Enhanced uptake of iodide on Ag@Cu2O nanoparticles.

In order to improve the uptake capacity of Cu2O for I- anions from water, Ag loaded Cu2O composites have been synthesized through a facile method, characterized using SEM, XRD, XPS and applied to remove I- anions under different experimental environments. The results show that the uptake capacity of Ag@Cu2O increased with the increasing Ag doped amount. Meanwhile, the uptake capacity (0.20 mmol g-1) of 1.0%-Ag@Cu2O for the removal of I- anions is ten times higher than that of pure Cu2O (0.02 mmol g-1). Furthermore, a mechanism explaining the highly efficient removal of I- anions has been proposed according to characterization analyses of the composites after adsorption and subsequently been verified by adsorption under visible light experiments. 1.0%-Ag@Cu2O (0.5%-Ag@Cu2O, 0.2%-Ag@Cu2O) shows a high iodide uptake efficiency of 98.5% (77.6%, 37.8%) in the visible light, much higher than that under the darkness (86.3%, 69.7% and 30.8%). In addition, the adsorbent showed excellent selectivity for I- anions in the presence of large concentrations of competitive anions, eg. uptake efficiencies are 78.2%, 62.8%, 70.2% and 77.9% in the presence of the Cl-, CO32-, SO42- and NO3- competitive anions, respectively, and could work in a wide pH range of 3-11. This study is hopefully to prompt Cu2O to become a new and highly efficient adsorbent for iodide adsorb from solutions.