Selective Removal of Cesium Ion from Water by Ferro-hexacyanoferrate Immobilized Polyacrylonitrile Film

After the accident at Fukushima Nuclear Power Plant, the removal of cesium from water became an emerging issue. In this study, ferro hexacyanoferrate-polyacrylonitrile (FeHCF-PAN) film was prepared and used as a adsorbent for the removal of cesium from water. A batch adsorption experiments were systematically carried out to assess the effect of different parameters such as presence of competing cations, contact time, initial cesium concentration and temperature on the adsorption of cesium on FeHCF-PAN film. The presence of competing cations showed no adverse effect on cesium removal. Langmuir, Freundlich and Dubinin-Radushkevich isotherm models were fitted to the obtained experimental adsorption data and it was observed that the adsorption of cesium on the FeHCF-PAN film was better represented by the Langmuir model. The maximum monolayer adsorption capacity was found to be 76.92 mg/g at DIW and 100.0 mg/g at seawater, respectively. The pseudo-second-order kinetic model described well the kinetic data, and resulted in the activation energy of 24.02 kJ/mol, which indicate that the adsorption mechanism was chemisorption. Adsorption thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated and showed that the adsorption of cesium is endothermic process and spontaneous in nature.