Production of Reactive Oxygen Species by the Reaction of Periodate and Hydroxylamine for Rapid Removal of Organic Pollutants and Waterborne Bacteria

Abstract

Abstract Periodate (PI, IO4–) can be activated by hydroxylamine (HA), resulting in the rapid removal of organic pollutants within seconds. While the previous studies on PI-based advanced oxidation processes (AOPs) have proposed iodate radical (•IO3) as the major reactive species, no evidence of •IO3 production was found in the present PI/HA system. Reactive oxygen species (ROS) including •OH, HO2•, and 1O2 are proposed to be the main oxidants of the PI/HA system, which is supported by various tests employing the scavengers, chemical probes, and spin-trapping electron paramagnetic resonance (EPR) technique. To minimize the risk of toxic iodinated byproduct formation caused by reactive iodine species such as HOI and I2, the molar ratio of HA/PI was optimized at 0.6 to achieve the stoichiometric conversion of IO4– to iodate (IO3–), a preferred nontoxic sink of iodine species. The PI/HA system also efficiently inactivated both Gram-positive and -negative bacteria with producing 1O2 as the dominant disinfectant. The mechanism of ROS production was also investigated and is discussed in detail. This work offers a simple and highly efficient option for PI activation and ROS production which might find useful applications where urgent and rapid removal of toxic pollutants is needed.