Periodate activation via metals and metal-based complexes: progress in degradation properties and mechanisms

Residuals of refractory organics in water create a deep hazard to the water environment and human health, hence it is urgent to develop efficient approaches to remove refractory organics. Being a novel oxidizer, periodate (PI, IO4-) is considered to be stable and efficient in advanced oxidation processes for degrading refractory organics, such as antibiotics, dyes, pesticides, etc. Since the activity of PI alone is low, it is necessary to activate the PI to form active species in effectively removing organics. The studies of PI activation via monometallic, bimetallic, metal oxides, metal complexes, etc., have obtained more concerns owing to the high efficiency in decomposing organics. However, no reviews related to these studies have been published in recent years. This review summarized the properties and uses of PI, analyzed degradation properties and mechanisms of various metals and metal-based complexes in activating PI to remove refractory organics, and highlighted the limitations of these processes as well as the future research directions.