Recovering ZnO-rich microcomposites from metallurgic acid-pickling wastewater: From residue processing to material application

• Published in: Journal of environmental chemical engineering 2024-06, Vol.12 (3), p.112637, Article 112637
• Main Authors: Kassab, Lais M., Martini, William S., Santos, Vinicius T., Lobo, Flavia G., Silva, Márcio R., Vital, Vitor G., Lima, Lucas F., de Vasconcellos, Suzan P., da Silva, Ricardo A.G., Pellosi, Diogo S.
• Format: Article
• Language: English
• Subjects: Cu-based alloys; Environmental; Materials engineering; Sustainability; Zinc oxide
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2024.112637

However, the process of cleaning the material using acid pickling generates hazardous metal-rich acid residue that is harmful to the environment and expensive to dispose of. Therefore, this study aimed to recover the acid pickling residue from the Cu0.69Zn0.26Ni0.05 alloy. By using an economically viable and surfactant-free one-pot coprecipitation hydrothermal process, a ZnO-rich microcomposite material was obtained, which had a high recovery yield of 20 g/L by reusing residual water in a cyclic process. The material's composition was confirmed through electronic and crystalline characterizations determined by UV-Vis, Photoluminescence, FTIR, XRD, and XPS. Moreover, the morphological characterization showed that the wurtzite ZnO grows on the CuO surface, forming rod-like structures with high surface areas, as observed through SEM and TEM analysis. The microstructure exhibits favorable properties that enable the degradation of a pollutant model in an aqueous solution, as well as the inactivation of multidrug-resistant bacteria. Unlike other works in the literature, the creation of a valuable product from a harmful residue did not require complex metal separation steps. These promising results bode well for the development of functional materials based on green economy principles, thereby facilitating large-scale treatment of industrial metallurgy residues. [Display omitted] •Recovering metal from a realistic metallurgic acid-pickling wastewater.•One-pot coprecipitation methodology allowed a high recovery yield of 20 g/L.•Wurtzite ZnO grows as rods on the CuO surface, forming high surface areas.•Composite material presents favorable photocatalytic and antibacterial properties.•Circular economy concepts applicable to large-scale metallurgy.