Preparation of Polyvinylidene Fluoride (PVDF) Hollow Fiber Composite Nanofiltration Membrane I.Fabrication of the Composite Nanofiltration Membrane

Using self-made polyvinylidene fluoride(PVDF) as support membrane of hollow fiber membrane,a novel polyamide PVDF composite nanofiltration membrane was prepared by interfacial polymerization.The effects of ratio of solute concentration in phases,additive concentration,reaction time and temperature on performance of composite nanofiltration membrane were systematically investigated.At the same time,the effect of secondary reaction on performance of composite membrane was specially discussed,by which a better route to prepare PVDF nanofiltration membrane could be drawn.Under the condition of the pressure 0.2 MPa and the temperature 22(°C),the rejection of prepared composite nanofiltration membrane on the concentration of 2 g/L,Na_2SO_4 was 97% and the permeation flux was 31.7 L/(m~2·h).The separation performance of this membrane was near to that of the commercial nanofiltration membrane.