Influence of acetate on the removal of diesel from contaminated soil using Fenton reaction.

When Fenton reactions are applied to treat contaminated soil, due to initial rapid reactions the hydrogen peroxide (H2O2) gets exhausted too early. This poses practical difficulty in treating contaminated soil using Fenton reactions. In present study acetate was employed as a ligand of Ferrous iron (Fe (II)) to enhance the removal efficiency of diesel by securing the stability of hydrogen peroxide. 0.5-2 times more of acetate was added compared to molar concentration of Fe (II). To eliminate the side effects of removal efficiency low initial concentration of hydrogen peroxide 2% was maintained. From the results it is evident that when more than 8mM of acetate was added the hydroxide life time lasted up to 72 hours which is 12 times more than normal life time. The diesel removal efficiency also improved up to 40% due to stabilized hydroxide conditions. Ferrous ion was oxidized to ferric ion. In the case of general Fenton system, the remained ferrous increased continuously all through the experiment. When more acetate was added the reduction rate of ferric to ferrous also decreased proportionally. Ferrous ion concentrations increased at the point of exhaust of H2O2 which is end point of Fenton reaction. The relative ferric/ferrous variation and reduction of ferric to ferrous ions can be explained by perhydroxyl radical mechanism. The study helps in finding the possibilities to treat contaminated soil by Fenton reactions and its economic feasibility