In situ deposition of double Fe-based Fenton catalysts on the porous membrane for the development of multi-defense against various foulants toward highly efficient water purification

Abstract

Membrane separation technology has been widely employed in wastewater separation, although, it is restricted by terrible membrane fouling. The acceptable “single defense” is insufficient to generate a desirable antifouling surface against various organic foulants in complex wastewater. Therefore, this work designs and constructs a porous surface with “multi-defense” by integrating hydrophilic, underwater superoleophobic, and anti-bacterial nano Fe-based Fenton catalysts of β-FeOOH nanorods and CuFeO2 nanoparticles on the polyvinylidene difluoride membrane via metal-ion-induced deposition process. The obtained composite membrane (MFeOOH/CF) has ultra-stable underwater superoleophobicity and ultra-low oil adhesion, which prevent oils from adhering to the membrane and benefit to separate various surfactant-stabilized oil-in-water emulsions with high water flux and separation efficiency of 99%. MFeOOH/CF also exhibits nearly 100% bactericidal activity against Escherichia coli. Moreover, the various foulants (such as bovine serum albumin, methylene blue, and crude oil) adhered to the membrane after filtration can be successfully degraded by MFeOOH/CF under the solar-driven Fenton process, leading to ultrahigh flux recovery ratio (FRRV) of 98.2 ± 0.3% and a low irreversible fouling ratio (RirV) of 2.0 ± 0.1%. The apparent degradation rate constant (k) of MFeOOH/CF is 2.5 times the β-FeOOH coated membrane (MFeOOH) because the introduction of CuFeO2 nanoparticles provides more reactive sites and lowers the Fe3+/Fe2+ redox potential. This study is working to bring about a highly efficient “multi-defense” on the porous membrane, which will realize membrane regeneration and boost wastewater purification.