A CeO2/CuCo2S4 composite for peroxymonosulfate activation to enhance elimination of tetracycline hydrochloride in wastewater

Abstract

In this work, a novel CeO₂/CuCo₂S₄ composite was fabricated by a hydrothermal method and utilized to catalyze peroxymonosulfate (PMS) for tetracycline hydrochloride (TCH) elimination. The results showed that the system with 90 mg L⁻¹ 0.5-CeO₂/CuCo₂S₄ and 0.9 mM PMS could degrade 96.5% of 15 mg L⁻¹ TCH within 120 min at 20 °C. Reactive oxygen species (ROS) capture experiments and electron paramagnetic resonance (EPR) tests showed that the captured ROS, including hydroxyl radicals (˙OH), superoxide anions (O₂˙⁻), singlet oxygen (¹O₂), and sulfate radicals (SO₄˙⁻), were involved in TCH decomposition. The superior catalytic activity of 0.5-CeO₂/CuCo₂S₄ stemmed from two critical factors: (i) the contribution of the Ce and S species to the Co³⁺/Co²⁺ redox cycle and (ii) the synergistic effect of Co³⁺/Co²⁺, Cu²⁺/Cu⁺, and Ce⁴⁺/Ce³⁺ cycles in activating PMS. The recycling experiments demonstrated that the TCH removal efficiency was 89.2% after four consecutive cycles, and the elemental composition and crystal structure of the catalyst remained unchanged, indicating that the 0.5-CeO₂/CuCo₂S₄ composite has good reusability. In summary, the 0.5-CeO₂/CuCo₂S₄ composite exhibits advantages including straightforward preparation, outstanding catalytic activity, and good reusability, making it a promising candidate for water pollution remediation.