Co2 Capture Enhancement by Encapsulation of Nanoparticles in Metal–Organic Frameworks Suspended in Physical Absorbents

In this study, CO2 nanoabsorbents composed of encapsulated Fe3O4 nanoparticles in metal-organic frameworks (MOFs) and methanol, are developed to overcome the limitations of conventional CO2 sorbents. The polyvinylpyrrolidone-functionalized Fe3O4 nanoparticles encapsulated in (Zn)MOF-74 [Zn2(DOBDC), DOBDC = 2, 5-dihydroxyterephthalic acid] are dispersed in the methanol. Compared with pure methanol, CO2 absorption and regeneration performances of Fe3O4 @ (Zn)MOF-74/methanol are improved by 13.07% and 16.25% (Abs.: 0.84 g-CO2/L-solvent and reg.: 0.77 g-CO2/L-solvent), respectively, at optimum conditions of 0.01 wt%. Cyclic stability experiments exhibit that the performance of Fe3O4 @ (Zn)MOF-74/methanol can preserve 93.76% of their initial capacities. It is finally concluded that the absorption performance is improved by hydrodynamic and shuttle effects while the CO2 sorbent regeneration performance is enhanced by metal-organic heat carriers (MOHCs) and nucleation from the surface of nanoparticles by introducing Fe3O4 @ (Zn)MOF-74 nanoparticles.