Iron activated sodium bisulfite enhances generation of Mn (III) species through the MnO2/bisulfite catalytic process

Abstract A series of compound oxides of Fe-MnX (Fe-Mn1, Fe-Mn2, Fe-Mn3, Fe-Mn4) were synthesized and tested in the activation of bisulfite for methylene blue (MB) degradation in aqueous solution under dark condition. X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area were used to characterize the Fe-MnX oxides. Fe-Mn2 could remove about 92% of MB from solution in 70 min, which was much more than the amounts removed by either Fe 2 O 3 or MnO 2 . Mechanism analysis of synergistic effects was validated by simple detection of ionic species such as, Fe (III), Fe (II) and Mn (III) and controlling different variables. After thermal treatment, the current catalysts could be regenerated and recycled for at least three times.