Ethanol-water hydration treated calcium-based adsorbents derived from clam shells and cockle shells for carbon dioxide adsorption

Carbon dioxide (CO2) capture by using calcium (Ca)-based adsorbents derived from natural wastes has attracted the attentions of many researchers nowadays. Utilization of these natural materials in CO2 capture is able to reduce the cost of the adsorbents and favor to the production cost. In this research, CaO-based adsorbents that derived from natural clam (Meretrix meretrix) shells and cockle (Anadara granosa) shells were modified for their properties through ethanol-water hydration treatment and studied for their performance in CO2 capture. The effect of ethanol concentrations in ethanol-water hydration treatment was investigated in order to identify the optimum ethanol concentration to achieve desired adsorbent properties and best performance in CO2 capture. Ethanol was found to have a role in expanding the pore structure of CaO sorbents in this study. Treated CaO-based adsorbents derived from shells were found to have a higher surface area and pore volume as compared to untreated samples. CaO-based adsorbent derived from clam shells and cockle shells treated with ethanol were found to achieve higher CO2 adsorption capacity at 13.72 mmol CO2 / g adsorbent and 16.57 mmol CO2 / g adsorbent, respectively, as compared to untreated clam shells and cockle shells, which recorded CO2 adsorption capacity of 7.95 mmol CO2 / g adsorbent and 9.61 mmol CO2 / g adsorbent, respectively. This was corresponded to the higher surface area of the treated adsorbent samples, which promoted the CO2 adsorption activity.