Removal of aqueous selenite anions from wastewater by electrodeposition and recycling used for catalyst of effective water splitting

Transforming toxic selenium in industrial wastewater into selenium resources is a significant challenge to realize the upgrading of valuable element resources and the removal of pollutants. Here, we chose copper, cobalt, and nickel foam as the electrode materials and used electrodeposition to capture selenite from selenium-containing wastewater. The effects of operating voltage, initial concentration, stirring rate and time on the removal efficiency of selenium were investigated. Among them, the removal efficiency of copper foam for 100 mg L−1 selenite could reach 91.2 % at −1.5 V operating voltage. The composition, morphology and structure of the products after electrodeposition were characterized by XPS, FESEM and TEM. The OER and HER properties of the electrodeposited products Cu2Se, CoSe2 and NiSe were evaluated by density functional theory calculations. It was proved that selenium could improve the electron transfer rate, and CoSe2 also had better HER performance than NiSe. The products formed after electrodeposition could be combined for overall water splitting to achieve efficient hydrogen production. This study proved the mechanism and resource utilization process of selenite removal through electrodeposition.