Polyethylenimine Functionalized As-Synthesized KIT-6 Adsorbent for Highly CO2/N2 Selective Separation

The present study targeted the synthesis of CO 2 adsorbent by impregnation of DETA, TEPA, PEHA, and polyethylenimine in KIT-6 with a confiscated structure directing agent in minimum time and energy. The adsorbents were characterized and revealed the influence of polyethylenimine with CO 2 at a wide range of temperatures. An examination by TGA confirmed that PluronicP123 present in adsorbent enhances its thermal stability and acts as a carrier for CO 2 to the inner layer of polyethylenimine during adsorption. CO 2 sorption capacity of the adsorbent was found to be dependent on the polyethylenimine loading, temperature, pressure, and the surfactant PluronicP123. At higher temperatures, adsorbents showed a positive impact for CO 2 adsorption; however, a negative effect was exhibited in amine efficiency. The sorption capacity decreased with increasing the molecular weight of polyethylenimine following the order PEI-25K (66 mg CO 2 /g) < PEI-800 (114 mg CO 2 /g) < TEPA (124 mg CO 2 /g) < PEHA (139 mg CO 2 /g) at 75 °C. However, 60 wt % PEHA impregnated KIT-6 showed the stable sorption capacity of 170–184 mg CO 2 /g at 90–105 °C and 1 bar.