Separation and Purification Technology, Vol.156, 259-268, 2015
Post-combustion CO2 capture using polyethyleneimine impregnated mesoporous cellular foams
In this work, mesoporous cellular foams (MCFs) were synthesized and impregnated with different weight percentage of polyethylenimine (PEI) for post-combustion CO2 capture. The synthesized adsorbents were characterized using various techniques such as nitrogen adsorption/desorption SEM, TEM, and FTIR analysis. The CO2 adsorption capacity of PEI-impregnated MCFs was measured using thermogravimetric analyzer (TGA). The effects of PEI loadings, adsorption temperatures, and CO2 partial pressures on CO2 adsorption performance were studied. 70 wt.% PEI was found to be the optimum PEI loading in MCFs for post-combustion CO2 capture with higher CO2 adsorption capacity, higher amine efficiency and fast kinetics. The adsorbent with optimal PEI loading was tested for CO2 adsorption capacity, multi-cycle stability and adsorption/desorption kinetics. The CO2 adsorption capacity of about 5.16 mmol/g in 95% CO2/5% N-2 gas mixture and 3.95 mmol/g in 10% CO2/90% N-2 gas mixture at 75 degrees C was observed. The CO2 adsorption performance of PEI-impregnated MCFs improved in the presence of moisture, only at low adsorption temperatures. The adsorbent with optimum PEI loading was also tested for multi-cycle stability and adsorption/desorption kinetics in both humid and dry conditions. A good thermal stability of adsorbent and no degradation in CO2 adsorption capacity was observed in multi-cycle tests. Fractional-order kinetic model was found to be the best fitted to describe the adsorption behavior of PEI-impregnated MCFs for CO2 capture. (C) 2015 Elsevier B.V. All rights reserved.