Removal of toluene from waste gas by adsorption-desorption process using corncob-based activated carbons as adsorbents.

The aim of this study is to obtain activated carbons from corncob wastes by ZnCl2 activation for toluene removal. Thermogravimetric analysis (TG), N2 adsorption-desorption, scanning electron microscope (SEM), energy dispersive X ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR) and Boehm's titration were used to test the characteristics of raw materials and carbon samples. The influences of preparation conditions such as carbonization temperature, impregnation ratio and carbonization time on the textural and chemical characteristics of carbons were investigated. Besides, the effects of porosity and surface functional group on the adsorption capacity were also studied. The best adsorption capacity of 414.6 ± 13.0 mg g-1 at 3000 mg m-3 was obtained when the condition was as follows: 1:1 impregnation ratio, 550 °C carbonization temperature and 1.0 h carbonization time. The Langmuir, Freundlich, Sips, Toth and Redlich-Peterson models were used to depict the adsorption mechanism of toluene on this sample. The recovery of toluene through vacuum swing adsorption (VSA)-temperature swing adsorption (TSA) process was also studied.