Waste PET Derived Beetle-like Membrane with High Mechanical Robustness for Regenerable Emulsion Separation

Biomimetic membranes have attracted extensive attention in oily wastewater treatment due to their exceptional selectivity and ability to remove micronano size droplets. However, their high cost of raw materials, inferior mechanical properties, and unsatisfied regeneration ability still remain shackles in the actual oil/water separation ability. Herein, a beetle-inspired waste potato starch/waste polyethylene terephthalate (WPS/WPET) biomimetic membrane with high mechanical robustness and excellent recyclability was fabricated via electrospinning and vacuum filtration without adding any chemical modification. Gaussian calculations indicated the strong hydrophilic property of WPS due to its low adsorption energy, suggesting that WPS can be used as "water catcher" to capture and aggregate emulsified water droplets, thus strengthening the demulsification ability of the membrane. The oil portion of the water-in-oil emulsion therefore can permeate through the WPS/WPET layer freely and get purified, achieving high separation efficiency (>99.7%) and filtration flux (>1200 L m-2 h-1). Moreover, the tensile strength of the WPS/WPET composite membrane was about twice that of the virgin WPET, which was attributed to the synergy of the stable biomimetic structure and strong intermolecular hydrogen bonds between WPS and WPET. Notably, in order to quickly and efficiently remove the water pollution remaining in the gaps of the bionic structure during the long-term separation process, the contaminated samples could be regenerated by hydrolysis cleaning and redeposition of WPS, and the efficiency remained over 98% even after 50 cycles. Therefore, this work may advance the development of a biomimetic membrane and achieve long-term serviceability in the purification of oil contaminated wastewater.