Physical properties of aqueous blends of sodium glycinate (SG) and piperazine (PZ) as a solvent for CO₂ capture

The physical properties including the density, viscosity, and refractive index of aqueous blends of sodium glycinate (SG) and piperazine (PZ) as a solvent for CO₂ absorption were measured under the wide temperature range (298.15 to 343.15) K. Different concentrations (mole fraction) of sodium glycinate and piperazine (SG + PZ) blends were (0.0348/0.0089, 0.0263/0.0177, 0.0177/0.0263, and 0.0089/0.0348), respectively. From the observations, it was found that the densities of the aqueous blends decrease when the piperazine concentration in the blend increases. It was noticed that the viscosity of the blend decreases initially by increasing the concentration of piperazine from 0.0089 to 0.0177 mole fraction; however, on further increasing the piperazine and decreasing the sodium glycinate concentration in the blend, the viscosity tends to increase. The refractive indices of the aqueous blend of sodium glycinate and piperazine decrease with increasing the concentration of piperazine in the blend. The density, viscosity, and refractive index of an aqueous blend of (SG + PZ) decreases with increasing temperature. The measured values of density, viscosity, and refractive index were correlated as a function of temperature by using standard equations of the least-squares method. All of the correlation parameters were reported together with the standard deviation.