Advanced electrooxidation of florfenicol using 3D printed Nb2O5/Ti electrodes: Degradation efficiency, dehalogenation performance, and toxicity reduction

In this study, a novel 3D printed (3DP) Nb2O5/Ti electrode with a three-dimensional pore structure was prepared using selective laser melting (SLM) 3DP technology. The electrode exhibited high degradation efficiency, low energy consumption (16.02 Wh/L for 90% removal of 5 mg/L of Florfenicol (FLO)), and promising lifetime. Specifically, the 3DP 3% Nb2O5/Ti electrode maintained a 97.0% degradation efficiency for FLO within 120 min when consecutively used for 20 cycles. It was proposed that the Nb2O5 served as an n-type dopant for Ti (IV), creating an electronegative surface environment that leads to stronger binding of electrons from H2O or FLO to the electrode surface. Consequently, the 3D-printed Nb2O5/Ti electrode exhibits higher OER potential and a greater yield of reactive oxygen species (ROSs) compared to the undoped Ti electrode. The electrode also achieved an 82.5% defluorination ratio for FLO, which is the best dehalogenation yield reported so far. Additionally, the toxicity of intermediates was significantly reduced after electrooxidation treatment, and 11 degradation products were identified by UPLC-MS/MS for potential degradation pathways identification. This study suggests that the 3D printed Nb2O5/Ti electrode holds great promise in remediating pharmaceuticals and personal care products (PPCPs)-contaminated water, and that SLM 3D printing technology is a beneficial method for producing Ti-stabilized anodes.