A Simple Strategy To Improve PEI Dispersion on MCM-48 with Long-Alkyl Chains Template for Efficient CO2 Adsorption

Polyethylenimine (PEI) impregnated MCM-48 samples without calcination (MCM-48-W) whose pores are covered with cetyltrimethylammonium bromide (CTAB with long-alkyl chains) were verified to be more efficient CO2 adsorbents than PEI impregnated conventional MCM-48 samples. The samples were characterized by thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), nitrogen adsorption–desorption, and Fourier transform infrared spectroscopy (FTIR) analysis. Also, CO2 adsorption behaviors including adsorption capacity, adsorption thermodynamics, and adsorbent stability were studied to reveal the CO2 adsorption performance on as-synthesized PEI supported materials. The experimental results indicated that the CO2 adsorption and amine efficiency of MCM-48-W were always higher than those of conventional MCM-48 samples at the same PEI loading. MCM-48-W impregnated with 40 wt % PEI (MCM-48-W(40)) exhibited 2.59 mmol·g–1 of CO2 adsorption capacity (6.9 mmol CO2/g PEI), the highest amine efficiency ever reported for MCM-48 impregnated PEI in pure CO2, which may be because the existence of long-alkyl chains improved the dispersion of PEI loading. We presented a simple strategy with the advantages of less consumption of PEI and omission of the calcination step for the improvement of PEI dispersion on MCM-48 with long-alkyl chains template for high efficiency CO2 adsorption.