The present study targeted the synthesis of CO2 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 CO2 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 CO2 to the inner layer of polyethylenimine during adsorption. CO2 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 CO2 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 CO2/g) < PEI-800 (114 mg CO2/g) < TEPA (124 mg CO2/g) < PEHA (139 mg CO2/g) at 75 degrees C. However, 60 wt % PEHA impregnated KIT-6 showed the stable sorption capacity of 170-184 mg CO2/g at 90-105 degrees C and 1 bar.