NH2-MIL-125 filled mixed matrix membrane contactor with SO2 enrichment for flue gas desulphurization

Abstract

Membrane absorption is a convenient and efficient flue SO2 capture technology. In this study, NH2-MIL-125 filled mixed matrix membrane contactor (MMMC) is constructed by Non-solvent Induced Phase Separation (NIPS) method. The functional groups and metal active sites on the surface of NH2-MIL-125(Ti) exhibit high affinity for SO2. The microporous structure of NH2-MIL-125(Ti) provides storage for adsorbed SO2, which is conducive to the formation of SO2 enrichment zone in the membrane. The membrane morphology, wetting resistance, and light responsiveness et al of MMMC have been tested. The combination of NH2-MIL-125(Ti) adsorption and membrane absorption process effectively promotes the transfer of gas molecules in the membrane pores. The SO2 absorption flux of MMMC filled by NH2-MIL-125(Ti) has a significant increment, reaching 8.81 × 10−4 mol·m−2·s−1 and 9.77 × 10−4 mol·m−2·s−1 under non-light and visible light conditions respectively, which is comparability with results in literature. The membrane phase mass transfer coefficient calculated by Wilson model is 149.6 s·m−1, which shows the low resistance in membrane. The SO2 absorption flux keep stable after 4 cycles of tests. The membrane contactor coupled with function fillers enhances the SO2 capture ability and further promotes the enrichment of SO2, which has favorable development foreground.