Effect of nitrite and nitrate as the source of OH radical in the O₃/UV process with or without benzene

This study suggests the prediction model for the concentration variation of NO_2- and NO_3- along with the rate constants of all reactions during ozonation under UV radiation (O₃/UV process). While NO_2-was completely converted into NO_3-during the O_3-only process, the production of NO₂ radical or N₂O₄ was expected in the O₃/ UV process. In addition, the quenching of OH radicals, by NO₂ radical in the O3/UV process, resulted in regeneration of NO_2- However, the regeneration of NO_2- was not observed in the O₃/UV process in the presence of C₆H₆ where the concentrations of NO_2- and NO_2-were significantly reduced compared to in the process without C₆H₆. The pseudo-first order rate constants of all species were calculated with and without the presence of C₆H₆ to predict the variation of concentrations of all species during the O₃/UV process. It was suggested that NO_2- and NO_2- in the O₃/UV process can be more effectively removed from an aqueous system with an OH radical scavenger such as C₆H₆.