Periodate activation for degradation of organic contaminants: Processes, performance and mechanism

• Processes of activating periodate for water decontamination were summarized. • Principles, main active substances, and influencing factors were discussed. • Advantages and disadvantages of various activation processes were compared. • Challenges and further research directions were predicted. Periodate (IO 4 - ) activation in environmental remediation has aroused tremendous attention, due to its high oxidative potential for the degradation of contaminants and fair stability in the water. In this review, we systematically summarized the periodate-based AOPs, where the activating methods were categorized into three types: (1) homogeneous activation (Mn 2+ /IO 4 - , Fe(II)/IO 4 - , H 2 O 2 /IO 4 - , HA/IO 4 - , UV or ultrasound/IO 4 - ); (2) heterogeneous activation (iron-based materials/IO 4 - , TiO 2 -based materials/IO 4 - , WO 3 /IO 4 - , carbon materials/IO 4 - , zinc-based materials/IO 4 - , and other metal oxides); (3) direct activation (freeze activation, heat activation, alkali activation). This review mainly summarized the effective pH range of the processes, production of reactive species, and degradation performance of target pollutants. Relevant reaction mechanisms were further elaborated, and the main active intermediates in the process of activating periodate as well as the specific paths of their generation were summarized. Finally, the challenges and prospects in the periodate-applied field were discussed. This review comprehensively summarized the processes of activating periodate to degrade pollutants, analyzed the controversy involved in the reaction mechanism, and provided a direction for the future research of periodate.