Green preparation of CaO-based CO2 adsorbent by calcium-induced hydrogenation of shell wastes at room/moderate temperature.

Capturing CO 2 using clamshell/eggshell-derived CaO adsorbent can not only reduce carbon emissions but also alleviate the impact of trash on the environment. However, organic acid was usually used, high-temperature calcination was often performed, and CO 2 was inevitably released during preparing CaO adsorbents from shell wastes. In this work, CaO-based CO 2 adsorbent was greenly prepared by calcium-induced hydrogenation of clamshell and eggshell wastes in one pot at room/moderate temperature. CO 2 adsorption experiments were performed in a thermogravimetric analyzer (TGA). The adsorption performance of the adsorbents obtained from the mechanochemical reaction (BM-C/E-CaO) was superior to that of the adsorbents obtained from the thermochemical reaction (Cal-C/E-CaO). The CO 2 adsorption capacity of BM-C-CaO at 650 °C is up to 36.82 wt%, but the adsorption decay rate of the sample after 20 carbonation/calcination cycles is only 30.17%. This study offers an alternative energy-saving method for greenly preparing CaO-based adsorbent from shell wastes. • CO 2 adsorbent was prepared by calcium-induced hydrogenation of shell wastes. • Both mechanochemical and thermochemical methods were used. • The CO 2 adsorption capacity of BM-C-CaO at 650 °C is as high as 36.82 wt%. • The adsorption decay rate after 20 carbonation/calcination cycles is only 30.17%. • This study offers a green method for preparing CO 2 adsorbent from shell wastes. [ABSTRACT FROM AUTHOR]