Harsh environment-tolerant and robust PTFE@ZIF-8 fibrous membrane for efficient photocatalytic organic pollutants degradation and oil/water separation

Abstract

Efficient treatment organic pollutants and oily wastewater with high toxicity under harsh environment is eagerly desired, while conventional membranes cannot meet the demand due to its poor chemical resistance which still remains a great challenge. Herein, biomimic polytetrafluoroethylene (PTFE) @ zeolite imidazole framework (ZIF-8) fibrous membrane for efficient photocatalytic organic pollutants degradation and oil-water separation under harsh environments was successfully developed, via electrospun PTFE nanofibrous membrane with numerous micro-nano rough papillae followed by in situ growth highly porous ZIF-8. The high surface area PTFE@ZIF-8 membrane with lotus-leaf-like structure exhibits excellent photocatalytic degradation performance to organic pollutants such as dyes (methylene blue and rhodamine B) and antibiotics (tetracycline) in harsh environments (strong acids/bases) with a remarkable high removal efficiency (99.99%). Meanwhile, the fluorinated PTFE@ZIF-8 membranes with super-hydrophobicity and super-lipophilicity property also exhibit outstanding oil/water separation performance (chloroform, kerosene, dichloromethane, toluene and n-hexane), with an extremely high flux of 2157 L m−2 h−1 (dichloromethane/water) and separation efficiency of 99.99% (kerosene/water). Furthermore, the membrane also able to separate water-in-oil emulsions effectively with an efficiency of as high as 99.99%. Most importantly, the robust PTFE@ZIF-8 membrane possesses excellent corrosion resistance, self-cleaning and recycling properties, which could still maintain such high separation efficiency and flux even after more than 10 cyclic oil-water separation tests under harsh environments. The multifunctional membrane with excellent harsh environment-tolerance offers an inspired strategy for efficient wastewater treatment under complex conditions and shows great potential for practical applications.