Effect of microstructure in mesoporous adsorbents on the adsorption of low concentrations of VOCs: An experimental and simulation study

• Published in: Journal of hazardous materials Vol. 458; p. 131934
• Main Authors: Liu, Yangyu, Peyravi, Arman, Dong, Xiongbo, Hashisho, Zaher, Zheng, Shuilin, Chen, Xiao, Gao, Du, Hao, Yongxing, Tong, Yuping, Wang, Jiuyue
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-09-2023
• Subjects: Adsorption; Desorption; Micropore; Molecular simulation; Volatile organic compounds; Volatile organic compounds; Molecular simulation; Desorption; Micropore; Adsorption
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131934

This study evaluated the adsorption of five volatile organic compounds (VOCs) on Opoka, precipitated silica, and palygorskite, to elucidate the effect of their pore size on VOCs adsorption. The adsorption capacity of these adsorbents is not only highly correlated with their surface area and pore volume, but also notably improved by the presence of micropores. The variation in adsorption capacity for different VOCs was primarily influenced by their boiling point and polarity. Palygorskite, which had the smallest total pore volume (0.357 cm3/g) but the largest micropore volume (0.043 cm3/g) among the three adsorbents, exhibited the highest adsorption capacity for all tested VOCs. Additionally, the study constructed slit pore models of palygorskite with micropores (0.5 and 1.5 nm) and mesopores (3.0 and 6.0 nm), calculated and discussed the heat of adsorption, concentration distribution, and interaction energy of VOCs adsorbed on different pore models. The results revealed that the adsorption heat, concentration distribution, total interaction energy, and van der Waals energy decrease with increasing pore size. The concentration of VOCs in 0.5 nm pore was nearly three times that in 6.0 nm pore. This work can also provide guidance for further research on using adsorbents with mixed microporous and mesoporous structures to control VOCs.
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●Adsorption behavior and related mechanisms of 3 adsorbents on VOCs were studied.●The adsorption capacity was influenced by boiling points and polarities of VOCs.●The micropores of an adsorbent can greatly improve its ability to adsorb VOCs.●Effect of palygorskite pore size on VOCs adsorption was studied by simulation.