Surface-Modified Wrinkled Mesoporous Nanosilica as an Effective Adsorbent for Benzene, Toluene, Ethylbenzene, and Xylene in Indoor Air

Abstract

Surfactant-extracted spherical porous silica nano particles with wrinkled structures were synthesized, and their adsorption performance was altered by grafting three organosilanes: n-octyltriethoxysilane, hexadecyltrimethoxysilane, and triethoxyphenylsilane onto their surface. The surface-modified silica nanoparticles were used to capture frequently detected hazardous indoor air chemicals. The physical and chemical properties of the samples were characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy, N2 adsorption-desorption experiments, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. Although the organosilane surface modification did not significantly change the surface areas and pore structures of porous silica nanoparticles, the capacities of the surface-modified porous silica nanoparticles for capturing benzene, toluene, ethylbenzene, and xylene (BTEX) molecules from air were considerably higher than those of pristine porous silica nanoparticles. The dispersion forces between adsorbates and adsorbents were the primary factor that affected the absorption capacity of the surface-modified porous silica nanoparticles. Consequently, the BTEX capturing potential of surface-modified mesoporous silica featuring a long alkyl chain was high because of the relatively high dispersion force between adsorbates and the adsorbent.