Poly(vinylidene fluoride) based mixed matrix membranes comprising metal organic frameworks for gas separation applications

Poly(vinylidene fluoride) (PVDF) based mixed matrix membranes (MMMs) comprising crystalline structures of Metal organic frameworks (MOFs), CuBTC, CuBDC, MIL-53(Al) and NH2-MIL-53(Al) were fabricated and investigated for gas separation applications. MOFs and membranes were extensively characterized by FT-IR, XRD, SEM and TGA techniques. 10 wt% loading of CuBTC in PVDF showed 43.6 and 118.7% permeability enhancement for He and CO2 gases compared to the pure membrane. Moreover, the high selectivity enhancement of 96% was observed for CO2/CH4. In regards to CuBDC, 37.5 and 117% permeability increase for He and CO2 gases was reported for 15% loading. Furthermore, the best selectivity was related to CO2/CH4 in which 109.3% increscent was achieved relative to the pure membrane. Since CuBTC and CuBDC exhibited interesting effects on CO2 transport, they can be promising additives for polymer membranes. The membranes containing 10% wt of NH2-MIL-53(Al) showed 11.25 and 22.41% selectivity enhancement for He/CH4 and CO2/CH4. However, for those membranes containing MIL-53(Al), were decreased by 3.33 and 1.33% compared to the pure PVDF membrane. The different behavior of NH2-MIL-53(Al) and MIL-53(Al) can be explained by their different surface properties related to the existence of amino groups on NH2-MIL-53(Al).