PVDF grafted Gallic acid to enhance the hydrophilicity and antibacterial properties of PVDF composite membrane

A kind of PVDF composite membrane of good hydrophilic performance and antibacterial property was developed via an in-situ blending process. The PVDF-g-PGAL powder was prepared by degrading PVDF powder in alkaline condition, then oxidizing and grafting with Gallic acid (GAL). After mixing the original PVDF and PVDF-g-PGAL powder to prepare the PVDF composite membrane was soaked in NaHSO3 to further improve its hydrophilicity. The oil-in-water emulsion separation efficiency of the composite membrane was regulated by varying the contents of the modified PVDF powder. When the content arrives at 30%, the composite membrane has the pore sizes in the range of 130.2–263.3 nm, the permeation flux of 2419.9L⋅m−2⋅h−1⋅bar−1, the oil rejection rate of 97.39%, the flux recovery rate (FRR) of 94.59% and possesses the good anti-fouling performances during the cross-flow separation of the oil-in-water emulsion with the particle sizes within the scope of 10.1–396.1 nm. In addition, it has excellent antibacterial properties against E. coli and S. aureus, and effectively solves the blocking of membrane pores caused by the surface colonies in application. Therefore, the new composite PVDF membrane has the broad application prospects in the practical treatment of the complex oily wastewater media.