Solubility of CO₂ in amino-acid-based solutions of (potassium sarcosinate), (potassium alaninate + piperazine), and (potassium serinate + piperazine)

Amino acid salt solutions are useful as carbon dioxide absorbents. In this study, vapor-liquid equilibrium (VLE) experiments were conducted using 4 M K-SAR, 1.5 M K-ALA-PZ, and 1.5 M K-SER-PZ solutions. Partial pressures and solubilities were measured for each absorbent solution at temperatures of 313.15 K, 333.15 K, and 353.15 K. The range of CO₂ partial pressure measured at 313.15 K over 4 M K-SAR was from 0 kPa to 812.5 kPa with loadings from 0.06 to 0.98. The partial pressures of CO₂ ranged from 0.2 kPa to 1041.7 kPa with loadings from 0.1 to 1.09 at 313.15 K over 1.5 M K-ALA-PZ absorbent solution. The partial pressures of CO₂ ranged from 0 kPa to 665.5 kPa with loadings from 0.1 to 1.14 at 313.15 K over 1.5 M K-SER-PZ absorbent solution.