https://doi.org/10.1016/j.ccst.2021.100011
“To minimize the overall cost for CO2 capture, alkaline solid wastes including potassium feldspar, calcium aluminate cement, clay, Portland cement and fly ash were tried as supports, and CO2 capture capacities of the alkaline waste-supported K2CO3 adsorbents were in the range of 0.36-1.74 mmol CO2/g (Guo et al., 2015a; Qin et al., 2014). Considering the business cost and overall performance concerns, Al2O3 might be a preferable support for potassium-based adsorbents. However, the issue of sorbent deactivation due to the formation of inactive byproduct needs to be addressed in future work. Another important issue is the limited loading of K2CO3 on the mesoporous Al2O3 support. Carbonation capacities of the K2CO3/Al2O3 adsorbents are expected to be enhanced by increasing K2CO3 loading, while excessive K2CO3 loading will trigger pore structure blockage and uneven dispersion of K2CO3, and these will further result in increased diffusion resistance and declined K2CO3 utilization efficiency. A perfect tradeoff should be gained among K2CO3 loading, porous structure and K2CO3 dispersion for the K2CO3/Al2O3 adsorbents.”