Studies on ion exchange behavior of cesium into zirconium molybdopyrophosphate and its application as precursor of cesium ion sieve

A new inorganic ion exchanger, zirconium molybdopyrophosphate, was synthesized by both precipitation and hydrothermal reactions. Through orthogonal experiments the sample obtaining the highest cesium exchange capacity was chosen and characterized by X-ray diffraction, scanning electron microscope, specific surface area along with determination of pH at the point of zero charge. Batch experiments were carried out to evaluate the effects of operational parameters such as initial pH, exchanger dose, contact time and Cs+ concentration on the cesium exchange capacity of the optimum sample. Evolution of solution pH presented in each case evidenced the main Cs+–H+ ion exchange mechanism. The pH at the point of zero charge indicated this ion exchanger as monofunctional and acidic in character. The ion exchange process followed the Langmuir and pseudo-second-order model. The results showed that the optimum sample with a considerable capacity of 1.21 mmol/g might be a suitable precursor for cesium ion-sieve.