Homogeneous/heterogeneous metal-catalyzed persulfate oxidation technology for organic pollutants elimination: A review

Metal-based catalysts have shown great effectiveness in the activation of persulfate to degrade refractory organic pollutants in water. Various reactive species are formed during the activation process. This review aims to provide a systematic and critical overview on the advance of metal-based catalysts for persulfate activation in homogeneous and heterogeneous domains, with emphasis on describing the activation mechanisms involved in the system. From monometallic to polymetallic materials, from cocatalysts to metal composites, the oxidation mechanism of the ever-evolving metal-based catalyst species to activate persulfate to eliminate organic pollutants is discussed in depth. In addition, we comprehensively analyzed the effect of multi-system coupling and surface treatment on the enhancement of metal-based catalysts. Finally, critical discussion and possible future outlook on the challenges were also proposed.