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

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 I2 vapor (4060 mg g-1); in comparison, LFC-KN with both micropores, mesopores and macropores had a higher adsorption capacity for I2 in water (1295 mg g-1). After several iodine adsorption and release cycles, the two adsorbents still exhibit excellent reusability.

Automated summary

Efficient adsorbents based on lignin-derived graphene flower-like carbon nanosheets have been developed for capturing and adsorbing radioactive iodine in air and aqueous solutions during nuclear disposal and accidents. By adjusting the activation methods, different pore size structures in the carbon nanosheets were achieved, resulting in excellent iodine adsorption capacities in various environments.