In this work, a series of Fe-based metal-organic frameworks (Fe-MOFs) were synthesized and served as Fenton-like catalysts for tetracycline hydrochloride (TC–HCl) degradation. Herein, for the first time, we have demonstrated that visible light can accelerate Fe(II)/Fe(III) cycle in the photo-Fenton system based on iron-oxo (Fe-O) clusters in frameworks. Among these Fe-MOFs, MIL-101 possessed the highest activity mainly ascribed to its largest specific surface area and pore volume, and the most coordinatively unsaturated iron sites. The synergistic effect in the MIL-101/H 2 O 2 /visible light system was derived from the efficient separation and migration of photogenerated carriers. Due to the function of solid acid catalysts, MIL-101 extended effective pH range up to 10.2 and exhibited good reusability and stability. Hydroxyl radicals generated from H 2 O 2 coordinated at iron active sites were determined as the main reactive oxidative species and acceleration of Fe(II)/Fe(III) cycle was responsible for highly effective degradation of TC–HCl.
Nanoscale FeWO 4 /BiVO 4 heterojunctions were directly grown on the graphite fiber felt (GF) with good conductivity to construct a FeWO 4 /BiVO 4 @GF solar photo-Fenton like wastewater treatment system. The removal effect of COD from phenolic wastewater and the mechanism of synergistic improvement of wastewater treatment efficiency by this system were investigated. The FeWO 4 /BiVO 4 heterojunction prepared by hydrothermal method exhibited higher photoelectric conversion efficiency and solar light utilization rate, thus endowing FeWO 4 /BiVO 4 with excellent solar-Fenton like reaction activity.The photo-Fenton activity can be maintained well even within the pH range of 2–8. Loading FeWO 4 /BiVO 4 nano-heterojunction on GF helped to increase the contact area between Fenton reagents and wastewater, facilitate the electron transfer on the FeWO 4 /BiVO 4 heterojunction and enable the recovery and reuse of the Fenton reagents.Under solar light radiation, the COD removal efficiency of FeWO 4 /BiVO 4 @GF/H 2 O 2 system in phenolic wastewater was more than 92%. Even after five cycles, the system still exhibited excellent operation stability. FeWO 4 /BiVO 4 @GF promoted the conversion and cycling of Fe(III)/Fe(II) by accelerating the separation and transport of photogenerated electrons/holes and increasing the concentration of active species, thereby stimulating excellent solar photo-Fenton like activity.The results are significance to the development of green and efficient photo-Fenton process for advanced treatment of industrial wastewater.