Efficiency of Fenton Oxidation in Reducing High Concentrations of Humic Acid in Aqueous Solutions

Document Type : Research Paper


1 MSc Graduate of Environmental Engineering, Islamic Azad University, Khuzistan Sciences and Research Branch, Ahvaz, Iran

2 Assoc. Prof., Research Center on Environmental Engineering and Faculty of Environmental Health, Isfahan University of Medical Sciences, Isfahan, Iran

3 Assoc. Prof., of Environmental Engineering, Islamic Azad University Tehran Science and Research Branch, Tehran, Iran


Advanced oxidation processes produce hyperactive hydroxyl radicals that have a high potential for the oxidation of organic compounds. One of these processes is the Fenton process in which iron ion as a catalyst reacts with oxidants in an acid environment to generate the hydroxyl radical. This is an oxidation-reduction reaction in which the metal ion transfers an electron. The efficiency of this method is influenced by such different factors as pH, iron and hydrogen peroxide concentrations, initial concentration of the contaminant, and reaction time. This study was conducted to investigate the removal of humic compounds in concentrations above 10 mg/L via an advanced oxidation process with Fenton technology. For this purpose, samples of synthetic humic acids were prepared and the effects of pH, different considerations of ferrous sulfate and peroxide hydrogen, different reaction times on the removal and filterability of humic acids from aqueous solutions were examined. The optimal ratio was determined based on the impact level of hydrogen peroxide to iron ratio. Results showed that the highest removal efficiency of 80% was achieved under the optimal conditions with pH 5, a molar hydrogen peroxide/iron ratio of 3.3:1, an oxidation time of 40 min, an initial concentration of 10 mg/L humic acid, and a UV254 absorbance level of 0.04/cm. In general, the results indicate that the Fenton process is capable of significantly reducing the humic acid present in aqueous environments.


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