(185m) Alkali Metal Impregnation of Hydrotalcite for the Enhancement of High-Temperature CO2 Adsorption Capacity

The awareness of symptoms of global warming and its seriousness urges the development of technologies to reduce greenhouse gas emissions. Carbon dioxide (CO2) is a representative greenhouse gas and various methods to capture and storage CO2 have been considered. Recently, the technology to remove high-temperature CO2 by adsorption has received lots of attention. The adsorption of high-temperature CO2 can be applied to the direct CO2 removal from flue gases without cooling process and to the CO2-adsorption enhanced reactions for the production of high-purity hydrogen. In this study, hydrotalcite, which has been known to have CO2 adsorption capacity at high temperature, was impregnated with alkali metals to enhance the CO2 adsorption capacity and the mechanism of CO2 adsorption on alkali metal impregnated hydrotalcite was investigated. Potassium carbonate (K2CO3) and sodium carbonate (Na2CO3) were chosen as alkali metals and compared in the aspect of the enhancement ability of CO2 adsorption. Thermogravimetric analysis was used to measure CO2 adsorption capacity and the results revealed that CO2 adsorption capacity on hydrotalcite can be increased up to 10 times by impregnation with K2CO3. The CO2 adsorption capacity on hydrotalcite was affected by the amount of K2CO3 and Na2CO3 added, and there was an optimal amount of alkali metal for the maximum CO2 adsorption capacity. The analyses based on BET surface area, XRD, FTIR, and FE-SEM were carried out to elucidate the characteristics of adsorbents and the mechanism of CO2 adsorption.