Constructing metal site into hierarchical porous activated carbon for enhanced toluene and dichloromethane co-adsorption kinetics before breakthrough stage

Volatile organic compounds (VOCs) from industrial sources exhibit complex compositional diversity, encompassing various components such as aromatic hydrocarbons and halogenated hydrocarbons; therefore, high-performance adsorbent materials must possess co-adsorption capability for different VOCs. Carbon-based adsorbent owns potential for simultaneously removal of diverse pollutants due to their tunable multiscale structures, which requires constructing hierarchical functional zones to improve co-adsorption thermodynamics and kinetics of different VOCs molecules. Compared to widely-focused equilibrium adsorption capability, co-adsorption kinetics carbon adsorbents before breakthrough stage (C/C₀ < 0.1) which is a critical indicator for practical adsorption craft, have received little attention. Herein, we find that integrating metal sites with hierarchical pore of activated carbon can simultaneously improve equilibrium and breakthrough adsorption capacities of activated carbon adsorbent. Compared to microporous activated carbon, hierarchical porous carbon with metal site decoration demonstrates a 324 mg·g⁻¹ increase in equilibrium co-adsorption capacity for toluene and dichloromethane. Particularly, breakthrough time of weakly adsorbed dichloromethane can be extended by 138 %, leading to a 132 mg·g⁻¹ enhancement in co-adsorption capacity before breakthrough stage. Simulation results indicate that improved co-adsorption kinetics are primarily attributed to enhanced electrostatic interactions with dichloromethane. This study provides a new strategy for improving co-adsorption of multiple pollutants in practical adsorption craft.