A novel strategy based on magnetic field assisted preparation of magnetic and photocatalytic membranes with improved performance

Membrane fouling problem is the bottleneck for commercial applications of separation membranes. The current study offered a first report on preparation and performance of the magnetic and photocatalytic poly (vinylidene fluoride) (PVDF)-Ni-ZnO composite membranes for the antifouling purpose. Magnetic Ni-ZnO particles (NZPs) was firstly prepared via an in-situ reduction reaction. Thereafter, the NZPs were attracted onto a PVDF membrane surface through a magnetic force effect. The PVDF-NZPs composite membrane displayed magnetic property, photocatalytic property and obviously higher antifouling performance than that of bare PVDF membrane. Particularly, the flux recovery rates (FRR) of the optimal PVDF-NZPs membrane reached to 100%, 100%, 83% and 83% for filtration of humic acid (HA), sodium alginate (SA), bovine serum albumin (BSA) and yeast solutions, respectively, which are comparable or much better than most of the literature data. In addition, it was found that acid-based (AB) interaction of the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) results played the predominant role during the fouling process. The ultrahigh FRR of the modified PVDF-NZPs membrane mainly stemmed from its in-situ and persistent photocatalytic activities. The current work not only offered a novel membrane modification method, but also presented the modified membranes with enhanced performance for water treatment.