The Differences Of Reaction Between Iron And Hydrogen Peroxide

For reactions with a medium, or “one to one”, ratio of iron (II) to hydrogen peroxide, the generation of hydroxyl radicals is also observed. In this particular ratio, the presence of organics does not seem to inhibit the effectiveness of the iron catalyst, as all the iron (II) was converted to iron (III) in a series of experiments. Without the organics present, the hydrogen peroxide reformed by reacting slowly with iron (III) to produce ferric salts, which then degrade into more hydroxyl radicals. The actions of these two iron species, iron (II) and iron (III) can be characterized into two specific systems. The ferrous system refers to the one-step case where the primary, hydroxyl radical producing reaction is the reaction between iron (II) and hydrogen peroxide. The ferric system refers to the two-step case in which iron (III) reacts with hydrogen peroxide at a very slow rate to produce ferric salts, which then …show more content…
The relative degradation of several specific organic pollutants has been studied and revealed some important trends. Firstly, the most susceptible species to hydroxyl radical oxidation were aromatic compounds. This is because of the electron rich environment of the systems allowing for more favored hydrogen abstractions and attaching of hydroxyl groups. As Figures 2 and 3 show, the aromatic contaminants were largely degraded after several hours, while the organic carbon of alicyclic cyclohexanol and cyclohexanone was barely attacked. This is because the pKa for the hydrogens in an alicyclic system is significantly higher than in an aromatic system, which makes them harder to abstract, making the carbons harder to add to. This trend makes Fenton treatment good for targeting waste material and not naturally occurring environmental carbon