Potassium-Based Solid Sorbents for CO2 Adsorption: Key Role of Interconnected Pores

Abstract

Industrial CO2 emissions contribute to pollution and greenhouse effects, highlighting the importance of carbon capture. Potassium carbonate (K2CO3) is an effective CO2 absorbent, yet its liquid-phase absorption faces issues like diffusion resistance and corrosion risks. In this work, the solid adsorbents were developed with K2CO3 immobilized on the selected porous supports. Al2O3 had an optimum CO2 adsorption capacity of 0.82 mmol g−1. After further optimization of its pore structure, the self-prepared support Al2O3-2, which has an average pore diameter of 11.89 nm and a pore volume of 0.59 cm3 g−1, achieved a maximum CO2 adsorption capacity of 1.12 mmol g−1 following K2CO3 impregnation. Additionally, the relationship between support structure and CO2 adsorption efficiency was also analyzed. The connectivity of the pores and the large pore diameter of the support may play a key role in enhancing CO2 adsorption performance. During 10 cycles of testing, the K2CO3-based adsorbents demonstrated consistent high CO2 adsorption capacity with negligible degradation.