Effect of surface chemistry of polyethyleneimine-grafted polypropylene fiber on its CO2 adsorption

A high amino density of grafted solid amine adsorption fiber (PP-AM-PEI) for CO2 adsorption was prepared by grafting acrylamide (AM) onto the surface of a polypropylene (PP) fiber and subsequently modified with polyethylenimine (PEI). The grafting of AM on PP fibers was beneficial for introducing and assembling PEI onto the fibers. An examination by infrared and scanning electron microscopies confirmed that AM and PEI were successfully introduced onto the surface of PP fiber. PP-AM-PEI showed good thermo-stability, a high adsorption capacity for CO2 (5.91 mmol g−1). It also has good regeneration performance and could maintain almost the same adsorption capacity for CO2 after 5 recycle numbers. In addition, two other polypropylene-based adsorbents, PP-GMA-PEI (using glycidyl methacrylate (GMA) as the active monomer) and PP-AM-EDA (using ethylenediamine (EDA) as the functional monomer) were prepared. Compared with PP-GMA-EDA, PP-AM-PEI was more suitable for CO2 capture in the presence of moisture due to its hydrophilicity. The results also showed that the adsorption capacity of PP-AM-PEI was superior to PP-AM-EDA due to the high amino density of PEI.