The Fenton process was reported by Fenton already over a hundred years ago for maleic acid oxidation:
Fe2+ + H2O2 —->Fe3+ + OH– + .OH
The rate constant for the reaction of ferrous ion with hydrogen peroxide is high and Fe (II) oxidizes to Fe(III) in a few seconds to minutes in the presence of excess amounts of hydrogen peroxide.
It has been demonstrated that Fenton’s reagent is able to destroy different phenols, nitrobenzene, and herbicides in water media as well as to reduce COD in municipal wastewater. The usefulness of the Fe(II)/H2O2 system as a potential oxidant for soil contaminants has also been investigated. It has been shown that PCP and trifluralin are extensively degraded while hexadecane and dieldrin are partially transformed in a soil suspension at acidic pH.
The use of Fe(II)/H2O2 as an oxidant for wastewater treatment is attractive due to the facts that:
- iron is a highly abundant and non-toxic element, and
- hydrogen peroxide is easy to handle and environmentally benign.Thus, the Fenton process is very effective for OH radicals generation; however, it involves consumption of one molecule of Fe2+ for each OH radical produced, demanding a high concentration of Fe(II).