User:Steelaway/Electro-Fenton

ElectroFenton Chemistry is a subset of Fenton Chemistry made possible by the development of sophisticated electrochemical cells for the destruction of refractory organics increasingly found in domestic water and wastewater. Many kinds of high concentration complex organic constituents, are not effectively treated by conventional water treatment operations such as coagulation. In particular, such processes are ineffective for removal of total organic carbon (TOC) and chemical oxygen demand (COD). Electro-Fenton is therefore a subset of the so-called Advanced oxidation processes (AOPs) which are increasingly being used to oxidize complex organic constituents found in wastewaters which are difficult to be degraded biologically into simpler end products. Fenton oxidation is particularly attractive because of its simplicity and high efficiency in organic pollutant removal. ElectroFenton relies on the ability to produce the powerful oxidant the hydoxyl radical, second only to fluorine gas in its oxidative potential. In the original Fenton Reagent reaction, highly reactive hydroxyl radicals (.OH) are generated from the reaction between hydrogen peroxide (H2O2) and ferrous ion Fe2+. In the more cost-effective Electro-Fenton process, the hydroxyl radical .OH - reacts with water in an electrochemical cell to form hydrogen peroxide - one of the essential components of the Fenton Reagent.

The ElectroFenton (EF) method also has the advantage of allowing a better control of hydroxyl radical production, since in the EF method, soluble Fe3+ can be cathodically reduced to Fe2+ with E0 = 0.77 V/SHE. To avoid the disadvantages of traditional Fenton, the generation of peroxide and using sacrifical iron anodes, the electro-generated Fe(II) can efficiently react with H2O to prolong the production of the hydroxyl radical.

Fe2+ + H2O   -->    Fe3+  + OH-  +  .OH               (1)

Fe3+ + H2O   -->   Fe2+  +  O.OH + H+                 (2)