钨掺杂的提铯离子筛的制备及离子交换性能研究

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

以ZrOCl_2、Na_2MoO_4、Na_2WO_4、K_4P_2O_7为原料,通过沉淀反应、Cs^+嵌入、固位、抽出等一系列程序合成了用于提取铯的钨掺杂离子筛(W-Cs-IS),研究了W的掺杂比例对离子筛Cs^+交换性能的影响。用X射线光电子能谱(XPS)、扫描电子显微镜(SEM)及能谱分析(EDS)、氮气吸附-解吸等手段表征了产物的微观结构,并测试了其耐酸性。结果表明:掺杂的W部分存在于产物表面,Mo包藏于内部;离子筛由不规则颗粒及膜状部分组成,具有微孔结构,微孔尺寸约为20nm;在HCl和HNO3中均显示出良好的耐酸性。W掺杂有利于提高离子筛的交换性能。随着掺杂比例的增加,离子交换容量先提高后基本不变,在中性(pH=6.98)和酸性(pH=1.05)条件下分别可达到1.66 mmol/g和1.47 mmol/g。W-Cs-IS对模拟高放废液中的Cs^+和Sr^(2+)具有较高的选择性,可同时将Cs^+和Sr^(2+)从高放废液中提取出,对模拟高放废液中Cs^+的提取率可达到88.2%。

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,N2absorption-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 about20 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 1.66mmol/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 Sr^2＋in simulated HLLW,and the extracting efficiency of Cs^＋is up to 88.2%.