Preparation and Ion Exchange Performance of Ion Sieve for Cesium Removal Doped with Tungsten

A kind of inorganic ion-exchanger for cesium removal, ion sieve doped with tungsten was synthesized from ZrOCl₂, Na₂MoO₄, Na₂WO₄ and K₄P₂O₇, via procedures including precipitation, embedding Cs⁺, fixing position and extraction of Cs⁺. The effect of W-doping ratio on ion exchange performance was investigated. The microstructure of ion sieve was analyzed by XPS, SEM, EDS, N₂ absorption-desorption, etc. The results show that part of doped tungsten exists on the surface of ion sieve, and Mo is wrapped in the interior. The ion sieve is composed of random particles and membranes. There are many micropores in the ion sieve, and the micropore size is about 20 nm. The ion sieve shows outstanding acidresistivity. Doping tungsten is favorable for ion exchange capacity of ion sieve, which increases early and maintains late with the W-doping ratio. The ion exchange capacity is up to 1.66 mmol/g in neutral solution (pH=6.98) and 1.47 mmol/g in acid solution (pH=1.05). W-Cs-IS exhibits excellent ion selectivity to Cs⁺ and Sr²⁺ in simulated HLLW, and the extracting efficiency of Cs⁺ is up to 88.2%.