Study on hydrophilic modification of anti-pollution PVDF-CTFE membrane coupling
Membrane fouling can be mitigated by improving the hydrophilicity of the membrane through bulk modification or surface modification.However,too many hydrophilic substances added to the bulk modification will cause the membrane to swell,resulting in a decrease in the tensile strength of the membrane.Surface modification of grafted macromolecules may cause pore plugging on the membrane surface and reduce membrane flux.In this paper,the hydrophilic modification of the membrane is carried out by coupling the two methods of bulk modification and small molecule surface modification,which is expected to break the limitations of a single modification method and better improve the anti-fouling performance of the membrane.In this paper,meglumine was first used to modify the bulk of the polyvinylidene fluoride-trifluoroethylene(PVDF-CTFE)membrane,and then the surface of the modified PVDF-CTFE membrane was modified by small molecule taurine.The results show that compared with the single bulk modified membrane,the water contact angle of the membrane prepared by the bulk-surface coupling modification method is reduced from 91.5° to 41.8°,the hydrophilicity of the membrane surface is greatly improved,and the filtration flux of BSA is significantly improved.Compared with the single surface modified membrane,the pure water flux of the membrane prepared by the bulk-surface coupling modification method increased from 3 394 L/(m2·h·MPa)to 4 743 L/(m2·h·MPa).The bulk-surface coupling modification method enables the two modification methods to produce a synergistic effect,which can effectively improve the pure water flux,hydrophilicity and anti-fouling performance.
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