Biomass-derived ultramicroporous carbon with narrow pore size distribution for record-high radon adsorption

Radon (Rn) is a radioactive noble gas and one of the primary culprits of lung cancer. Developing efficient adsorbents for Rn removal is of paramount importance, yet remains a daunting challenge due to the weak interaction between Rn and the adsorbent, particularly when low concentrations of Rn are present. Herein, a renewable biomass-derived carbon material consisting of rich ultramicropores was synthesized for record-high Rn adsorption under ambient condition. By meticulously selecting the carbonization precursor, chemical activator, and pyrolysis temperature, the optimized adsorbent, GC-700-2.4, exhibits a narrow pore distribution in the ultramicroporous range (<7 Å). The dynamic adsorption coefficient (Kd) of GC-700-2.4 is determined to be 9.51 L/g based on radon breakthrough experiments, which is twice the value of the commercial Rn adsorbent, coconut shell activated carbon (Kd = 4.65 L/g), and outperforms all other reported Rn adsorbents under comparable conditions. The superior Rn adsorption performance of GC-700-2.4 is attributed to the narrow ultramicropores in GC-700-2.4 that show enhanced confinement effect toward Rn. Consequently, GC-700-2.4 shows promising potential for practical applications as an efficient and cost-effective Rn adsorbent.