Amine-based solid sorbents are promising candidates for post-combustion CO2 capture owing to their high sorption capacity at operating temperatures. Sorbents are required for stable CO2 mixture sorption and regeneration. Herein, we report a novel alkyl-functionalization method for the stoichiometric conversion of primary amines to secondary amines in solid sorbents. (3-Aminopropyl)triethoxysilane (APTES) and alkyl-functionalized-APTES were grafted on zeolite beta through a reflux reaction; the alkyl-functionalization was confirmed by nuclear magnetic resonance and Fourier transform infrared analyses. Alkyl-functionalized-APTES zeolite exhibited a sorption capacity of 1.44 mmol/g (15% CO2 balanced with N2 at 90 °C), very high sorption rate of t1/2 = 0.69 min (over 90% of the total sorption capacity within 5 min), and long-term stability after 20 cycles in a temperature swing adsorption (TSA) operation (above 0.9 mmol/g at pure CO2 regeneration). Alkyl-functionalized-APTES zeolite beta showed higher sorption capacity and stability than APTES zeolite and PEI silica in TSA operation at CO2 mixture sorption and CO2 flow regeneration.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering