Estudo da obtenção e caracterização da quitina e quitosana a partir de resíduos de carcinicultura e suas aplicações energéticas sustentáveis

Abstract

Currently one of humanity's biggest concerns today is the fate of industrial waste and the study of alternatives to sustainable energy. In this context, the aim of this work was to obtain chitosan from the discards of carniciculture, the biopolymer chitin results the deacetylation by means of alkaline hydrolysis. The demineralization steps were performed through deproteinization to obtain chitin, and deacetylation to obtain chitosan, were characterized by X-ray diffraction (XRD), X-ray fluorescence (FRX), scanning electron microscopy (SEM/EDS/TEM), thermogravimetry (TG), UV-visible and Fourier transformer spectroscopy (FTIR) for confirmation of the obtain chitin and chitosan with an acetylation degree of the DA of 70% and 75%, respectively. The biopolymers was possible to perform the hydrothermal carbonization synthesis, which is a low cost process, of two renewable precursors, which are materials derived from biomass (chitin and chitosan) and graphite as a third material used to obtain two solid phase and liquid. The liquid phase was used for the formation of carbon quantum dots (CQDs) with application in solar cells and photocatalysis, and the solid phase for the formation of heterogeneous catalysts for reactions of transesterification of biodiesel. The phases were characterized arrange for needed of their applications obtaining for the liquid phase a CQDs with quantum yield of 17.1% with doping in ZnO / CQDs for the apllicattions on the photocatalysis property. The solid phase a heterogeneous graphite-chitosan catalyst obtained process efficiency by gas chromatography with 36% conversion. Obtaining chitin and chitosan biopolymers is a great solution for the tons of waste produced in the shrimp industry. The realization of hydrothermal carbonization synthesis to obtain two products, the CQDs and graphite-chitosan catalysts demonstrated great alternatives for the use of sustainable energy in photocatalysis and transesterification reactions.