Ru and MWCNTs-OH co-modified copper foam as high-performance electrode materials for electrocatalytic degradation of doxycycline

Abstract

In this study, an efficient composite electrode for the degradation of doxycycline (DC), i.e., the ruthenium/hydroxylated multi-walled carbon nanotube/copper foam composite electrode (Ru/MWCNTs-OH/CF), was prepared by the constant current deposition method. The composite electrode was characterized by SEM, XRD and XPS. Impedance testing, polarization curve analysis, and linear voltammetry analysis were conducted on the composite electrode, confirming that the combination of MWCNTs-OH and Ru can reduce the charge transfer resistance of the electrode and significantly improve catalytic activity. Under optimal conditions, the degradation efficiency of the Ru/MWCNTs-OH/CF composite electrode for 10 mg/L DC reached 77.20 % at 60 min. The degradation reaction followed the proposed primary reaction kinetics. The degradation efficiency only decreased by 2.23 % after ten cycles of the experiment, indicating the excellent stability of the electrode. The reaction mechanism was investigated by LSV and quenching experiments. The results showed that DC was degraded under the synergistic action of ·OH, H* and active chlorine species. The degradation path of DC was deduced by LC-MS. The E. coli inhibition experiment and toxicological assessment based on ecological conformational relationships confirmed that the toxicity of the product organisms generated by DC degradation at the Ru/MWCNTs-OH/CF electrode was significantly reduced. The results indicate that the Ru/MWCNTs-OH/CF electrode has high activity and stability and is a promising material for practical applications in the removal of antibiotics from water.