Activity Coefficient and CO2 Solubility Studies of Aqueous Alkyl Ammonium Salts Using Electrolyte PC-SAFT EOS

In this work, the electrolyte PC-SAFT equation of state (EOS) was utilized to study the alkylammonium salts in aqueous solutions. In this regard, the mean ionic activity coefficient (MIAC) experimental data of thirteen binary salt-water systems were studied. For each ion, five adjustable parameters were fitted using the MIAC experimental data. The ion-based and fully dissociated approaches were used to optimize the model parameters. The average deviation between experimental data and the model calculated is about 5%. The results show that the electrolyte PC-SAFT EOS can reasonably correlate the MIACs of alkylammonium salts in aqueous solutions. In addition, the electrolyte PC-SAFT EOS was used to estimate the CO2 solubility in the aqueous tetrabutylammonium bromide solution. In this regard, the ion-specific parameters were used and a binary interaction coefficient between CO2 and cation was fitted to correlate the gas solubility at different temperatures. The results show that the electrolyte PC-SAFT EOS can estimate the CO2 solubility reasonably well from a quantitative point of view.