Catalysis of CO2 absorption in aqueous solution by vanadate and sulfate and their application to post combustion capture

• Catalytic rate constants of sulfate and vanadate on CO2 hydration were determined.
• Vanadate was found to be a better catalyst than several inorganic oxoanions.
• The mechanism of the interaction between oxoanions and CO2 was confirmed.
• Application of sulfate and vanadate to Post Combustion Capture was also studied.

A promising option to improve post combustion capture (PCC) is to use inorganic catalysts to accelerate the absorption process of CO2, in particular the reaction between CO2 and water to form carbonic acid. In this study, the efficiency of sulfate and vanadate on enhancing the hydration reaction of CO2 to form H2CO3 for PCC has been studied at 25 °C by stopped-flow spectrophotometry. The catalytic rate constants were determined to be 14.2(2) and 277(6) M−1 s−1 for sulfate and vanadate, respectively. Their application to PCC was further investigated by simulating the effect of these catalysts on the absorption process under PCC operating conditions. Vanadate was confirmed to have a greater efficiency toward CO2 hydration than sulfate and also a series of other inorganic catalysts reported earlier.