ObjectiveThis paper aims to explore the environmental and economic value of reusing industrial waste, particularly using steel industry pickling iron mud as a raw material to prepare efficient catalysts through hydrothermal method for water treatment, especially for removing organic pollutants such as tetracycline hydrochloride (TCH) from water. The goal is to promote resource recycling and reduce environmental pollution.MethodsHydrothermal method was employed to convert pickling iron mud into CoFe₂O₄ composite catalyst, and a composite catalyst/peroxymonosulfate (PMS) advanced oxidation system was constructed. The reaction system was optimized by adjusting pH, catalyst dosages, and PMS dosages. The degradation mechanism was analyzed using free radical trapping experiments.ResultsUnder optimal conditions (pH value was from 3.5 to 10.0, composite catalyst dosage of 0.3 g/L, PMS dosage of 0.6 g/L), the removal rate of TCH reached 80% after 30 minutes of reaction. The CoFe₂O₄ composite catalyst maintained high catalytic activity and stability after multiple uses. Free radical trapping experiments confirmed that ·OH and $S{O}_4^{·-}$ were the main active species responsible for TCH degradation, indicating that the system efficiently degraded pollutants through a free radical oxidation mechanism. This paper successfully achieved the high-value utilization of industrial waste pickling iron mud. The prepared CoFe₂O₄ composite catalyst demonstrated excellent catalytic performance and stability in the advanced oxidation system.ConclusionThis technology not only reduces catalyst preparation costs but also provides a green and sustainable solution for water pollution control, contributing significantly to promoting resource recycling and environmental protection.