Study of Solubility of Carbon Dioxide in Seawater

Abstract

Carbon dioxide (CO₂) ocean sequestration technologies, such as dissolution into seawater, are important to promote protection of the global environment. In this study, the solution process of CO₂gas in seawater and pure water was experimentally studied under various pressures and temperatures to evaluate the solubilities of CO₂in seawater. The solubilities of CO₂in seawater and pure water were measured by the change in pressure due to absorption at pressures up to 1500 kPa and temperatures ranging from 20°C to 60°C. We found that the solubilities of CO₂were between 0.27×10^-3and 5.45×10^-3in seawater, and between 0.26×10^-3and 0.6×10^-3in pure water near atmospheric pressure. They increase with an increase in pressure, but decrease with an increase in temperature. The Henry's law constant of CO₂was about 200 MPa at a temperature of 20°C in seawater under 500 kPa, and increased with an increase in temperature. The solubility of CO₂in seawater was lower than that in pure water. We obtained empiri-cal correlations for solubilities of CO₂in seawater and pure water at various temperatures under atmospheric pressure, based on the experimental data.