Experimental and simulation investigation of water vapor adsorption on mesoporous MCM-41 derived from natural Opoka

• Published in: Separation and purification technology Vol. 309; p. 123056
• Main Authors: Liu, Yangyu, Peyravi, Arman, Hashisho, Zaher, Zheng, Shuilin, Sun, Zhiming, Chen, Xiao, Tong, Yuping, Hao, Yongxing, Wang, Jiuyue
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-03-2023
• Subjects: MCM-41; Mechanism; Mesoporous; Moisture adsorption; Molecular simulation; Molecular simulation; MCM-41; Moisture adsorption; Mesoporous; Mechanism
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.123056

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•A novel mesoporous HCM, MCM-41 was synthesized using natural opoka.•The MCM-41 possessed large surface area and a 82 % moisture adsorption content.•MCM-41 model was constructed and compared with the experimental results.•Adsorption mechanism of moisture onto MCM-41 was elucidated at molecular level.
Highly ordered hexagonal mesoporous silica was successfully synthesized from natural Opoka minerals, and an all-atom model of MCM-41 was constructed by simulation. The samples were characterized by XRD, N2 adsorption, FE-SEM, TEM and FT-IR, and its water vapor adsorption/desorption performance were also evaluated. The structural rationality of MCM-41 model was verified by XRD, Connolly volume, and radial distribution function. The adsorption behavior of water molecules on MCM-41 model was simulated by Monte Carlo method, and the adsorption mechanism was discussed at the micro level. Results showed that the synthesized MCM-41 possessed a large surface area of 988 m2/g and pore volume of 1.02 cm3/g, and an average pore diameter of 4.1 nm. The moisture adsorption/desorption content of MCM-41 can be as high as 82 % and 67 %, respectively, with a high adsorption/desorption rate. The simulation results show that the adsorption sites of water molecules on MCM-41 are mainly concentrated on the silanol groups and skeleton defects of the pore surface. With the increase of pressure, the adsorption of water molecules on the surface of MCM-41 pores changes from mono-layer to multi-layer. Meanwhile, microdroplets are formed due to hydrogen bonding, and further capillary condensation occurs in the pores.