Advanced solar photo-Fenton-like process with directly growing nano-heterojunctions on graphite fiber felt for phenolic wastewater treatment: Synergistically expand the pH activity range and facilitate the Fe(III)/Fe(II) cycle

Abstract

Nanoscale FeWO₄/BiVO₄ heterojunctions were directly grown on the graphite fiber felt (GF) with good conductivity to construct a FeWO₄/BiVO₄ @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 FeWO₄/BiVO₄ heterojunction prepared by hydrothermal method exhibited higher photoelectric conversion efficiency and solar light utilization rate, thus endowing FeWO₄/BiVO₄ with excellent solar-Fenton like reaction activity.The photo-Fenton activity can be maintained well even within the pH range of 2–8. Loading FeWO₄/BiVO₄ nano-heterojunction on GF helped to increase the contact area between Fenton reagents and wastewater, facilitate the electron transfer on the FeWO₄/BiVO₄ heterojunction and enable the recovery and reuse of the Fenton reagents.Under solar light radiation, the COD removal efficiency of FeWO₄/BiVO₄ @GF/H₂O₂ system in phenolic wastewater was more than 92%. Even after five cycles, the system still exhibited excellent operation stability. FeWO₄/BiVO₄@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.