High-purity porous carbon via synergistic PTFE etching/KOH activation for efficient iodine capture

Iodine pollution, especially from radioactive isotopes, poses serious risks to environmental safety and public health. Porous activated carbon adsorption offers an efficient and economical approach for capturing gaseous iodine pollutants. This study develops a novel synthesis strategy combining PTFE-mediated silica etching and controlled KOH activation to produce activated carbons with simultaneously high surface area and optimized oxygen functional groups for superior iodine capture. By precisely modulating textural properties, the specific surface area of activated carbon is between 225 and 1185 m 2 /g, the pore volume modulated from 0.8 cm 3 /g to 2.2 cm 3 /g, and the content of the C O group increased from 12.1% to 19.3% after KOH activation. In addition, the obtained materials (CA20PCK) feature homogeneous solid spherical morphology, and the surface elements are mainly composed of carbon (94.4At.%) and oxygen (5.5 At.%). The better fit to the pseudo-first-order model (R 2  > 0.99) indicates that the addition of oxygen-containing groups (O-C=O et al.) improved both adsorption affinity and kinetics. It achieves an exceptional iodine capacity of 4253 mg/g – 1.8 times higher than conventionally activated counterparts – while maintaining 3741 mg/g under dynamic conditions. Mechanism analysis reveals that the enhanced performance originates from strengthened dispersion–repulsion interactions in confined micropores, as quantified by Steele 10–4-3 potential calculations, coupled with accelerated adsorption kinetics facilitated by oxygen functional groups. Grey relational analysis further identifies BET surface area, micropore volume and oxygen content as governing parameters. This work provides not only a high-performance adsorbent with immediate application potential, but also a generalizable synthesis paradigm advancing the rational design of functional porous materials for environmental remediation.