Efficient removal of radioactive iodide by three-dimensional Cu@Cu2O: An adsorption and electrocatalytic oxidation coupling process

Electrochemical promotion technology, an environmentally friendly and facile strategy, is becoming increasingly attractive to researchers. In this work, a novel Cu@Cu2O foam block composite material was constructed through a one-step hydrothermal method. The product was then employed as the anode and electrified to catalyse removal of radioactive iodide ions (I-) in the liquid phase. The removal rate of I- sharply increased to 96.65 % under electrification, which is a 4.5-fold increase over that without electrification. The current strength had an impact on this result, and the removal was still relatively high in a wide range of pH values. The composite material had good reusability and could maintain good performance after simple separation. Therefore, based on X-ray diffraction and X-ray photoelectron spectroscopy analysis, we proposed a mechanism of electrochemical oxidation and adsorption coupling for the iodine removal. As Cu@Cu2O adsorbed I- to form CuI, the current flow oxidised I- to I-2 , which finally was adsorbed by the formed CuI. Therefore, the current provides services of accelerating I- movement and oxidation. This coupling model of electrocatalytic oxidation and adsorption provides us with a new research method to remove iodide from water.