Bimetallic AgCu/Cu₂O hybrid for the synergetic adsorption of iodide from solution

To further improve the capacity of Cu₂O to absorb I^- anions from solution, and to understand the difference between the adsorption mechanisms of Ag/Cu₂O and Cu/Cu₂O adsorbents, bimetallic AgCu was doped into Cu₂O through a facile solvothermal route. Samples were characterized and employed to adsorb I^- anions under different experimental conditions. The results show that the Cu content can be tuned by adding different volumes of Ag sols. After doping bimetallic AgCu, the adsorption capacity of the samples can be increased from 0.02 mmol g^-1 to 0.52 mmol g^-1. Moreover, the optimal adsorption is reached within only 240 min. Meanwhile, the difference between the adsorption mechanisms of Ag/Cu₂O and Cu/Cu₂O adsorbents was verified, and the cooperative adsorption mechanism of the AgCu/Cu₂O hybrid was proposed and verified. In addition, the AgCu/Cu₂O hybrid showed excellent selectivity, e.g., its adsorption efficiencies are 85.1%, 81.9%, 85.9% and 85.7% in the presence of the Cl^-, CO₃^2-, SO₄^2- and NO₃^- competitive anions, respectively. Furthermore, the AgCu/Cu₂O hybrid can worked well in other harsh environments (e.g., acidic, alkaline and seawater environments). Therefore, this study is expected to promote the development of Cu₂O into a highly efficient adsorbent for the removal of iodide from solution.