Preparation Of PVDF/ZNO/GO Hybrid Membrane And Its Study On The Removal Performance Of Methylene Blue

Polyvinylidene fluoride(PVDF)separation membraneis widely used in chemical,sewage treatment,bio-engineering and other fields.ZnO as a photocatalyst can be used to degrade organic dyes in water.The surface and side edges of the graphene oxide(GO)contain a large number of oxygen-containing functional groups,and electronegative oxygen groups can adsorb cationic dyes via electrostatic forces.In this paper,ZnO and GO were introduced into the PVDF membrane matrix to improve the removal performance of PVDF membrane to organic dyes,An organic-inorganic hybrid membrane with excellent performance was prepared for the purification of organic dye wastewater.Firstly,GO was prepared by the improved Hummers method,and its surface morphology,chemical composition and dispersion properties were characterized and studied.The results show that the layer and edge part of GO contain a large number of oxygen-containing groups,these oxygen-containing groups mainly exist in the form of hydroxyl,carboxyl and epoxy groups,the presence of these oxygen-containing groups increases the dispersibility and stability of GO in aqueous solutions.PVDF/ZnO/GO hybrid membrane were prepared by immersion precipitation method using PVDF as the base material,ZnO and GO as functional additives,and its structure and properties were studied.Compared with the pure PVDF membrane,the introduction of ZnO and GO leads to the roughening of the surface of the PVDF membrane and the enhancement of the permeability,the retention of BSA and the adsorption of MB of the PVDF membrane.When the hybrid membrane adsorbs MB,the increase of temperature was beneficial to the adsorption of MB at lower temperature;The increase of initial MB concentration was not conducive to the removal ofMB;It was favorable for the removal of MB under alkaline condition;The adsorption of MB was inhibited by increasing the ionic strength The adsorption kinetics and isotherm analysis indicated that the adsorption mechanism conformed to the pseudo-second-order kinetics model,Freundlich isotherm equation could better described the isothermal adsorption process.Finally,the PVDF/ZnO/GO hybrid membrane was used for the photocatalytic degradation of MB.The results show that the photocatalytic efficiency of the hybrid membrane is higher under the alkaline condition and irradiation of visible light;the increase of the ionic strength and initial concentration of MB solution could decrease the photocatalytic efficiency of the hybrid membrane;The addition of H2O2 can promote the photocatalytic reaction.The photo catalytic degradation process of the hybrid membrane conforms to Langmuir-Hinshelwood first-order kinetic equation.