Sorption of Volatile Organic Compounds on Organic Substance-Modified Titanate Nanotubes

Abstract

This study investigates the removal of volatile organic compounds (VOCs) from the air through the use of organic substance-modified titanate nanotubes (TNTs). The TNTs were derived from TiO2 through a hydrothermal method, and were modified using hexadecyltrimethylammonium bromide and octadecyltrichlorosilane (OTS) to change the surface hydrophilicity to hydrophobicity. The properties of the TNT and modified TNT were characterized through scanning electron microscopy , transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, and nitrogen adsorption–desorption isotherms. The fabricated adsorbents were used to remove the VOCs of toluene, ethylbenzene 1,1,2-trichloroethane, and tetrachloroethene in the air. The adsorption amounts of the VOCs were estimated using the Thomas equation. The results revealed that adsorbent modification raised the adsorption capacities of these VOCs, which also grew with increasing surface hydrophobicity. The aromatic compounds accumulated easily in the pores to generate relatively high adsorption amounts. VOCs adsorbed on the TNT surface or partitioned into the organic substance on TNTs. The adsorption amounts of VOCs on the OTS-modified TNTs were higher than those on commercial activated carbon. The results imply that organic substance-modified TNTs can effectively remove VOCs in the air and become excellent adsorbents.