Stability of mesoporous MgO based CO2 Capture

https://doi.org/10.3390/catal7040116

“High regenerability under repeated cycles of CO₂ adsorption and desorption is an obligatory requirement for CO₂ adsorbents practically utilized in CSU systems. Therefore, the CO₂ adsorption/desorption cycling stability of the synthetic SDS-assisted MgO was comprehensively examined via typical TSA procedures with circulation times fixed at 20 cycles. Figure 8a,b show the continuous adsorption/desorption cycling stability of the synthetic SDS-assisted MgO performed at different desorption temperatures (350 or 400 °C). During the first few cycles, the CO₂ capture capacity of SDS-assisted MgO particles degraded slightly, and in later cycles the uptake displays an excellent regenerability in terms of both rate and extent of uptake of CO₂. Notably, the comparatively obvious decline in CO₂ uptake initially occurred at 350 °C may be attributed to the incomplete decomposition of MgCO₃ due to the unsuitable desorption temperature. It is noteworthy that although the CO₂ uptake of SDS-assisted MgO nanoparticles has met a gradual decline of 0.1 mmol g⁻¹ when exposed to 50% CO₂ atmosphere during the adsorption period, as shown in Figure 8c, the adsorption capacity became considerably stable with a reversible capacity of more than 0.4 mmol g⁻¹. In general, it can be concluded that the CO₂ adsorption performance became weakened to a certain extent with the decrease in CO₂ concentration. Figure 8b indicated that the CO₂ capture capacity of the SDS-assisted MgO sample eventually reaches a steady value of 0.5 mmol g⁻¹ without further significant degradation, suggesting a great prospect of application in the sorption-enhanced hydrogen production processes [49,50].”

“Figure 8. CO₂ uptake over repeated cycles by SDS-assisted MgO particles of (a) CO₂ adsorption in 100% CO₂ for 30 min at 300 °C and desorption in 100% N₂ for 30 min at 350 °C; (b) CO₂ adsorption in 100% CO₂ for 30 min at 300 °C and desorption in 100% N₂ for 30 min at 400 °C; (c) CO₂ adsorption in 50% CO₂ and 50% N₂ for 30 min at 300 °C and desorption in 100% N₂ for 30 min at 400 °C; (d) FTIR spectra of SDS-assisted MgO nanomaterial.”