Occurrence of Iodophenols in Aquatic Environments and the Deiodination of Organic Iodine with Ferrate(VI)

Abstract

Toxic and odorous iodophenols are commonly identified as disinfection by-products (DBPs) in drinking water. Herein, ng/L levels of iodophenols were identified in river water, wastewater treatment plant effluent, and medical wastewater, with the simultaneous identification of μg/L to mg/L levels of iodide (I–) and total organic iodine (TOI). Oxidation experiment suggested that the I–, TOI, and iodophenols could be oxidized by ferrate [Fe(VI)], and more than 97% of TOI had been transformed into stable and nontoxic IO3 –. Fe(VI) initially cleaved the C–I bond of iodophenols and led to the deiodination of iodophenols. The resulted I– was swiftly oxidized into HOI and IO3 –, with the intermediate phenolic products be further oxidized into lower molecular weight products. The Gibbs free energy change (ΔG) of the overall reaction was negative, indicating that the deiodination of iodophenols by Fe(VI) was spontaneous. In the disinfection of iodine-containing river water, ng/L levels of iodophenols and chloro-iodophenols formed in the reaction with NaClO/NH2Cl, while Fe(VI) preoxidation was effective for inhibiting the formation of iodinated DBPs. Fe(VI) exhibited multiple functions for oxidizing organic iodine, abating their acute toxicity/cytotoxicity and controlling the formation of iodinated DBPs for the treatment of iodide/organic iodine-containing waters.

Removal of 3,4-dichlorophenol from water utilizing ferrate(vi): kinetic and mechanistic investigations and effects of coexisting anions

“…Based on the measuring principle mentioned in SI-Text-4, † kinetic measurements for the reaction between Fe(VI) and organic contaminants were performed under pseudo-order conditions with either Fe(VI) or the organic compound present in large excess. 27,29,30 Initially, Fe(VI) solution at a fixed initial concentration of 25 μM was mixed in a 1 : 1 volume ratio with 3,4-DCP solution at various initial concentrations of 250, 275, 300, 325, 350 μM, respectively, and then the kinetic measurements were carried out by monitoring the concentration of Fe(VI) as a function of time. Fig.…”

Oxidation of Pharmaceuticals by Ferrate(VI)–Amino Acid Systems: Enhancement by Proline

“…Fe­(VI) performs multimodal actions in water purification, including disinfection, coagulation, and oxidation. ,− Its inactivation of bacteria and viruses in water, wastewater, and hospital surfaces has been demonstrated. − The importance of Fe­(VI) oxidation in decreasing levels of disinfection byproducts in subsequent chlorination has been suggested. − Significantly, the removal of lead, arsenic, cadmium, nickel, and phosphate using Fe­(VI) has been shown. − Most of the studies on Fe­(VI) have been conducted on the oxidation of different pollutants, which included cyanides, thiocyanate, hydrogen sulfide, thiols, pesticides, phenols, anilines, sulfonamides, and tetracyclines. ,− In the past few years, the focus has been on the oxidation of pharmaceuticals and personal care products by Fe­(VI). Some of the pharmaceuticals showed sluggish reactivity with Fe­(VI) that resulted in a decreased removal efficiency with a low oxidation capacity. , Researchers thus have examined various activators to increase the removal efficiency of pharmaceuticals .…”

Influence of Humic Acids on the Removal of Arsenic and Antimony by Potassium Ferrate

“…Natural organic matters (NOMs) exist in most natural waters and most of them are highly sensitive to iron oxides [31]. Additionally, the existence of these dissolved organics would also react with/influence many target pollutants during the treatment by ferrate, such as iodide and total iodine [32], bisphenol A & F, acetaminophen, and 4-tertbutylphenol [33]. Previous studies have demonstrated that NOMs directly impact on the transformation of iron minerals [34].…”