Catalytic oxidation of Rhodamine B in aqueous solutions with sulphate radicals over Co3O4/MgO and CoFe2O4/MgO

The oxidative degradation of Rhodamine B (RhB) in aqueous solutions with peroxymonosulphate (PMS) was studied using Co3O4/MgO and CoFe2O4/MgO as catalysts. The as-prepared samples demonstrated strong PMS-activating ability despite low active phase loading percentage (5 wt%) and very low catalysts concentration (0.15 g dm(-3)). The performance of the supported catalysts was found much better than that of their bulk analogues and mechanical mixtures of corresponding bulk oxide and bare MgO due to the crucial role of basic support for facilitating decomposition of PMS into highly reactive radicals. RhB degradation was found to follow the first order kinetics. The effect of catalyst dosage, PMS concentration, and pH on the rate of RhB oxidation was investigated. The radical species generated from the catalytic decomposition of PMS were identified by quenching studies.