Remoção de lignina e hemiceluloses do sisal utilizando pré-tratamentos ácidos e alcalinos

Abstract

An alternative to the shortage of oil reserves is the production of substitutes based on renewable organic matter. The production of ethanol from plant biomass is a promising alternative, because it is a renewable and plentiful source. There are different organic materials for the production of ethanol, sugarcane, corn, vegetable fibers, bamboo. In the semiarid region is used sisal (Agave sisalana Perrine), which is one of the plants with higher biomass production capacity in dry regions, the fibers have a high concentration of carbohydrates. The pre-treatment is one of very important step because it makes the fiber more accessible for the production of ethanol. This study aims to evaluate the acid and alkaline pretreatments and the experimental conditions employed in relation to greater efficiency in the removal of hemicellulose and lignin. The work was developed in the chemistry laboratory and technology of wood from the Federal University of Bahia Reconcavo in partnership with the Pulp and Paper Laboratory (LCP) of the Federal University of Viçosa. Sisal fiber samples were used, analyzing chemical fibers, extractives, determining the carbohydrate content and the total lignin. Several methods for pretreatment of biomass, among these techniques, the pre-treatment with NaOH was used at three different concentrations: 1, 1.5 and 2 mol/L and at different temperatures: 30, 50, 70 and 90 ° C. And the pretreatment with dilute H2SO4, 0.5%, 1% and 2%, the time ranging from 10 to 60 minutes. The Klason Lignin content found for these fibers (10,7%), are typical materials considered as non-wood fibers (8.0 -13.0%). Total lignin content of sisal fibers (14.2%) are relatively low compared to wood (from 20.0 to 30.0%) indicating that these fibers are easier delignification in the pulp production process and also to ethanol production. Based on the results of this research, it was possible to suggest that the sisal fibers are great raw materials for the production of pulp and paper and also for the production of ethanol, since they have high cellulose content, good hemicellulose content and low levels of lignin.