Recent progress on heterogeneous Fe-based materials induced persulfate activation for organics removal

Abstract

Fe-based heterogeneous materials have been the most used transition metal catalysts for advanced oxidation processes (AOPs) due to their versatility, flexibility, high efficiency, and environmental friendliness. Herein, we primarily review the latest progress in various heterogeneous Fe-based catalysts such as single zero-valent iron, monometallic iron (hydr)oxides, bimetallic iron oxides (e.g., ferrospinel, perovskite, layered double (hydr)oxide, and metal–organic frameworks), Fe-based sulfide/carbide/nitride, and other Fe-based materials for peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation. Meanwhile, the hybrid activation systems assisted with light, electric field, ultrasound, microwave, and magnetic field have been made a detailed introduction. In addition to the special attention paid to the activation mechanism, main reactive oxygen species (ROS) existed in the radical (e.g., sulfate radicals (SO4−), hydroxyl radical (HO), and superoxide radical (O2−)) and nonradical (e.g., singlet oxygen (1O2) and high-valent iron-oxo species) activation processes have been summarized. In addition, toxicity evaluation of catalysts and degradation intermediate through two common methods (i.e., predictive models and toxicity tests) were introduced. Finally, we highlight the great potential of PMS/PDS activation using Fe-based heterogeneous materials for organic pollutants removal and put forward the challenges that may be faced in future research and practical applications.