Rapid Ferric Transformation by Reductive Dissolution of Schwertmannite for Highly Efficient Catalytic Degradation of Rhodamine B

In this study, reductive dissolution of iron oxides was considered for the acceleration of the transformation from Fe(III) to Fe(II) to improve the degradation of rhodamine B (RhB) by potassium persulfate (PS) activation on schwertmannite. The addition of hydroxylamine (HA) showed an enhancement effect on the degradation at pH 3 and 5, but insignificant efficiency of the addition was obtained at pH 9. The surface reduction from Fe(III)-OH to Fe(II)-OH by HA was considered dominant for the acceleration of PS activation through the reductive dissolution process, and the hydroxyl and sulfate radicals generated by the decomposition of surface complexes were main primary reactive oxidants that contributed to the degradation of RhB.