Dynamic adsorption and molecular simulation of aliphatic VOCs on industrial USY zeolites: Two-component competitive behavior

Abstract

In this study, the single-component and two-component competitive adsorption behaviors of six aliphatic VOCs (cyclohexane, n-hexane, methyl-cyclopentane, n-butanol, butyl-acetate and methyl-methacrylate) on industrial USY zeolites were systematically investigated through dynamic adsorption experiments and molecular simulations. The results of the single-component dynamic adsorption experiments showed that the saturated adsorption capacity of high-polarity VOCs (n-butanol, butyl-acetate and methyl-methacrylate) were significantly higher than low-polarity VOCs (cyclohexane, n-hexane and methyl-cyclopentane) on USY-10, USY-40 and USY-60 zeolites. Furthermore, the high-polarity VOCs with high molecular weights and boiling points had weak diffusion properties and strong adsorption capacity on USY zeolites. In two-component competitive adsorption experiments, the competitive adsorption abilities of high-polarity VOCs exhibited stronger than low-polarity VOCs on USY-60. Meanwhile, linear-structured molecules demonstrated competitive advantages owing to their superior diffusion capabilities. Single-component DFT calculation results showed that the adsorption energy of high-polarity VOCs (from −181.29 KJ/mol to −140.49 KJ/mol) was significantly more negative than low-polarity VOCs (from −122.47 KJ/mol to −99.07 KJ/mol) on USY zeolites. The adsorption site calculations of two-component adsorption on USY-60 indicated that high-polarity VOCs interacted more strongly with Na⁺ ions. The energy calculation results of two-component competitive adsorption indicated that high-polarity and linear-structured VOCs exhibited low interaction energies on USY-60. This study provided theoretical insights and practical guidance for the removal of industrial two-component VOCs.