| The problem of energy shortage and the ecological deterioration condition is becoming more and more serious,which urges to develop the new separation membrane with comprehensive performance so that it can broaden the application of the membrane technology.Membrane separation technology plays an important role in the development of ecological and environmental-friendly society.The ideal separation membrane materials need both high permeability and high permeability selectivity,pollution resistance and other excellent physical-chemical properties.However,the performance of polymer membranes is severely hampered by the problem of poor flux and other contaminant fouling.For these problems,the organic-inorganic hybrid membrane provides an effective method to improve the performance of the polymer separation membrane.In this paper,TiO2-GO and TiO2-GO-PEG nanocomposites were synthesized by impregnation-reduction method,then TiO2-GO/polyimide?TiO2-GO/PI?and TiO2-GO-PEG/polyimide?TiO2-GO-PEG/PI?hybrid membranes were fabricated via in-situ polymerization with 4,4'-?hexafluoroisopropylidene?diphthalic anhydride?6FDA?and 4,4'-oxydianiline?ODA?for CO2 gas separation,and TiO2-GO/poly?vinylidene fluoride??TiO2-GO/PVDF?and TiO2-GO-PEG/poly?vinylidene fluoride??TiO2-GO-PEG/PVDF?hybrid ultrafiltration membranes were prepared by blending and impregnation precipitation phase conversion for the anti-pollution performance test.Preparation and study of titanium dioxide-graphene nanocompositesTiO2-GO and TiO2-GO-PEG nanocomposites were synthesized by impregnation-reduction method using tetrabutyl titanate?C16H36O4Ti?as the source of TiO2 and the structures then characterized by Fourier transform infrared spectroscopy?FT-IR?,Raman spectroscopy,Transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?and Thermo-gravimetric analysis?TGA?.The results suggested that,the dispersibility of the nanocomposites in DMAc was better than that of GO,and the thermal stability was also enhanced.When better than that of GO,and the thermal stability was also enhanced.When the mass fraction of TiO2 in TiO2-GO was 15%,TiO2 nanoparticles could be distributed evenly on the GO layer.When the molecular weight of PEG of TiO2-GO-PEG was 2000,the dispersion of nanocomposites in DMAc was the best.Research of titanium dioxide-graphene/polyimide gas separationhybrid membranesTiO2-GO and TiO2-GO-PEG nanocomposites were put into polyimide to prepare hybrid membranes via in-situ polymerization.The structure and morphology of TiO2-GO/PI and TiO2-GO-PEG/PI hybrid membranes were characterized by FT-IR,SEM,TGA,Zeta and Surface contact angle?DSA?.The effect of nanocomposites on gas separation performance of the hybrid membranes was investigated.Like pure PI membrane,the hybrid membranes assumed a uniform state,so that the CO2 and N2 permeaation properties of the hybrid membranes could be improved.The TiO2 nanoparticles in TiO2-GO help improve the dispersion of nanocomposites in the hybrid membrane,thus enhance the permeability performance of the hybrid membrane.However,the excess of TiO2-doping leads to the aggregation of TiO2 particles on the GO surface,which depressed the permeability performance of the hybrid membrane.When the mass fraction of TiO2 in TiO2-GO was 15%and the content of composites was lwt%,the hybrid membrane demonstrated good permeability performance,and the selectivity of CO2/N2 reached 30 and the CO2 permeability was 360 Barrer.When the content of TiO2-GO-PEG was lwt%,the mass fraction of TiO2 was 15%,and molecular weight of PEG was 1000 in composites,the CO2 permeability of TiO2-GO-PEG/PI hybrid membrane was 458.09 Barrer,and when it was 2000,the selectivity of CO2/N2 reached 25.12.Research of titanium dioxide-graphene/poly?vinylidene fluoride?ultrafiltration hybrid membranesTiO2-GO and TiO2-GO-PEG nanocomposites were put into poly?vinylidene fluoride?to prepare hybrid membranes by blending and impregnation precipitation phase inversion method.The structure and morphology of TiO2-GO/PVDF and TiO2-GO-PEG/PVDF hybrid membranes were characterized by FT-IR,SEM,TGA,Zeta and DSA.The effect of nanocomposites on anti-fouling performance of the hybrid membranes was investigated.The results revealed that the TiO2-GO and TiO2-GO-PEG nanocomposites could improve the surface hydrophilicity of the hybrid membranes and accelerate the liquid-liquid separation rate,which increased the porosity of the hybrid membrnanes,thus improved the water flux and pollution resistance of the hybrid membrane.But,excessive hydrophilic groups led to the formation in the hybrid membranes,which reduced the hydrophilic and anti-pollution properties of hybrid membranes.When the mass fraction of TiO2 in TiO2-GO was 15%and the content of composites was 1 wt%,the hybrid membrane demonstrated the best water flux,and the rejection to BSA of hybrid membrane reached 88.44%and the water flux was 158.43 L*m-2*h-1.When the content of TiO2-GO-PEG was lwt%,the mass fraction of TiO2 was 15%and the molecular weight of PEG was 1000 in composites,the rejection to BSA of TiO2-GO-PEG/PVDF hybrid membrane was the best,it reached 88.38%and the water flux was 244.97 L*m-2*h-1. |
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