CO2 adsorption kinetics using MMOs derived from LDHs

https://doi.org/10.3389/fenrg.2022.882182

“Figure 12 shows the CO₂ adsorption capacity versus time (minutes) profile of MMOs derived by the LDHs synthesized by the urea hydrolysis and co-precipitation method to evaluate the effects of the synthesis method and metal salts precursors on the CO₂ sorption kinetics of MMOs. The absence of a clear plateau in all sorption profiles after 120 min shows the nonequilibrium adsorption behavior of CO₂ in the LDH-derived MMOs sorbents. The vast difference in the uptake slopes of these profiles suggests two different kinetic regimes: a steep increase in the first few minutes of adsorption (fast reaction) followed by a small increase until the end of the adsorption step (slow reaction). In a cyclic adsorption operation, the fast reaction is often the desired reaction as it mostly occurs on the sorbent surface and requires lower heat of adsorption (Ebner et al., 2006, 2007; Walspurger et al., 2010; Du et al., 2011). In contrast, the slow reaction is generally not favored and forms bulk MgCO₃ species, which tend to be difficult to regenerate and cause process issues such as poor mechanical stability and CO₂ slip through the adsorption bed (Jansen et al., 2013).”

“FIGURE 12. CO₂ adsorption capacity vs. time (minutes) profile of MMOs derived by the LDHs synthesized by (A) urea hydrolysis and (B) co-precipitation methods.”