Ammonium salt of heteropoly acid immobilized on mesoporous silica (SBA-15): An efficient ion exchanger for cesium ion

The ammonium salt of heteropoly acid (NH₄HPA) deposited on the surface of mesoporous silica (SBA-15) support was prepared and characterized using the following analytical techniques: X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscopy (SEM), particle size analysis and infrared spectra. The spectroscopic results revealed that the NH₄HPA was well dispersed on the internal and external silica surfaces. The ion exchange capacity tests demonstrated that the insertion of the NH₄HPA phase on the silica surface increased the specific activity for Cs removal. The ion exchange capacity of Cs increased with increasing the HPA loading. The NH₄HPA at a loading of 50wt% supported on silica showed a high ion exchange capacity (70.9mg/g) for Cs ion. The effects of co-existing cations, nitric acid and temperature on the Cs sorption efficiency onto the composites were investigated.