Enhanced CO2 Solubility in Hybrid Adsorbents: Optimization of Solid Support and Solvent Properties for CO2 Capture

In this study, we optimize the CO2 adsorption performance of hybrid adsorbents prepared by confining physical solvents in porous solid supports. A number of prospective solid supports and physical solvents are chosen to prepare hybrid adsorbents, and are subsequently evaluated in CO2 adsorption experiments. Generally, all the hybrid adsorbents show an enhancement of CO2 solubility compared to the bulk physical solvent. However, not all the adsorbents positively display an improvement in the CO2 adsorption performance as compared with the original solids after confining the physical solvent into the solids' pore. The micropore blocking effect is observed in the impregnated forms of zeolite, activated carbon, silicagel, and cecagel. Furthermore, we have obtained certain requisites for a good solid support, as efficient structures should be mesoporous with large surface area. In addition, there is an optimized solvent's size to achieve an optimized enhanced solubility. As a result, among the candidates, N-methyl-2-pyrrolidone confined in MCM-41 and alumina are identified as the most suitable hybrid adsorbents for an effective CO2-removal application.