Enhancement in CO 2 Adsorption on Hydrotalcite-based Material by Novel Carbon Support Combined with K 2 CO 3 Impregnation

In recent years, a great deal of interest has been shown for high-temperature adsorption of CO 2 on hydrotalcite-like compounds (HTlcs). Numerous efforts have been undertaken to enhance the CO 2 capture property of HTlcs, including alkali-metal impregnation, use of support materials, and modification of chemical composition. The present work demonstrates the applicability of coal-derived graphitic material (CGM) as an effective support for neat as well as K 2 CO 3 -promoted Mg–Al HTlc, enhancing the CO 2 adsorption capacity. Both surface area and basic site density affect the adsorption capacity. The K 2 CO 3 -promoted CGM-supported Mg–Al HTlc exhibited a fresh adsorption capacity of 1.10 mmol g –1 at 300 °C under a total pressure of 1 bar. After the initial drop, it maintained an average working capacity of 0.42 mmol g –1 during nine cycles of adsorption–desorption in the temperature range of 300–400 °C. The Yoon–Nelson kinetic model fit well with the experimental data.