Modificação da fração lignocelulósica durante o processo de compostagem do bagaço de cana-de-açúcar
Carregando...
Arquivos
Data
2012-04-13
Autores
Bernabé, Giseli Aparecida [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O crescimento na produção brasileira de cana-de-açúcar devido, principalmente, à obtenção de açúcar e álcool é motivado pelo aumento na exportação deste subproduto e produção de veículos bicombustíveis, respectivamente. Desta maneira, há maior geração de bagaço, embora possuindo inúmeras utilidades, muitas vezes existe um excesso remanescente do total gerado. Assim, são necessários estudos que viabilizem o uso deste resíduo. Neste trabalho foi estudada a modificação da fração lignocelulósica durante o processo de compostagem e biodigestão anaeróbia do bagaço de cana-de-açúcar. Amostras foram coletadas em diferentes períodos para ambos os processos (0 (cru), 7; 45; 60; 90; 120; 272 dias; 1 ano e 1 ano e 2 meses) e acompanhadas por meio de parâmetros como: pH, umidade, temperatura, presença de metais e demanda química de oxigênio. A caracterização foi feita com o auxílio de técnicas termoanalíticas (TG/DTG/DTA e DSC) e espectroscopia na região do infravermelho. As amostras provenientes dos processos aeróbios e anaeróbios foram submetidas às extrações de lignina, utilizando-se dioxano/HCl (9:1) e, de celulose e hemicelulose, as quais foram obtidas do resíduo sólido resultante da extração de lignina. O comportamento térmico e espectros de infravermelho dessas substâncias foram avaliados e, comparadas suas degradações e modificações na ausência e presença de oxigênio. Os resultados obtidos mostraram que a digestão anaeróbia é mais lenta que a compostagem na decomposição de seus constituintes, principalmente, lignina e celulose/hemicelulose, fato comprovado por suas respectivas curvas de Calorimetria Exploratória Diferencial (DSC); além da constatação de modificações nas estruturas de lignina e celulose ao longo dos dois processos, bem como, fortes evidências...
The growth in the Brazilian sugarcane production, mainly, due to obtain sugar and alcohol is motivated by the increase in export of this subproduct and production of flex-fuel vehicles, respectively. This way, there is a larger bagasse generation, although having many uses, often there is an excess remaining of the total generated. Thus, studies are needed that allow the use of this waste. The modification lignocellulosic fraction during composting and anaerobic biodigestion process of sugarcane bagasse was studied in this work. Samples were collected in different periods for both process (0 (raw); 7; 45; 60; 90; 120; 272 days and 1 year and 1 year and 2 months) and monitored by parameters, such as: pH, humidity, temperature, presence of metals and chemical oxygen demand. The characterization was made with help of thermoanalytical techniques (TG/DTG/DTA e DSC) and infrared spectroscopy. The samples from aerobic and anaerobic process were submitted to lignin extraction, using dioxane/ HCl (9:1), and hemicelluloses/cellulose extraction which were obtained from solid residue resulting of lignin extraction. The thermal behavior and infrared spectra from these substances were evaluated and then compared their degradation and changes in the oxygen presence and absence. The obtained results have showed that anaerobic digestion is slower than composting in its constituents decomposition, mainly, lignin and cellulose/hemicellulose, as demonstrated by their respective curves of Differential Scanning Calorimetry (DSC); besides verifying changes in the cellulose and lignin structures through the two process, as well as, strong evidences of lignin in the cellulose extract and, rare assignments of cellulose to lignin extracted. Concerning to humification, a greater tendency for composting samples was observed, mainly... (Complete abstract click electronic access below)
The growth in the Brazilian sugarcane production, mainly, due to obtain sugar and alcohol is motivated by the increase in export of this subproduct and production of flex-fuel vehicles, respectively. This way, there is a larger bagasse generation, although having many uses, often there is an excess remaining of the total generated. Thus, studies are needed that allow the use of this waste. The modification lignocellulosic fraction during composting and anaerobic biodigestion process of sugarcane bagasse was studied in this work. Samples were collected in different periods for both process (0 (raw); 7; 45; 60; 90; 120; 272 days and 1 year and 1 year and 2 months) and monitored by parameters, such as: pH, humidity, temperature, presence of metals and chemical oxygen demand. The characterization was made with help of thermoanalytical techniques (TG/DTG/DTA e DSC) and infrared spectroscopy. The samples from aerobic and anaerobic process were submitted to lignin extraction, using dioxane/ HCl (9:1), and hemicelluloses/cellulose extraction which were obtained from solid residue resulting of lignin extraction. The thermal behavior and infrared spectra from these substances were evaluated and then compared their degradation and changes in the oxygen presence and absence. The obtained results have showed that anaerobic digestion is slower than composting in its constituents decomposition, mainly, lignin and cellulose/hemicellulose, as demonstrated by their respective curves of Differential Scanning Calorimetry (DSC); besides verifying changes in the cellulose and lignin structures through the two process, as well as, strong evidences of lignin in the cellulose extract and, rare assignments of cellulose to lignin extracted. Concerning to humification, a greater tendency for composting samples was observed, mainly... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Quimica analitica, Adubos compostos, Lignina, Digestão anaeróbia, Analytical chemistry, Compost, Lignin, Anaerobic digestion
Como citar
BERNABÉ, Giseli Aparecida. Modificação da fração lignocelulósica durante o processo de compostagem do bagaço de cana-de-açúcar. 2012. 158 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Química de Araraquara, 2012.