Avaliação da degradação de poluentes orgânicos utilizando catalisador de cobalto sintetizado a partir de baterias íon-lítio exauridas

Abstract

In the present work, the recovery of cobalt (Co) from exhausted lithium-ion batteries from notebooks was tudied, adopting the chemical precipitation methodology for the recovery of cobalt oxide (CoOx). The recovered material was subjected to physiosorption of N2, MEV, TXRF, DRX, FTIR, and Raman characterization analyzes, which provided information on the structure, morphology and elementary concentration of the synthesized material. CoOx was used as a catalyst in the degradation tests of reactive blue 5G dye with an initial concentration of 100 mg L-1 using the techniques of photolysis, catalysis and photocatalysis. In order to find the best operational conditions, the DCCR 22 experimental design was used using 2 independent variables, namely pH and catalyst dosage, considering as a response the degradation percentage of the 5G reactive blue dye for the catalysis tests and photocatalysis. The best operational conditions indicated were for pH 1.8 and catalyst dosage 1.5 g L-1, obtaining 83.32% degradation for catalysis and 99.13% for photocatalysis. In addition, kinetic degradation tests were performed, with operating conditions of pH 2 and 1 g L-1 catalyst dosage for photolysis, catalysis and photocatalysis techniques. The catalysis process was presented as the best degradation proposal, considering the economic and sustainable viability of the process, as UV light exposure is not required for the treatment, with a degradation greater than 80% after 60 minutes of operation. For the reuse tests of the catalyst, it was found that there were no significant losses in the catalytic efficiency of CoOx, enabling the use in more degradation cycles of the reactive blue 5G dye. In addition, pollutant degradation tests were carried out using the synthesized catalyst and sunlight as a photoactivation source, showing promise for the treatment of effluents evaluated as from the paint, dairy, refrigerator and sulfur black textile dye industries. In this context, the synthesis of the CoOx catalyst proved to be economically and environmentally viable, since the circular economy concept is used, creating new products and consequently reducing environmental impacts resulting from solid waste (lithium-ion batteries) and liquids (effluents) that need an appropriate destination.