Degradation of Orange II by the Fe0/H2O2 system

Abstract

The degradation of Orange II by the Fe0/H2O2 system was examined. The effects of Orange II concentration, H2O2 concentration, Fe0 dosage, initial solution pH value on the degradation of Orange II were investigated. The experimental results showed that Fe0 was exhibited high catalytic activity on the activation of H2O2 for the degradation of Orange II. The reactive hydroxyl radical (·OH) produced in the Fe0/H2O2 system was significant the key for the degradation of Orange II. The mechanism of the degradation of Orange II was discussed by the UV-Vis spectra analysis and determining intermediate products of the reaction solution by LC-MS. It was speculated that in the process of oxidative degradation, Orange II was first dissociated into 4-(2-hydroxy-1-naphthylazo) benzenesulfonate, and then its azo structure was oxidized and destroyed by hydroxyl radicals (·OH). Secondly, the reaction solution faded to produce benzenesulfonate and 1, 2-naphthoquinone, and then 1, 2-naphthoquinone was further oxidized by ·OH to phthalate. Finally, phthalate and benzenesulfonate could be further mineralized into CO2, H2O and SO4 2-.