Os compostos fenólicos, quando em altas concentrações na água, são poluentes de alta periculosidade, difíceis de serem eliminados até mesmo por métodos convencionais, como por exemplo, a biorremediação microbiológica dos lodos ativados e os métodos físico-químicos. Sabendo da presença dos fenóis em muitos efluentes industriais se faz necessário o estudo de novos processos para o tratamento desses efluentes que possuam aplicações eficazes e, sobretudo, ecologicamente corretas. A presente pesquisa visou a degradação de poluentes fenólicos em soluções aquosas através da oxidação enzimática com tirosinase imobilizada em quitosana. A contribuição tecnológica relaciona-se com a possibilidade de aplicação do estudo em escala industrial em processos de tratamento de efluentes industriais que contenham poluentes fenólicos. Fenóis como o 4-clorofenol, 4-cresol, 4-nitrofenol e o próprio fenol, foram utilizados em ensaios de oxidação enzimática em vaso agitado, em regime dinâmico, em processo de batelada, temperatura de 45°C e três faixas de concentração enzimática (40, 60 e 80 U/ml). Além disso, foram testadas três formas de quitosana utilizadas na imobilização enzimática e aplicadas nos processos de oxidação de fenol: esferas, flocos e micro partículas de quitosana. A enzima tirosinase foi eficiente na degradação de fenol, 4-cresol e 4-clorofenol, diminuindo consideravelmente a concentração destes poluentes nas soluções aquosas. Porém, a tirosinase não oxidou significativamente o 4-nitrofenol. Verificou-se que o efeito de alguns substituintes do anel aromático do fenol e a posição desse substituinte no anel aromático, exerce influência direta na atividade da enzima durante as reações oxidativas envolvendo os compostos fenólicos. Embora o presente estudo tenha apresentado bons resultados na remoção de alguns compostos fenólicos em soluções aquosas por meio da oxidação de tais poluentes pela enzima tirosinase imobilizada em quitosana, o complexo enzima-suporte não apresentou a mesma eficiência nos ensaios subseqüentes, nos quais foi estudada a reutilização da enzima imobilizada. / The phenolic compounds when in high concentrations in water are extremely dangerous pollutants and difficult to be eliminated even by conventional methods such as the microbiological bioremediation with activated sludge and physico-chemical methods. Phenols are present in many industrial effluents and is necessary to develop new and effective processes for the treatment of that effluents and, if possible, environmentally friendly. This research aimed the degradation of phenolic pollutants in aqueous solutions by enzymatic oxidation with tyrosinase immobilized in chitosan. Phenols such as 4-chlorophenol, 4-cresol, 4-nitrophenol and phenol, had been used in assays of enzymatic oxidation in an agitated reactor, in dynamic regime, in a batch process, temperature of 45°C and three values of enzymatic concentration ( 40, 60 and 80 U/ml). In addition, three forms of chitosan had been used in enzymatic immobilization and applied in the processes of oxidation of phenol: pellets, flakes and small particles of chitosan. Tyrosinase was efficient in the degradation of phenol, 4-cresol and 4-chlorophenol, reducing significantly the concentration of these pollutants in aqueous solutions. However, tyrosinase did not oxidized 4-nitrophenol. It was verified that the effect of some substitutes and their position in the aromatic ring has a direct influence on the activity of the enzyme during the oxidative reactions involving phenolic compounds. Although this study has shown good results in the removal of some phenolic compounds in aqueous solutions through the oxidation of such pollutants by the tyrosinase immobilized on chitosan, the enzyme-support did not present the same efficiency in subsequent assays, in which we studied the reuse of the immobilized enzyme.

Neste trabalho é apresentado o estudo da degradação eletroquímica de fenol, formaldeído e misturas de fenol-formaldeído sobre ânodos dimensionalmente estáveis (ADE). Foi utilizado um ADE comercial (composição nominal Ti/Ti0,7Ru0,3O2), em uma célula eletroquímica de compartimento único sob agitação constante. As concentrações utilizadas nas misturas de fenol-formaldeído foram similares às concentrações encontradas no efluente fornecido pela indústria de resinas fenólicas Schenectady Crios, localizada na cidade de Rio Claro, SP. No final do trabalho também foi feita a degradação eletroquímica do efluente industrial com os melhores parâmetros. O recobrimento do ADE foi caracterizado por Microscopia Eletrônica de Varredura (MEV) e análises de Energia Dispersiva de Raios X (EDX). A caracterização eletroquímica foi feita por voltametria cíclica na ausência e na presença das substâncias orgânicas sob estudo. Durantes as eletrólises, a degradação das substâncias inicialmente presentes em solução foi verificadas por análises de Cromatografia Líquida de Alta Eficiência (CLAE) e Carbono Orgânico Total (COT). Os subprodutos formados (ácido fórmico, benzoquinona, hidroquinona, catecol e resorcinol) também foram identificados e quantificados por CLAE. Cálculos de estimativa do consumo energético também foram realizados para cada eletrólise.Foram variados os seguintes parâmetros: as densidades de corrente aplicadas, o controle da temperatura das soluções durante as eletrólises, o pH e as concentrações iniciais de fenol e formaldeído contidas nas soluções.O decaimento das concentrações das substâncias orgânicas apresenta uma cinética de pseudo primeira ordem. Observou se que quanto maior a densidade de corrente aplicada, maior é a taxa de remoção de COT, porém o consumo energético também é maior. Não se obteve a mineralização total do poluente, porém foi possível atingir uma remoção de aproximadamente 90% de COT para as soluções contendo apenas formaldeído, aplicando uma densidade de corrente de 40 mA cm-2 durante 2 horas de eletrólise. Foi possível a identificação e a quantificação dos subprodutos presentes nas soluções e no efluente industrial. As degradações eletroquímicas realizadas sem o controle da temperatura das soluções obtiveram um consumo energético menor e maior remoção de COT. / In this work presents the study of electrochemical degradation of phenol, formaldehyde and phenol-formaldehyde mixtures at dimensionally stable anodes (DSA®). Commercial DSA® electrodes (nominal composition: Ti/Ti0,7Ru0,3O2), ) were employed in a single compartment electrochemical cell under constant agitation. The concentrations used for the mixtures of phenol-formaldehyde were similar to concentrations found in effluent provided by the phenolic resin producer Crios Schenectady, located in Rio Claro, São Paulo state. In the final stage of the present study, the electrochemical degradation of real industrial effluent was performed employing the best parameters observed for the simulated effluents. The oxide coating of the electrode was characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X Ray analyses (EDX). The electrochemical characterization of the DSA® was performed using cyclic voltammetry in the absence and presence of organic substances. The degradation of the substances inicially present in solution were monitored by High Performance Liquid Chromatography (HPLC) and Total Organic Carbon (TOC) analyses. The products formed (formic acid, benzoquinone, hydroquinone, catechol and resorcinol) were also identified and quantified by HPLC. Estimates of the energy consumption were also performed for each electrolysis.The current densities applied, the concentrations of organic substance of the solution were varied during the electrochemical oxidation.The concentration decay of organic substances displayed pseudo first order kinetics of. It was observed that the higher the applied current density, the higher the TOC removal rate , but the energy consumption is higher. Total mineralization was not attained, but removals of approximately 90% of TOC were shown to be possible. It was possible the identification and quantification of products into the solutions and industrial effluents. The electrochemical degradation carried out without controlling the temperature of the solutions obtained a lower energy consumption and higher removal of TOC.

Orientadores: Elizabete Jordão, Carlos Augusto de Moraes Pires / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T09:13:33Z (GMT). No. of bitstreams: 1 Paschoalino_FlaviaCristinaSertori_M.pdf: 5135552 bytes, checksum: e4bb125b1c8aa2e74689b42ad19d43bb (MD5) Previous issue date: 2008 / Resumo: O fenol e seus derivados estão presentes em efluentes de diversos processos industriais como refino de petróleo e indústria farmacêutica. Devido à sua característica recalcitrante e sua toxicidade, são poucos os processos biológicos capazes de degradá-lo adequadamente sem que uma grande diluição seja realizada, o que o direciona muitas vezes a tecnologias mais caras como a incineração ou o uso de reagentes oxidantes. Uma alternativa a estes métodos é a fotocatálise heterogênea, que é baseada na irradiação (UV) de um catalisador, promovendo a geração de radicais hidroxila ( OH) altamente reativos. Neste trabalho desenvolveu-se um fotoreator confeccionado em vidro PyrexTM, utilizando-se uma lâmpada de vapor de Hg de 250 W em seu centro, o qual era resfriado por uma camisa de vidro concêntrica a uma câmara externa de 290 mL reservada à passagem do efluente a ser tratado. O fotoreator foi acoplado a um recipiente de 500 mL, utilizando-se uma bomba para recirculação do efluente, tornando-o um reator em batelada com recirculação. A eficiência do reator foi avaliada utilizando-se TiO2 e ZnO como fotocatalisadores em suspensão aquosa de 0,5 ou 1,0 g L-1, e fenol a 100 ou 200 mg L-1 como solução-teste. A concentração de fenol foi medida em intervalos de tempo pré-determinados utilizando-se cromatógrafo a gás com detector por ionização em chama. O sistema demonstrou-se muito eficiente, pois atingiu em pouco tempo (135 min), independentemente do catalisador utilizado, a degradação quase que total de fenol para a solução-teste de 100 mg L-1, que é superior às concentrações normalmente utilizadas em trabalhos similares. Para as soluções de 200 mg L-1 a cinética foi mais lenta, mas o processo fotocatalítico foi mais eficiente do que os controles de fotólise e adsorção em todas as combinações testadas. / Abstract: Phenol and its derivatives are present in effluents from various industrial processes like oil refining and pharmaceutical industry. Due its recalcitrant character and toxicity, few biological processes are capable to degrade it properly, requiring expensive technologies such incineration or the use of oxidants. An alternative to these methods is the heterogeneous photocatalysis, which is based on irradiation (UV) of a catalyst, promoting the generation of hydroxyl radicals ( OH) highly reactive. In this work it was developed a photoreactor made in a PyrexTM glass, using a 250 W Hg vapor lamp at its center, which was cooled by a water flux that was concentric to a 290 mL irradiated chamber glass. The photoreactor was attached to a container of 500 mL, using a recirculation pump, making it in a batch reactor with recirculation. The efficiency of the reactor was evaluated by using TiO2 and ZnO as photocatalysis in 0,5 or 1,0 g L-1 slurries, and phenol at 100 or 200 mg L-1 as a solution-test. The concentration of phenol was measured at pre-determined time intervals by using a gas chromatograph with a flame ionization detector. The system proved to be very efficient, because reached in a short time (135 minutes), regardless of the catalyst used, the almost total degradation to the solution of phenol-test of 100 mg L-1, which is higher than the concentrations usually used in similar work. For solutions of 200 mg L-1 the kinetics was slower, but the photocatalytic process was more efficient than the controls of photolysis and adsorption in all combinations tested. / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Philosophiae Doctor - PhD / In this thesis typical homogeneous and dendritic immobilized catalysts derived from salicylaldimines were investigated as catalysts for the oxidation of hydrocarbons using hydrogen peroxide as oxidant under aerobic conditions. This research work thus describes the synthesis of several new N-(aryl)salicylaldimines as well as peripheral functionalised salicylaldimine poly(propyleneimine) dendrimers. The dendritic ligands were obtained by modifying the peripheral groups of Generation 1 and Generation 2 poly(propyleneimine) dendrimer, (DAB-(NH2)n) which are commercially available. Both types of ligands were utilized to synthesize Cu(II) and Co(II) complexes using appropriate acetate salts. The ligands systems and metal complexes prepared were fully characterized using a range of physical techniques. The Cu(II) and Co(II) complexes were evaluated as catalysts for the oxidation of phenol and cyclohexene using hydrogen peroxide as oxidant under an oxygen atmosphere. The catalytic oxidation of phenol to the dihydroxybenzenes, catechol (CT) and hydroquinone (HQ), was investigated in aqueous media at various pH values. All the complexes investigated were active for the hydroxylation process producing CT as major product. The pH of the reaction medium was found to have much more of an influence on the activity and product selectivity of the Co(II) complexes as compared to the case for the Cu(II) complexes. All the catalysts investigated were also found to exhibit good activity for the oxidation of cyclohexene producing predominantly the allylic oxidation products 2-cyclohexene-1-one and 2-cyclohexene-1-ol. However the formation of the epoxide, cyclohexene oxide was also observed as minor product or in trace quantities. It was found that the cobalt catalysts produced 2-cyclohexene-1-one as major product, however higher levels of 2-cyclohexene- 1-ol was produced by all catalysts in catalytic runs where the oxidant to substrate ratio was reduced and when the metal loading was increased. In the case of the copper catalysts 2- cyclohexene-1-ol was produce in slightly higher levels than 2-cyclohexene-1-one.

Phenolic compounds are a group of organic chemicals present in the wastewaters of many synthetic industrial processes. Due to their extreme toxicity to man and animals, and deleterious impact on the environment, a range of techniques exist for the effective treatment and disposal of these pollutants. Biological degradation using microbial enzymes presents a valuable alternative to conventional wastewater treatment systems. This research was therefore initiated to investigate the polyphenol oxidase enzyme system and the feasibility of its application for effluent treatment and studies in organic solvents. The enzyme system is widely distributed in nature, with Agaricus bisporus (the common mushroom) being the best known producer. Biochemical investigations of the enzyme system were therefore carried out using this extract. A screening programme was initiated to identify microbial polyphenol oxidase producers which could be cultured in liquid media, thereby enabling the production of large quantities of enzyme in fermentation systems. Extensive growth optimization and enzyme induction and optimization studies were carried out on selected cultures. A number of good producers were isolated, namely a bacterial culture designated AECI culture no. 26, Streptomyces antibioticus, Streptomyces glaucescens and a manipulated strain, Streptomyces lividans (pIJ702). Enzyme production by Agaricus bisporus mycelia was optimized in deep-liquid culture; enzyme extracts showed high phenol removal efficiencies. Streptomyces antibioticus, Streptomyces glaucescens, Streptomyces lividans (pIJ702) and AECI culture no. 26 whole cells were also investigated for phenol-removing ability in simulated phenolic effluents. The use of whole cells reduces enzyme inactivation and instability due to the protection of the enzyme system within the cell. All cultures showed improved removal efficiencies in phenolic growth media. These results strongly suggest their use for phenol removal in continuous systems.

L'oxydation du phenol et des cresols en milieu aqueux par le procédé électro-Fenton en utilisant une cathode en feutre de carbone a été étudiée. 10?4 M de sulfate de fer (II) a été la concentration optimale de catalyseur, permettant d'éliminer 100% du carbone organique total (Cot) de solutions aqueuses de phenol. Les principaux intermédiaires formés (70%) au cours de la destruction du phenol ont été identifiés comme l'hydroquinone, p-benzoquinone et le catechol. Au cours de l'électrolyse de l'o-cresol, les intermédiaires identifiés (58%) ont été le 3-méthyl-catechol et le méthyl-hydroquinone. Pendant l'oxydation de phenols, les acides prédominants ont été identifiés. Ces expériences ont permis de proposer un mécanisme complet de minéralisation pour le phenol et l'o-cresol. Au cours du traitement des rejets de décapage d'avions, le remplacement des anodes de PT par diamant dope bore a augmenté l'efficacité, en supprimant environ 98% de TOC en 20 heures / The present work verified the efficiency of electro-Fenton to destroy phenolic compounds present in Stripping Aircraft Wastewater. This research aimed to elucidate the influence of the catalyst nature, its concentration and of electric current density in efficiency of electro-Fenton process using an indivisible cell with a carbon felt cathode and platinum or borod doped diamond anodes. The experiments compared the effect of these variables to destroy phenol, cresols and their intermediates. The compounds and many intermediates formed were identified in High Perfomance Liquid Chromatograph and allowed obtaining apparent and/or absolute constants and simplified degradation mechanisms. In optimum conditions, measures of Total Organic Carbon showed high mineralization rates. At the end, the application of electro-Fenton process to high organics loads of real Stripping Aircraft wastewater allowed obtaining almost complete mineralization replacing Pt anode by Boron Doped Diamond.

abstract: Organic compounds are influenced by hydrothermal conditions in both marine and terrestrial environments. Sedimentary organic reservoirs make up the largest share of organic carbon in the carbon cycle, leading to petroleum generation and to chemoautotrophic microbial communities. There have been numerous studies on the reactivity of organic compounds in water at elevated temperatures, but these studies rarely explore the consequences of inorganic solutes in hydrothermal fluids. The experiments in this thesis explore new reaction pathways of organic compounds mediated by aqueous and solid phase metals, mainly Earth-abundant copper. These experiments show that copper species have the potential to oxidize benzene and toluene, which are typically viewed as unreactive. These pathways add to the growing list of known organic transformations that are possible in natural hydrothermal systems. In addition to the characterization of reactions in natural systems, there has been recent interest in using hydrothermal conditions to facilitate organic transformations that would be useful in an applied, industrial or synthetic setting. This thesis identifies two sets of conditions that may serve as alternatives to commonplace industrial processes. The first process is the oxidation of benzene with copper to form phenol and chlorobenzene. The second is the copper mediated dehalogenation of aryl halides. Both of these processes apply the concepts of geomimicry by carrying out organic reactions under Earth-like conditions. Only water and copper are needed to implement these processes and there is no need for exotic catalysts or toxic reagents. / Dissertation/Thesis / Masters Thesis Geological Sciences 2020

The perception of wine’s quality is directly influenced by its color. Anthocyanin molecules are responsible for imparting color to red wines. They are extracted from grape skins during alcoholic fermentation. This work compares the effects of three parameters: berry integrity, enzyme addition, and fermentation temperature, on phenolic compound extraction (total phenol, tannin and anthocyanin) during the production of Paso Robles’ Cabernet Sauvignon wine. Analyses on phenolic compounds were completed during alcoholic fermentation and barrel aging over the course of eighteen months. Berry integrity compared the degree of berry crushing (whole destemmed berries versus fully crushed berries). Results showed that phenolic compound content after alcoholic fermentation seem to be unaffected by this parameter, while minor increases in total phenol concentration (3%) and tannin concentration (3%) during barrel aging were observed. Adding pectinase-rich macerating enzymes increased the total phenols by 8.7 and 21.0% to the 2010 and 2011 vintage, respectively, and tannin concentrations by 20.8 and 48.8%, respectively, during barrel aging. Alcoholic fermentation temperature of 25.0°C was compared to a fermentation temperature of 32.2°C in the 2011 vintage. When fermented at 32.2°C, concentrations of total phenol and tannin were significantly increased (20.6% and 28.9%, for the 2010 and 2011 vintages, respectively) when compared to 25.0°C. A cooler fermentation temperature led to 57.5% greater anthocyanin concentration throughout barrel aging. The results suggested that fermenting berries at a cooler temperature (25.0°C) increased anthocyanin levels and decreased total phenol and tannin concentration, which are desired outcomes for Paso Robles’ Cabernet Sauvignon wine quality.

Degradation of organic contaminants in wastewaters emanating from industrial processing plants could render the water streams reusable for the purpose of reducing water consumption while protecting the environment from harmful pollutants. Organic pollutants can be removed from water using biological processes that mineralise the organics to H2O and CO2. However, mineralisation by biological processes take a long time and in many cases, total mineralisation is impossible to achieve. Alternatively, organics can be completely degraded and mineralised rapidly using chemical and/or photocatalytic advanced oxidation processes (AOP). Both systems have some short comings. In chemical AOP such as Fenton and photo-Fenton reagents, the chemical agents used remain in the water as pollutants requiring further removal. In photocatalytic oxidation processes, most current technologies use UV light as an energy source. The chemical processes are environmentally incompatible, whereas, the “green” photocatalysis is extremely expensive due to the consumption of electricity by high pressure UV light. Forerunner investigators of photocatalysis utilised TiO2 as the photocatalyst of choice. It has major drawbacks of which the most important one is that it is only activated under ultraviolet (UV) light irradiation. This high energy consumption made the process practically unfeasible. Solar energy (natural light and heat from sun) has great prospects with regards to acting as a substitute for UV since it is a renewable and cheaper energy source. This work therefore investigated the development of a heterogeneous all-solid-state Z-scheme silver/ silver chloride/ bismuth oxychloride (Ag/AgCl/BiOCl) photocatalyst that is able to utilise natural light through being activated by visible light irradiation. This will successfully serve as a green alternative in the use of renewable energy for pollution reduction while saving energy. The synthesised photocatalysts were characterised using various techniques. The purity and crystallinity of the synthesised photocatalysts were determined using x-ray diffraction (XRD) while x-ray photoelectron spectroscopy (XPS) was used to determine the elemental composition and chemical states present in the synthesised catalysts as well as confirm the presence of elemental Ag. Fourier-transform infrared spectroscopy (FTIR) specified the functional groups present while the morphology and chemical composition were determined on a scanning electron microscopy (SEM)/ energy dispersive x-ray spectroscopy (EDS). The surface area and pore size were measured on a Brunauer-Emmett-Teller (BET) and thermogravimetric analysis (TGA) was done to determine the thermal degradation of synthesised particles. Ultraviolet-visible spectroscopy (UV-VIS) was done to determine the photoabsorption range and bandgap of the particles as efficiency of photocatalysis is dependent on the properties and morphology of the semiconductor material. Degradation studies were carried out under both visible and UV light irradiation in a batch reactor. The activity of the synthesised Ag/AgCl/BiOCl photocatalyst was compared to that of commonly used TiO2. Specifically, while 60% degradation was achieved under UV light irradiation by both TiO2 and Ag/AgCl/BiOCl photocatalyst, in visible light irradiation, TiO2 measures only 14% in 4 h while Ag/AgCl/BiOCl measures a photodegradation efficiency of 53%. Other factors such as initial organic contaminants concentration, initial catalyst concentration, pH effects and individual compounds effect were also investigated. The reusability of the catalyst was also reported showing stability of the synthesised catalyst as after a total irradiation time of 48 h, 65% phenol degradation was measured. The phenol degradation kinetics were found to fit the widely used first-order Langmuir-Hinshelwood model. The result from the current study proves the feasibility of a novel process for mineralisation of organic compounds in water under cost effective visible light irradiation for the removal of recalcitrant and refractory organics from water. / Dissertation (MEng)--University of Pretoria, 2019. / Chemical Engineering / MEng / Unrestricted

Phenol-formaldehyde adhesives are important adhesives known to have superior water resistance capacity and high mechanical strength when utilized in wood-based applications. Due to unsustainability and environmental issues associated with the use of fossil fuels, there is an urgent need to look for alternative raw materials, which are renewable in nature. Pinyon-juniper biomass has been found to be a suitable replacement for petroleum-based phenol because it is renewable, abundant, and readily available. In this thesis, bio-oil produced from the pyrolysis of pinyon-juniper biomass using red mud alumina catalyst was used to produce wood adhesives. The characterization of pinyon-juniper bio-oil showed the presence of phenolics, aromatic hydrocarbons, aliphatic hydrocarbons, carboxylic acids, ethers, ketones, aldehydes, and aliphatic alcohols. Resol synthesis parameters such as formaldehyde-to-phenol molar ratio (1.8 and 2), catalyst loading (0.25, 0.63, and 1.25 g of NaOH), reaction time (60 minutes), and reaction temperature (95°C), were investigated in the production of pinyon-juniper adhesives. Based on the results obtained, the extent of phenol substitution with pinyon-juniper bio-oil was dependent on the amount catalyst used during the synthesis process. The maximum phenol substitution of 80% was achieved using a catalyst loading of 1.25 g of NaOH while the minimum phenol substitution of 50% was obtained at a catalyst loading of 0.25 g of NaOH. Dry shear strength (8.99 to 12.73 MPa) and wet shear strength of (5.16 to 7.36 MPa) for both pure phenol-formaldehyde resols and pinyon-juniper substituted resols were comparable and exceeded the minimum requirement of 0.66 MPa for plywood. Finally, the chemical structure of pure phenol-formaldehyde resols showed the presence of more phenolic OH groups compared to pinyon-juniper substituted resols. This observation was corroborated by the higher concentration of free phenol in pure phenol-formaldehyde adhesives compared to pinyon-juniper substituted resols.