Hierarchical pore structure modulation of ZIF-8/CA composite porous carbon for efficient benzene vapor adsorption

Benzene, as a ubiquitous and carcinogenic volatile organic compound (VOC), presents substantial health risks through inhalation exposure from ambient indoor environments and cigarette mainstream smoke, necessitating the development of advanced adsorbent materials. Herein, zeolitic imidazolate framework-8/cellulose acetate (ZIF-8/CA) composite porous carbon materials were synthesized via a dual emulsion-solvent evaporation method coupled with subsequent high-temperature carbonization. Systematic studies were conducted to evaluate the effects of ZIF-8/CA mass ratios on the microstructure, pore architecture, and the benzene adsorption property. The results of the relevant characterizations revealed that the composite prepared at a 4/6 mass ratio exhibited an excellent BET specific surface area with the highest value of 1380 m 2 /g and mesopore volume of 0.77 cm 3 /g, alongside a well-defined hierarchical pore network spanning microporous, mesoporous, and macroporous regimes. Dynamic benzene vapor adsorption tests demonstrated that this optimized formulation achieved a dynamic saturation adsorption capacity of 235.0 mg/g. Kinetic analysis employing the Apiratikul-Chu and Adams-Bohart models yielded high correlation coefficients, indicating that benzene adsorption was governed by surface adsorption and mass‑transfer mechanisms. When applied in cigarette mainstream smoke purification, the ZIF-8/CA composite exhibited a benzene removal efficiency of 49.0%, significantly outperforming the ZIF-8/polylactic acid (PLA) composite (20.7%). This enhanced efficacy stemmed from the cooperative interplay between the hierarchical porosity and enhanced π-π stacking interactions. This work underscores the ZIF‑8/CA composite porous carbon as a promising candidate for benzene abatement, with potential applications in cigarette filter modification and indoor air purification.