| Polymer materials researches of gas separation increase deeply. However,gas separation using polymeric membranes show distinct trade-off trends. Thebest permeability and selectivity gas separation membrane is the current focusstudy. The main work of this paper is focus on how to improve the overall per-formance of the gas separation membranes. Fluorine-containing polysulfone(DDS-6FpDA) was selected as matrix membrane and inorganic particles such asmulti-walled carbon nanotubes, ZIF-8metal organic framework materials wasselected as the dispersed phase to synthesis the hybrid membranes. The purposeis to combine gas permeation advantage of both materials maximum. Specificresearch work and conclusions include:1. Firstly, fluorine-containing polysulfone (DDS-6FpDA) was synthesizedby free radical polymerization and analysed by1H NMR of the NMR spectraand test by gas separation. Gas separation performance of the commercial andsynthetic fluorine-containing polysulfone were measured and compared. Theresults showed that: the fluorine-containing polysulfone membranes are betterthan commercial polysulfone membrane, under the same conditions. The syn-thesis fluorine-containing polysulfone membrane introduced-CF3groups can interact with CO2weakly at the transfer process exhibiting high permeability.Besides the presence of-CF3groups, the free volume is much larger than mem-brane with-CH3group, which lead the gas permeability increasing.2. MWCNTs selected as inorganic particles were added into a fluo-rine-containing polysulfone matrix to make hybrid membranes. In order to im-prove the compatibility of multi-walled carbon nanotubes with the matrix mem-brane, acid (H2SO4/HNO3=3/1) modification introduced–COOH method wasused in this work. IR spectra of raw and modificated carbon nanotubes waschanged in the1709cm-1that appears the C=O peak signal, and combined-OHpeak signal3425cm-1can certify carboxyl introduced successfully. According toSEM results, the particles of AT-MWCNTs have relatively uniform dispersion inpolymer matrix at low fraction. The influence of loading (1-4wt%),transmembrane pressure (0.5,1.0,1.5atm) and temperature (25oC,35oC,45oC,55oC) on the gas permeability coefficient (P) and the ideal coefficient (α) wasstudied. when2wt%content AT-MWCNTs, gas permeability coefficient is12.73Barrer, select coefficient is28.9, increased19%and5.5%respectively at1atm pressure and25oC. Gas permeability coefficient was changed flatten un-der different trends transmembrane pressure. All gases permeability coefficientsincreased significantly with the temperature increasing, but select coefficientdecreased significantly. According to Arrhenius equation, temperature affectsgas with high activation energy significantly in the same membrane system,Ep(CH4)>Ep(CO2), so the CO2/CH4separation factor decreased. Gas transmis- sion in multi-walled carbon nanotubes is much faster than other else generallyknown porous materials, and the free volume of polymer increased which en-hancing the permeability of gases.3. ZIF-8nano-particles were synthesized and proved by XRD. Hybridmembranes were prepared and Characterized by XRD. The added ZIF-8struc-ture was not destroyed in membranes; the IR peaks of hybrid membrane werefurther proved the characteristic peak of ZIF-8and matrix both containing; theEDS of membrane cross-sectional prove the added ZIF-8particles were uni-formly dispersed in the matrix membrane effectively. When contain10wt%ZIF-8particles, gas permeability coefficient was up to27Barrer (pure mem-brane is10.69Barrer) improved by153%, the separation factor is19.0(puremembrane is27.8) decreased by30%. In addition, the presence of ZIF-8pro-vided another channel for gas passing through the membrane, the free volume ofhybrid membrane enhanced the gas permeability. |
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