Photocatalytic self-cleaning PVDF-g-NMA@FeOOH nanofiber membrane via microchip grafting

Although membrane separation technology has been widely used for oily wastewater treatment in recent years, surface fouling still poses a great threat to application. Due to the strong adsorption of oil droplets onto membrane surface and within pores, pristine membranes are inadequate for long-term oil-water separation applications. Here, a novel photocatalytic nanofiber membrane via microchip grafting with in-situ mineralization was proposed. N-Methylolacrylamide (NMA) was successfully grafted on polyvinylidene fluoride (PVDF) by microfluidic electrospinning, and the grafting amount was 9 times that under conventional bottle reaction conditions. The in-situ mineralization time via the polyphenol-metal network was reduced from 27 h to 18 h, while the mineralization rate increased by threefold compared with the bottle-grafted membrane. For oil-water emulsion separation, the developed PVDF-g-NMA@FeOOH membrane successfully showed the high permeability of 38870 L·m −2 ·h −1 ·bar −1 with the outstanding rejection rate of 99.2%. It displayed great photocatalytic self-cleaning performance, and the flux recovery rate was up to 95.8% after cycle tests. Methhyllene blue (MB) removal rate reached 96.3% in 50 min. The developed membrane holds great promise for applications in oil-water separation and organic contaminant degradation.