Estudo térmico e caracterização química de amostras de resíduos sólidos de aterro sanitário
Carregando...
Arquivos
Data
2007-12-19
Autores
Almeida, Sonia de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os resíduos sólidos domiciliares são classificados como IIA de acordo com a ABNT (NBR 10004, 2004), que são resíduos não inertes. A pesquisa de campo foi realizada no aterro sanitário de São Carlos, em duas etapas: a primeira, em 2004 e a segunda, em 2006, cujo objetivo central foi a amostragem de resíduos dispostos entre o anos de 1999 até 2006. A fração orgânica dos resíduos domiciliares dispostos em aterros sanitários, sofre decomposição e gera o biogás e o chorume, que são fontes de poluição. As amostras foram retiradas do aterro em várias células de diversos anos, que após tratamentos, foram submetidas à análise de metais, difratometria de raios X, determinação da Demanda Química de Oxigênio e a determinação dos parâmetros cinéticos utilizando o método isoconversional de Flynn-Wall-Ozawa e determinação da alcalinidade total. As diferenças de alcalinidade encontradas nas amostras se devem às diferentes etapas de degradação da matéria orgânica presentes nos resíduos coletados no aterro sanitário. As curvas termogravimétricas (TG) e as curvas termogravimentricas derivadas (DTG) obtidas nessa pesquisa, em atmosfera de nitrogênio, foram análogas as obtidas para composto de lixo e permitiram verificar que a decomposição térmica dos resíduos sólidos domiciliares ocorre em quatro etapas consecutivas. As curvas mostraram também certa tendência de aumento na porcentagem da matéria orgânica em função da idade dos resíduos. A composição do produto gerado da decomposição térmica foi basicamente sílica e em menor quantidade de ZnO, NiO, Fe2O3, Al2O3, Mn3O4, CuO ou Cu e Cr2O3, PbSO4 e carvão. As técnicas analíticas TG e DTG foram eficientes e rápidas no estudo da estabilidade térmica de amostras retiradas de aterro sanitário e permitiram realizar o estudo cinético.
Domiciliary waste are classified as II A (non inert) according to the ABNT (NBR 10004, 2004). The field research was carried out in São Carlos sanitary landfill, in two steps: the first in 2004 and the second one in 2006, whose central objective was the residue sampling disposition from 1999 until 2006. The organic fraction of domiciliary residue disposition in sanitary landfills suffers decomposition and produces the biogas and the lixiviating, which are pollution sources. The samples were collected from the landfill in several cells corresponding to different years, and after treatments, they were submitted to metal analysis, X ray diffractometry, COD determination and kinetic parameters determination by using the Flynn-Wall- Ozawa method. TG/DTG curves of the samples, under nitrogen atmosphere, were similar to the waste composting come from urban solid residue and they allow verifying that the thermal decomposition occurs in four consecutive steps. The curves also show a tendency of increase in percent of organic matter in function of residue maturity. The composition of the product originated from the thermal decomposition was basically silica and in smaller quantity, the ZnO, NiO, Fe2O3, Al2O3, Mn3O4, CuO or Cu and Cr2O3, PbSO4 and coal. The kinetic study indicated that the analyzed thermal decomposition reaction is due to the presence of components with the same basic organic composition and is probably related with the presence of inorganic residue. The result was the linear relationship between the two kinetic parameters (ln A and E), determined by the Flynn-Wall-Ozawa isoconversional method, which is known as kinetic compensation effect (KCE). TG and DTG analytical techniques were fast and efficient in the study of stability thermical of samples from de sanitary landfill which showed that the reaction of thermical decomposition (dehydration) is caused by components that have the same basic organic composition.
Domiciliary waste are classified as II A (non inert) according to the ABNT (NBR 10004, 2004). The field research was carried out in São Carlos sanitary landfill, in two steps: the first in 2004 and the second one in 2006, whose central objective was the residue sampling disposition from 1999 until 2006. The organic fraction of domiciliary residue disposition in sanitary landfills suffers decomposition and produces the biogas and the lixiviating, which are pollution sources. The samples were collected from the landfill in several cells corresponding to different years, and after treatments, they were submitted to metal analysis, X ray diffractometry, COD determination and kinetic parameters determination by using the Flynn-Wall- Ozawa method. TG/DTG curves of the samples, under nitrogen atmosphere, were similar to the waste composting come from urban solid residue and they allow verifying that the thermal decomposition occurs in four consecutive steps. The curves also show a tendency of increase in percent of organic matter in function of residue maturity. The composition of the product originated from the thermal decomposition was basically silica and in smaller quantity, the ZnO, NiO, Fe2O3, Al2O3, Mn3O4, CuO or Cu and Cr2O3, PbSO4 and coal. The kinetic study indicated that the analyzed thermal decomposition reaction is due to the presence of components with the same basic organic composition and is probably related with the presence of inorganic residue. The result was the linear relationship between the two kinetic parameters (ln A and E), determined by the Flynn-Wall-Ozawa isoconversional method, which is known as kinetic compensation effect (KCE). TG and DTG analytical techniques were fast and efficient in the study of stability thermical of samples from de sanitary landfill which showed that the reaction of thermical decomposition (dehydration) is caused by components that have the same basic organic composition.
Descrição
Palavras-chave
Quimica analitica, Termogravimetria
Como citar
ALMEIDA, Sonia de. Estudo térmico e caracterização química de amostras de resíduos sólidos de aterro sanitário. 2007. 107 f. Tese (Doutorado) - Universidade Estadual Paulista, Instituto de Química., 2007.