Synthesis of Cu/Cu₂O hydrides for enhanced removal of iodide from water

In order to improve the removal capacity of Cu₂O for I^- anions from water, Cu/Cu₂O hybrids have been synthesized through a facile hydrothermal route, characterized by using SEM, XRD, XPS, and applied to remove I^- anions under different experimental environments. The results demonstrate that the Cu content and morphology of samples can be tuned by the adding amount of ammonia. Meanwhile, the possible crystalline mechanism, Cu₂O formed firstly and then metallic Cu generated, was presented. With the increasing of Cu doped amount, the removal capacity of Cu/Cu₂O hybrids increased significantly from 0.02mmolg^-1 to 0.18mmolg^-1. Furthermore, a reaction mechanism of I^- anions and Cu₂O, which generated from the disproportionation reaction of metallic Cu and CuO, has been proposed according to the characterization analyses of the composites before and after adsorption, explaining the highly efficient removal of I^- anions. In addition, Cu/Cu₂O hybrids showed excellent selectivity for I^- anions in the presence of large concentrations of competitive anions such as SO₄^2- and NO₃^- and could work in an acidic and neutral environment. This study is hopefully to prompt Cu₂O to grow up to be a new and highly efficient adsorbent for the removal of iodide from solutions.