Fate of inorganic nitrogen species under homogeneous Fenton combined with electro-oxidation/reduction treatments in synthetic solutions and reclaimed municipal wastewater.

The fate of inorganic nitrogen species has been studied for the first time in electro-Fenton (EF) conditions in acid media. A redox cycle is first obtained and validated with a kinetic model in synthetic solution and highlights the removal of nitrite that is quickly oxidized into nitrate while the reduction conditions are sufficient to reduce nitrate into ammonium cation. However, NH ₄ ⁺ and gaseous nitrogen accumulate in such solution. The study in reclaimed municipal wastewater emphasize the removal of NH ₄ ⁺ with formation of chloramines in the presence of initial chloride ions, a species widely present in wastewater effluent. Contrastingly, NO ₃ ^- remain constant all along the electrolysis even after 2.1 Ah L ^-1 . The oxidation conditions were not sufficient to produce perchlorate while chlorate accumulated in solution. Therefore, it limits the use of EF for direct use for drinking water purpose but could be considered as complementary treatment for wastewater reuse applications.
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