Leaf vein-biomimetic nanofibrous membrane with self-assembled nanonet for surface filtration of water contaminants

Purifying fresh water, especially water contaminated with pathogenic microbes, in an effective way is of great significance. The current water treatment technologies, however, are often chemically intensive, insufficiently validated for spore-forming bacteria, or have high energy consumption. Herein, an innovative biomimetic nanofibrous membrane (BNFM) with self-assembled nanonet structure inspired by natural leaf veins is constructed by nonsolvent-induced phase inversion. Regulation of the phase separation process by selection of the solvents and addition of the surfactant enables the generation of a self-assembled nanonet with a nanoscale diameter of 38 nm. The resultant BNFM exhibits intriguing properties involving small pore size (∼0.18 μm), high porosity (93.8%), and good interconnectivity, together with good hydrophilicity, enabling it to effectively surfacely filtrate E. coli-contaminated water with a high log reduction value (8.5) and robust permeation flux (2803 L m−2 h−1). Meanwhile, the BNFM can also effectively intercept submicron-sized TiO2 particles with particle size of 0.3 μm by surface filtration with excellent removal efficiency (>99.80%) and remarkable permeation flux (>4.3 × 103 L m−2 h−1). The construction of BNFMs may open up entirely fresh pathways for designing new nanofibrous materials for various separation applications.