Measurement and Correlation of Solubility Data for CO₂ in NaHCO₃ Aqueous Solution

To investigate the influence of NaHCO3 on the CO2 absorption in aqueous solution, the solubility of CO2 in NaHCO3 aqueous solutions [(0, 0.05, 0.1, 0.5, and 1.0) mol·kg−1] was measured in the temperature range from (313 to 333) K with pressure range from (0.3 to 2.0) MPa by employing a new designed batch apparatus. The results showed that the solubility data for CO2 in NaHCO3 aqueous solutions agreed well with Henry's law, and the Henry constant appeared to be a function of temperature and the concentration of NaHCO3. Two thermodynamic models were proposed for correlating the experimental data, that is, the modified Setschenow and Peng−Robinson (PR)-Duan equations. It was proved that the models fitted well in with the experimental data, and the average relative deviations were (4.06 and 3.90) %, respectively. In addition, the Henry constant in pure water can be basically predicted at a certain temperature range. The influence of NaHCO3 on the solubility of CO2 is interpreted by “salting-out effect” which is usual for the salt-containing solutions.