Study On PVDF UF Membrane Modified Via Hydrophilic Polymers And Carbon Nano Materials

This paper is based on the hudrophilicity modification of polyvinylidene fluoride ultrafiltration ?UF? membrane and prepared three different composite membranes, which can enhance its application effects and scale.Polyvinylidene fluoride ?PVDF?/polyvinyl alcohol ?PVA? composite UF membranes were prepared via blending and non-solvent induced phase inversion ?NIPS? method, investigate the effects on the structure and performances affect by different contents of carboxylated multi-walled carbon nanotubes ?MWCNTs-COOH?. FT-IR spectra identified the introduction of carboxyl, SEM images exhibited the asymmetric morphology with the appearance of a sponge-like inner structure. AFM analyzed more hydrophilic topography. The composite membrane containing 0.09 wt.% of MWCNTs-COOH showed best hydrophilicity and permeability which has the highest pure water flux 126.6 L·m^-2·h^-1, flux recovery rate showing an increase of 17.0%, and the best fouling resistance ability. Porosity and dynamic contact angle also proved those enhancement. Dextran 600k rejection reached 91.0%. Break strength, elongation at break and Young's modulus also had improvements of 60.0%.215.5% and 56.7%. respectively, when the MWCNTs-COOH content was 0.12 wt.%.Polyvinylidene fluoride ?PVDF?/polyvinyl butyral ?PVB? composite UF membranes were prepared via blending and non-solvent induced phase inversion ?NIPS? method, investigate the effects on the structure and performances affect by different contents of fullerene ?C60?. The composite membranes were analyzed using SEM, FT-IR, AFM, XPS and TG which identified asymmetrical structures, the introduction of hydroxy, more hydrophilic topography, increased oxygen atom contents and excellent thermal resistances. The optimal ratios of F-127 and fullerene were 1.0 wt.% and 0.100 wt.%, respectively. Under these ratios, the pure water flux was the maximum, the flux recovery rate was doubled, the reversible fouling ratio was increased and the irreversible fouling ratio was decreased. Dynamic contact angle measurements testified that the surface was more hydrophilic. Besides, mechanical properties, porosity, molecular weight cut-off ?MWCO? and pore size distribution affect by F-127-wrapped fullerene were also investigated. This series of membrane can offer selectable methods for protein waste-water separation applications.Polyvinylidene fluoride ?PVDF?/polyvinyl alcohol ?PVA?/calcium alginate ?CaAlg? composite membranes were prepared via dip-coating method which gave the composite membrane a gel layer. The prepared membrane owned excellent anti-fouling ability which the flux recovery rate was reached 99.2%, and even no attenuate after six times pollution and its total fouling ratio was only 10.5%.