Carbonate-radical-anions, and not hydroxyl radicals, are the products of the Fenton reaction in neutral solutions containing bicarbonate

Erzsébet Illés; Amir Mizrahi; Vered Marks; Dan Meyerstein

doi:10.1016/j.freeradbiomed.2018.11.015

Carbonate-radical-anions, and not hydroxyl radicals, are the products of the Fenton reaction in neutral solutions containing bicarbonate

Free Radic Biol Med. 2019 Feb 1:131:1-6. doi: 10.1016/j.freeradbiomed.2018.11.015. Epub 2018 Nov 17.

Authors

Erzsébet Illés¹, Amir Mizrahi², Vered Marks³, Dan Meyerstein⁴

Affiliations

¹ Department of Chemical Sciences, and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel; Radiation Chemistry Department, Institute for Energy Security and Environmental Safety, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary.
² Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel.
³ Department of Chemical Sciences, and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel.
⁴ Department of Chemical Sciences, and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel; Chemistry Department, Ben-Gurion University, Beer-Sheva, Israel. Electronic address: danm@ariel.ac.il.

PMID: 30458276
DOI: 10.1016/j.freeradbiomed.2018.11.015

Abstract

The Fenton reaction, Fe(H₂O)₆²⁺ + H₂O₂ → Oxidizing product, is of major importance in biology as the major cause of oxidative stress, and in advanced oxidation processes. It is commonly assumed that ·OH is the product of the Fenton reaction. The results presented herein point out that ·OH is indeed the oxidizing product in acidic solutions for [Fe(H₂O)₆²⁺] > [H₂O₂]; Fe^IV_aq is the active oxidizing product in neutral solutions; in slightly acidic solutions for [H₂O₂] > [Fe(H₂O)₆²⁺] a mixture of ·OH and Fe^IV_aq is formed. However CO₃·^- is the active oxidizing product in neutral solutions containing HCO₃^- even at low concentrations, i.e. under physiological conditions. The implications to our understanding of the origins of oxidative stress and of catalytic oxidations in advanced oxidation processes are discussed.

Keywords: Bicarbonate; Carbonate-radical-anion; Fenton reaction; Iron; Radicals.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbonates / chemistry*
Catalysis
Hydrogen Peroxide / chemistry*
Hydrogen-Ion Concentration
Hydroxyl Radical / chemistry
Iron / chemistry*
Kinetics
Magnetic Resonance Spectroscopy
Oxidation-Reduction
Solutions

Substances

Carbonates
Fenton's reagent
Solutions
Hydroxyl Radical
Hydrogen Peroxide
Iron