Microwave-assisted synthesis of Cu-doped UiO-66 activated persulfate for tetracycline degradation

To address the limited selectivity and stability of conventional PMS activation systems for antibiotic removal, a Cu-doped UiO-66 catalyst was rapidly synthesized via a microwave-assisted strategy (30 min) for efficient tetracycline (TC) degradation. Under optimal conditions ([TC] = 10 mg L^-1, catalyst = 0.5 g L^-1, PMS = 0.4 g L^-1, pH = 7, 25 °C), more than 95% TC removal was achieved within 80 min (k = 0.0113 min^-1), which was significantly higher than that of pristine UiO-66. The system exhibited broad pH adaptability and retained over 60% degradation efficiency after five reuse cycles, with preserved structural integrity. Quenching experiments and electron paramagnetic resonance identified singlet oxygen (¹O₂) as the dominant oxidant, while O₂•^- and minor radical species contributed secondarily. The enhanced PMS activation originated from the synergistic Cu²⁺/Cu⁺ redox cycle and oxygen vacancies, which facilitated interfacial electron transfer and promoted a ¹O₂-dominated non-radical pathway. LC-MS analysis and phytotoxicity assays further confirmed deep mineralization and significant toxicity reduction. This study provides an efficient and environmentally adaptable strategy for sustainable antibiotic wastewater treatment.