Metal sulfide functionalized activated carbon for efficient capture of gaseous iodine

Emission control of gaseous elemental iodine discharged from nuclear industries is of extreme importance for ecological environment and human health. An obvious barrier hindering the extensive application of activated carbon-based sorbents primarily derives from the absence of active ligands with satisfactory binding towards iodine. To effectively face this challenge, copper sulfide (CuS) with high binding affinity for iodine was introduced and to graft on activated carbon matrix through a simple room-temperature precipitation method under mild conditions. The as-prepared CuS/AC sorbent exhibits favorable textual properties (large specific surface area and developed pore channel) and was enriched with abundance active sites including CuS components and hydroxy functional groups (–OH). Those excellent characteristics contributed to that the iodine uptake capacity of CuS/AC reached to 486 mg g⁻¹. CuS with rich abundance and high accessibility was found to be main ligands accounting for the conversion and immobilization of gaseous iodine. The elemental iodine was reduced into iodine ions and reacted with CuS to form the ultimate adsorbate CuI, effectively avoid the secondary emission of vapor-phase iodine. The whole iodine adsorption process was synergetic controlled by physisorption and chemisorption. The goal of this work not only extends the performance enhancement of the carbon-based sorbents for iodine removal but also inspires further exploitation for the cost-effective and high-performance sorbents for iodine abatement from nuclear industries.