Preparation of natural cation exchanger from persimmon waste and its application for the removal of cesium from water

A novel bioadsorbent prepared from persimmon waste via cross-linking with concentrated sulphuric acid was investigated for its adsorption behavior towards Cs+. The adsorbent characterization included functional group analysis, elemental analysis, total organic carbon measurements and thermo-gravimetric analysis. The maximum adsorption capacity of PW (0.11 mmol/g) for Cs+ was drastically improved after cross-linking (0.76 mmol/g), furthermore the uptake capacity of the resulting cross-linked adsorbent appeared to increase with increasing temperature. The observed positive value of enthalpy change and negative value of Gibbs free energy change suggest that adsorption of Cs+ by this adsorbent is endothermic and spontaneous in nature. The mutual separation of Cs+ from Na+ can be successfully achieved with quantitative removal of Cs+ within 105 h using a packed column of the adsorbent. Thus, it can be expected that the CPW investigated in this study will contribute to the remediation of water polluted by radioactive cesium. (C) 2013 Elsevier B.V. All rights reserved.