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

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 k_d 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 (ΔG_{TEDA+Ag activated charcoal}~ −14.41 kJ mol⁻¹, ΔG_{Ag activated charcoal} ~ -14.35 kJ mol⁻¹ and ΔG_{Activated 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.

KEYWORDS:

• Radioiodine sequestration
• Ag-activated charcoal
• endothermic sorption
• diamine functionalized Ag-activated charcoal

Acknowledgments

The author wishes to acknowledge P.K. Mohapatra, Associate Director, RC & I Group and Head, Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, India. The author wishes to acknowledge Dr M.S. Kulkarni, Head, HPD and Shri R.V. Kolekar, Head, RPS-SF, HPD and Dr Ashok Kumar, Group Leader, HP Unit Isotope wing, HPD.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

J Sapkal: Experiments and Data acquisition; Pankaj Sorate: Experiments; Arijit Sengupta: Conceptualization and manuscript writing.