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Polyvinylidene fluoride (poly (vinylidene fluoride), PVDF) ultrafiltration separation membrane was prepared in the typical polymer material, having a heat radiation resistance, the chemical resistance is very excellent, and mechanical properties are also high. PVDF itself there is a drawback, i.e. hydrophilic very bad, seriously affect antifouling performance of the ultrafiltration membrane. Methods to improve the PVDF ultrafiltration membrane hydrophilic many graphene oxide (Graphene Oxide, GO) as a new carbon nanomaterials, their excellent hydrophilic PVDF hydrophilic modified to provide a new avenue. GO particle size of the structure and performance of the nanocomposites great influence on how to control the size of the GO to meet the requirements of the composite ultrafiltration membranes become an urgent need to address the problem. Starting from Hummer law designed two sets of programs preparing graphene oxide, GO-1 (the original Hummer Act) and GO-2, respectively (increased reaction time and the amount of oxidant the modified Hummer law), and the mixed acid treatment and GO-1 sample size was modified by the method of the physical milled. Characterization of the means of the Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that GO The carbon skeleton with a rich hydroxy oxygen-containing functional groups such as epoxy group and a carboxyl group, GO lamellar structure is obvious. The two solutions prepared from the GO sample its degree of oxidation, and there are significant differences in the particle size, GO-1 and GO-2 carboxyhemoglobin ratios were 2.18 and 1.88, and a particle size of ~ 400nm and ~ 40nm. Modified after GO-1, and its size reduced to ~ 100nm, and after the mixed acid treatment GO (GO-Ac), its carbon skeleton structure destroyed, a further increase in the degree of oxidation. By immersion - precipitate phase transformation method, modified GO GO, and polyvinyl pyrrolidone (PVP) as the additive, the the GO / PVDF and GO-PVP/PVDF composite ultrafiltration membrane was prepared. Determination of the water flux of the composite membrane (F0), bovine serum albumin (BSA) retention rate (R), as well as the water flux attenuation coefficient (m) of the ultrafiltration membrane, such as the performance index, using a scanning electron microscope (SEM) and atomic force microscopy (AFM) to characterize the microstructure of the composite membrane cross section and surfaces. The contact angle measurements show that the contact angle of the composite membrane is reduced to 20 °. GO and PVP composite additives, ultrafiltration membrane water flux rapid rise with increasing PVP content, but significantly reduce the rate of rejection of BSA. GO and PVP content was 0.5 wt% the performance of the composite membrane most excellent water flux 348.56L / (m ~~ 2 h), BSA retention rate of 84.37%, the water flux attenuation coefficient of 56.52%. The results show that the GO added to improve the water flux and the hydrophilicity of the ultrafiltration membrane, but the rejection rate is decreased, reduce water flux attenuation coefficient, and its antifouling performance enhancements.
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