Phosphorus (P) pollution of waterbodies is a global issue with detrimental environmental, social and economic impacts. Low-cost and sustainable P removal technologies are therefore required to tackle P pollution, whilst also offering a technique for reclaiming P. Ochre, a waste product from minewater treatment plants (MWTPs), has been proposed as a suitable material for the removal of P from enriched waters due to a high content of Fe, Al, Ca and Mg, which have high affinities for P removal. Whilst a range of studies have been conducted investigating ochre as a P adsorbent, most of these are large-scale field experiments and lack understanding of the underlying processes of P removal by ochre. There have also been very few detailed comparisons of different ochre types. The primary focus of this thesis is thus to provide a process-based understanding of P removal by various ochres, in order to investigate the optimal conditions for the use of ochres in the treatment of aquatic P pollution. Seven ochres from six MWTPs in the UK and Ireland were investigated, one of which was in a pelleted form. The ochres were largely comprised of Al, Ca, Fe and Mg (42-68 % by dry weight), had a high B.E.T. surface area, 56-243 m2 g-1, and contained mineral surfaces with a high affinity for P adsorption, such as goethite and calcite. A novel batch experiment methodology was utilised to calculate the adsorption characteristics of ochre at discrete pH conditions. The variation of these characteristics with pH indicates the importance and requirement for such a method to study adsorption by materials at the expected pH conditions of application. At the pH conditions of wastewater streams (~pH 7), the P adsorption capacities of the ochres, determined from fitting adsorption isotherms, was 11.8–43.1 mg P g-1. Results of P adsorption batch experiments were modelled in ORCHESTRA, wherein P removal by the ochres was described well by adsorption onto hydrous ferric oxides. Three of the ochres contain relatively high calcite contents and due to a poor fit of the model to the observed datasets at high pH conditions, with equilibrium P concentrations lower in the batch experiments than the modelled result, adsorption onto calcite is suggested as a P removal mechanism for these ochres at pH > 7. Environmental application of ochre filters will require P removal under flow-through transport conditions. Column experiments were therefore conducted using two ochres, coarse-grained Polkemmet ochre and Acomb pellets (column volume 1055 cm3, pore space 490-661 cm3, typical pore volumes of experiments: 220-400). P removal efficiency increased with contact time, and the presence of competing ions had only marginal effects on P removal. Resting the column substrate for 48 hours between P applications greatly increased the P removal efficiency of a packed column of Polkemmet ochre, resulting in 81 % of influent P removed over 1000 pore volumes of operation (7.68 mg P g-1). Acomb pellets had a lower P removal efficiency than Polkemmet ochre. It is suggested that the high calcium content of the pellets, as a result of the pelletisation process, has created a substrate where the dominant P removal mechanism at neutral pH conditions is adsorption to calcite, which has slower reaction kinetics than adsorption onto goethite. Therefore, this pelleted ochre requires a higher contact time for adsorption reactions to occur. It is suggested that ochre filters are most suitable for application in situations where flow rate is constant or can be controlled e.g. septic tank effluent. Ochres which dry to a coarse particle size are preferred for use as a substrate as pelletisation requires capital, expertise and can produce substrates with slower P sorption kinetics. Resting the filter substrate between P application regenerates surface sites for adsorption, and filters should be run in parallel to maximise P removal efficiency. Acomb pellets, which are a mix of iron hydroxides and alkaline materials, may have potential application as a permeable reactive barrier substrate to treat P enriched ground waters. Further research utilising fine-grained ochres as an additive to P rich fertilisers or for use in continuously stirred tank reactors is recommended.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Na cultura da cana-de-aÃÃcar, por razÃes econÃmicas e ambientais, a queima da palhada, feita para facilitar a colheita e o transporte, vem sendo substituÃda pela colheita mecanizada. Sabe-se que a manutenÃÃo da palhada sobre o solo influencia a dinÃmica da Ãgua, nutrientes e matÃria orgÃnica, mas seus efeitos ainda nÃo sÃo suficientemente conhecidos. Nesse contexto, o objetivo do presente estudo foi avaliar o efeito do manejo do solo cultivado com cana-de-aÃÃcar sem a queima prÃvia do canavial para a colheita, comparado com a mata nativa, sobre a matÃria orgÃnica do solo e, por consequÃncia, os efeitos desta sobre o fÃsforo do solo. Para tanto, foram determinados, nas profundidades de 0 â 2,5, 2,5 â 5, 5 â 10 , 10 â 20 e 20 â 30 cm, os teores de carbono orgÃnico total (COT) e particulado (COP) e seus respectivos estoques (EstCOT e EstCOP), a matÃria orgÃnica leve (MOL), fracionada pelo mÃtodo da flotaÃÃo em Ãgua, as concentraÃÃes de fÃsforo orgÃnico e inorgÃnico obtidas atravÃs da extraÃÃo sequencial proposta por Hedley et al.(1982) com modificaÃÃes e a capacidade mÃxima de adsorÃÃo de fÃsforo do solo (CMAP). As amostras de solo para as anÃlises foram coletadas de uma Ãrea sob cultivo de cana-de-aÃÃcar e de uma Ãrea contÃgua sob vegetaÃÃo nativa, ambas localizadas no municÃpio de Paraipaba â CE. Os resultados obtidos foram submetidos à anÃlise de variÃncia e comparados entre si pelo Teste de Tukey (p< 0,05) utilizando-se para tanto, o programa estatÃstico Assistat. Os maiores teores de COT e COP foram encontrados na primeira camada da Ãrea de mata. Em profundidade, os teores de COP na Ãrea de cana foram superiores. O EstCOT foi superior na Ãrea de mata, no entanto, o EstCOP foi superior na Ãrea sob cultivo de cana. As maiores concentraÃÃes de MOL foram encontradas nas primeiras camadas da Ãrea cultivada, nÃo diferindo da Ãrea de mata em profundidade. A concentraÃÃo de fÃsforo orgÃnico foi superior a concentraÃÃo de fÃsforo inorgÃnico nas duas Ãreas. Entre as fraÃÃes orgÃnicas obtidas pelo fracionamento de Hedley, a fraÃÃo orgÃnica bicarbonato (Po bic) foi a que obteve maior proporÃÃo em relaÃÃo ao fÃsforo total do solo. Dentre as fraÃÃes inorgÃnicas, a fraÃÃo inorgÃnica hidrÃxido 0,1 (Pi hid 0,1) apresentou-se em maiores concentraÃÃes que as demais. O maior valor de CMAP foi obtido na ultima camada da Ãrea de mata e o menor valor encontrado na primeira camada da Ãrea cultivada. Observou-se correlaÃÃo negativa entre os valores de COP e MOL com os valores de CMAP na Ãrea sob cultivo. Os maiores valores de CMAP foram encontrados nas camadas com menores concentraÃÃes de COP e MOL. Essa tendÃncia nÃo foi observada na Ãrea de mata. No geral, na ultima camada avaliada (20 â 30 cm), nÃo se observou diferenÃas significativas para as caracterÃsticas avaliadas entre as duas Ãreas. Nessa profundidade, a influÃncia do sistema de manejo à mÃnima. / Considering the sugar cane crop, for economic and environmental reasons, the burning of straw, used to facilitate the crop harvest and transportation, has been replaced by mechanical harvesting. It is known that the maintenance of straw on the soil influences the dynamics of water, nutrients and organic matter, but its effects are not yet sufficiently known. In this context, the objective of this study was to evaluate the effect of soil management cultivated with sugar cane without burning the plants prior to harvest, compared with the soil under native forest, on soil organic matter and, consequently, the effect on the phosphorus in the soil profile. To do so, it was determined, at depths from 0 - 2.5, 2.5 - 5, 5-10, 10-20 and 20 - 30 cm, the concentrations of the total organic carbon (TOC) and the particulate organic carbon (POC), as well as their accumulated amounts (EstCOT and EstCOP), light organic matter (LOM), which was fractionated by the method of flotation in water, concentrations of organic and inorganic phosphorus, obtained by sequential extraction proposed by Hedley et al. (1982) with modifications, and soil P maximum adsorption capacity (PMAC). Soil samples for analysis were collected from an area under cultivation of sugar cane and from a contiguous soil area under native vegetation, both located in the municipality of Paraipaba - CE. The results were subjected to analysis of variance and compared by Tukey test (p <0.05), using, for this purpose, the statistical program Assistat. The highest TOC and POC were found in the first soil layer of the forest area. At depth, the concentrations of COP in the area of sugar cane crop were higher. The EstCOT was higher in the forest, however, it was also higher in EstCOP in the area under sugar cane cultivation. The highest concentrations of MOL were found in the first soil layers of the sugar cane cultivated area, but not differing from the soil forest area in depth. The concentration of organic phosphorus was higher than the concentration of inorganic phosphorus in the two areas. Among the organic fractions, obtained by fractionation of Hedley method, the organic bicarbonate fraction P (bic Po) was proportionally the highest one present in the total soil phosphorus. Among the inorganic, the 0.1 hydroxide inorganic P fraction (Pi hid 0.1) appeared in higher concentrations than the others. The highest value of PMAC was obtained in the deepest soil layer of the forest area and the lowest PMAC value was found in the first soil layer of the sugar cane cultivated area. There was negative correlation between the values of both COP and MOL with CMAP values in the area under cane cultivation. The highest values of CMAP were found in layers with lower concentrations of COP and MOL. This trend was not observed in the forested area. Considering the deepest soil layer evaluated (20-30 cm) for the two soil areas, it was found no significant differences for the evaluated characteristics between the two areas. At this soil layer, the influence of the management system was almost null.

Nano-cellulose fibers/suspension has very high viscosity, its viscosity has to be lower before it can be applied in the paper coating recipe. For this purpose the adsorption behaviour of polyvinyl alcohol on nano-cellulose fibers were investigated using method developed by Zwick in 1960, based on the formation of PVA-iodide blue complex in the presence of boric acid. The experiments showed that the maximum adsorbed amount i.e. 0.13 g PVA/g NFC was obtained in a dispersion with 0.2 % PVA concentration. It should be possible to further increase the PVA adsorption as the adsorbed amount didn’t reach a saturation point where the PVA adsorption attained a constant value. It was also found that adsorption of PVA on NFC is time dependent. The absorbance measurement after four days of mixing PVA/NFC suspension showed only partially adsorption of PVA on nano-cellulose surface.  An equilibrium time of 10-13 days was needed for PVA to fully adsorb on nano-cellulose fibers surface. Another important observation was that PVA adsorption also depends on the concentration of nano-cellulose fibers. A lower concentration of NFC easily allows PVA to adsorb on its surface, as compared to higher NFC concentration. An important finding during the methodology development was the method to get rid of formation of flocs in the blue iodide complex solution; by slowly addition of reactants, especially the KI/I2 solution under continuous stirring around 60oC the tendency to flocs formation was suppressed.

Carbonaceous engine deposits tend to accumulate on most of the inner surfaces of the car engine. The presence of these deposits leads to a deteriorated efficiency of the engine and a number of adverse effects, such as higher propensity of the engine to knock. It has been proposed that selective adsorption of some of the fuel components in the porous deposits (and changing composition of the pre-combustion fuel) could be a contributing mechanism of the diminished efficiency of the engine. This, as well as other mechanisms of the deposits action, crucially depend on the porous structure of the material. Therefore, the aim of this investigation is to develop a method, which is able to accurately characterize the internal porous structure of the engine deposits and predict their adsorption properties at different conditions. This should allow us to assess whether the selective adsorption of fuel components is indeed a plausible contributing mechanism to the diminished performance of the engine. Accurate characterization of the engine deposits faces several difficulties due to their complex porous structure and chemical composition. A widely adopted approach in the characterization of activated carbons, which combines molecular simulation, specifically grand canonical Monte Carlo (GCMC) in slit pores, and experimental adsorption isotherms, is the starting point for the method suggested in this work. In this thesis, we will demonstrate that, by systematic modification of the solid-fluid interaction in the molecular simulation, we are able to correctly account for the chemical structural heterogeneity of the samples used. The new parameters of solid-fluid interaction allow us to extract representative pore size distributions and investigate the adsorption properties under different conditions of temperature and pressure, based on the obtained pore size distribution. Specifically, using the experimental data from a single ethane isotherm at 278K we accurately predict ethane adsorption at other temperatures and in different samples. Additionally, the proposed method is able to predict the adsorption of more complex hydrocarbons, i.e. n-butane and isobutane. The performance of the method is assessed by comparing the simulations results with the experimental adsorption measurements data on the engine deposits samples. Another important capability of the method is that it enables us to generate adsorption predictions of two key components commonly used to represent the combustion properties of the fuel, n-heptane and isooctane. We explore the equilibrium adsorption properties of these components based on the determined pore size distributions of the deposit samples. The results presented in the thesis highlight the importance of the adsorption in the internal porous structure of the engine deposits. The present study reinforces the value of molecular simulation combined with a limited number of experimental measurements, to accurately characterize heterogeneous carbonaceous materials and to make predictions at different conditions with sufficient precision.

Os resíduos sólidos da indústria coureira são produzidos em diferentes etapas de limpeza, classificação e ajuste da espessura do couro, e são classificados como perigosos quando gerados nas etapas posteriores ao curtimento com cromo. Os resíduos que já passaram pela etapa de curtimento apresentam elevada estabilidade, não sendo facilmente degradados. Além disso, nas etapas do acabamento molhado do couro, em especial no tingimento, corantes são utilizados para conferir cor aos artigos. Devido à necessidade de utilização de água e corantes em excesso, são gerados, nessas etapas, efluentes coloridos. Esses efluentes possuem quantidades elevadas de substâncias solúveis e coloridas que, devido ao seu potencial recalcitrante, não são facilmente removidas em sistemas convencionais de tratamento de efluentes. Neste trabalho, é apresentada uma nova proposta para o uso dos resíduos sólidos da indústria coureira antes de seu destino final, possibilitando assim uma sobrevida a esses resíduos como adsorventes alternativos de substâncias presentes em efluentes industriais do processamento do couro, em especial, os corantes oriundos das operações de acabamento molhado, com perspectivas ao reuso dos efluentes. Os efluentes oriundos da etapa de acabamento molhado de couro em escala piloto foram caracterizados. Assim, soluções aquosas sintéticas no intervalo de concentrações de corantes de efluentes foram preparadas e foi avaliada a capacidade de adsorção de dois tipos de resíduos de couro (curtido ao cromo e vegetal) em diferentes valores de pH. As isotermas de adsorção e cinética dos corantes Amarelo Ácido 194, Vermelho Ácido 357 e Preto Ácido 210 foram obtidos para os resíduos de couro curtido ao cromo no pH ideal de adsorção (entre 2 e 3). Além disso, a remoção do corante presente em efluente de tingimento (obtido em escala piloto) foi otimizada utilizando técnicas sequenciais de planejamento de experimentos. As isotermas apresentaram diferentes comportamentos, sendo do tipo C1, H2 e H3/L3 para os corantes Amarelo 194, Vermelho 357 e Preto 210, respectivamente. Os estudos dos mecanismos de transferência de massa demonstraram que a adsorção do corante Amarelo 194 é controlada pela transferência de massa na camada limite, enquanto que para os corantes Vermelho 357 e Preto 210 também foi observada a difusão no interior da partícula. Para esses dois últimos corantes, as difusividades foram da ordem de 10-9 e 10-11 m2 min-1. Os dados termodinâmicos, associados a análises instrumentais, confirmaram a natureza de adsorção por interações entre os grupos SO3 - e NO2 - dos corantes com os grupos NH(n) + do couro. Para a remoção do corante Vermelho 357 de efluentes de tingimento, uma região de ótimo foi observada para capacidade de adsorção no equilíbrio, correspondente ao pH 3,0 e temperatura entre 16 e 18 °C, sendo obsevado aproximadamente 74 mg g-1 para a concentração de 6,0 g L-1 de adsorvente. Entretanto, na região de estudo não foi observado região de ótimo para a remoção, sendo que para isso seria necessário um deslocamento no planejamento para pH inferiores a 3 e temperaturas superiores a 35 °C, o que de certa forma é inviável. Observouse que a máxima remoção em pH 3 e 35 °C foi de 75 %. O processo de remoção do corante por adsorção foi capaz ainda de reduzir a toxicidade do efluente em cerca de 90 %. / The solid wastes from the tannery industry are produced in different steps of cleaning, sorting and adjusting the thickness of the leather, and they are classified as hazardous waste when they are produced after chrome tanning. The tanned leather wastes present high stability and are not easily degraded. Moreover, in the wet leather finish, particularly during the dyeing process, dyes are used to color the items. Due to the need of using water and dye in excess, colored effluents are generated in these steps. These effluents have high amounts of soluble and colored substances that, due to their recalcitrant potential, are not easily treated in conventional eflluent treatment systems. In this research, a new proposal for the use of solid waste in the leather industry before its final destination is presented, which enables the reuse of these wastes as alternative adsorbents of substances in industrial effluents from the leather processing, particularly dyes derived from wet finishing operations, with the aim of reusing the wastewater. The effluents from the wet leather finish steps in a pilot scale were characterized. Thus, aqueous synthetic solutions in the concentration range of effluent dyes were prepared and the adsorption capacity of two types of leather waste (chrome tanned and vegetable leather) was evaluated at different pH values. Adsorption isotherms and kinetics of Acid Yellow 194, Acid Red 357 and Acid Black 210 dyes were obtained for chrome tanned leather waste in optimal adsorption pH (between 2 and 3). Furthermore, the removal of the dyes in deing wastewater (obtained in a pilot scale) was optimized by using sequential experimental design techniques. The isotherms presented different results: C1, H2 and H3/L3 types for the Yellow 194, Red 357 and Black 210 dyes, respectively. Studies on the mechanisms of mass transfer have shown that the adsorption of the Yellow 194 dye is controlled by mass transfer in the boundary layer, whereas in Red 357 and Black 210 dyes a diffusion was also observed inside the particle. For these last two dyes, diffusivities were 10-9 and 10-11 m2 min-1. The thermodynamic data, associated with instrumental analysis, confirmed the nature of adsorption by interactions between the NO2 - and SO3 - groups of the dyes with the NHn + groups of the leather. For removing the Red 357 dye in dyeing effluents, an optimum region was observed for the adsorption capacity in equilibrium, which corresponds to pH 3.0 to 3.2 and temperature between 16 and 18 °C, with about 74 mg g-1 for the concentration of 6.0 g L-1 adsorbent. However, in the study region an optimum region for the removal was not observed, and this would require a shift in planning for pH below 3 and temperatures above 35 °C, which is somewhat impractical. It was observed that the maximum removal at pH 3 and 35 °C was 75 %. The removing process the dye by adsorption was also able to reduce the toxicity of the effluent by about 90 %.

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Os resíduos sólidos da indústria coureira são produzidos em diferentes etapas de limpeza, classificação e ajuste da espessura do couro, e são classificados como perigosos quando gerados nas etapas posteriores ao curtimento com cromo. Os resíduos que já passaram pela etapa de curtimento apresentam elevada estabilidade, não sendo facilmente degradados. Além disso, nas etapas do acabamento molhado do couro, em especial no tingimento, corantes são utilizados para conferir cor aos artigos. Devido à necessidade de utilização de água e corantes em excesso, são gerados, nessas etapas, efluentes coloridos. Esses efluentes possuem quantidades elevadas de substâncias solúveis e coloridas que, devido ao seu potencial recalcitrante, não são facilmente removidas em sistemas convencionais de tratamento de efluentes. Neste trabalho, é apresentada uma nova proposta para o uso dos resíduos sólidos da indústria coureira antes de seu destino final, possibilitando assim uma sobrevida a esses resíduos como adsorventes alternativos de substâncias presentes em efluentes industriais do processamento do couro, em especial, os corantes oriundos das operações de acabamento molhado, com perspectivas ao reuso dos efluentes. Os efluentes oriundos da etapa de acabamento molhado de couro em escala piloto foram caracterizados. Assim, soluções aquosas sintéticas no intervalo de concentrações de corantes de efluentes foram preparadas e foi avaliada a capacidade de adsorção de dois tipos de resíduos de couro (curtido ao cromo e vegetal) em diferentes valores de pH. As isotermas de adsorção e cinética dos corantes Amarelo Ácido 194, Vermelho Ácido 357 e Preto Ácido 210 foram obtidos para os resíduos de couro curtido ao cromo no pH ideal de adsorção (entre 2 e 3). Além disso, a remoção do corante presente em efluente de tingimento (obtido em escala piloto) foi otimizada utilizando técnicas sequenciais de planejamento de experimentos. As isotermas apresentaram diferentes comportamentos, sendo do tipo C1, H2 e H3/L3 para os corantes Amarelo 194, Vermelho 357 e Preto 210, respectivamente. Os estudos dos mecanismos de transferência de massa demonstraram que a adsorção do corante Amarelo 194 é controlada pela transferência de massa na camada limite, enquanto que para os corantes Vermelho 357 e Preto 210 também foi observada a difusão no interior da partícula. Para esses dois últimos corantes, as difusividades foram da ordem de 10-9 e 10-11 m2 min-1. Os dados termodinâmicos, associados a análises instrumentais, confirmaram a natureza de adsorção por interações entre os grupos SO3 - e NO2 - dos corantes com os grupos NH(n) + do couro. Para a remoção do corante Vermelho 357 de efluentes de tingimento, uma região de ótimo foi observada para capacidade de adsorção no equilíbrio, correspondente ao pH 3,0 e temperatura entre 16 e 18 °C, sendo obsevado aproximadamente 74 mg g-1 para a concentração de 6,0 g L-1 de adsorvente. Entretanto, na região de estudo não foi observado região de ótimo para a remoção, sendo que para isso seria necessário um deslocamento no planejamento para pH inferiores a 3 e temperaturas superiores a 35 °C, o que de certa forma é inviável. Observouse que a máxima remoção em pH 3 e 35 °C foi de 75 %. O processo de remoção do corante por adsorção foi capaz ainda de reduzir a toxicidade do efluente em cerca de 90 %. / The solid wastes from the tannery industry are produced in different steps of cleaning, sorting and adjusting the thickness of the leather, and they are classified as hazardous waste when they are produced after chrome tanning. The tanned leather wastes present high stability and are not easily degraded. Moreover, in the wet leather finish, particularly during the dyeing process, dyes are used to color the items. Due to the need of using water and dye in excess, colored effluents are generated in these steps. These effluents have high amounts of soluble and colored substances that, due to their recalcitrant potential, are not easily treated in conventional eflluent treatment systems. In this research, a new proposal for the use of solid waste in the leather industry before its final destination is presented, which enables the reuse of these wastes as alternative adsorbents of substances in industrial effluents from the leather processing, particularly dyes derived from wet finishing operations, with the aim of reusing the wastewater. The effluents from the wet leather finish steps in a pilot scale were characterized. Thus, aqueous synthetic solutions in the concentration range of effluent dyes were prepared and the adsorption capacity of two types of leather waste (chrome tanned and vegetable leather) was evaluated at different pH values. Adsorption isotherms and kinetics of Acid Yellow 194, Acid Red 357 and Acid Black 210 dyes were obtained for chrome tanned leather waste in optimal adsorption pH (between 2 and 3). Furthermore, the removal of the dyes in deing wastewater (obtained in a pilot scale) was optimized by using sequential experimental design techniques. The isotherms presented different results: C1, H2 and H3/L3 types for the Yellow 194, Red 357 and Black 210 dyes, respectively. Studies on the mechanisms of mass transfer have shown that the adsorption of the Yellow 194 dye is controlled by mass transfer in the boundary layer, whereas in Red 357 and Black 210 dyes a diffusion was also observed inside the particle. For these last two dyes, diffusivities were 10-9 and 10-11 m2 min-1. The thermodynamic data, associated with instrumental analysis, confirmed the nature of adsorption by interactions between the NO2 - and SO3 - groups of the dyes with the NHn + groups of the leather. For removing the Red 357 dye in dyeing effluents, an optimum region was observed for the adsorption capacity in equilibrium, which corresponds to pH 3.0 to 3.2 and temperature between 16 and 18 °C, with about 74 mg g-1 for the concentration of 6.0 g L-1 adsorbent. However, in the study region an optimum region for the removal was not observed, and this would require a shift in planning for pH below 3 and temperatures above 35 °C, which is somewhat impractical. It was observed that the maximum removal at pH 3 and 35 °C was 75 %. The removing process the dye by adsorption was also able to reduce the toxicity of the effluent by about 90 %.

Os resíduos sólidos da indústria coureira são produzidos em diferentes etapas de limpeza, classificação e ajuste da espessura do couro, e são classificados como perigosos quando gerados nas etapas posteriores ao curtimento com cromo. Os resíduos que já passaram pela etapa de curtimento apresentam elevada estabilidade, não sendo facilmente degradados. Além disso, nas etapas do acabamento molhado do couro, em especial no tingimento, corantes são utilizados para conferir cor aos artigos. Devido à necessidade de utilização de água e corantes em excesso, são gerados, nessas etapas, efluentes coloridos. Esses efluentes possuem quantidades elevadas de substâncias solúveis e coloridas que, devido ao seu potencial recalcitrante, não são facilmente removidas em sistemas convencionais de tratamento de efluentes. Neste trabalho, é apresentada uma nova proposta para o uso dos resíduos sólidos da indústria coureira antes de seu destino final, possibilitando assim uma sobrevida a esses resíduos como adsorventes alternativos de substâncias presentes em efluentes industriais do processamento do couro, em especial, os corantes oriundos das operações de acabamento molhado, com perspectivas ao reuso dos efluentes. Os efluentes oriundos da etapa de acabamento molhado de couro em escala piloto foram caracterizados. Assim, soluções aquosas sintéticas no intervalo de concentrações de corantes de efluentes foram preparadas e foi avaliada a capacidade de adsorção de dois tipos de resíduos de couro (curtido ao cromo e vegetal) em diferentes valores de pH. As isotermas de adsorção e cinética dos corantes Amarelo Ácido 194, Vermelho Ácido 357 e Preto Ácido 210 foram obtidos para os resíduos de couro curtido ao cromo no pH ideal de adsorção (entre 2 e 3). Além disso, a remoção do corante presente em efluente de tingimento (obtido em escala piloto) foi otimizada utilizando técnicas sequenciais de planejamento de experimentos. As isotermas apresentaram diferentes comportamentos, sendo do tipo C1, H2 e H3/L3 para os corantes Amarelo 194, Vermelho 357 e Preto 210, respectivamente. Os estudos dos mecanismos de transferência de massa demonstraram que a adsorção do corante Amarelo 194 é controlada pela transferência de massa na camada limite, enquanto que para os corantes Vermelho 357 e Preto 210 também foi observada a difusão no interior da partícula. Para esses dois últimos corantes, as difusividades foram da ordem de 10-9 e 10-11 m2 min-1. Os dados termodinâmicos, associados a análises instrumentais, confirmaram a natureza de adsorção por interações entre os grupos SO3 - e NO2 - dos corantes com os grupos NH(n) + do couro. Para a remoção do corante Vermelho 357 de efluentes de tingimento, uma região de ótimo foi observada para capacidade de adsorção no equilíbrio, correspondente ao pH 3,0 e temperatura entre 16 e 18 °C, sendo obsevado aproximadamente 74 mg g-1 para a concentração de 6,0 g L-1 de adsorvente. Entretanto, na região de estudo não foi observado região de ótimo para a remoção, sendo que para isso seria necessário um deslocamento no planejamento para pH inferiores a 3 e temperaturas superiores a 35 °C, o que de certa forma é inviável. Observouse que a máxima remoção em pH 3 e 35 °C foi de 75 %. O processo de remoção do corante por adsorção foi capaz ainda de reduzir a toxicidade do efluente em cerca de 90 %. / The solid wastes from the tannery industry are produced in different steps of cleaning, sorting and adjusting the thickness of the leather, and they are classified as hazardous waste when they are produced after chrome tanning. The tanned leather wastes present high stability and are not easily degraded. Moreover, in the wet leather finish, particularly during the dyeing process, dyes are used to color the items. Due to the need of using water and dye in excess, colored effluents are generated in these steps. These effluents have high amounts of soluble and colored substances that, due to their recalcitrant potential, are not easily treated in conventional eflluent treatment systems. In this research, a new proposal for the use of solid waste in the leather industry before its final destination is presented, which enables the reuse of these wastes as alternative adsorbents of substances in industrial effluents from the leather processing, particularly dyes derived from wet finishing operations, with the aim of reusing the wastewater. The effluents from the wet leather finish steps in a pilot scale were characterized. Thus, aqueous synthetic solutions in the concentration range of effluent dyes were prepared and the adsorption capacity of two types of leather waste (chrome tanned and vegetable leather) was evaluated at different pH values. Adsorption isotherms and kinetics of Acid Yellow 194, Acid Red 357 and Acid Black 210 dyes were obtained for chrome tanned leather waste in optimal adsorption pH (between 2 and 3). Furthermore, the removal of the dyes in deing wastewater (obtained in a pilot scale) was optimized by using sequential experimental design techniques. The isotherms presented different results: C1, H2 and H3/L3 types for the Yellow 194, Red 357 and Black 210 dyes, respectively. Studies on the mechanisms of mass transfer have shown that the adsorption of the Yellow 194 dye is controlled by mass transfer in the boundary layer, whereas in Red 357 and Black 210 dyes a diffusion was also observed inside the particle. For these last two dyes, diffusivities were 10-9 and 10-11 m2 min-1. The thermodynamic data, associated with instrumental analysis, confirmed the nature of adsorption by interactions between the NO2 - and SO3 - groups of the dyes with the NHn + groups of the leather. For removing the Red 357 dye in dyeing effluents, an optimum region was observed for the adsorption capacity in equilibrium, which corresponds to pH 3.0 to 3.2 and temperature between 16 and 18 °C, with about 74 mg g-1 for the concentration of 6.0 g L-1 adsorbent. However, in the study region an optimum region for the removal was not observed, and this would require a shift in planning for pH below 3 and temperatures above 35 °C, which is somewhat impractical. It was observed that the maximum removal at pH 3 and 35 °C was 75 %. The removing process the dye by adsorption was also able to reduce the toxicity of the effluent by about 90 %.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-15T14:59:01Z No. of bitstreams: 1 Joycyely Marytza de Araujo Souza Freitas.pdf: 1276370 bytes, checksum: e10a572ebdb1134c06165a605d65f64a (MD5) / Made available in DSpace on 2016-08-15T14:59:02Z (GMT). No. of bitstreams: 1 Joycyely Marytza de Araujo Souza Freitas.pdf: 1276370 bytes, checksum: e10a572ebdb1134c06165a605d65f64a (MD5) Previous issue date: 2015-08-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The vinasse is rich in nutrients, particularly potassium, but it is classified as waste distillation process the juice of sugarcane for alcohol manufacturing process, which has no current state legislation on the discharge to the environment. Thus, the objective of the study is to evaluate the potassium ion interactions (K+), applied via vinasse in a representative soil of sugarcane zone (coastal board sandy texture) using adsorption isotherms. The methodology was based on physical, chemical and soil mineralogical and batch tests based on the recommendations of the Environmental Protection Agency (EPA-USA), where the experimental curves were adjusted by Langmuir and Freundlich isotherm models using the Sigma Plot 11.0 Software. Regarding the isotherms, the Freundlich model showed better fit the curve in two ways: linear and non-linear (direct adjustment), the non-linear model chosen on the basis of values of the coefficient of determination (R²). The potassium interaction with soil was mainly with organic matter and the presence of soil kaolinite, it had negative ions on the outer surface, thereby promoting the adsorption. The soil potassium adsorption capacity was higher for the first layer (0-20 cm) decreasing in depth. / A vinhaça é rica em nutrientes, principalmente em potássio, porém é classificada como rejeito do processo de destilação do caldo da cana-de-açúcar para processo de fabricação do álcool, que não possui legislação estadual vigente sobre o descarte no meio ambiente. Dessa forma, o objetivo do estudo é avaliar as interações do íon potássio (K+), aplicados via vinhaça, em um solo representativo da zona canavieira (tabuleiro costeiro de textura arenosa) por meio de isotermas de adsorção. A metodologia empregada foi baseada na caracterização física, química e mineralógica do solo, bem como de ensaios de equilíbrio em lote baseado nas recomendações da Environmental Protection Agency (EPA-USA), onde as curvas experimentais foram ajustadas pelos modelos de Isotermas de Langmuir e Freundlich com auxílio do software Sigma Plot versão 11.0. Com relação as isotermas, o modelo de Freundlich demonstrou melhor ajuste da curva nas duas formas: linear e não-linear (ajuste direto), sendo o modelo não-linear escolhido em função dos valores do coeficiente de determinação (R²). A interação do potássio com o solo se deu principalmente com a matéria orgânica e a presença de caulinita do solo, pois apresentaram íons negativos na superfície externa, favorecendo assim a adsorção. A capacidade de adsorção do potássio ao solo foi maior para a primeira camada (0-20 cm), diminuindo em profundidade.

Made available in DSpace on 2014-10-09T12:48:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:16Z (GMT). No. of bitstreams: 1 09620.pdf: 6546860 bytes, checksum: eb65a0c5c525fc6fd0305ce23a55fd85 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP