Facile Preparation of MCM-41/Ag2O Nanomaterials with High Iodide-Removal Efficiency

The elimination of iodide (I−) from water is a tough subject due to its low adsorption tendency and high mobility. In this work, MCM-41/Ag2O nanomaterials were prepared, characterized, and employed to adsorb I− from water. The Ag2O nanoparticles were dispersed homogeneously in the pores or at the surface of the MCM-41 support, and the Ag2O nanoparticles in the pores had small particles sizes due to the confinement of the mesoporous channel. The prepared MCM-41/Ag2O nanomaterials exhibited a higher specific surface area than previously reported Ag2O-based composites. The adsorption of I− by the nanomaterials was able to reach equilibrium at 180 min. The MCM-41/Ag2O nanomaterials showed a better adsorption capacity per unit mass of Ag2O than pure Ag2O nanoparticles and previously reported Ag2O-based composites prepared using other supports. Furthermore, the MCM-41/Ag2O nanomaterials exhibited high selectivity for I− in the presence of high concentrations of competitive anions, such as Cl− or Br−, and could function in a wide range of pH. The chemical reaction between Ag2O and I− and the surface adsorption were the main adsorption mechanisms. These results indicate that MCM-41/Ag2O nanomaterials are a promising and efficient adsorbent material suitable for the removal of I− for practical application.