| Carbon dioxide (CO2) emitted by power plants is the major pollutants that cause greenhouse effect. Control of CO2has been considered as a challenging research topic. One of the more advanced techniques for the removal of CO2is the chemical absorption of CO2with solid sorbents. Titanium-based supports with high surface area and pore volume could accommodate large amount of basic groups to capture CO2.Titanium-based adsorbents for CO2capture were prepared through impregnating TiO2powders, mesoporous T1O2and TiO2nanotubes with amines. The resultant samples were characterized by X-ray diffraction, low temperature N2adsorption, transmission electron microscopy, infrared spectroscopy as well as thermogravimetric analysis. The absorption of CO2was carried out in a dynamic packed column. CO2adsorption capacity increases with the increasing of the amount of amine loaded and amine-modified TiO2nanotubes showed the highest CO2adsorption capacity among the three titanium-based adsorbents. CO2fixation was investigated at the temperatures of60,70, and80℃.70℃was the optimal temperature. Concerning the water vapor content in flue gas, we studied the effect of moisture on CO2adsorption and found that appropriate amount of water vapor didn’t damage the CO2adsorption performance but assist in the CO2capturing and stabilizing.Following the adsorption step, the sorbents were regenerated by Temperature Programmed Desorption (TPD). In the case of the raw-sample, the CO2molecules captured by physical interforces can be detached in a lower temperature. That is because physical adsorption is a readily reversible process. As for amine-modified sample, desorption peak was detected at a higher temperature. The adsorption/desorption behavior was studied in the absence/presence of moisture. While the former is fairly stable after5adsorption/desorption cycles, the latter decreases dramatically. |
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