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 TiO 2 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 OTSmodified 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.

Adsorption of volatile organic compounds on peanut shell activated carbon

“…Moreover, the surface hydrophilicity/hydrophobicity affects the adsorption capacity of the volatile organic compounds of the adsorbent, e.g., adsorption capacities of the VOCs increase with an increase in the surface hydrophobicity . In addition, the molecular structure of the VOCs may affect the adsorption amounts of VOCs on adsorbent.…”

“…In addition, the molecular structure of the VOCs may affect the adsorption amounts of VOCs on adsorbent. For example, higher adsorption amounts were observed for aromatics than for chlorinated compounds due to their planar structure, which enabled the aromatic compounds to build up more easily in the micropores …”

“…Previous studies report that the toluene adsorption capacity of activated carbons is highly dependent on the porous structure, and, thus, controlling the properties of the activated carbon at the preparation stage is very important. The presence of water vapour also affects the adsorption of toluene on the activated carbon, e.g., the presence of water vapour decreases the toluene adsorption capacity as the sites available for adsorption will be occupied or partially occupied by the stronger adsorbed water vapour molecules .…”

Fabrication and Characterization of Lanthanide-TiO<sub>2</sub> Nanotube Composites

“…This helped conjunction and Open Journal of Physical Chemistry dispersion of the metal particles on the TNT walls [49] [50] [51] [52], and also captured photoexcited electrons and holes to produce reactive oxygen species for photocatalysis of organic wastewater. The peaks at 1627.87 cm −1 and 1349.52 cm −1 corresponded to undoped TNTs [50]. The unchanged intensity of the 3432.53 cm −1 band may have been due to the interactions of doped Nd and Gd in the TiO 2 lattice that did not replace -OH groups on the oxide surface.…”

Effects of Molecular Properties on Adsorption of Six-Carbon VOCs by Activated Carbon in a Fixed Adsorber

“…In addition, a two-dimensional mathematical model combining an isotherm equation with a dynamic adsorption model was derived by Tefera et al to study competitive adsorption of n -component mixtures in a fixed-bed adsorber. The adsorbents, including granular activated carbon, glucose- and almond shell-based adsorbents, activated carbon fibers, and zeolite, were used to remove VOCs to investigate the effects of operating variables on the adsorption capacity. − For adsorbents, the effects of the preparation variables of the adsorbents on the surface properties and the amounts of VOCs removed by the prepared adsorbent were reported, − and some studies − reported that the removal amount of VOCs could be increased by the modified adsorbent. However, discussions of the relationship between adsorption performance and physicochemical properties in the literature have been limited.…”