Metal organic frameworks decorated membrane contactor constructing SO2-philic channels for efficient flue gas desulphurization

Abstract

Membrane contactor has been considered to be a prospective alternative to traditional technology for toxic acid gases capture. In this study, the mixed matix membrane contactors (MMMCs) with the metal organic frameworks (MOFs, MIL-101(Cr)) as fillers are fabricated for high-efficiency SO2 removal. The MIL-101(Cr) with microporous structure provides more SO2 channels for the enhancement of SO2 absorption flux. Moreover, the open metal sites from MIL-101(Cr) display the high affinity to SO2, which construct “SO2-philic” channels in the finger-like pore structure, resulting in the increment of SO2 removal efficiency. The introduction of MIL-101(Cr) into PVDF modifies the physical structure verified by scanning electron microscope (SEM), liquid entry pressure (LEPw) and gas permeation test et al. The newly developed MIL-101(Cr) doped MMMCs exhibit competitive hydrophobicity with the water contact angle of 119°. In particular, the M915 MMMC with MIL-101(Cr) loading 15 wt% displays the optimum SO2 absorption performance with the SO2 absorption flux and SO2 removal efficiency of 1.09 × 10−3 mol m−2 s−1 and 89.51%, respectively. The SO2 mass transfer coefficient in membrane (Km) is significantly enhanced to 4.44 × 10−3 m s−1 and membrane phase resistance (H/Km) is noticeably decreased to 92.96 s m−1. Besides, the MIL-101(Cr) doped MMMCs show both the alkali resistance and long-term stability.