LAUSR

Abstract Amino acids are considered as potential solvents for carbon dioxide (CO 2 ) capture. In this research, the reaction kinetics and reaction mechanism between histidine and CO 2 were investigated. Results showed that histidine anion ions (His – ) are the main species reacting with CO 2 in basic conditions (pH > 9) with a reaction order of 1.18 ± 0.08 across the temperature range of 298–313 K. The zwitterion mechanism was used to fit the kinetic data and it showed that both protonation and deprotonation reactions contributed to the overall reaction rate. Ionic strength was also shown to have a significant influence on the reaction kinetics when the histidine concentration is high (⩾0.2 M). The reaction rate between histidine and CO 2 is slower than that of glycine and proline and slightly faster than that of taurine at low concentrations (