Preparation of Ferric Oxide/Titanium Silicalite Catalyst for Synergistic Adsorption-Persulfate Oxidation Degradation of Tetracycline Hydrochloride

The development of a sustainable and highly efficient catalyst for advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) activation shows great potential for effectively degrading organic pollutants. This study focused on the development of a ferric oxide/titanium silicalite (Fe₂O₃/TS-1) to activate PMS to degrade tetracycline hydrochloride (TC). The optimized 14% Fe₂O₃/TS-1 achieves the TC removal efficiency of 99.2% within 1 h. It mainly results from the adsorption-degradation synergy of Fe₂O₃/TS-1, where TS-1 has a strong adsorption ability for TC and Fe₂O₃ provides an abundance of active sites for the generation of free radicals by activating PMS. These techniques indicate the involvement of both radical species (SO₄^⋅−, ⋅OH and O₂^⋅−) and non-radical species (¹O₂) in the process. Notably, O₂^⋅− emerged as a pivotal player in the degradation of TC. The effect of coexisting anions (Cl⁻, NO₃⁻, SO₄²⁻ and HCO₃⁻) confirms that Fe₂O₃/TS-1 is still effective in complex water. Three degradation pathways are confirmed by liquid chromatography-mass spectrometry (LC–MS). Recycling experiments and toxicity evaluation experiments show that the Fe₂O₃/TS-1 composite catalyst is stable and efficient, and the leaching concentration of iron is much lower than that in the normal range. This study shows the application prospect of the Fe₂O₃/TS-1 + PMS system in the degradation of refractory organic pollutants.

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