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 .