Preparation and characterization of polyethylenimine-modified mesoporous silicas as CO_2 sorbents

摘要

Functionalization of MCM-48 and SBA-15 mesoporous silicas with polyethylenimine (PEI) has been achieved using the wet impregnation technique, and the obtained materials have been tested as media for CO_2 adsorption. Increasing PEI loading resulted in decreasing of the surface area and pore size of the potential adsorbents. PEI-modified mesoporous systems did not sorb any N_2 at 77 K, on the contrary both materials were able to sorb large amounts of CO_2 at 348 K and at very low pressure. At PEI loading of 50 wt% in MCM-48 and 44 wt% in SBA-15 adsorption capacities over 6 wt% were obtained. CO_2 desorption from the mesoporous silica samples under vacuum was close to 100%. These materials could be successfully used as sorbents to capture CO_2 after combustion or as H_2 stream purification media.