Magnetically induced construction of core–shell architecture Fe3O4@TiO2–Co nanocomposites for effective photocatalytic degradation of tetracycline

Abstract

Owing to the advantages of easy separation and recovery, the development of magnetic photocatalysts is essential to create a viable photocatalytic technology for the degradation of antibiotic contaminants in water. Herein, magnetic Fe₃O₄@TiO₂–Co nanocomposites as a highly recyclable and effective photocatalyst with various Co loading percentages were successfully prepared via a facile route and evaluated for the photodegradation of model tetracycline (TC) antibiotics. As a result, the optimal Fe₃O₄@TiO₂–Co-2.7 sample possesses a removal rate of 92.4% for TC degradation, which is 3.2 fold and 1.6 fold higher than those of single Fe₃O₄ (28.8%) and Fe₃O₄@TiO₂ (58.7%), respectively. The enhanced photocatalytic activity is mainly attributed to the advantages of integrating magnetic Fe₃O₄ nanospheres and metal Co nanoparticles, resulting in the overall magnetic composites of Fe₃O₄@TiO₂–Co having an ameliorative light collection ability, energy-saving recycling process, excellent photocatalytic activity, and high chemical and environmental stability. Satisfactorily, the Fe₃O₄@TiO₂–Co photocatalyst could be easily recovered from the reaction solution by an applied magnetic field, and its photocatalytic activity shows almost no loss after five cycles of repetitive use. Moreover, the intermediates in the degradation pathway were identified via high-performance liquid chromatography–mass spectrometry (HPLC-MS) and the TC degradation pathway in the photocatalytic reaction of the as-designed system was proposed. The present work was successfully applied for the purification of tetracycline antibiotics in water pollutants, demonstrating a promising prospect for application to other pollutant degradation systems.