Simulation and Experimental Study of Silica-Based Adsorbents for Competitive Adsorption of Toluene from Binary...

Physical adsorption is a green separation technology with industrial potential. Precise control of the pore structure of adsorbent is key to achieving highly selective separation of target molecules of similar size. In this study, a combined molecular simulation and experimental approach was employed to investigate the influence of pore size on the adsorption behavior of benzene, toluene and o-xylene over silica-based adsorbents. The simulation results show that methyl groups enhance the interfacial interactions between adsorbate molecules and pore walls, whereas steric hindrance limits the packing efficiency of the adsorbates within the pores. Consequently, adsorption selectivity is governed by the balance between confinement-enhanced adsorbate-adsorbent interactions and steric accessibility, with a pore size of approximately 0.7 nm providing the most favorable adsorption environment for toluene. The experimental results are consistent with the simulation results. When benzene and toluene are co-adsorbed, the NaY adsorbent with an average pore size of 0.7 nm exhibits the highest adsorption capacity and selectivity for toluene.