VLE of CO2 in aqueous potassium salt of L-phenylalanine: experimental data and modeling using modified Kent-Eisenberg model

In this study, vapor-liquid equilibrium (VLE) of CO in aqueous potassium salt of l-phenylalanine (K-Phe) was investigated. A high pressure solubility cell was used to measure the solubility of CO in aqueous solution of (10, 20 and 25) wt% K-Phe at 303.15, 313.15 and 333.15\ua0K over a CO pressure range of 200–2500\ua0kPa. Equilibrium CO solubility was defined in terms of CO loading (mole CO/mole of amine). The effect of temperature, concentration and equilibrium CO pressure on CO loading was discussed. Experimental CO loading data in aqueous K-Phe solutions show that the solvent has good potential for CO capture systems. Also, a modified Kent-Eisenberg model was used to correlate the experimental CO solubility data and carbamate hydrolysis and amine deprotonation equilibrium constants were regressed as a function of temperature, concentration and equilibrium CO pressure. An average absolute deviation of 7.70% between experimental and predicted data indicated the good prediction capability of the applied thermodynamic model