H. Kierzkowska-Pawlak, E. Kruszczak, J. Tyczkowski
Lodz University of Technology, Faculty of Process and Environmental Engineering, Łódź, PL


The increasing emission of CO2 from combustion of fossil fuels fosters the development of different technologies for its removal from flue gases. Although CO2 capture by absorption in aqueous amine solutions is the most feasible approach, it suffers from several drawbacks including high energy consumption and the required large absorber size. Since accelerating the CO2 reaction rate with water could improve the overall CO2 mass transfer rate in aqueous amine solutions, and subsequently, reduce the dimensions of the absorber, there have been substantial efforts to develop effective catalysts for this reaction, mostly based on enzymatic promoters such as carbonic anhydrase. In this study, we proposed a novel nanocatalytic system based on CoOx deposited as a thin-film on the metallic structured support for accelerating the CO2 hydration reaction, i.e. the transformation of CO2 to bicarbonate ion in reaction of dissolved CO2 with water. The cobalt-oxide thin films were prepared by the cold plasma deposition method. The fine wire-gauze applied as a support for the catalyst provides additional performance benefits since it can be flexibly combined with the structured packing of the absorption column. The activity of the CoOx nanocatalyst on enhancing the CO2 hydration reaction was studied at 303 K by measuring the change in pH of the solution during dissolution of CO2 in water. The observed rate of decrease in the pH value was significantly higher in the presence of the CoOx catalyst than in its absence under the same hydrodynamic conditions. Therefore, the results demonstrated that the used nanocatalyst contributed to the enhancement of CO2 hydration. This outcome can find a further application in enhancing the rate of CO2 absorption by aqueous amine solvents.

Keywords:CO2 capture, CO2 hydration, CoOx nanocatalyst, catalyst activity