HYDROTALCITES FOR CARBON DIOXIDE ADSORBENTS AT HIGH TEMPERATURE

摘要

Carbon dioxide adsorbing capacity was investigated using bydrotalcites as high temperature adsorbents. A gravimetric method was used to determine the CO_2 adsorbing capacities of the hydrotalcites, and the temperature was 450°C. Hydrotalcite took higher adsorbing capacity compared to other basic materials such as MgO, Al_2O_3. To increase the CO_2 adsorbing capacity of the hydrotalcite, Mg/Al ratios, preparation methods, and K_2CO_3 impregnation were checked. As a result, the hydrotalcite prepared by high supersaturation with Mg/Al=2 showed desirable adsorption-desorption pattern and a higher CO_2 adsorbing capacity. Furthermore, K_2CO_3 impregnation on the hydrotalcite increased the CO_2 adsorbing amount and the optimum value of K_2CO_3 impregnation was 20 wt%. The hydrotalcite prepared by high supersaturation with Mg/Al=2 and 20 wt% K_2CO_3 impregnation took the highest CO_2 adsorbing capacity of 0.77 mmol/g at 450°C and 800 mmHg.