Heterogeneous Fenton catalytic water treatment technology is an effective method for degradation of organic pollutants in water. Compared to the homogeneous Fenton reaction, it has the advantages of recyclability, wide pH response range, easy solid-liquid separation and non-production of iron sludge. This article mainly reviews the classical Fenton reaction mechanism, the heterogeneous Fenton reaction mechanism, and the developed heterogeneous Fenton/Fenton-like catalysts based on the basic mechanism. The bottleneck problems of the present heterogeneous Fenton system, including low activity under neutral condition, poor stability of the catalyst and low utilization efficiency of H₂O₂, are summarized. Particularly, the emphasis is to introduce the developed new type heterogeneous Fenton systems, including the one-center Cu-based Fenton-like system and the dual-center Fenton-like system, for solving the bottleneck problems. We think the dual-center Fenton-like system has actually broke the concept of the classical Fenton reaction, creating the electron-rich centers and electron-deficiency centers based on the polarization theory of electron distribution, which realizes the efficiently selective reduction of hydrogen peroxide and oxidative degradation of pollutants, solving the technical bottleneck problems of the classical Fenton reaction in water treatment.
Contents
1 Introduction
2 Classical Fenton reaction mechanism
3 Heterogeneous Fenton catalytic reaction mechanism
3.1 Heterogeneous Fenton reaction mechanism without considering organic pollutants
3.2 Heterogeneous Fenton reaction mechanism in consideration of organic pollutants
4 Development and utilization of heterogeneous Fenton catalysts
4.1 Zero-valent metal catalyst
4.2 Transition metal oxide catalyst
4.3 Metal species-supported catalysts
4.4 Metal ions-doped catalysts
5 Existing problems of heterogeneous Fenton catalytic system
6 Development of novel heterogeneous Fenton system and its catalytic mechanism for degradation of organic pollutants in water
6.1 One-center heterogeneous Fenton system
6.2 Dual-center heterogeneous Fenton-like system induced by lattice oxygen
6.3 Dual-center heterogeneous Fenton-like system induced by surface organic ligand
7 Conclusion and outlook