Use of Vanadium(V) oxide as a catalyst for CO2 hydration in potassium carbonate systems

Abstract

The kinetics of CO2 absorption into 30% w/w K2CO 3 solutions containing 0.1-0.5 M K4V2O 7 was investigated at temperatures of 40, 60, and 75 °C using a wetted wall column. Vanadium(V) speciation diagrams were developed under these conditions as a function of CO2 loading using 51V NMR spectroscopy. From these studies it was determined that there are two oxyvanadate ions that promote the absorption of CO2, HVO 42-, and HV2O73-. The Arrhenius expressions for the rate constants of these two species were found to be kHVO4 = 2 × 1011 exp(-4992/T) and k HV2O7 = 5 × 1018 exp(-10218/T), respectively. Comparison of the observed rate constants with other promoters revealed that both active vanadium spe..