Degradation of Orange II by Fe2O3 and CeO2 nanocomposite when assisted by NaHSO3

Fe 2 O 3 @CeO 2 nanocomposites were synthesized by water bath heating method to activate NaHSO 3 for Orange II dye (50 mg L −1 ) degradation, which reached up to 98.2% within 120 min. The Fe 2 O 3 @CeO 2 and NaHSO 3 dosages and the molar ratios of Ce and Fe in Fe 2 O 3 @CeO 2 were investigated to obtain the optimum conditions as follows: 0.02 g Fe 2 O@CeO 2 , 0.1 g NaHSO 3 and the molar ratio of Ce and Fe was 5:2 (designated as Ce-Fe-1, or simply Fe 2 O 3 @CeO 2 ). In addition, Fe 2 O 3 @CeO 2 catalyst displayed superior catalytic performance to those materials that were previously reported, as verified by the good stability (reached 90.9% after three cycles) and high degradation rate of Orange II (98.2%) of the currently developed material. Existence of · SO 4 – and · OH radicals were verified by Electron Spin Resonance Spectroscopy during degradation, and these radicals are proposed to have high degradation efficiency of Orange II. On the basis of the detected radicals, a possible degradation mechanism was proposed to provide more choices for the application of sulfite in advanced oxidation processes (AOPs).