Adsorption studies of cesium on potassium copper nickel hexacyanoferrate(II) from aqueous solutions

Abstract

Adsorption of cesium from aqueous solutions on potassium copper nickel hexacyanoferrate(II) (KCNF) has been investigated in batch experiments and optimized as a function of concentration of acids, salts and adsorbate using a radiotracer technique. The results are presented in terms of distribution coefficient, K_d (ml·g⁻¹). The uptake of cesium obeys a Freundlich adsorption isotherm over the concentration range of 3.7 to 37 mmol·l⁻¹ with b values of 0.77, 0.68 and 0.56 at temperatures of 293, 313, 333 K, respectively. The Langmuir adsorption isotherm is followed in the concentration range of 15 to 75 mmol·l⁻¹ in the same temperature range. The values of limiting adsorption concentration (C_m) have been found to be 2.58, 2.44 and 2.32 mmol·g⁻¹. The heat of adsorption was calculated as 26.43 kJ·mol⁻¹. The influence of a number of anions and cations on cesium retention has also been studied. Column experiments have been performed and breakthrough have been obtained under different operating conditions. The low cesium capacity of 1.1 mmol·g⁻¹ has been obtained under dynamic conditions as compared to batch experiments. Desorption of cesium from the column has been achieved (45.4%) by nitric acid solution of 8M concentration at a flow rate of 0.5 ml·min⁻¹.