Diffusion of benzene through water film confined in silica mesopores: Effect of competitive adsorption of solvent. (12th October 2020)

• Record Type: Journal Article
• Authors: Pu, Jing-Cao; Doka Dari, Moumouni; Tang, Xu-Quan; Yuan, Pei-Qing
• Is Part Of: Chemical engineering science. Volume 224(2020)
• Publication Date: 2020-10-12
• Subjects: Molecular dynamics simulation -- Diffusion -- Benzene -- Competitive adsorption -- Mesopores; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2020.115793
• Languages: English
• ISSNs: 0009-2509

Abstract

Graphical abstract: Adsorption competition between solute benzene and solvent water exists during the diffusion of benzene through a water film confined in mesopores, by which the diffusion coefficient of benzene can be adjusted by surface hydroxylation. Highlights: Diffusion of benzene through a water film confined in mesopores was studied. Competitive adsorption between benzene and water on hydrophilic surface exists. The presence of water weakens interaction of benzene with hydrophilic surface. Benzene diffusion in mesopores depends on pore diameter and surface properties. Surface hydroxylation can be used to adjust benzene diffusion in mesopores. Abstract: To understand the partial hydrogenation of benzene on Ru particles coated with hydrophilic materials, the diffusion of benzene through the water film confined in silica mesopores was studied by molecular dynamics simulation. There is an unconventional hydrogen bond between benzene and the surface hydroxyl group, which was previously supposed to retard benzene diffusion in hydrophilic mesopores. Driven by stronger hydrogen bonding, solvent water, however, is preferentially adsorbed onto the hydroxylated silica surface. Benzene dissolved in the water film has to diffuse away from the interfacial region, thereby weakening its interaction with the surface. Benzene may diffuse faster in hydroxylated mesopores than in bare mesopores, and the difference depends on the pore diameter. With a pore diameter of 4 to 6 nm, the diffusion coefficient of benzene along the pore axis, varying from 0.04 × 10 −8 to 0.12 × 10 −8 m 2 /s, could be adjusted by surface hydroxylation.