Effect of carbon nanotubes and activated carbon addition to the blends of monoethanolamine and triethanolamine on CO2 absorption at low partial pressures


Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran


Carbon dioxide is a major greenhouse gas that contributes to the global warming by more than %60. Absorption has been widely used to treat high concentrations of CO2 in synthesis gas production, hydrogen manufacturing, and natural gas processing. The most well established method to capture CO2 is its removal by absorption into amine solutions in the presence of activators. In this research, CO2 absorption was measured in aqueous solutions of triethanolamine+monoethanolamine with different concentrations in the presence and absence of carbon nanotubes and activated carbon at temperatures ranging from 30 to 70 oC and low partial pressures in an absorption cell. Partial pressures were changed in the range of 10-70 kPa. The results revealed that the CO2 absorption rate and capacity increases by adding small amounts of MEA to TEA. Moreover, CO2 absorption rate and capacity increased with addition of carbon nanotubes and activated carbon to amine mixtures and the enhancement is higher for carbon nanotubes than activated carbon. Lowering the temperature increases CO2 loading in solution.