Highly Selective Physical/Chemical CO2 Separation by Functionalized Fe3O4Nanoparticles in Hollow Fiber Membrane Contactors: Experimental and Modeling Approaches

Herein, different water-based modified magnetitenanodispersions of Fe3O4-proline (Fe3O4-P), Fe3O4-lysine (Fe3O4-L), Fe3O4@SiO2-proline (Fe3O4@SiO2-P), and Fe3O4@SiO2-lysine (Fe3O4@SiO2-L) were prepared to improve the stabilityand absorption capacity of bare Fe3O4nanodispersion for selectivephysical/chemical carbon dioxide (CO2) separation in apolypropylene hollowfiber membrane contactor (PP HFMC).The liquid was passed through the tube side and CO2gas waspassed through the shell side concurrently. Subsequently, theimpacts of varying nanoparticle (NP) loadings, gas/liquidflowrates (Ql/Qg), and NP stability on CO2separation were elucidated.Considering the achieved results, all modified NPs revealed higherselective CO2separation performances compared to bare Fe3O4NPs because of functionalization with chemical reactants of CO2. Also, for thefirst time, to evaluate the influence of the CO2inletconcentration and wetting parameter, a new and simple model was proposed in which the behavior of functional NPs wasconsidered. Ultimately, the CO2removal enhancements of 27.5, 57.14, 64.28, 72.8, and 96.42% were achieved for Fe3O4,Fe3O4-P,Fe3O4-L, Fe3O4@SiO2-P, and Fe3O4@SiO2-L at optimal NP loadings and in the best operational conditions (i.e.,Ql=10mLmiddotmin-1andQg= 100 mLmiddotmin-1).