Preparation Of Porous Skeleton / Polysulfone Composite Hollow Fiber Membrane And Study On Gas Separation Performance

The main content in this thesis includes:(1) the syntheses of two types of microporous materials; (2) the preparations of mixed matrix membranes using the synthesized porous materials as the active phase and polysulfone (PSF) as the continuous phase via dry jet-wet quench method; (3) the exploitation of the mixed matrix membranes in the gas separations on the basis of pore size effect of microporous materials. The typical details are described as follows.(I) The preparation of PAF-56P/PSF hollow fiber membranes:this membrane is composed of porous aromatic framework PAF-56P and PSF. PAF-56P was facilely synthesized by the cross-coupling reaction of triangle-shaped cyanuric chloride and linear p-terophenyl monomers. The as-prepared PAF-56P material possesses an extended conjugated network, the structure of which are confirmed by NMR and IR characterizations; as well as a permanent porosity with a BET surface area of 553.4 m2·g-1 and a pore size of 1.2 nm. PAF-56P was subsequently integrated with PSF matrix into PAF-56P/PSF asymmetric hollow fiber membranes via the dry jet-wet quench method employing PAF-56P/PSF suspensions. SEM studies show that PAF-56P particles are embedded in PSF matrix to form continuous membranes. Fabricated PAF-56P/PSF membranes were further exploited for CO2 capture, which was exemplified by gas separations of CO2/N2 mixtures. The PAF-56P/PSF membranes show a high selectivity of CO2 over N2 with a separation factor of 38.9 owing to the abundant nitrogen groups in the PAF-56P framework. A preferred permeance for CO2 in the binary gas mixture of CO2/N2 is obtained in the range of 93-141 GPU due to the large CO2 adsorption capacity and a large pore size of PAF-56P. Additionally, PAF-56P/PSF membranes exhibit excellent thermal and mechanical stabilities, which were examined by thermal analysis and gas separation tests with the dependences of temperatures and pressures. The merits of high selectivity for CO2, good stability, and easy scale up; make PAF-56P/PSF hollow fiber membranes of great interest in the industrial separations of CO2 from the gas exhausts.(II) The preparation of CIF-1/PSF hollow fiber membranes:the CIF-1/PSF membrane is fabricated by using CIF-1 metal organic framework and PSF. CIF-1 is constructed from Cu+ as metal center and dicyanoiazole as the ligand through strong coordination bonds. CIF-1 exhibits crystalline structure with uniform pore size of 1.0 nm and large surface area of 772.2 m2·g-1, which are studied by XRD and N2 sorption measurements. The result from SEM inspection shows that CIF-1 crystals are homogeneously distributed in CIF-1/PSF hollow fiber membrane. Gas separation property of CIF-1/PSF membranes was evaluated by the permeations of CO2/N2 mixtures. The separation tests reveal that the CIF-1/PSF membrane with 3 wt% CIF-1 shows a preferential permeation of CO2 over N2 with a separation factor of 28 and a CO2 permeance of 131.6 GPU, thanks to the basic nitrogen atoms in the CIF-1 framework. CO2 permeances increase from 101.6 GPU to 153.1 GPU with the pressures elevated from 0.16 MPa to 0.20 MPa, and the separation factors decrease from 30.8 to 17.8 accordingly.