Modification of commercially available adsorbents for CO₂ selective adsorption

Abstract

To reduce the carbon dioxide emission into the atmosphere, adsorption is believed to be one of the most attractive methods for post-combustion treatment of flue gas. In this work, activated carbon was modified by monoisopropanolamine (MIPA), a primary amine, N-methyethanolamine (NMEA), a secondary amine, piperazin, and K₂CO₃ via impregnation in order to enhance CO₂ adsorption capacity. The amounts of each amine loading were varied from 10 to 30 wt% in methanol and in water for K₂CO₃. The adsorption was carried out at a temperature ranging from 30 to 75 °C and four different gas pressures up to 1 atm. The adsorbents were characterized by TGA and BET to study their characteristics. The introduction of amine has a significant effect on the surface area and pore volume. The surface area and pore volume decreased with the increased in the amount of the amine loading. Effectiveness of the adsorbents on the CO₂ adsorption including CO₂ adsorption capacity and adsorption temperature was also investigated. At 50°C and 1 atm, the modified adsorbents showed higher adsorption capacity than the unmodified carbon. The carbon loaded with piperazine gave the highest CO₂ adsorption capacity.