Surface silylation of natural mesoporous/macroporous diatomite for adsorption of benzene

• Published in: Journal of colloid and interface science 2015-06, Vol.448, p.545-552
• Main Authors: Yu, Wenbin, Deng, Liangliang, Yuan, Peng, Liu, Dong, Yuan, Weiwei, Liu, Peng, He, Hongping, Li, Zhaohui, Chen, Fanrong
• Format: Article
• Language: English
• Subjects: Benzene adsorption; Diatomite; Hydrophobicity; Phenyltriethoxysilane; Silylation
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2015.02.067

[Display omitted] Naturally occurring porous diatomite (Dt) was functionalized with phenyltriethoxysilane (PTES), and the PTES-modified diatomite (PTES-Dt) was characterized using diffuse reflectance Fourier transform infrared spectroscopy, nitrogen adsorption, nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. After silylation, a functional group (C6H5, phenyl) was successfully introduced onto the surface of Dt. PTES-Dt exhibited hydrophobic properties with a water contact angle (WCA) as high as 120°±1°, whereas Dt was superhydrophilic with a WCA of 0°. The benzene adsorption data on both Dt and PTES-Dt fit well with the Langmuir isotherm equation. The Langmuir adsorption capacity of benzene on PTES-Dt is 28.1mg/g, more than 4-fold greater than that on Dt. Moreover, the adsorption kinetics results show that equilibrium was achieved faster for PTES-Dt than for Dt, over the relative pressure range of 0.118–0.157. The excellent benzene adsorption performance of PTES-Dt is attributed to strong π-system interactions between the phenyl groups and the benzene molecules as well as to the macroporosity of the PTES-Dt. These results show that the silylated diatomite could be a new and inexpensive adsorbent suitable for use in benzene emission control.