Photo-Fenton catalyst Fe(III)@PCN-222 grafted on PVDF membrane for multitasking applications: Oil/water separation, aromatic pollutants degradation and bacterial inactivation

In this work, a novel PCN-222 metal-organic framework based multitasking membrane was developed for separation of emulsified oils as well as photo-Fenton degradation of refractory aromatic pollutants and inacti-vation of pathogenic bacteria in water. Fe(III)@PCN-222 nanorods were prepared via impregnation method and subjected to amino-modification, and then robustly anchored on polydopamine (PDA) decorated PVDF mem-brane via catechol-amine reaction. The as-prepared N-Fe(III)@PCN-222/PDA/PVDF composite membrane exhibited underwater superoleophobicity, and showed high separation efficiency (above 99.4 %) as well as relatively favorable permeation flux (874.9-1592.3 Lm-2h-1) in the separation of emulsified oils ranged from nanoscale to microscale from water. Meanwhile, the membrane serving as a recyclable photo-Fenton platform showed an extensive degradation capacity towards aromatic contaminants and high inactivation activity against bacteria under visible light. The grafted Fe(III) is used as an electron acceptor to promote the separation of photo -generated charge carriers, adjusted the band structure to shorten the bandgap value, and can be reduced to Fe(II) by photo-generated electrons as a Fenton-like catalyst. The photo-Fenton mechanism was studied in detail from the aspects of photoelectric properties, band structure and reactive oxygen species. This work could promote the application of PCN subclass MOFs based superwetting membrane as a recyclable platform for complex waste-water treatment.

Automated summary

A novel PCN-222 metal-organic framework-based membrane was developed for oil-water separation, photo-Fenton degradation, and bacteria inactivation. The membrane showed excellent separation efficiency for nanoscale to microscale emulsified oils in water and also exhibited high degradation capacity for aromatic contaminants and inactivation activity for bacteria under visible light. The incorporation of Fe(III) in the membrane improved the separation of photo-generated charge carriers and promoted the Fenton-like catalytic reaction. This work has the potential to advance the application of PCN subclass MOFs as recyclable platforms for complex wastewater treatment.