Neste trabalho, foram preparadas resinas contendo o grupo sulfônico a partir de copolímeros sintetizados à base de estireno e divinilbenzeno (Sty-DVB), utilizando a técnica de polimerização em suspensão aquosa via radical livre. Os copolímeros foram preparados com diferentes graus de porosidade designados como: poros menores, porosidade intermediária e poros grandes. Esses copolímeros foram caracterizados por FTIR, ASAP, densidade aparente, grau de inchamento, termogravimetria e microscopia eletrônica de varredura. Os copolímeros de Sty-DVB foram modificados quimicamente com sulfato de acetila para a obtenção de resinas sulfonadas. A modificação química dos copolímeros foi confirmada pelo aparecimento das bandas de absorção características no infravermelho do grupo sulfônico, pela capacidade de troca iônica introduzida por esse grupo funcional (aproximadamente 5 mmol/g) e pela modificação das características térmicas. As resinas sulfonadas foram impregnadas com metais de Ni ou Co para a obtenção de materiais magnéticos. Os compósitos obtidos foram caracterizados por microscopia eletrônica de varredura, sendo possível visualizar as partículas metálicas sobre a superfície da matriz polimérica. O comportamento magnético desses materiais foi investigado, sendo observado um pequeno campo coercivo, que é característico de materiais magnéticos moles. Os materiais sintetizados foram avaliados na remoção de fenol de soluções aquosas. A remoção de fenol foi mais efetiva quando os compósitos de Ni foram empregados. / In this work, resins containing the sulfonic group were prepared from synthesized copolymer beads based on styrene and divinylbenzene (Sty-DVB) by suspension polymerization. These crosslinked copolymers were prepared with different porosities, namely small, intermediate and large porosity. These copolymers were characterized by infra-red spectrometry (FTIR), bulk density, specific area, swelling degree , termogravimetry (TG/DTG) and scanning electron microscopy (SEM). The synthesized copolymers were modified with acetyl sulphate aiming to obtain sulphonated resins. The chemical modification of the copolymers as confirmed by the displaying of the characteristc bands of sulfonic groups in the infrared spectra, by the ionic exchange capacity given by this functional group (around 5 mmol/g) and by the changes of thermal profiles. Ni or Co particles were anchored on the sulphonated copolymer matrix aiming to obtaining different magnetic materials. These composites were characterized by scanning electron micrscopy (SEM), permiting the observation of particles on the resin surfaces. The magnetic behavior of the composites was investigated. They presented behavior of soft materials due to their low coercive field. These composites were evaluated on the phenol removal from the aqueous solutions. The phenol removal was more efficient from materials containing Ni particles.

Neste trabalho, foram preparadas resinas contendo o grupo sulfônico a partir de copolímeros sintetizados à base de estireno e divinilbenzeno (Sty-DVB), utilizando a técnica de polimerização em suspensão aquosa via radical livre. Os copolímeros foram preparados com diferentes graus de porosidade designados como: poros menores, porosidade intermediária e poros grandes. Esses copolímeros foram caracterizados por FTIR, ASAP, densidade aparente, grau de inchamento, termogravimetria e microscopia eletrônica de varredura. Os copolímeros de Sty-DVB foram modificados quimicamente com sulfato de acetila para a obtenção de resinas sulfonadas. A modificação química dos copolímeros foi confirmada pelo aparecimento das bandas de absorção características no infravermelho do grupo sulfônico, pela capacidade de troca iônica introduzida por esse grupo funcional (aproximadamente 5 mmol/g) e pela modificação das características térmicas. As resinas sulfonadas foram impregnadas com metais de Ni ou Co para a obtenção de materiais magnéticos. Os compósitos obtidos foram caracterizados por microscopia eletrônica de varredura, sendo possível visualizar as partículas metálicas sobre a superfície da matriz polimérica. O comportamento magnético desses materiais foi investigado, sendo observado um pequeno campo coercivo, que é característico de materiais magnéticos moles. Os materiais sintetizados foram avaliados na remoção de fenol de soluções aquosas. A remoção de fenol foi mais efetiva quando os compósitos de Ni foram empregados. / In this work, resins containing the sulfonic group were prepared from synthesized copolymer beads based on styrene and divinylbenzene (Sty-DVB) by suspension polymerization. These crosslinked copolymers were prepared with different porosities, namely small, intermediate and large porosity. These copolymers were characterized by infra-red spectrometry (FTIR), bulk density, specific area, swelling degree , termogravimetry (TG/DTG) and scanning electron microscopy (SEM). The synthesized copolymers were modified with acetyl sulphate aiming to obtain sulphonated resins. The chemical modification of the copolymers as confirmed by the displaying of the characteristc bands of sulfonic groups in the infrared spectra, by the ionic exchange capacity given by this functional group (around 5 mmol/g) and by the changes of thermal profiles. Ni or Co particles were anchored on the sulphonated copolymer matrix aiming to obtaining different magnetic materials. These composites were characterized by scanning electron micrscopy (SEM), permiting the observation of particles on the resin surfaces. The magnetic behavior of the composites was investigated. They presented behavior of soft materials due to their low coercive field. These composites were evaluated on the phenol removal from the aqueous solutions. The phenol removal was more efficient from materials containing Ni particles.

Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.

Yes / The removal of the ubiquitous phenol and phenolic compounds in industrial wastes is a critical environmental issue due to their harmful threats to wildlife and potential adverse human health effects. The removal of such compounds is therefore of significant importance in water treatment and reuse. In recent years, reverse osmosis (RO) has been successfully utilised in several industrial processes and wastewater treatment including phenol removal. In this paper, a new model based on a spiral-wound RO process is developed for the removal of phenol from wastewater. A simplified mathematical algorithm using an irreversible thermodynamic approach is developed. This results in a set of non-linear Differential and Algebraic Equations (DAEs), which are solved based on a number of optimised model parameters using a combined methodology of parameter estimation and experimental phenol-water data derived from the literature. The effects of several operational parameters on the performance (in terms of removal of phenol) of the process are explored using the model.

Co-disposal with refuse in a controlled landfill is the cheapest option for the disposal of hazardous waste and, if carefully controlled, can be an effective treatment option. In this present study a high-strength phenolic wastewater and activated sewage sludge were co-disposed with refuse. The effectiveness of phenol catabolism at two organic loading rates (500mgt1 and 1000mgtl) was assessed in the presence of various co-disposal strategies. Leachate recycle at the lower phenol organic loading rate was found to facilitate the greatest rate of phenol catabolism. Despite the effective removal of phenol, however, leachate recycle promoted the production of high concentrations of ammoniacal-N and hydrogen sulphide. At the higher phenol organic loading rate, recirculation was ineffective in reducing the residual phenol concentration due to inhibition of the phenol-catabolisers. Microcosms operated with single elution and batch co-disposal strategies at both phenol organic loading rates resulted in serious detrimental effects on the refuse fermentation and subsequent leachate quality. A high-strength leachate obtained from a closed co-disposal site was characterised to determine its chemical composition and was assessed for its susceptibility to biological treatment. If carefully controlled, co-disposal sites should produce leachates which differ little in quality to those produced by municipal waste sites. The exceptionally high specific conductivity of the leachate used in this present study was, however, uncharacteristic of a leachate from a municipal waste site. The leachate required dilution to 25 % (v/v) before responding to aerobic biological treatment due to the presence of bactericidal/bacteriostatic components. Anaerobic treatment was ineffective even at a final dilution of 10% (v/v) of the original due to the inhibition of methanogenesis caused indirectly by the high concentration of sulphate in the leachate. Following phosphate addition, aerobic biological treatment effected a significant reduction in the chemical oxygen demand (COD) but did not reduce the ammoniacal-N concentration. Scaling and precipitation occurred following addition of the phosphate, and although these did not affect the biological process they can cause operational problems in full-scale leachate treatment plants. Ion exchange, with soil, and lime treatment, were, therefore, considered for their ability to reduce the inorganic content of the leachate prior to biological treatment. However, these particular pretreatments were unsuitable due to their ineffectiveness to reduce calcium, the main inorganic element involved in scaling, to an acceptable concentration. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.

D. Tech. Chemical Engineering / Aims of this research project was to add value to largely wasted South African sawdust by development of low-cost AC of high efficiency for removal of toxic Cr (VI), phenol and glutaraldehyde from dilute aqueous media. The main objectives of the research project were: a) To develop low-cost AC based on South African P. patula sawdust using economical physical superheated steam activation.Characterization of carbon samples for selection of optimum preparation conditions for development of low-cost AC of effective microporosity mesoporosity and surface functionality for enhanced adsorption capacity of Cr (VI) and/or phenol and/or glutaraldehyde from dilute aqueous solution. Acid-amine surface groups modification of optimally developed AC for further enhancement of adsorption capacity for mixed polarized glutaraldehyde molecules from aqueous solution. b) To evaluate the aqueous phase batch adsorption properties of developed AC for Cr (VI) and phenol and, of acid-amine modified developed AC for glutaraldehyde. Determination of optimum pH for adsorption; accurate adsorption isotherm modelling for determination of maximum adsorption capacity, comparison of maximum adsorption capacities for Cr (VI) and phenol of developed AC with commercial AC and literature ACs, and attempt to establish average micropore size for enhanced capacity for Cr (VI) and phenol from dilute aqueous solution.Kinetics reaction and diffusion modelling for determination of adsorption rate constants and diffusion parameters; and determination of adsorption thermodynamic parameters.Evaluation of equilibrium selectivity of developed AC for Cr (VI) and/or phenol in binary aqueous solutions. c) To evaluate aqueous phase fixed-bed adsorption characteristics of developed AC for single Cr (VI) and mixed solution using Rapid Small Scale column Tests (RSSCTs). Generation of breakthrough curves at optimum adsorption conditions for evaluation of column performance indicators at different process conditions, bed regeneration-reusability potential, and dynamic adsorption selectivity of developed AC for Cr (VI) from solution of base metals. Determination of column diffusion parameters; accurate mass transfer and empirical modelling of breakthrough data; determination of applicable RSSCT scaling equation; and optimization of breakthrough data for accurate RSSCT scale-up.