Fe-based Fenton-like catalysts for water treatment: Catalytic mechanisms and applications

Fenton reaction is based on the hydroxyl radicals produced by ferrous iron (Fe2+) and hydrogen peroxide (H2O2), which has been extensively studied for the degradation of emerging contaminants in water. To overcome the drawbacks of conventional Fenton reaction, such as working at acidic pH range, yielding iron-containing sludge, Fenton-like reaction has been developed, in which solid catalysts rather than dissolved Fe2+ are used. In this review, the current status of various Fe-based Fenton-like catalysts were systematically summarized, including (1) zero-valent iron (ZVI) and nanoscale zero-valent iron (nZVI); (2) Iron oxides and oxyhydroxides, such as Fe3O4 (magnetite), γ-Fe2O3 (maghemite), α-Fe2O3 (hematite) and α-FeOOH (goethite); (3) Iron disulfide (FeS2), Iron oxychloride (FeOCl). This review mainly focused on the catalytic mechanisms and applications for degradation of emerging contaminants. Firstly, the principle and chemistry of Fenton-like reaction was briefly introduced; then the catalytic mechanisms of the Fe-based catalysts were discussed in detail, including carbon-supported Fe-based catalysts and bimetallic reactive center; thirdly, their applications for the degradation of emerging contaminants in water were summarized, including dyes, phenols, pharmaceutical active compounds, pesticides and other contaminants; finally, the concluding remarks and future perspectives were given. Fenton-like reaction is a promising technology for the removal of toxic organic pollutants from water and wastewater.