Introduction of Mesopores Effectively Enhances the Accessibility of Vocs in Ctf Micropores

Abstract

Porous organic polymers (POPs) with abundant pores have great potential for the treatment of VOCs. However, narrow microporous increase gas diffusion resistance, limited micropore accessibility in VOCs adsorption. Here, we have synthesized mpCTFs with abundant mesopores using nano-silica. And the effects of the introduced micropore structure on the sorption performances of CTF were further investigated by 1,2-dichloroethane adsorption. The results indicate that mpCTF12.5 has the most suitable mesopore volume, and its specific surface area and total pore volume are 2.40 and 2.17 times that of CTF, respectively. Meanwhile, the mpCTF12.5 exhibited excellent adsorption performance for methanol, ethanol, acetone, benzene, ethyl acetate, 1,2-dichloroethane and toluene due to the multiple C-H…O, C-H…Cl, O-H…N and C-H…π interactions between VOCs and mpCTFX framework, demonstrated via DFT calculations. Additionally, the two-component gas-competitive adsorption behaviour and the influence of water vapour on the adsorption performance of mpCTFX were investigated, and the adsorption mechanism was studied in detail using the GCMC model. The introduced abundant mesopores no doubt greatly shortened the microporous diffusion path in CTFs, which significantly improves their microporous accessibility in VOCs adsorption. This study provides a feasible strategy to improve the performance of porous materials for adsorbing VOCs.

Keywords: Volatile organic compounds, covalent triazine frameworks, Adsorption