TECHNOLOGIES / CHEMICAL OXIDATION / MODIFIED FENTON’S REAGENT
CHEMICAL OXIDATION: MODIFIED FENTON’S REAGENT
ISOTEC’s modified Fenton’s reagent (MFR) is based on the fundamental principles of Fenton’s chemistry. Henry J.H. Fenton was a British chemist who first demonstrated the use of Fenton’s chemistry in 1894 in the laboratory. ISOTEC modified the chemistry mitigating its instability while significantly enhancing safety, the reagent’s distribution in-situ, and its capacity to remediate organic contaminants in soil and groundwater. The process initially generates an abundance of hydroxyl radical (the most powerful oxidant radical species) when the proprietary catalyst reacts with stabilized hydrogen peroxide. In addition to hydroxyl and perhydroxyl radicals generated, additional radical species are propagated, including the reductants superoxide radical and hydroperoxide anion, both of which are also weak nucleophiles.
The co-existing oxidation-reduction radicals generated by the unique circum-neutral pH modified Fenton’s process promote enhanced desorption and degradation of many organic contaminants. The inherent nucleophilic processes generated by MFR allow for degradation of compounds including carbon tetrachloride and chloroform, which are recalcitrant to other oxidizing reagents including traditional Fenton’s reagent.
H2O2 + Fe2+ → OH• + OH– + Fe3+
Where:
H202 = Hydrogen Peroxide OH• = Hydroxyl Radicals
Fe2+= Ferrous Ion. OH- = Hydroxide Ion
Fe3+= Ferric Ion
In addition to the initial reaction that produces hydroxyl radical oxidants, the modified Fenton’s process also produces superoxide radical and hydroperoxide anion reductants through additional chain propagation reactions. The perhydroxyl radical is known to be a weaker reductant compared to superoxide radical and hydroperoxide anions.
H2O2 + OH• → HO2• + H2O
HO2• + O2• – → HO2–
HO2• + O2• – → HO2– + O2
Where:
02•– = Superoxide Radical Anion
HO2– = Hydroperoxide Anion
HO2• = Perhydroxyl Radical
The co-existing oxidation-reduction reactions associated with a modified Fenton’s process promote enhanced desorption and degradation of recalcitrant compounds. These include compounds such as carbon tetrachloride and chloroform, which were previously considered untreatable by Fenton’s chemistry.
WHY USE MODIFIED FENTON’S AGENT?
MFR is a controlled short-lived oxidant that generates significantly more radical species per given volume of reagent to any oxidant currently available to the remediation industry. It has a unique ability to desorb and phase change contaminant mass through both the production of superoxide radicals and the physical perturbation of the treatment zone by the generation of oxygen bubbles. Additionally, the increase in dissolved oxygen can promote subsequent aerobic bioremediation of hydrocarbons after oxidizing conditions cease.
Despite MFR’s limited duration, it is still the industry’s most active oxidant while proprietary stabilization additives allow for optimal distribution. The inherent stability significantly slows down the reaction allowing ISOTEC technicians to safely distribute this powerful remedial product to contaminated aquifers.
COMPARISON WITH OTHER PEROXIDE-BASED TECHNOLOGIES
