Surface modifications of carbonaceous materials for carbon dioxide adsorption: A review

Carbon capture and storage is a crucial technology for reducing atmospheric CO2 emissions from power plants and other industrial facilities. While many technologies have been developed, the high cost and energy requirements of current CO2 capture methods still are the primary barriers. Adsorption is one of the cost-effective options for CO2 capture because of its low energy requirement, cost advantage, and ease of applicability over a relatively wide range of temperature and pressure. However, the success of adsorption methods depends on the development of the adsorbents with high CO2 selectivity and capacity and easy regeneration. Although some adsorbents exhibited good CO2 adsorption capacity, their adsorption for water vapor is an important issue for this purpose because water usually exists in flue gas streams. Activated carbons are proposed as suitable candidates for CO2 capture: they do not require moisture removal, present a high CO2 capacity at ambient pressures, and are easy to regenerate. However, the low selectivity to CO2 for activated carbons is the restriction. This article reviews recent advances in surface microstructure or chemistry of carbonaceous materials as CO2 adsorbents with emphasis on the reactions of surface functionalization, CO2 adsorption performance and mechanism on the carbons with different features.