Metal-based activation of periodate as an advanced oxidation process for water decontamination: A critical review

Abstract

Periodate (PI, IO₄⁻)-based advanced oxidation processes (AOPs) have recently received increasing attention in water treatment. The activation of PI to generate different reactive species is crucial for decontaminants in PI-AOPs. This review provides a comprehensive experimental data and analysis information in metal-activated PI processes for the contaminant degradation. Various categories of metals for PI activation, including single metal and bimetals with their activation mechanisms were discussed. Among them, manganese (Mn) and iron (Fe) were the two dominant activators in PI activation. Noble metals including ruthenium (Ru), osmium (Os) and metal-complexes also showed promising prospects in PI activation, which was first noticed in this review. The importance of external and internal metal complexes in metal-activated PI activation was perceived for the first time, especially distinct production pathways of reactive species (i.e high-valent manganese-oxygen species and generated reactive complexes) produced by different metal complex sources. The identification of various reactive species was defined in details. Besides, the potential risks and strategies for iodine-containing disinfection by-products (I-DBPs) reduction were summarized for the first time. Ultimately, the challenges, knowledge gaps and future development are proposed to facilitate the metal-activated PI technology to take a step further for practical application.