Facile synthesis of N-doped biomass derived porous carbon from Opuntia humifusa using simple solid state activation method for reversible capture of volatile iodine

The search for adsorbent materials capable of extracting and storing radioactive iodine derived from nuclear power plants has intensified owing to the growing nuclear waste concerns. Herein, we report a novel method, which is simple and effective, to synthesize biomass-derived porous carbon from an easily available biomass, Opuntia humifusa, via simple solid-state activation with zinc chloride. The resulting porous carbon exhibits a large specific surface area, with up to 1869 m2/g of micropores. The textural properties of activated carbons can be easily modified by adjusting the amount of zinc chloride and activation temperature. The optimal conditions were found to be a ZnCl2 to biomass ratio of 5 and a carbonization temperature of 500 °C. The obtained porous carbons can function as multifunctional solid sorbents for radioactive iodine because of their high porosity and advantageous hierarchical porous structure. Specifically, the obtained activated carbon exhibited high iodine affinity with an absorption of 408 wt%. Considering its global abundance and recyclability, Opuntia humifusa can be used as a new biomass source for the efficient production of highly effective porous carbon materials with potential applications in environmental restoration. Furthermore, the straightforward single-step synthesis method described in this study offers a technique for producing several unique activated mesoporous carbons from various biomasses.