Efficient removal of tetracycline hydrochloride over a Co-doped metal–organic framework MIL-125(Ti) derivate via Fenton-like catalysis

Abstract

Recently, metal–organic framework (MOF)/peroxymonosulfate (PMS) systems have shown great potential in the treatment of antibiotic-containing wastewater. Herein, a Co–Ti-400 Fenton-like catalyst was synthesized by calcining Co-doped MIL-125(Ti) (Co–Ti) at 400 °C. Co–Ti-400 revealed an excellent catalytic performance for tetracycline hydrochloride (TCH) removal by activating PMS in a wide pH range (pH = 2–11). Significantly, 96.2% of TCH was removed in 1 hour over the catalyst (70 mg L⁻¹ of TCH, 0.2 g L⁻¹ of catalyst, 1 mM PMS, and pH = 4). Furthermore, Co–Ti-400 exhibited enhanced catalytic activity and stability in four cycles compared to the uncalcined sample (Co–Ti). Radicals (·OH, O₂˙⁻, and SO₄˙⁻) and ¹O₂ were proved to be the main active species during TCH degradation. Notably, Co–Ti-400/PMS showed good anti-interference towards inorganic salts in water. A reasonable degradation mechanism was proposed based on LC-MS analysis. With its exceptional catalytic performance and broad pH adaptability, Co–Ti-400 can be considered a potential catalyst for antibiotic removal.