State-of-the-art of CO2 capture with amino acid salt solutions

The emission of large amounts of CO2 into the atmosphere is believed to be a major reason behind climate change, which has led to increased demand for CO2 capture. Postcombustion CO2 capture with chemical solvent is considered one of the most important technologies in order to reduce CO2 emission. Amino acid salt solutions have attracted special attention in recent years due to their excellent physicochemical properties, e.g., low volatility, less toxicity, and high oxidative stability, as well as capture performance comparable with conventional amines. In this study, physicochemical properties of 20 amino acids are reported and their CO2 absorption performance discussed. The topics covered in this review include the most relevant properties of amino acids including CO2 loading capacity, cyclic capacity, equilibrium constant, density, viscosity, dissociation constant, CO2 solubility, CO2 diffusivity, reaction kinetic between CO2 and amino acid salts, reaction rate constant, surface tension, heat of CO2 absorption, precipitation, toxicity, solvent degradation, and corrosion rate. This review provides the most recent information available in the literature on the potential of using amino acid salts as a solvent for CO2 capture which can help improve the performance of the CO2 capture process from flue gas streams.