Hydrophilic modification of PVDF membrane with solution bulk polymerization graft and separation performance of oil-water

摘要

The surface of polyvinylidene fluoride (PVDF) membrane is modified with styrene and acetyl sulfate by the method of solution bulk polymerization graft, and polystyrene sulfonated (PSSA) grafted-modified membrane (PVDF-PSSA) is prepared. The surface structure and performance of PVDF-PSSA membrane are characterized and analyzed using scanning electron microscope, Fourier-transform infrared spectroscopy-attenuated total refraction, UV-visible spectrophotometer, X-ray photoelectron spectrophotometer, X-ray diffractometer, contact angle (CA), mercury porosimetry, thermogravimetric analyzer-differential thermal analysis and electronic tensile testing machine, respectively. The flux and separation performance of PVDF-PSSA membrane are studied. The results show that PVDF membrane surface occurs to have defluorination reaction so as to generate an unsaturated double bond through the alkali treatment. Styrene and sulfonic group are grafted to membrane surface. The modified membrane inherits a-phase crystalline phase, and the thermal decomposition temperature is over 300 degrees C. The CA of modified membrane decreases from 114 degrees to 33 degrees. Both hydrophilicity and permeability are enhanced. The pure water flux of modified membrane increases compared with PVDF membrane, and rejection rate for diesel fuel can reach to 99.8%. The flux decline ratio of modified membrane reduces from 39.92% to1.34%, and the flux recovery ratio increases from 60% to 84.87% after cleaning. The modified membranes exhibited enhanced stability, antifouling properties, and rejection rate, which can prove the potential of the membrane in petrochemical wastewater treatment.