Pyrite-embedded porous carbon nanocatalysts assembled in polyvinylidene difluoride membrane for organic pollutant oxidation

FeS 2 -embedded in porous carbon (FeS 2 /C) was prepared by simultaneous sulfidation and carbonization of an iron-based metal–organic framework precursor, and subsequently immobilized in polyvinylidene fluoride membranes (FeS 2 /C@PVDF) for organics removal via peroxymonosulfate (PMS) activation. The composition , structure, and morphology of the FeS 2 /C@PVDF membrane were extensively characterized. Scanning electron microscopy images manifest that the FeS 2 /C nanoparticles with an average diameter of 40 nm are assembled on the external and internal membrane surface. The as-prepared FeS 2 /C@PVDF membrane exhibits excellent performances over a wide pH range of 1.53–9.50, exceeding carbon-free syn -FeS 2 @PVDF. The effective degradation could be improved by inner pyrite FeS 2 cores and thus enhanced the electron transfer between carbon shell and PMS. Electron paramagnetic resonance and quenching experiments elucidated that radical ( HO ∙ , SO 4 ∙ - ) and nonradical ( 1 O 2 ) species were the predominant reactive oxidants. In addition, FeS 2 /C@PVDF exhibited high stability with low Fe leaching (0.377 mg/L) owing to the effective protection of the outer carbon skeleton. Plentiful porosity of PVDF membranes not only affords a controlled size and confined uniform distribution of the immobilized FeS 2 /C nanoparticles, but also enables a persistent exposure of active sites and enhanced mass transfer efficiency. Our findings demonstrate a promise for utilizing the novel FeS 2 /C@PVDF membrane as an efficient catalyst for the environmental cleanup.