Document Type : Research Paper
State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tiangong University, Tianjin 300387, China
School of Chemical Engineering and Technology, Tiangong University, Tianjin 300387, China
Institute of Separation Material and Process Control, School of Material Science and Engineering, Tiangong University, Tianjin 300387, China
Developing mixed matrix membranes (MMMs) is a way to fabricate high permeation-performance membranes. The arrangement of the fillers, especially the specific-shaped ones, in the membranes has a non-negotiable influence on the gas-transport performance. With the assistance of a magnetic field, the Fe3O4 decorated attapulgite (ATP) is orderly arranged into the polymer of intrinsic microporosity (PIM-1) to form ATP/PIM-1 MMMs. Moreover, Fe3O4 decorated ATPs were coated with polydimethylsiloxane to avoid the polymeric matrix filling the cavity of ATPs. Chemical compositions of modified ATPs were determined by Fourier transform infrared spectroscopy. Morphologies of modified ATPs were observed via transmission electron microscopy and wide-angle X-ray diffraction. Morphologies of ATP/PIM-1 MMMs investigated by field-emission scanning electron microscopy. The effects of the vertically-arranged, parallelly-arranged, and disorderly-arranged ATPs on gas permeation-separation performances of ATP/PIM-1 MMMs were also reported. The parallelly-arranged ATP/PIM-1 MMMs display the best gas permeability compared with vertically-arranged and disorderly-arranged ATP/PIM-1 MMMs. And introducing the parallelly-arranged ATP brings about higher gas permeability and selectivity. Compared with the original PIM-1 membrane, the parallelly-arranged ATP/PIM-1 MMM with 5 wt.% ATP loading shows CO2 permeability of ~4018 Barrer coupled with CO2/N2 selectivity of ~19, and O2 permeability of ~672 Barrer coupled with O2/N2 selectivity of ~3. The CO2 permeability and O2 permeability increases to ~2.7 times.