PVDF ultrafiltration membranes with superior antibacterial and self-cleaning properties by embedding quaternary ammonium functionalized MWNTs

2-Dimethylaminoethyl chloride hydrochloride(DCH), a precursor of quaternary ammoniumsalt, was grafted onto oxidized multi-walled carbon nanotubes(O-MWNTs)by epichlorohydrin. The obtained quaternary ammonium functionalized MWNTs(N+-MWNTs) were added into casting solution to prepare polyvinylidene fluoride(PVDF) hybrid ultrafiltration membranes(PVDF/N+-MWNTs). Field emission scanning electron microscopy(FESEM)was used to observe the morphology. The results demonstrated that the surface roughness and hydrophilicity of PVDF/N+-MWNTs hybrid membrane were obviously improved.Besides, in the ultrafiltration-regeneration cycles with bovine serum albumin(BSA)as model biofoulant, the pure water permeation was improved from 110.5×10-5 to 197.4×10-5 L·m-2·h-1·Pa-1.Especially in the third cycle, the flux recovery ratio (FRR)was evidently improved.The prepared PVDF/N+-MWNTs hybrid membranes had excellent antibacterial efficacy against Escherichia coli and Staphylococcus aureus.Especially after three cycles, the antibacterial ratio remains high