, with a water jacket to keeping temperature in the range from 8 0C. The best potential to produce hydrogen peroxide in these conditions was -1,6 V vs. SCE. In following stage, the degradation of 2,4-D was investigated by tree different process: H2O2 electrogenerated, H2O2/UV and photo electro-Fenton being the last at pH 2,5. The degradation of 2,4-D was followed by HPLC, moreover TOC and COD analyses. The most efficient process was the catalyzed UV/Fe2+ process that presented a TOC reduction of 69 %. In a sequence, a pilot scale reactor was mounted for hydrogen peroxide electrogeneration. The reactor is formed by two anolytes and one catholyte compartments, separated by a N424 Nafion® membrane. The reactor was optimized considering three different parameters: the applied potential, oxygen flow and the electrolyte flow. Best operational parameters electrogeneration rate of hydrogen peroxide in a K2SO4 0,3 mol L-1 electrolyte support were: -1,6 V vs. Pt, 500 L h-1 of electrolyte flow and 6 L s-1 of oxygen flow. Considering these results, the experiments for the degradation of 2,4-D were conducted with the optimized reactor. In this new series of experiments, six different processes were tested. In alkaline medium, the degradation occurred only with H2O2 and H2O2, catalyzed by UV radiation. Four processes were used in acidic medium: H2O2, H2O2 catalyzed by UV radiation, Fe2+ (electro Fenton process) and H2O2 with Fe2+ catalyzed by UV radiation (photo-electro Fenton process). In catalyzed experiments in acidic medium, degradation rates were higher TOC decay presented a pseudo-first order kinetic. The differences between electro Fenton and photo-electro Fenton processes appeared only when TOC reduction was considered. A greater degree of organics combustion was observed for the last process, with 95 % of TOC was eliminated. / Mestrado / Engenharia de Materiais / Mestre em Engenharia Mecânica

Philosophiae Doctor - PhD / Emerging micropollutants such as bisphenol-A and 2-nitrophenol present a great threat in drinking water due to their adverse effects. Most conventional technologies in water and wastewater treatment are not designed to eliminate these xenobiotics; instead pollutants are merely transferred from one phase to another. Advanced oxidation technologies (AOTs) however, have been identified as suitable routes for the degradation of these potential damaging substances based on free radical mechanisms and use of less expensive chemicals. Moreover, due to the structural complexity of wastewater and the existence of pollutants as mixtures, no single advanced oxidation technology can convincingly remove all forms of contaminants and then most often than not, a combination of treatment processes is required for an effective purification process. Besides, the problem of adequate degradation of emerging contaminants in the environment, when AOT(s) are used individually, they present inherent problems. For instance, powder TiO₂ photocatalysts obstruct light penetration, thus prevent effective interaction of UV light with the target pollutants, and particulates present problems of post-filtration and recovery of catalyst particles after treatment. Additionally, TiO₂ has a high band gap energy, high electron-hole recombination rate, and is prone to aggregation of the suspended particles. Similarly, the dielectric barrier discharge (DBD) system produces ultra violet light and hydrogen peroxide within the plasma zone which is not fully maximised for the mineralization of persistent organic pollutants. Rapid oxidation and aggregation of nano zero valent iron particles in photo-Fentons process reduce the particles mobility and affect its performance. In the same vein, the jet loop reactor (JLR) system is characterised by low impingement yield, which is responsible for low mineralization rate. In light of this background, this research investigated the degradation of bisphenol-A and 2- nitrophenol in aqueous solution using the following combined advanced oxidation methods: DBD/supported TiO₂ or Ag doped TiO₂ photocatalysts, DBD/photo-Fenton induced process and JLR/UV/H₂O₂. The target was to assess the performance of each single system and then identify the best combined AOTs capable of significantly mineralizing the target compounds. Firstly, two materials were developed namely supported TiO₂ and stabilized nano zero valent Fe. The TiO₂ photocatalyst supported on a stainless steel mesh was synthesised using sol-gel solution of 8 % PAN/DMF/TiCl₄. The influence of calcination temperature and holding time on the formation of nanocrystals was investigated. Afterwards, various amounts of metallic silver were deposited on the (optimum) supported TiO₂ photocatalyst using thermal evaporation. The catalysts were characterized by several analytical methods; HRSEM, HRTEM, EDS, SAED, FTIR, TGA-DSC, UV-vis/diffuse reflectance spectroscopy, XRD, BET, and XPS. The photocatalytic activity of the prepared catalysts was determined using methylene blue as a model pollutant under ultra-violet light irradiation. Secondly, the TiO2 photocatalyst and 2.4 % Ag doped TiO₂ nanocomposites obtained as optimums (in section 1) were combined with the DBD to decompose BPA or 2-NP in aqueous solution. Moreover, the photo-Fenton process was applied for degradation of the model pollutants, and different dosages of stabilized nZVI (in the range of 0.02 -1.00 g) were added to the DBD system to induce the photo-Fenton process and improve BPA or 2-NP degradation efficiency. Finally, a jet loop reactor (JLR) presenting advanced mixing by the “impinging effect” was explored to decompose BPA or 2-NP in aqueous solution as a function of inlet applied pressure, solution pH, and initial concentration of BPA or 2-NP. Subsequently, different concentrations of hydrogen peroxide (H₂O₂) were added to the JLR to enhance the mineralization process. Furthermore, a combination of JLR with in-line UV light and H₂O₂ were further utilised to decompose BPA or 2-NP in aqueous solution. The residual concentration of the model compounds and intermediates were analysed using high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LCMS). The concentration of the ozone, hydrogen peroxide and hydroxyl radicals generated by the DBD in the presence or absence of a catalyst was monitored using Ultraviolet-visible spectroscopy and Photoluminescence spectroscopy. The results revealed that the optimal thermal conditions to obtain well supported uniformly grown, highly active crystalline TiO₂ catalysts with high specific surface area was 350 ºC at a 3 h holding time in N2 atmosphere with a flow rate of 20 mL/min. Pyrolysis temperature and holding time played an important role on the crystalline nature and photocatalytic activity of the catalyst. Moreover, 2.4 % Ag doped TiO₂ nanocomposites exhibited higher photocatalytic activity for methylene blue degradation than the undoped supported TiO₂ nanocrystals. The results indicated that combining DBD with 2.4 % Ag doped TiO₂ nanocomposites achieved 89 % and 81 % removal efficiency for BPA or 2-NP compared to 67.22 % or 56.8 % obtain when using the DBD system alone. The 2.4 % Ag doped TiO₂ nanocomposites demonstrated excellent activity and offered photochemical stability after four repeated applications.In the case of the photo-Fenton induced process, nano zero valent iron particles (nZVI) stabilized with polyethylene glycol were synthesised using a modified borohydride reduction method. The HRSEM, BET, XRD, and XPS analysis confirmed the formation of filamentous, high surface area iron nanoparticles in the zero valent state. Unlike combined DBD/Ag doped TiO2 nanocomposites, 100 % or complete removal of BPA or 2-NP in aqueous solution was achieved with DBD/nZVI system within 30 minutes compared to 67.9 % (BPA) or 56.8 % (2-NP) with DBD alone after 80 minutes. The removal efficiency was attributable to the production of an increased concentration of OH radicals as well as existence of a synergetic effect in the combined DBD/nZVI system. Five new transformation products namely: 4-nitrophenol (C₆H₅NO₃), 4-nitrosophenolate (C₆H₄NO₂), 4-(prop-1-en-2-yl) cyclohexa-3,5-diene-1,2-dione, (C₉H₈O₂), 4-(2- hydroxylpropan-2-yl)cyclohexane-3,5-diene-1,2-dione (C₉H₁₀O₃), and 1,2-dimethyl-4-(2- nitropropan-2-yl)benzene (C₉H₁₀NO₄) were identified during the degradation of BPA. While, three aromatic intermediate compounds such as 2-nitro-1,3,5-benzenetriolate (C₆H₂NO₅), 2- nitro-1,4-benzoquinone (C₆H₃NO₄), and 2,5-dihydroxyl-1,4-benzoquinone (C₆H₄O₄) respectively were identified during the degradation of 2-NP for the first time in the DBD with JT14 or JT17 using LC-MS. These intermediate compounds have never been reported in the literature, thereby expanding the number of BPA or 2-NP intermediates in the data base in the DBD/JT14 or DBD/nZVI system. BPA degradation proceeded via ozonation, hydroxylation, dimerization, and decarboxylation and nitration step, while 2-NP proceeded via hydroxylation, nitration and denitration respectively. Furthermore, maximum removal efficiency of BPA or 2-NP in aqueous solution using JLR alone under the optimum solution pH (3), inlet pressure (4 bar), flow rate (0.0007 m3/s) was 14.0 % and 13.2 % respectively after 80 minutes. A removal efficiency of 34.9 % was recorded for BPA while 33.2 % was achieved for 2-NP using combined JLR/UV under the same conditions as JLR alone. For the combined JLR/H₂O₂ under optimum conditions of inlet pressure (4 bar), solution pH (3) and peroxide dosage (0.34 g/L), a 51.3 % and 50.1 % removal efficiency was achieved for BPA and 2-NP respectively under same conditions relative to JLR alone. Combination of JLR/UV/H₂O₂ achieved 77.7 % (BPA) or 76.6 % (2- NP) removal efficiency under the same conditions. The combined JLR/UV/H₂O₂ process was found to be most effective combination under the optimized operating parameters due to existence of a synergetic index value of 6.42 or 6.84. This implies that JLR should be coupled with UV and H₂O₂ to achieve greater mineralization efficiency instead of using the system individually. The obtained experimental data of these combined treatment processes fitted the pseudo-first order kinetic models. The combination of the JLR/UV/H₂O₂ was found to be energy efficient and could effectively degrade BPA or 2-NP in aqueous solution to a greater extent than the JLR, JLR/UV or JLR/H₂O₂ system. However, the total organic carbon (TOC) reduction value by all combined DBD and JLR system recorded was not completely achieved due to the formation of recalcitrant intermediate compounds under the applied conditions. In conclusion, this study is reporting for the first time a combination of supported 2.4 % Ag doped TiO₂ nanocomposites with dielectric barrier discharge system for BPA/2-NP degradation in aqueous solution; a combination jet loop reactor based on impingement with in-line UV lamp and H2O2 for successfully decomposing BPA or 2-NP in aqueous solution; as well as a combination of dielectric barrier discharge system and stabilised nano zero valent iron particles, which induced a photo-Fenton process for highly effective removal of BPA or 2-NP in aqueous solution. This study conclusively supports the hypothesis that combined advanced oxidation technologies offer a sustainable and highly efficient means of achieving partial or complete removal of BPA or 2-NP in aqueous solutions. Considering all the combinations of AOTs investigated in this study, the novel DBD/photo-Fenton-induced process under optimised operating parameters was found to be the most efficient in the elimination of BPA or 2-NP in aqueous solutions. The combination of DBD with photo- Fenton like process offers a promising advanced waste water purification technology in the immediate future. Based on these findings, it is recommended that DBD should be redesigned to prevent loss of ozone and JLR system reconfigured to increase impingement and cavitational yield in order to have an effective combination treatment strategy for waste water purification especially in large scale waste water management. / National Research Foundation (NRF) and Water Research Commission, South Africa

La remédiation des sols contaminés par les polluants organiques persistants comme les hydrocarbures aromatiques polycycliques (HAP) s’est largement développée après la découverte de milliers de sites pollués partout dans le monde. Parmi les polluants organiques, les HAP méritent l'attention, car ils sont, pour la plupart, considérés comme persistants, « bioréfractaires », relativement immobiles dans les sols, toxiques, carcinogènes et mutagènes. Plusieurs techniques ont été étudiées pour éliminer ces polluants des sols, et, parmi elles, les Procédés d’Oxydation Avancés (POA) ont été proposés récemment. Les POAs sont considérés comme une méthode alternative pour traiter les matrices contaminées par des substances bioréfractaires. Dans ce travail, les POA ont été étudiés pour évaluer leur efficacité pour l'oxydation de HAP contenus dans quatre types d’échantillons de sol d’origines brésilienne et française, portant des contaminations récentes ou anciennes. Ces POA étaient : (i) le traitement par réactif de Fenton (H2O2 en présence de Fe(II)), (ii) le réactif de Fenton sans ajout de Fe(II), considérant que les minéraux présents constituent une source suffisante, c’est le traitement dit «Fenton-like», (iii) et (iv) les deux traitements précédents avec exposition au rayonnement UV, dits « photo-Fenton » et « photo-Fenton like », et enfin (v) le permanganate de potassium. Dans chaque cas conditions optimales de traitement ont été déterminées par la méthode des plans d’expériences. De plus, on a étudié la sélectivité du traitement en comparant la dégradation de HAP de différents poids moléculaire inférieur et on a cherché à mettre en évidence la formation ou non de sous-produits d’oxydation. Enfin, la qualité des sols après traitement a été évaluée, par mesure des propriétés physico-chimiques des sols, et surtout par des expériences de germination et croissance d’une plante modèle, le ray grass, en vue de savoir si le traitement par POA permet une revégétalisation ultérieure des terrains traités. D'une manière générale, des résultats satisfaisants ont été atteints dans tous les cas pour l'oxydation du HAPs par POAs. Quant à la qualité des sols après traitement ;, on a montré que le traitement par KMnO4 n'était pas compatible avec la revégétalisation. Par contre le traitement par le réactif de Fenton favorise la revégétalisation des sols traités. / Remediation of soils contaminated by persistent organic pollutants like Polycyclic Aromatic Hydrocarbons (PAHs) have been widely developed after the discovery of thousands of contaminated sites all over the world. Among the organic pollutants, PAHs are considered as biorefractory compounds, relatively immobile in soils, toxic, carcinogenic and mutagenic. Several techniques have been studied to remove these pollutants from soils, as the Advanced Oxidation Processes (AOPs) that have been proposed in recent years. AOPs are considered as an attractive alternative able to clean up matrices contaminated by refractory substances. In this work, AOPs have been studied to assess their efficacy in the oxidation of PAHs contained in four soil samples from Brazil and France. These AOPs were: (i) treatment by Fenton reactant (H2O2 and Fe(II), (ii) Fenton-like reactant, i.e. Fenton reactant without Fe(II) addition, considering that naturally occurring minerals provided Fe(II), (iii) and (iv) the same treatment with UV radiation, so-called photo-Fenton and photo-Fenton like reactions, and eventually (v) potassium permanganate. In each case, the optimal conditions were determined following factorial designs. Moreover, treatment selectivity was investigated, comparing the oxidation of lower and higher molecular weight PAHs. The formation of oxidation by-procducts was also assessed. To finish, the quality of treated soils was evaluated, by measuring the physico-chemical properties and above all by germination and growth experiments with ray grass chosen as a model plant. The objective was to assess if the treatments allowed further revegetation. In all cases, good oxidation results were reached. Concerning the evaluation of soil quality, it was shown that the treatment by KMnO4, was not compatible with further revegetation. Fenton’s reactant had a good effect on soil quality for further revegetation. / Remediação de solos contaminados por poluentes orgânicos persistentes tem merecido destaque devido a descoberta de milhares de áreas contaminadas em todo mundo. Dentre os poluentes orgânicos, que merecem atenção encontram-se os hidrocarbonetos políciclicos aromáticos (HPAs) pois são compostos recalcitrantes, relativamente imóvel no solo, tóxicos, carcinogênicos e mutagênicos. Várias técnicas vêm sendo estudada a fim de remover estes poluentes dos solos podendo citar atualmente os Processos Oxidativos Avançados (POAs). Os POAs trata-se de um tratamento alternativo capaz de degradar das matrizes contaminadas por substâncias refratárias. Neste trabalho, os POAs têm sido estudado para avaliar seu comportamento na oxidação dos HPAs em quatro diferentes tipos de solo, originados do Brasil e da França. Avaliou-se como esses processos se comportam em relação a uma antiga e recente contaminação, bem como avaliar a existência da seletividade em relação aos HPAs de baixo e alto peso molecular e identificar a possibilidade de formação de intermediários de oxidação. Também pretende-se analisar a qualidade do solo após o tratamento visando avaliar se este solo pode ser revegetalizado ou torna-se inerte. Os POAs que aplicados nestes solos foram: Reagente de Fenton, Reagente Fenton-like, Reagente Foto-Fenton empregando-se a radiação natural e artificial, Reagente Foto-Fenton like e Permanganato de Potássio. De uma maneira geral, resultados satisfatórios foram alcançados em todos os solos estudados para a oxidação dos HPAs pelos POAs. Em relação a avaliação da qualidade dos solos da França após aplicar os POAs , o tratamento por Permanganato de Potássio não foi compatível com o processo de revegetalização. Já o tratamento por reagente de Fenton foi compatível ao processo e ainda observou uma melhora no crescimento das plantas quando comparado ao solo contaminado.

The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a fully bleached birch (Betula verucosa) kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment with a monocomponent endoglucanase (FiberCare® R). The mechanical treatment to MFC was performed in a laboratory colloid mill or in a pilot high-pressure homogeniser and the pre-treated pulps as well as the produced MFCs were chemically and morphologically characterised. Additionally, the MFCs produced in the colloid mill were evaluated as strength enhancers in test sheets representing the middle ply of paperboard. From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. The increase in carbonyl groups could not be explained by the formation of new reducing end groups due to depolymerisation which indicates that carbonyl groups are introduced along the cellulose chain. The enzymatic pre-treatment as performed in this study caused less impact on the cellulosic material, i.e. resulted in a pulp with a higher DP and a much lower amount of carbonyl- and carboxylic groups compared with the Fenton pre-treated pulps. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically i.e. reached a higher specific surface area and a higher surface charge at a given mechanical treatment time compared to enzymatic pre-treated pulps and pulps not subjected to any pre-treatment. These findings were confirmed when MFCs were produced by homogenisation at high pressure in multiple passes; the birch kraft pulp was either pre-treated with Fenton’s reagent or the combined mechanic and enzymatic pre-treatment methodology used at the Centre Technique du Papier (CTP, France). By size fractionation, rheological measurements and scanning electron microscopy, it was revealed that Fenton pre-treatment resulted in MFC suspension containing a significantly higher proportion of small sized material (< 0.2 mm). When the MFCs were evaluated as strength enhancers in test sheets produced from a furnish consisting of a spruce (Picea abies) chemithermomechanical pulp, MFC and a retention system containing cationic starch and an anionic silica sol, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition. / The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a bleached birch kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment. Additionally, the MFCs evaluated as strength enhancers in test sheets representing the middle ply of paperboard. From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically indicating a potential to lower the energy consumption. When the MFCs were evaluated as strength enhancers in test sheets, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs at a given mechanical treatment time. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition.

Zur Modellierung der Ausbreitung von Aktionspotentialen im menschlichen Vorhof wurde in der Vergangenheit eine Vielzahl von Modellen entwickelt, welche den Einfluss der zahlreichen Ionenströme, die durch die Zellmembran fließen, im Detail berücksichtigen. Mit dem Ziel einer vereinfachten Beschreibung ist kürzlich das Modell von Bueno-Orovio, Cherry und Fenton (BOCF-Modell) an die Elektrophysiologie des Vorhofs angepasst worden, welches ursprünglich für die elektrische Erregungsausbreitung in den Herzkammern entwickelt wurde. In dieser Arbeit wird dieses angepasste BOCF-Modell in Bezug auf seine Fähigkeit untersucht, raum-zeitliche Erregungsmuster zu erzeugen, die beim anatomischen und spiralförmigen Reentry gefunden werden. Hierzu werden die Ergebnisse des BOCF-Modells mit denen des detaillierten Modells von Courtemanche, Ramirez und Nattel (CRN-Modell) verglichen. Es zeigt sich, dass die charakteristischen Merkmale von Reentry-Mustern im CRN-Modell gut mit dem BOCF-Modell wiedergegeben werden. Dies eröffnet die Möglichkeit, die Ursprünge des Vorhofflimmerns basierend auf einer vereinfachten, aber immer noch zuverlässigen Beschreibung der Elektrophysiologie zu untersuchen. Eine effektive Methode wird entwickelt, um empirische Aktionspotentiale von Patienten in den menschlichen Vorhöfen anhand des BOCF-Modells zu modellieren. Grundlage dieser Methode ist die Anpassung von drei relevanten Zeitkonstanten im BOCF-Modell mit Hilfe eines nicht-linearen Optimierungsverfahrens. Die Methode ermöglicht, spezifische Aktionspotentiale mit einer gegebenen Amplitude, Breite und Form zu reproduzieren. Sie kann als Prädiktor für pathologische Befunde verwendet werden.

Field and greenhouse experiments were conducted to determine the effect of auxin injury on soybean and cotton due to spray hose material, formulation and cleanout procedures on auxin equipment cleanout. Visual estimations of injury (VEOI) in wheat, height reduction, and yield reduction due to rimsulfuron and glyphosate titration was higher when compared to rimsulfuron only treatments with respect to 1/2X through the 1/256X treatments. Sequestration of 2,4-D within agricultural hose types did differ due to hose type and is confirmed by analytical testing, but field observation of wheat did not show differences among treatments due to VEOI, height reduction or yield reduction. Using soybean as a bio-indicator, differences did occur with respect to dicamba sequestration in agricultural hose types with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte retained. Results indicate chemical makeup of hose type in determination of ppm analyte dicamba retained. Cleaning procedures of water or ammonia do not prove to be different with respect to VEOI, height reduction, yield reduction or ppm analyte retained. Sequestration of 2,4-D within valved manifold systems and using water or ammonia as cleanout procedures in conjunction with rinse procedures did not show differences with respect to VEOI, height reduction, nodes above cracked boll (NACB), yield reduction or ppm analyte retained. It was not until standard 2,4-D applications were applied in field experiments when differences were observed. Deactivation of dicamba and 2,4-D using the Fenton procedure within various rates, showed an interaction with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte. Using soybean as a bio-indicator showed differences with the Fenton procedure deactivating the dicamba analyte in the 1/16X, 1/64X and 1/256X rate with respect to VEOI, height reduction, node reduction, yield reduction and ppm analyte retained. Using cotton as a bio-indicator showed differences with the Fenton procedure deactivating the 2,4-D analyte in every rate with respect to VEOI, height reduction, yield reduction and ppm analyte.

Landfilling is the most common approach to dispose of municipal solid wastes but inevitably leads to leachate formation. Persistent UV quenching substances (UVQS) in landfill leachate can affect the effectiveness of UV disinfection in municipal wastewater treatment systems when leachate co-treatment is applied. Membrane electrochemical reactor (MER) treatment was investigated to reduce the UV quenching capability and simultaneously recover resources in the leachate as an effective onsite pre-treatment. Ion-selective membranes were used in this MER to create two different conditions: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher removals of both dissolved organic carbon and UV254nm absorbance than membrane-less electrochemical treatment. The MER was able to remove a large percentage of total nitrogen from the leachate while recovering about half of the influent ammonia in the catholyte with less specific energy consumption. The second study coupled MER with Fenton oxidation through providing synergistic benefits with the low solution pH, reduced organics, and ammonia removal. This two-stage coupled system reduced the more leachate COD than the standalone Fenton process treating raw leachate. Also, the usage of chemicals as Fenton reagents has been greatly reduced: FeSO4 and H2O2 by 39%, H2SO4 by 100%, and NaOH by 55%. Consequently, the sludge production was reduced by 51% in weight and 12% in volume. Despite electricity consumption by the MER, the coupled system cost $4.76 per m3 leachate less than the standalone Fenton treatment. More notably, direct Fenton oxidation removed only 21% of ammonia; in comparison, the MER-Fenton system removed ammonia by 98% with the possibility for recovery at a rate of 30.6 -55.2 kg N m-3 reactor d-1. Those results demonstrated that coupling MER with the Fenton process could mitigate some inherent drawbacks of Fenton oxidation such as ineffective ammonia removal, high acid and chemical reagents dose requirements, and a large amount of sludge generation. The third study investigated the formation of total halogenated organics (DBP) and the associated toxicity as the side effect of leachate treatment in the MER. Compared to the 4538±100 µg L-1 from the control membrane-less electrochemical oxidation reactor, the amount of DBP generated in the MER only accounted for 19.1±4.5 % after the same treatment period. The total toxicity value (26.6 ×10-3 ) was low for MER effluent, only 15.1% of that in the control group. Both high pH and high ammonia concentration introduced more DBP mass and toxicity production after MER treatment. DBP concentrations were shown to increase with applied current density and possible temperature raise. With 67.5% of DBP mass concentration and 74.4% of the additive toxicity removal, the granular activated carbon (GAC) electrode system was shown more effective than GAC adsorption alone in remediating DBP harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate through performance demonstration, process integration and by-product remediation. / Doctor of Philosophy / Municipal solid waste is often disposed of in landfills because of the most economics and convenience. However, one of the most challenging problems is the leachate formation and treatment. In the US, leachate is currently often diluted in domestic wastewater treatment systems; meanwhile, the persistent contaminants in landfill leachate can lower the effectiveness of UV disinfection and result in high cost and permit violation. In this study, the membrane electrochemical reactor (MER) using electricity as the driving force was applied to solve the issue and simultaneously recover valuable resources in the leachate. Membranes as a barrier for selective ions were used in this MER to create two different conditions with different purposes: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher contaminants removals than membrane-less electrochemical treatment. The second study coupled MER with one of the established advanced oxidation processes, also known as Fenton oxidation through providing mutual benefits with the low solution pH, reduced organics, and ammonia removal/recovery. This two-stage coupled system reduced the leachate contaminants effectively towards the direct discharge standard. In addition, the usage of chemical reagents, as well as the amount of process residual, has significantly been reduced. The third study investigated the formation of by-products as the side effect of leachate treatment in the MER. Compared to the membrane-less reactor, the undesirable by-products generated in the MER only accounted for one fifth after the same treatment period. A granular activated carbon electrode system was shown effective in remediating the harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate as one of the toughest wastewaters.