Hydrophilic modification of polyvinylidene fluoride membrane surface by polyetheramine D230 and its oil-water separation performance
In response to the common problems of poor separation efficiency and susceptibility to oil contamination in polyvinylidene fluoride(PVDF)oil-water separation membranes,in the light of the chemical structure of the multibranched polyethers of demulsifiers and the submerged ultra-oleophobic surface,polyetheramine D230 with polyoxypropylene chain segments were introduced into the PVDF membrane surface to construct polye-theramine functionalized PVDF ultrafiltration membrane.Firstly,PVDF was blended with polystyrene maleic anhydride(SMA),and SMA/PVDF membranes with surface rich in anhydride groups were prepared by non-solvent induced phase transformation method.Then the membranes were immersed in polyetheramine D230 so-lution,and the terminal amine groups of polyetheramine were surface grafted in situ with the anhydride groups on the membrane surface.Thus,hydrophilic polyether segments are immobilized on the surface of the membrane to improve the wettability and anti-fouling properties of membrane surface.The effects of polyetheramine D230 on the hydrophilic modification of membrane surface and the separation performance of O/W emulsion were in-vestigated.The results showed that the grafting rate of D230 on the membrane surface increased with the increase of reaction time.The grafting rate of 387.8 mg/g was reached at the optimal reaction time of 9 h.The grafting of D230 on the surface of SMA/PVDF membrane significantly enhanced the hydrophilicity of the membrane surface,reduced the pure water contact angle to 48.5°,and increased the water flux from 30 U(m2·h)to 87 U(m2·h).In addition,the D230 grafted SMA/PVDF membrane exhibited super underwater oleophobic properties,with a un-derwater oil contact angle of 152° for kerosene and no adhesion to oil,showing good anti-oil fouling performance.D230 grafted SMA/PVDF membrane has a separation effect on SDS stabilized kerosene/water emulsion with an oil rejection rate of 99.0％,which was much higher than that of SMA/PVDF membranes(60.8％).It has potential application in the field of oil-water separation.
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