Recovery of copper ions from acidic cleaning wastewater of printed circuit board using a hybrid membrane-electrodeposition process

The acidic cleaning wastewater generated during printed circuit board(PCB) manufacturing contains copper ions(Cu2+) at concentrations of 2-6 g/L. The recovery of these copper ions holds significant importance for promoting green development and achieving synergistic effects in pollution reduction and carbon mitigation within the PCB industry. The traditional treatment methods represented by chemical precipitation, ion exchange and adsorption are faced with three major problems in the process of treating PCB acidic cleaning wastewater including susceptibility to secondary pollution is easy to occur, serious waste of resources and low treatment efficiency. This study presented an innovative hybrid process combining physical concentration and chemical reduction-the “membrane concentration-electrodeposition” system. The front-end membrane concentration system employed nanofiltration to separate Cu2+ and Na+, followed by reverse osmosis and specialized separation processes that can concentrate Cu2+ up to 32 g/L. In the subsequent electrodeposition unit, selective reduction of Cu2+ was achieved under the condition of 500-900 A DC current, achieving a copper recovery rate>95% with a purity>99.5%. The direct economic benefit was 11 900 yuan/d, providing a valuable reference for the treatment of similar wastewater.