High iodine adsorption by lignin-based hierarchically porous flower-like carbon nanosheets.

[Display omitted] • The influence of the pore structure on the adsorption of iodine vapor and iodine in aqueous was investigated. • The LFC expressed excellent absorption capability for iodine vapor (4060 mg g−1) and iodine in water (1295 mg g−1). • The adsorbent showed superior adsorption cycle stability for iodine adsorption. Developing an efficient adsorbent for adsorbing and capture radioactive iodine as a fission product in air and aqueous solution during the nuclear disposal process and in the event of a nuclear accident is of great importance. In this work, lignin-based porous flower-like carbon nanosheets have been developed by using lignin as a carbon precursor, MgO as a template coupled with KOH-activation (LFC-K), and KOH/NaOH eutectic activation (LFC-KN), which were tested for the adsorption of iodine molecules in iodine vapor and in solution. The combination of nanosheets structure and abundant pores makes LFC-K, and LFC-KN excellent absorbability for iodine. The LFC-K with both micropores and mesopores had a higher adsorption capacity for I 2 vapor (4060 mg g−1); in comparison, LFC-KN with both micropores, mesopores and macropores had a higher adsorption capacity for I 2 in water (1295 mg g−1). After several iodine adsorption and release cycles, the two adsorbents still exhibit excellent reusability. [ABSTRACT FROM AUTHOR]