Study on Density, Viscosity, and Thermodynamic Properties of MDEA and l‐Arginine Blends as a Potential Solvent for CO2 Capture

This study investigates the effect of adding l‐arginine (Arg) on the density and viscosity of aqueous solutions of methyldiethanolamine (MDEA). Densities and viscosities were measured at different MDEA (1, 2, and 3 M) and Arg concentrations (0, 0.01, 0.03, 0.05, 0.1, 0.15, 0.2 M) at a temperature range of 293.15–323.15 K. The experimental results were used to deduce various thermodynamic properties, namely, coefficient of thermal expansion (αP), excess molar volume (VE), viscosity deviation (∆η), the activation energy (Ea), activation molar enthalpy (∆H), activation molar entropy (∆S), and activation molar Gibbs free energy (∆G). Simple empirical correlations were used to model the obtained density and viscosity data for MDEA and arginine solutions. The Eyring–NRTL and Eyring–Wilson thermodynamics models were used to correlate viscosity. The results indicated that the experimental data obtained were more conforming towards the Eyring–Wilson model than the Eyring–NRTL.