CHEMICAL TREATMENT OF WATER CONTAMINATED WITH METHYL PARATHION BY FENTON OXIDATION REACTION

Abstract

In this study, we evaluated the efficiency of the dark Fenton reaction to treat agricultural effluents contaminated with the pesticide methyl parathion. For this purpose, different concentrations of H2O2 and Fe2+were tested. The experiments were carried out in batches and consisted of four treatments, each with a different pesticide: H2O2: Fe2+ ratio (1:4:0.1, 1:4:1, 1:4:10, 1:0.4:1). The chemical oxygen demand (COD), determined by the closed reflux colorimetric method, was monitored with time to assess the degree of oxidation achieved. The residual H2O2 was measured by the colorimetric method using ammonium metavandate catalyst. Finally, the removal of the active ingredient was evaluated by analysis of the molecule with a gas chromatograph Clarus 500 (Perkin Elmer) equipped with both an electron capture detector and a flame ionization detector (GC-ECD/FID). It was found that the reagents proportion of 1:4:1 (pesticide: H2O2: Fe +2) led to a high COD removal from the effluent. Methyl parathion was rapidly degraded within 10 min via the Fenton reaction. Removal of the active ingredient (ai) was almost complete (>98%) and the COD removal obtained after treating an aqueous solution of the commercial product (1000 mg COD / L and 2100 mg ai / L) was superior to 90%.

Keywords: Fenton, Methyl Parathion, Pesticide, Wastewater.