Recuperação de cobre a partir de baterias íon-lítio exauridas

Abstract

Technological advancement and the increasing use of electronic devices have increased the generation of electronic waste, with lithium-ion batteries standing out. The improper disposal of these materials poses a severe risk to the environment and public health and wastes mineral resources. Given this scenario, this work aimed to evaluate strategies for recovering copper from the anode of spent lithium-ion batteries and to assess the application of the obtained materials in the degradation of textile dyes. The methodology involved dismantling the batteries and extracting the metal through an acid leaching process with nitric acid (HNO3). A 2² factorial experimental design was used to optimize the operational conditions of the reagents, sulfuric acid (H2SO4), and hydrogen peroxide (H2O2), obtaining the recovered copper, which was characterized by UV-Vis spectrophotometry, X-ray diffraction, and total reflection X-ray fluorescence. As an alternative technological route, the green synthesis using carqueja extract confirmed the structural viability of copper oxide formation, reinforcing the use of environmentally sustainable methods in the valorization of the recovered metal. The recovered materials, including uncalcined leached compounds (CuL) and calcined copper oxide (CuC), were tested as catalysts for the catalytic degradation of methylene blue and reactive blue 5G dyes under ultraviolet irradiation (lamp) and solar irradiation, and in the absence of light. The results demonstrated that copper recovery was efficient under the conditions of [HNO₃] = 4,0 mol/L, [H₂SO₄] = 0,5 mol/L, and [H₂O₂] = 0,04 mL/g, yielding a solution containing approximately 0,75 mol/L of recovered copper. Characterization by X-ray diffraction confirmed the predominant formation of copper oxide after calcination in both the material obtained by acid leaching and that produced through green synthesis. In contrast, the compound recovered directly from leaching (CuL) exhibited excellent performance in degrading the reactive blue 5G dye, achieving degradation rates exceeding 90% in a solution with an initial concentration of around 100 mg/L within just over 2 hours of exposure to ultraviolet light. Furthermore, the CuL catalyst demonstrated good catalytic activity under solar irradiation and in purely catalytic reactions in the dark. It is concluded that the employed method is technically and environmentally promising, aligning with the principles of the circular economy by transforming a potentially toxic component into a value-added functional material capable of degrading dyes in contaminated water.