Magnetic field assisted arrangement of photocatalytic TiO2 particles on membrane surface to enhance membrane antifouling performance for water treatment.

Fabrication of membranes with high antifouling and self-cleaning ability is a long-term pursuit of research community. For this purpose, the current work proposed a strategy to use an external magnetic field to arrange the magnetic TiO2@Ni particles (MNPs) onto the polymeric polyether sulfone (PES) membrane surface. The characterization results clearly indicated that the MNPs were successfully embedded onto the membrane surface instead of uniformly distributing into the membrane bulk. Because of this superficial distribution, the prepared composite membrane exhibited a flux of 871.2 ± 2.9 L·m-2·h-1·bar-1, which was 5 times flux of the pristine PES membrane. Meanwhile, it remained a rejection of 95.85% bovine serum albumin (BSA), which was also better than that of the pristine PES membrane. The cycle filtration experiments verified that the composite membrane possessed promoted antifouling ability for filtrating BSA, yeast extract fermentation (YEF), ammonium alginate (SA) and humic acid (HA) solutions. The antifouling mechanism was analyzed by the total interaction energies (ΔGTotal), which were quantitatively evaluated by using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Moreover, it was interestingly found that the composite membrane possessed a self-cleaning property under radiation of UV light and sunlight. The optimal membrane after self-cleaning presented flux recovery ratio (FRR) of 75.4%, 99.56%, 92.11% and 98.26% for BSA, YEF, SA and HA solutions, respectively. This work demonstrated a novel way to fabricate membranes with high antifouling and self-cleaning ability for water treatment.