Physical Properties of Aqueous Piperazine + Glycine Solutions as Blended Absorbent for Carbon Dioxide Capture

The density, vapor pressure, and dynamic viscosity of piperazine (PZ) + glycine solutions were measured for various equimolal concentration ranges (m_{PZ and Gly} = (0.501–3.009)) at 0.1 MPa pressure and temperature ranging from 303.15 to 353.15 K. The diffusion coefficient, thermal expansion coefficient, and viscosity activation energy values were computed based on the measured data of density and dynamic viscosity. These physical properties data would be of great significance for designing post-combustion CO₂ capture systems utilizing PZ-based absorbent blended with aqueous amino acids solutions. The investigation of data on physical properties revealed that as the molality of the PZ-glycine solution increases, both the density and viscosity increase, whereas the vapor pressure decreases. Moreover, as the temperature rises, the density and dynamic viscosity decrease, while the vapor pressure increases.