Polyethyleneimine-modified layered double hydroxide/SBA-15 composites: A novel kind of highly efficient CO2 adsorbents

Abstract

The SBA-15-supported polyethyleneimine (PEI)-modified layered double hydroxides (xLDH-yPEI/SBA-15) were prepared by the in situ coprecipitation method, and their CO2 adsorption performance and involved mechanisms were studied. After loading of PEI and LDH on the surface of SBA-15, the composite materials still maintained an ordered two-dimensional hexagonal porous structure. The optimal CO2 adsorption capacity (2.01 mmol/g) of 40LDH-2PEI/SBA-15 at 50 °C was 1.88 times larger than that (1.07 mmol/g) of SBA-15. Such an excellent CO2 adsorption capacity of 40LDH-2PEI/SBA-15 was associated with its high BET surface area, abundant basic sites, and fast adsorption kinetics. The regeneration efficiency of 40LDH-2PEI/SBA-15 was still 94% after 11 recycles. We are sure that the SBA-15-supported PEI-modified LDH materials are good performance adsorbents for the adsorption of carbon dioxide.