Stochiometry of Fenton's reagent in the oxidation of chlorinated aliphatic organic pollutants

The stoichiometry of Fenton's reagent in the oxidation of dichloroethylene (DCE), trichloroethylene (TCE), tehrachloroethylene (tetra-CE), and dichloroethane (DCEA) was investigated. The theoretical optimal ratio between H2O2 and Fe2+ is found to be 11. However, the experimentally determined optimal ratio between H2O2 and Fe2+ ranged from 5 to 11 at optimal pH of 3.5. The amount of H2O2, required for a specific percentage removal of the organic compounds depends upon the initial organic concentration to be oxidized. The accumulation of chloride ion released also depends upon the initial organic substance concentrations. The typical percentage removal of organic compounds and percentage release of chloride ion were reported at 100%, 70%, 50%, 40%, 30%, 20%, 10%, and 1%. The amount of H2O2 required to achieve a certain percentage removal follows the order of TCE < Tetra-CE < DCE << DCEA. However, the amount of chloride ion detected at a constant concentration of H2O2, follows the order of DCEA << DCE < TCE < Teha-CE.