Abstract: To investigate the impact of porous material pore structure (characterized by pore diameter, pore shape, pore volume, and specific surface area) on radon dynamic adsorption, experiments were conducted using molecular sieves with an uniform pore diameter (3A, 4A, 5A, ZSM-5, and 13X types) and activated carbon materials with different pore shapes (coconut shell activated carbon and activated carbon fibers) in a standard radon chamber. The results indicated that pore size matching is crucial to enhancing adsorption thermodynamics, with ZSM-5 molecular sieve exhibiting optimal performance among the several molecular sieve materials due to its effective pore diameter of 5.3~5.8 Å; pore shape significantly affects adsorption kinetics. Coconut shell activated carbon, featuring large effective micropore volume and hierarchically connected pore structure serving as mass transfer channels, achieved a radon adsorption coefficient of 4.45 L/g, which is much higher than that of activated carbon fibers (1.52 L/g), which have shorter pores and smaller effective micropore volumes. While increasing the pore-specific surface area and total pore volume of the adsorbent, increasing the effective micropore volume in the 0.5~0.7 nm range and constructing an appropriate amount of mesopores can enhance radon adsorption capacity. These findings can provide a basis for the targeted design of efficient radon adsorbents.

Key words: porous material, pore structure, radon, dynamic adsorption