Polyethylenimine-functionalized SBA-15 mesoporous silica for CO2 direct air capture and conversion to methane in a coupled catalytic reactor
Technologies that capture and store or utilize CO2 have the potential to reduce the concentration of this gas in the atmosphere or provide carbon-neutral energy vectors. In this work, materials based on mesoporous silica SBA-15 functionalized with different polyethylenimine (PEI) loadings, i.e. 30,...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-07-01
|
| Series: | Journal of CO2 Utilization |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2212982025001180 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Technologies that capture and store or utilize CO2 have the potential to reduce the concentration of this gas in the atmosphere or provide carbon-neutral energy vectors. In this work, materials based on mesoporous silica SBA-15 functionalized with different polyethylenimine (PEI) loadings, i.e. 30, 40 and 50 wt% were synthesized. The 50 wt% PEI/SBA-15 sample exhibited the highest CO2 capture capacity of 6.0 g CO2/100 g when exposed to 400 ppm CO2. The sorption performance in a capture unit feeding 420 ppm of CO2 showed negligible influence of the inclusion of 21 % oxygen, whereas 64 % humidity enhanced by 17 % the CO2 sorption capacity with respect to a dry feeding at 20 °C. Desorption of H2O preceded CO2 during temperature swing at 80 °C, revealing a stronger interaction of CO2 with the sorbent. Finally, experiments were conducted by coupling the capture unit with a downstream catalytic reactor loaded with 10 % Ni/Al2O3 catalyst. A gas stream composed of 420 ppm CO2, 21 % O2 and 64 % humidity was admitted to the capture unit working at 20 °C. The CO2 captured under direct air capture (DAC) conditions was desorbed in a 1 % H2/N2 gas stream by temperature swing at 80 °C. The desorption of H2O along with CO2 impeded the conversion of CO2 into CH4 in the reaction unit. The inclusion of an isothermal step at 45 °C during temperature swing allowed to decouple CO2 and H2O desorption, achieving a CO2 conversion of 80.4 % with a CH4 selectivity of 97.6 %. |
|---|---|
| ISSN: | 2212-9839 |