Iodate(V) activated ferrate(VI) for enhanced oxidation of micropollutants from water and sediment media

In this study, a new Fe(VI)/I(V) system was developed to efficiently strengthen utilization efficiency of generated Fe(IV)/Fe(V). This system could effectively degrade sulfamethoxazole, carbamazepine, bisphenol A and tetracycline within 4 min with k1 values of 0.60648 min-1, 1.39726 min-1, 0.65921 min-1 and 0.93298 min-1, which were 21-66 times higher than the sum of k1 values of I(V) alone and Fe(VI) alone systems, and also much better than H2O2, peroxydisulfate, and peroxymonosulfate strengthened Fe(VI) systems. In addition, Fe(VI)/I(V) exhibited favorable anti-interference, that high-salinity and high organic showed negligible inhibition on pollutant degradation. More importantly, I(V), as an excellent catalyst, hardly decayed during treatment process, which broadens the application field of Fe(VI)/I(V) in different contaminated environmental media and provides a distinguished efficiency for recycling use in contaminated sediment with only consumed Fe(VI) supplement. Fe (VI) consumption in Fe(VI)/I(V) system was not enhanced compared with Fe(VI) alone system, and thus saving agent costs is another significant advantage of Fe(VI)/I(V) system. Above multiple superiorities are still obvious even compared with the systems of other oxidants enhancing Fe(VI) developed in recent years. The main active species was identified as Fe(IV)/Fe(V). The mechanisms of I(V) strengthening Fe(VI) were determined as Fe(IV)/ Fe(V) oxidation enhancement, rather than Fe(VI) decay enhancement. Utilization efficiency of Fe(IV)/Fe(V) was improved by oxidation reactivity modulation with I(V) complexes formation, thereby strengthening decontamination significantly. This study proposed a strategy for decontamination in different mediums with high treatment efficiency, high selectivity, satisfactory reusability, and low consumption of agents.