An electrodeposition-capacitive deionization combined process for efficient copper removal from wastewater

Following the design concept of high efficiency, environmental friendliness, and stable performance, the application of an electrodeposition-capacitive deionization combined process for copper removal from high-concentration wastewater is the first time proposed in this study. As a pretreatment, electrodeposition exhibited efficient copper ions removal capacity (94.53 %) within only 80 min, and the optimal operation conditions were obtained as 75 mA/cm 2 current density, 1.5 cm electrode spacing, pH value 4, and 1000 mg/L initial copper ion concentration. The electrodeposit predominantly consisted of Cu 0 with minor copper oxide impurities was characterized and can be reintroduced into the production process as a valuable raw material. Subsequently, the wastewater underwent advanced treatment via capacitive deionization technology, resulting in the final copper ion concentration of 0.43 mg/L, which met the discharge limit of criteria (GB 39731–2020, less than 0.5 mg/L). The experimental results demonstrate that the combined process is feasible for treating high-concentration copper-containing wastewater, thereby offering a new technological pathway for the efficient wastewater treatment and resource recovery.