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Made available in DSpace on 2014-06-11T19:24:38Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-11-05Bitstream added on 2014-06-13T18:52:21Z : No. of bitstreams: 1 breda_cc_me_botfca.pdf: 821980 bytes, checksum: a49ce00ac1caf716ae66bf9ea700c42b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os efluentes de indústrias de chapa dura de fibra de madeira originários da exploração de eucalipto, são caracterizados por altos valores em DQO e material sólido em suspensão, tornando-os altamente poluentes para o ambiente e, principalmente, para os recursos hídricos. As empresas que atuam nesse segmento fazem o tratamento de seus efluentes de diversas maneiras, sendo a disposição por irrigação em solos cultivados, uma das formas utilizadas. Essa prática tem como base a melhoria da qualidade da água pela sua infiltração e principalmente pela evapotranspiração das plantas. Porém o lançamento em solos tem consequências, às vezes, muito graves, principalmente no que se refere a colmatação do solo e também à possível contaminação do lençol freático. O presente trabalho teve como objetivo o desenvolvimento de um sistema de tratamento de tais efluentes através do processo de peneiramento, visando a remoção das fibras em suspensão. Para isso desenvolveu-se um equipamento composto por peneiras rotativas substituíveis, com base em modelo francês, recomendado para o tratamento de efluentes industriais. Optou-se por esse sistema após a verificação da presença de grande quantidade de material sólido presente no efluente. Foram realizados 5 ensaios combinando-se peneiras rotativas de diferentes malhas (0,25 ; 0,50 ; 0,75 ; 1,00 e 1,50 mm) com suas respectivas rotações (13 ; 20 ; 33 ; 41 e 53 rpm) e vazões de entrada do efluente no sistema, que também foram 5 para cada ensaio. Para se verificar a influência do sistema proposto na redução da carga poluidora do efluente foram coletadas amostras na entrada do sistema (efluente “in natura”) e na saída (efluente após peneiramento) totalizando 150 amostras. Nessas amostras foram analisadas as seguintes variáveis:... / The wastewater from hardboard industries coming from the eucalyptus exploration are characterized by high values of COD and suspended solid matter. For this reason, the wastewater significantly pollute the environment, specially the water resources. The industries that act in this area treat their wastewater by different ways. The irrigation of cultivated lands is one of the options for treatment of the wastewater. By using this procedure, there should be an improvement in the water quality because of its infiltration into the soil and because of the plant’s evapotranspiration. However, the wastewater irrigation of the soil sometimes brings severe consequences, which are mainly related to the development of crusts on the soil surface and the possible contamination of the ground water. The objective of the present research was based on the development of a system to treat such wastewater by using the screening process, in order to remove the fibers in suspension. To do so, it has been developed an equipment that contains rotating changeable screens based on a French model that is recommended for the treatment of industry’s wastewater. Five trials have been performed combining rotating screens with different nets (0.25, 0.50, 0.75, 1.00, and 1.50 mm) with their respective rotations (13, 20, 33, 41, and 53 rpm) and also with 5 different flows of the wastewater incoming in the system. In order to verify the influence of the proposed system on the reduction of the pollutant capacity of the wastewater, 150 samples were collected at the inlet of the system (“in natura” wastewater) and at it’s outlet (wastewater after screening). From these samples, the following variables have been analyzed: total solids, fixed total solids, volatile total solids, pH, turbidity, electrical conductivity, COD, BOD, and... (Complete abstract click electronic access below)

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Activated carbons are used widely for the adsorption of environmentally unfriendly species from both liquid and gas phases, the separation of gases and adsorption of species from aqueous solution. Examples of the processes are the adsorption of Au(CN)2 and Ag(CN)2 from aqueous solution for the recovery of precious metals, the treatment of waste water containing organic chemicals and toxic metal species and the preparation of metal catalysts supported on carbon. This investigation has involved the study of the influence of porous structure and surface functional groups on the adsorption of both anionic and cationic metal species in order to understand the mechanism of adsorption of these species on active carbon from aqueous solution. Various types of oxygen functional groups were introduced onto the surface of coconut shell derived activated carbon through oxidation using nitric acid. Fourier transform infrared spectroscopy (FTIR), temperature programmed desorption (TPD) and selective neutralisation were used to characterise the surface oxygen functional groups. The oxidised carbons were also heat treated to provide a suite of carbons where the oxygen functional groups of various thermal stability were varied progressively. It was found that acidic oxygen functional groups mainly as carboxylic acid groups were incorporated into activated carbon by HNO3 oxidation. The phenol and quinone groups were also introduced by the oxidation process while the lactone groups were formed during heat treatment. The oxygen functional groups had a range of thermal stabilities with carboxylic acid groups being the least stable. A coconut shell derived active carbon was treated with ammonia and nitric acid followed by ammonia to incorporate nitrogen functional groups into the carbon. Active carbon with high nitrogen content was also prepared from nitrogen-rich precursor polyacrylonitrile (PAN). X-ray absorption near edge structure spectroscopy (XANES) and FTIR were used to investigate the structures of the nitrogen functional groups in carbons. The possible nitrogen functional groups present on carbon surface were pyridinic, pyrrolic (or indolic), pyridonic and aromatic amine-like structures. The adsorption characteristics of gold and silver cyanide anionic species on a suite of active carbons derived from coconut shell, polyacrylonitrile and chemical modification of the coconut shell carbon were investigated. The gold and silver cyanide adsorption capacities for coconut shell derived carbons correlate with total pore volume. Nitric acid oxidation treatment of the carbon was detrimental to gold adsorption in spite of the incorporation of oxygen content of carbon. The influence of nitrogen functional groups in the carbon structure on gold and silver adsorption was investigated using carbons derived from polyacrylonitrile. The addition of ethanol and butanol to the solution had an adverse effect on gold adsorption. Adsorption of silver cyanide ionic species on the active carbon was suppressed in the presence of excess free cyanide ions in solution whereas gold cyanide adsorption was not greatly affected at room temperature. The adsorption of gold cyanide was suppressed by the excess free cyanide and sodium sulphide at 70 °C. The adsorption of cadmium ions was enhanced dramatically by oxidation of the carbon. The ratio of released proton to adsorbed cadmium on oxidised carbon was approximately 2 indicating cation exchange was involved in the adsorption process. Na+ exchange studies with the oxidised carbon gave a similar ratio. After heat treatment of the oxidised carbons to remove oxygen functional groups, the ratio of H+/Cd2+ decreased significantly as well as the adsorption capacity. Both reversible and irreversible adsorption were involved in the process of cadmium adsorption with reversible adsorption having higher enthalpy. The irreversible adsorption resulted from cation exchange with carboxylic acid groups whereas the reversible adsorption probably involved physisorption of the partially hydrated cadmium ion. The nitrogen functional groups may act as ligands which can coordinate with transition metal cations. The adsorption of transition metal cations such as Cd 2+, Ni2+ and Cu2+ on active carbon was appreciably increased by the nitrogen functional groups present on carbon surface whereas ammonia treatment of the carbon showed little effect on the adsorption of alkali earth metal cation Cat+. There is little difference in the adsorption capacities of cadmium ions on coconut shell derived carbon at pH 4.1 and pH 7 whereas the adsorption of cadmium ions was significantly enhanced with increasing pH for the carbons with high nitrogen content. The nitrogen rich carbons show selectivity towards various transition metal cations reflected by adsorbing more Cu 2+ than Cd2+. This is consistent with the fact that the coordination compound of Cu 2+ with pyridine has higher stability constant than that of cadmium.

Orientador: Paulo Rodolfo Leopoldo / Banca: Jorge de Lucas Junior / Banca: Maria de Lourdes Conte / Resumo: Os efluentes de indústrias de chapa dura de fibra de madeira originários da exploração de eucalipto, são caracterizados por altos valores em DQO e material sólido em suspensão, tornando-os altamente poluentes para o ambiente e, principalmente, para os recursos hídricos. As empresas que atuam nesse segmento fazem o tratamento de seus efluentes de diversas maneiras, sendo a disposição por irrigação em solos cultivados, uma das formas utilizadas. Essa prática tem como base a melhoria da qualidade da água pela sua infiltração e principalmente pela evapotranspiração das plantas. Porém o lançamento em solos tem consequências, às vezes, muito graves, principalmente no que se refere a colmatação do solo e também à possível contaminação do lençol freático. O presente trabalho teve como objetivo o desenvolvimento de um sistema de tratamento de tais efluentes através do processo de peneiramento, visando a remoção das fibras em suspensão. Para isso desenvolveu-se um equipamento composto por peneiras rotativas substituíveis, com base em modelo francês, recomendado para o tratamento de efluentes industriais. Optou-se por esse sistema após a verificação da presença de grande quantidade de material sólido presente no efluente. Foram realizados 5 ensaios combinando-se peneiras rotativas de diferentes malhas (0,25 ; 0,50 ; 0,75 ; 1,00 e 1,50 mm) com suas respectivas rotações (13 ; 20 ; 33 ; 41 e 53 rpm) e vazões de entrada do efluente no sistema, que também foram 5 para cada ensaio. Para se verificar a influência do sistema proposto na redução da carga poluidora do efluente foram coletadas amostras na entrada do sistema (efluente "in natura") e na saída (efluente após peneiramento) totalizando 150 amostras. Nessas amostras foram analisadas as seguintes variáveis: ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The wastewater from hardboard industries coming from the eucalyptus exploration are characterized by high values of COD and suspended solid matter. For this reason, the wastewater significantly pollute the environment, specially the water resources. The industries that act in this area treat their wastewater by different ways. The irrigation of cultivated lands is one of the options for treatment of the wastewater. By using this procedure, there should be an improvement in the water quality because of its infiltration into the soil and because of the plant's evapotranspiration. However, the wastewater irrigation of the soil sometimes brings severe consequences, which are mainly related to the development of crusts on the soil surface and the possible contamination of the ground water. The objective of the present research was based on the development of a system to treat such wastewater by using the screening process, in order to remove the fibers in suspension. To do so, it has been developed an equipment that contains rotating changeable screens based on a French model that is recommended for the treatment of industry's wastewater. Five trials have been performed combining rotating screens with different nets (0.25, 0.50, 0.75, 1.00, and 1.50 mm) with their respective rotations (13, 20, 33, 41, and 53 rpm) and also with 5 different flows of the wastewater incoming in the system. In order to verify the influence of the proposed system on the reduction of the pollutant capacity of the wastewater, 150 samples were collected at the inlet of the system ("in natura" wastewater) and at it's outlet (wastewater after screening). From these samples, the following variables have been analyzed: total solids, fixed total solids, volatile total solids, pH, turbidity, electrical conductivity, COD, BOD, and... (Complete abstract click electronic access below) / Mestre