Estudo de redução do cromo no lodo primário de curtume por solubilização.

Abstract

The main challenge of the leather industry is the concern with the use of chromium salts in the processing of leather, providing a rising polluting load. The industrial process of the leather, produces solid residues proceeding from the stages of processing, finishing and treatment of the effluent in the station. The solid residue (primary sludge), the focus of our study, is originated in the stage of physical - chemistry treatment of the effluent, this it represents 60% of residues generated for the leather industry. The primary sludge presents some problems in its final disposal due to presence in its constitution of a diversity of harmful chemical elements to the environment, especially the heavy metal chromium (IE) and chromium (IV). In this context, an alternative to minimize the discharge of chromium to the environment for the solid residue (thus diminishing, the ambient impact, as well as the high costs in the final disposal) would be to remove chromium (EI) and chromium (IV) contained in the residue. This study it was carried through with samples (primary sludge) deriving from the Station of Treatment of Effluent of the Technological Center of Leather and Footwear - Albano Franco, with the objective of: a) characterizing chemically b) classifying the solid residue c) evaluating electrokinetic properties d) solubilization of the primary silt through the ionization of ions. The selected fractions in the sampling practice and the quarting had been analyzed through analytical assays by means of atomic absorption espectofometro; extreme violet-visible, Kjeldahlean method and espectofometrico method. The study concluded that the primary sludge presents a high index of toxicity due the presence of heavy metals, with Cr3+, Cr6", Pb, Mn, Cd, but also of micronutnents and macronutrients essential to the soil. With the solubilization of ions, the chromium presented a certain resistance of ionization, thus needing, to evaluate other parameters physical-chemistry capable to intensify its power of solubility.