Peroxymonosulfate Activation by CoFe₂O₄/MgAl-LDH Catalyst for the Boosted Degradation of Antibiotic

Owing to outstanding hydrophilicity and ionic interaction, layered double hydroxides (LDHs) have emerged as a promising carrier for high performance catalysts.However, the synthesis of new specialized catalytic LDHs for degradation of antibiotics still faces some challenges.In this study, a CoFe 2 O 4 /MgAl-LDH composite catalyst was synthesized using a hydrothermal coprecipitation method.Comprehensive characterization reveals that the surface of MgAl-LDH is covered with nanometer CoFe 2 O 4 particles.The specific surface area of CoFe 2 O 4 /MgAl-LDH is 82.84 m 2 g -1 , which is 2.34 times that of CoFe 2 O 4 .CoFe 2 O 4 /MgAl-LDH has a saturation magnetic strength of 22.24 Am 2 kg -1 facilitating efficient solid-liquid separation.The composite catalyst was employed to activate peroxymonosulfate (PMS) for the efficient degradation of tetracycline hydrochloride (TCH).It is found that the catalytic performance of CoFe 2 O 4 /MgAl-LDH significantly exceeds that of CoFe 2 O 4 .The maximum TCH removal reaches 98.2% under the optimal conditions ([TCH] = 25 mg/L, [PMS] = 1.5 mmol/L, CoFe 2 O 4 /MgAl-LDH = 0.20 g/L, pH 7, and T = 25 ).Coexisting ions in the solution, such as SO 4 2-, Cl-, H 2 PO 4 -, and CO 3 2-, have a negligible effect on catalytic performance.Cyclic tests demonstrate that the catalytic performance of CoFe 2 O 4 /MgAl-LDH remains 67.2% after five cycles.Mechanism investigations suggest that O 2 -and 1 O 2 produced by CoFe 2 O 4 /MgAl-LDH play a critical role in the catalytic degradation.