Degradation of tartrazine by peroxymonosulfate through magnetic Fe2O3/Mn2O3 composites activation

In this study, Fe₂O₃/Mn₂O₃ composite was synthesized by a facile two-step technique, and several methods were carried out to characterize it. Then, the decomposition experiments of tartrazine (TTZ), a kind of refractory organic pollutant, were conducted under various environmental condition to detect the catalyst performance, such as reaction system, the dosage of catalyst, peroxymonosulfate (PMS) concentration, initial pH, different natural water substances. The results exhibited that Fe₂O₃/Mn₂O₃ composite with the mole rate 2:3 had the best PMS activation performance and the removal efficiency was 97.3% within 30 min. Besides, the optimum degradation conditions of TTZ were also discussed, that is catalyst dosage (0.6 g/L), PMS concentration (0.8 g/L) and the initial pH 11. In addition, proved by the natural water substances adding experiments, HPO₄²⁻, HCO₃^‒, NO₃^‒ and NOM (nature organic matter) could slow down the experiments progressing, but Cl^‒ could boost it. Then inhibitor experiments indicated both the HO and SO4^‒ played a vital role in the experiments. Reusability and ions leaching experiments as well as the used catalyst physical characterization images exhibited the excellent stability and cyclicity of the Fe₂O₃/Mn₂O₃ composite. Finally, based on the XPS (X-ray photoelectron spectroscopy) and the experiments results, the possible mechanism of TTZ degradation was proposed. This system might provide a novel thought for the decomposition of refractory organic pollutant and had potential in promotion of actual sewage treatment technology.