Engineered FeVO4/CeO2 nanocomposite as a two-way superior electro-Fenton catalyst for model and real wastewater treatment

Abstract

FeVO₄/CeO₂ was applied in the electro-Fenton (EF) degradation of Methyl Orange (MO) as a model of wastewater pollution. The results of the characterization techniques indicate that FeVO₄ with triclinic structure and face-centered cubic fluorite CeO₂ maintained their structures during the nanocomposite synthesis. The effect of applied current intensity, initial pollutant concentration, initial pH, and catalyst weight was investigated. The MO removal reached 96.31% and chemical oxygen demand (COD) removal 70% for 60 min of the reaction. The presence of CeO₂ in the nanocomposite plays a key role in H₂O₂ electro-generation as a significant factor in the electro-Fenton (EF) system. The metal leaching from FeVO₄/CeO₂ was negligible (cerium 4.1%, iron 4.3%, and vanadium 1.7%), which indicates that the active species in the nanocomposite are strongly interacting with each other and are stable. The performance of the nanocatalyst in real wastewaters, salty, and binary systems was acceptable and the pollutions were removed efficiently. The synergistic effect between V, Fe, and Ce could be account as the reason for the respectable function of FeVO₄/CeO₂. The electron transfer proceeds via Haber-Weiss mechanism. A degradation pathway was proposed through by-products analysis using gas chromatography-mass spectrometry (GC-MS) technique. The pseudo-first-order kinetic model described the obtained experimental results (R² = 0.9906). The electro-Fenton system efficiency was improved by adding persulfate. The nanocomposite preserved almost its efficiency after six cycles. The obtained results demonstrate that the synergistic catalyst (FeVO₄/CeO₂) has the capability to introduce as a promising replacement of conventional catalysts in the electro-Fenton processes with brilliant proficiency.

Keywords: Electro-Fenton; FeVO(4); Methyl Orange; Persulfate; Synergistic effect.