UV/Periodate Advanced Oxidation Process: Fundamentals and Applications

Ozone- and Hydroxyl Radical-Induced Degradation of Micropollutants in a Novel UVA-LED-Activated Periodate Advanced Oxidation Process

“…As shown in Figure a and Figure S3a, the addition of 100 mM MeOH nearly completely (>90%) inhibited the degradation of NPX by the UVA-LED/PI AOP, indicating that IO 3 • played a minor role therein. Similarly, IO 4 • was unlikely to contribute to NPX degradation due to its widely accepted low reactivities toward organic compounds. , In addition to IO 3 • and IO 4 • , RIS such as hypoiodous acid (HOI) and iodine (I 2 ) have also been reported in PI-based AOPs, and they may participate in the NPX degradation process. Phenol was used as a scavenger for HOI and I 2 , and formation of iodo-phenols during transformation of phenol by the UVA-LED/PI AOP was detected but below the detection limit (0.02 μM for both of p -iodophenol and o -iodophenol).…”

“…Hence, specific efforts have been made to enhance PI oxidation ability. Recent studies showed that PI could be effectively activated by light, − metal-involved catalysts, − carbon materials, − sonochemical process, , H 2 O 2 , , and etc. ,,, for the efficient removal of micropollutants in an aqueous environment by generating reactive iodine species (RIS) and/or reactive oxygen species (ROS). PI-based advanced oxidation processes (PI-AOPs) have thus emerged as promising water treatment processes.…”

“…Currently, a mercury-vapor ultraviolet (UV) lamp with irradiation wavelength in the UVC range (190–280 nm) has been the most frequently studied light source for PI activation (i.e., UV/PI AOP). ,,,− Although most of the studies ascribed the degradation of organic compounds to the contributions of RIS (e.g., IO 3 • and/or IO 4 • ) ,, and/or ROS (e.g., O( 3 P), O 2 •– , and • OH) ,,, by UV decomposition of PI (e.g., eqs –), there is no unanimity on the main driving species therein, indicating the sensitivity of the UV/PI AOP to experimental conditions (e.g., the irradiation wavelength and pH). IO 4 − → h ν IO 3 • + O • − IO 4 − → h ν IO 3 − + O ( 3 P ) IO 4 − → h ν IO 4 • + e − …”

“…PI-based advanced oxidation processes (PI-AOPs) have thus emerged as promising water treatment processes. Particularly, light-assisted PI-AOPs stood out among those activation approaches, as they required no additional chemicals and enabled easy upgrading of the existing treatment trains. , …”

“…• was unlikely to contribute to NPX degradation due to its widely accepted low reactivities toward organic compounds. 2,27 In addition to IO 3…”