Study of CO2 capture by seawater and its reinforcement

Abstract Numerous coal-fired power plants, cement plants and steel mills are concentrated in coastal areas of China, and are three major CO 2 emitters. Seawater may be a potential resource to capture CO 2 in coastal areas. In this study, we used seawater as a CO 2 absorbent to capture CO 2 . An online chromatography apparatus was used to determine CO 2 solubility in seawater with different temperatures, pressures and salinities. Then, the thermodynamics and kinetics were studied for the influences of temperature and salinity on CO 2 capture in seawater. The experimental results show that increasing temperature and salinity were adverse to CO 2 capture by seawater because of an increase in Henry's constant from a thermodynamics aspect. The kinetic results show that high temperature and low salinity can increase the CO 2 absorption rate. In order to improve the CO 2 absorption ability of seawater and promote CO 2 fixation in carbonate precipitation, we added CaO as major components of industrial alkaline substances to enhance the seawater absorption of CO 2 . CO 2 solubility in seawater with 0.4% CaO increased by 79.25%. It shows that the addition of CaO can enhance greatly seawater capture of CO 2 . The seawater and its reinforcement with CaO is a potential method to capture CO 2 .