Oxidation kinetics of degradation of 1,4-dioxane in aqueous solution by H₂O₂/Fe(II) system

Abstract

Kinetic studies of oxidative degradation of 1,4-dioxane present in aqueous solutions in the concentration range between 2.27 × 10⁻³ mol/L (200 ppm) and 5.68 × 10⁻³ mol/L (500 ppm) were conducted in batch rector. This analysis considers the hydroxyl radicals (^·OH) produced by Fenton reagent as the main species responsible for the degradation process. 1,4-dioxane was degraded to the extent of 97 to 99% after 30 min of reaction time. The pH of the reaction medium decreased substantially during the experiment. In all cases, most of 1,4-dixane degradation occurred during the initial 5 min of reaction. A kinetic model is proposed for the oxidation of 1,4-dioxane by Fenton reagent and this model is applied to calculate the kinetic rate constant for the reaction between hydroxyl radicals and 1,4 dioxane. The reaction rate constant for the reaction of 1,4-dioxane with ^·OH radicals was evaluated and the value is 2.25 × 10⁸/M-s.

Keywords:

• Advanced oxidation process
• Fenton's reagent
• hydroxyl radical
• rate constant
• 1,4-dioxane