Recyclable ferroferric oxide@titanium dioxide@molybdenum disulfide with enhanced enzyme-like activity under visible light for effectively inhibiting the growth of drug-resistant bacteria in sewage

Abstract

With the development of social industry and the increase in domestic sewage discharge, pathogenic bacterial contamination in water has become a serious health and environmental problem. It is important to design sewage treatment reagents with effective pathogenic bacterial removal and recyclability. In this work, we developed a nanocomposite, Fe₃O₄@TiO₂@MoS₂, with once-for-all effects of photocatalytic, magnetic, and peroxidase-like activities for solving the above-mentioned problems. The loading of MoS₂ may cause the band gap of Fe₃O₄@TiO₂ to decrease from 3.11 eV to 2.85 eV, demonstrating increased photocatalytic activity under visible light, based on the synergistic impact of Fe₃O₄@TiO₂ and MoS₂. In return, the peroxidase-like activity of Fe₃O₄@TiO₂@MoS₂ was significantly higher than that of Fe₃O₄ and MoS₂ alone, resulting in the generation of more hydroxyl radicals (˙OH) for combating the drug-resistant broad-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus. The antibacterial mechanism study showed that Fe₃O₄@TiO₂@MoS₂ could effectively inhibit bacterial growth by destroying the bacterial biofilm and genome via the peroxidase-like activity as well as photocatalytic activity. In addition, Fe₃O₄@TiO₂@MoS₂ has excellent paramagnetic properties, which can achieve magnetic recovery after wastewater treatment. Even after three times of recycling, its antibacterial effect can remain above 98.8%.