Effective degradation of tetracycline by Pd/AG/ITO electrode: Electrode preparation, characterization, kinetics, degradation mechanism and toxicity assessment

Abstract

The presence of antibiotics such as Tetracycline (TC) in the water environment poses new challenges to traditional water treatment technologies. Simple and clean electrocatalytic technology has been widely used in the degradation of antibiotic-based wastewater. In this study, agarose (AG) was loaded onto ITO using an impregnation method, and Pd was deposited onto the AG/ITO electrode by electrodeposition, the Pd/AG/ITO composite electrode was prepared. The electrode was then observed and analyzed using SEM, XRD, FT-IR, and XPS. The optimal conditions for the electrocatalytic reaction were explored as follows: PdCl2 concentration of 0.20 mmol/L, PdCl2 deposition current of 3 mA, deposition time of 10 min, and degradation current of 8 mA. Under these optimal working conditions, the Pd/AG/ITO composite electrode achieved a degradation efficiency of 85.21% within 120 min. Through five replications, the degradation efficiency of the electrodes decreased by less than 3.50%, which indicated its good reusability and stability. Based on the generation of active substances during degradation and the analysis of LC-MS, potential degradation products, and degradation pathways were deduced, and it was proposed that the degradation of TC was completed by a synchronous redox reaction co-led by·OH and H*. Toxicity analysis of TC and its degradation products was performed using ECOSAR software. This study will promise to provide an effective method of degrading TC wastewater.