Adsorption of carbon dioxide on naturally occurring solid amino acids

sAdsorption of CO2 on solid natural amino acids (AAs) D-arginine, bis(2-hydroxypropyl)amine, cysteamine, l-leucine, d-serine, l-valine, sarcosine, and taurine has been studied in the temperature range of 303–423 K. In a temperature programmed thermal reactor, CO2 adsorption was carried out in an isothermally controlled flow of CO2 and the adsorbed CO2 was desorbed by shifting temperature to 523 K. Based on the experimental results, the amino acid taurine (TAU) was found to adsorb the highest quantity of CO2 (3.7 mmol g−1) among the studied AAs which was two-fold higher than the quantity of CO2 absorbed by activated carbon at 303 K. Theoretical calculations have agreed with the experimental results and have revealed that the interaction between the AAs and CO2 is non-covalent in nature. The polar side chains of AAs are responsible for their high binding ability with CO2. AAs with heteroatoms such as sulfur has great potential as ligands in developing selective adsorbents for CO2 capture.