Oxygen vacancy engineered molecular imprinted TiO2 for preferential florfenicol remediation by electro-reductive approach: Enhanced dehalogenation performance and elimination of antibiotic resistance genes

Abstract

To achieve the precision removal of trace florfenicol (FLO) with presence of various high-concentration interferents in water matrices, an oxygen vacancy engineered molecular imprinted TiO2 (MI-TiO2−x) cathode material was customized rationally. Benefiting from the increased recognition and the accelerated interfacial charge transfer contributed by molecular imprinted sites and oxygen vacancy, respectively, MI-TiO2−x deeply dehalogenates 10 mg L−1 FLO via direct electron transfer with the degradation rate constant of 0.021 min−1. Such electrode material outperforms most of the recent electrocatalysts, and show resistance to co-existing interferents (e.g. reduced sulfur species). In an electro-reductive and biological coupling system, MI-TiO2−x removes the antibacterial activity of 2 mg L−1 FLO in swine wastewater and thus eliminates the abundance of FLO resistance genes. This study provides insights into not only rational design of the noble-metal-free electrocatalyst for preferential remediation of low-concentration organic halides, but also the significance of mitigating ecological risk by dehalogenation treatment.