Adsorption and desorption of small molecule volatile organic compounds over carbide-derived carbon

摘要

Carbide-derived carbon (CDC) was prepared by selective extraction of titanium from titanium carbide in a flow of freshly prepared chlorine. The dynamic adsorption and desorption performance of CDC of small molecule volatile organic compounds (VOCs) including methanol, acetaldehyde and acetone, was investigated and compared with that of two types of commercial activated carbons. The physicochemical properties of carbons were characterized by nitrogen adsorption, temperature programmed desorption, Raman spectroscopy and transmission electron microscopy. It was observed that the CDC could adsorb much more VOCs than commercial activated carbons (especially for the less polar methanol). The desorption behavior of VOCs from the saturated CDC was similar to that of commercial activated carbons, with adsorbed VOCs desorbed in the maximum degree at 110-150 °C, which indicated that the adsorption sites for the VOCs on the three carbon adsorbents were similar and the saturated CDC could be effectively regenerated by simple heat treatment just like commercial activated carbons. Based on the characterizations, the large adsorption capacity of CDC was attributed to its larger micropore volume, narrower pore distributions (0.7-1.5 nm), as well as higher specific surface area than those of two commercial activated carbons.