An investigation into the use of cuprous chloride for the removal of radioactive iodide from aqueous solutions

Cuprous chloride (CuCl) was examined as a precipitant to remove iodide (I−) from aqueous solutions. The effects of the dosage of CuCl, reaction time, initial concentrations of I− and bicarbonate (HCO3−) on I− removal were investigated. The results showed that the optimized removal efficiency of I− reached approximately 95.8% when the dosage was 150 mg/L, the initial I− concentration ranged from 5 to 40 mg/L and the reaction time was 15 min. The removal efficiency decreased from 95.8% to 76.0% with the addition of HCO3− at a concentration in the range of 0-107 mg/L. Furthermore, the dissociation of CuCl, the disproportionation reaction of Cu+, the precipitation of cuprous iodide (CuI) and cuprous oxide (Cu2O), and the formations of copper sulfide (CuxS, 1 ≤ x <2) were identified as the primary reactions using the PHREEQC software and the measurements of water quality parameters under various conditions. X-rays photoelectron spectroscopy (XPS) analysis was performed before and after the reaction, helping to elucidate the reaction mechanism. This study can provide a promising method to address radioactive I− pollution in water.