Gerenciamento eco-inovador para resíduos viabilizando uma rota de baixo custo para extração do Cr3+ do couro wet-blue e promovendo adsorção dos íons Cr3+ do efluente.

Abstract

The tannery industry is responsible for transforming the “green” skin into leather through a tanning agent, usually the basic chromium sulfate. The disposal of Cr3+ depending on abrasive conditions may oxidize it to Cr6+ being in this oxidizing state, a carcinogenic and mutagenic metal for living organisms. In this study it had been used concepts of CP regarding the development of ideas to treat solid waste of “wet-blue” and the total effluent of tannery. In order to promote the extraction of Cr3+ from “wet-blue” leather residues produced, an unprecedented route of decolorization was elaborated using low cost inputs with three distinct time reactions, 8, 12 and 18 hours. The efficiency of the process was evaluated by determining the Cr2O3 content from the “wet-blue” leather and from the produced residue after dechromating, collagen. The latter was further characterized according to spectroscopic and thermogravimetric methods. For the total effluent treatment it was used forage cactus (Opuntia ssp) as a biosorbent to reduce the Cr3+ from the total effluent. Therefore, two systems of adsorption were studied, with different masses of cactus powder in a set period of time under disturbance and volume of effluents. The results indicated a reduction in the Cr2O3 content from 81,03%, 94,82% and 95,99% within 8, 12 and 18 hours, respectively. The most satisfactory results for reducing the Cr3+ content of the total effluent happened within 5 minutes of contact. Obtaining for the tests with 2,0g and 4,0g of biomass a reduction of 74,80% and 84,88%. The tests showed that the cactus can be used to reduce the content of Cr3+ from the total effluent.