Abstract

The degradation of olive mill wastewater (OMW) with hydroxyl radicals generated from zero-valent iron and hydrogen peroxide has been investigated by means of chemical oxygen demand (COD) and phenolic compounds analyses. The mechanism uses zero-valent iron activated by oxygen at room temperature to generate Hydroxyl-free radicals that subsequently oxidize organic constituents and clean wastewater. The effects of the iron mass, the pH and the organic matter concentration have been studied. Our experimental results demonstrate that the continuous presence of oxygen and iron in an acidic solution with a pH 2-4 allows the generation of maximum hydroxyl free radicals. The lack of oxygen prevents oxidative reaction, and then the generation of free radicals cannot occur. Coloration of OMW disappeared and phenolic compound decreased after 40 minutes of reaction time. The results show that Fe⁰/H⁺ /air or oxygen, could be considered as an effective alternative solution for the treatment of OMW.

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