新型铯选择性吸附剂的合成及性能

在金属镍粉表面原位合成了与金属基体紧密结合的亚铁氰化镍钾(KNiFC/Ni)吸附剂。经分析,其表面为面心立方晶系的亚铁氰化镍钾(KNiFC),厚度约为40~80nm,晶格参数为0.996 0nm,化学组成可表示为K1.4Ni1.3Fe(CN)6。结果表明:该吸附剂不水解,对137 Cs具有较高的吸附容量,非常快的吸附速率,很高的选择性,Cs的吸附分配系数(Kd)可达105 mL/g,即使在1.0mol/L NaNO3溶液中,Kd值也大于103 mL/g;该吸附剂吸附137 Cs为典型的离子交换机制,NH+4由于具有和Cs+相近的离子半径所以竞争最为强烈。本吸附剂有望用于含铯废液的处理及137 Cs的分离或提取。

Fabrication of a Novel Selective Adsorbent for Cesium and Its Performance Research

A novel inorganic selective adsorbent for cesium, potassium nickel hexacyanoferrate (KNiFC/Ni) based on the surface of nickel matrix, was synthesized in site by a simple water chemical method. Its surface chemical composition is K_1.4Ni_1.3Fe(CN)₆ determined by X-ray photoelectron spectrometry (XPS), and the crystalline structure of KNiFC is face-centered lattice with a=0.9960 nm determined by the X-ray diffractometry (XRD), and its thick is about 40-80 nm. The adsorbent is stable in aqueous media. It has high adsorption capacity, rapid adsorption kinetics and high selectivity for Cs⁺. The distribution coefficient (K_d) for ¹³⁷Cs is up to 10⁵ mL/g, and even in the 1.0 mol/L NaNO₃ solution, it is still over 10³ mL/g. It is found that the adsorbent for ¹³⁷Cs is typical ion exchange mechanism. Because NH⁺₄ ion radius is close to Cs⁺, NH⁺₄ has the strongest competition as compared to Na⁺, Sr²⁺, and H⁺. The adsorbent is promising for ¹³⁷Cs separation and treatment of ¹³⁷Cs liquid waste .