Triethylene diamine-functionalized silver-activated charcoal for efficient, exothermic and spontaneous sequestration of radioiodine

Abstract

ABSTRACT Efficient sequestration of radioiodine is one of the challenging tasks in nuclear establishment due to the radio-pharmaceutical applications as well as radiation release into environment point of view. In the present manuscript, an efficient and simple sequestration has been reported by triethylene diamine (TEDA)-functionalized Ag-activated charcoal, and the separation characteristics were compared to the virgin charcoal and Ag-activated charcoal. The kd values at 3 M HNO3 were found to follow the trend TEDA+Ag-activated charcoal > Ag-activated charcoal > charcoal. Pseudo-second-order kinetics was found to be predominating. Chemisorption involving Langmuir isotherm was operative with good sorption capacity (99.4 mg g−1). The sorption processes were found to be endothermic but spontaneous (ΔGTEDA+Ag activated charcoal~ −14.41 kJ mol−1, ΔGAg activated charcoal ~ -14.35 kJ mol−1 and ΔGActivated charcoal ~ -14.34 kJ mol−1). Though functionalization improved the separation efficiency, the radiological robustness was only moderate. Sodium thiosulfate as aqueous complexing agent was utilized for effective back extraction of iodine from loaded sorbents.