Synthesis, characterisation and performance evaluation of silver-coated alumina for the sorption of iodine, iodide and iodate from aqueous streams
摘要
Iodine species in aqueous streams inside the nuclear reactor containment pose significant challenges to nuclear safety due to their volatility and radiotoxicity, emphasising the importance of their efficient removal. In this study, silver-coated alumina was synthesised by wet impregnation, characterised by XRD, SEM–EDX, FTIR, Raman spectrum and evaluated as a sorbent for iodine, iodide, and iodate under simulated nuclear reactor conditions. Batch experiments demonstrated high sorption efficiency for iodine and iodide, while iodate removal was comparatively lower. Sorption efficiency was quantified using ion chromatography and distribution coefficient values confirmed the stronger affinity of iodine and iodide relative to iodate. Kinetic analysis indicated that iodide adsorption follows a pseudo-second-order model, while isotherm studies aligned with the Langmuir model, yielding a maximum adsorption capacity of 351 mg g⁻1. The sorbent maintained performance across different pH conditions and under gamma irradiation, indicating excellent structural and radiation stability. Results indicate that silver-coated alumina is a highly effective sorbent for iodine species, particularly iodine and iodide, under simulated nuclear reactor conditions.