Unlocking sustainable solutions: controlled Cu²⁺ dosing enables efficient recovery and reuse of high-purity copper...

The electroplating process of copper pyrophosphate (Cu₂P₂O₇) results in the production of a large volume of wastewater that contains a high concentration of copper (Cu). Currently, conventional lime precipitation creates a substantial amount of secondary pollution, which adds extra economic and environmental burdens. In this study, we suggest a straightforward method for on-site recovery of Cu from Cu₂P₂O₇ electroplating wastewater. By optimizing various parameters, characterizing the resulting product, assessing its electroplating capabilities, and analyzing the speciation during the reaction, we comprehensively investigated the feasibility and mechanism of this technique. The results demonstrated that, under the optimal conditions (Cu/P molar ratio of 0.96, pH of 5.0, and a reaction time of 5.0 min), the concentration of residual Cu remained stable between 22.2 and 27.7 mg/L, even when the initial Cu concentrations varied. The addition of Cu triggered a series of hydrolysis and ionization reactions, primarily leading to the formation of Cu₂P₂O₇·3H₂O. The harvested Cu₂P₂O₇·3H₂O proved to be suitable for practical electroplating applications, exhibiting comparable performance to commercially available Cu₂P₂O₇·3H₂O. This demonstrates the feasibility of recovering high-purity Cu₂P₂O₇·3H₂O from copper electroplating wastewater, offering a promising approach for on-site copper reuse and concurrently reducing the demand for natural copper resources. Furthermore, this approach significantly reduces the generation of solid waste, aligning with the principles of sustainable development.