Enhancing the permeation and fouling resistance of PVDF microfiltration membranes by constructing an auto-soak surface

Abstract

A new kind of hydrophilic polyvinylidene fluoride (PVDF) microfiltration membrane with an auto-soak surface was fabricated by plasma treatment and interfacial crosslinking to improve the separation efficiency and fouling resistance in water treatment. Based on the anchored hydrophilic polyvinyl alcohol (PVA) network and the porous structure, the modified PVDF membrane was able to exhibit an auto-soak ability. The separation test results showed that to obtain the same separation efficiency, the operating pressure of the modified PVDF membranes was significantly reduced as compared with that of the neat PVDF membrane, due to the decreased permeation resistance. The fouling test results also demonstrated that this auto-soak surface of the PVDF membrane was able to alleviate the irreversible fouling problem during dynamic filtration, and the water flux recovery ratio (FRR) remained above 75% even after three fouling cycles. All these results indicated that the modified PVDF membrane with the auto-soak surface provided a new means for the reduction of the permeation resistance, as well as the membrane fouling problem of the hydrophobic porous membranes.