Degradation of Orange IV dye solution catalyzed by Fe³⁺/Cu²⁺ loaded resin in the presence of H₂O₂

A new heterogeneous catalyst, Fe³⁺/Cu²⁺/R where Fe³⁺ and Cu²⁺ were exchanged into cationic exchange resin D001 (R), was prepared which had a better catalytic reactivity to decompose H₂O₂ than Fe³⁺/ R. The removal rate of Orange IV increased 10% with this catalyst compared with Fe³⁺/R. The effect of the initial concentration of H₂O₂, the initial dye concentration, the catalyst dosage, the initial pH and temperature on the reaction rate constant was also studied. The reaction follows pseudo-first-order kinetics. The activation energy for Fe³⁺/Cu²⁺/R catalyzed oxidation of the dye was determined to be 10.71 kJ·mol^-1. Repeated use of catalyst did not decrease the removal rate of Orange IV. EPR (electron paramagnetic resonance) showed that the addition of Cu²⁺ into the catalyst of Fe³⁺/R could effectively enhance the formation of OH. XPS (X-ray photoelectron spectroscopy) measurements showed that a ferryl species was formed during the reaction. So the reactive intermediates for this reaction were both OH· and ferryl species.