Electrochemical reductive degradation of diclofenac using a palladium-modified multi-walled carbon-nanotubes electrode

摘要

Electrochemical reductive degradation of diclofenac in aqueous solution was studied using a palladium-loaded multi-walled carbon nanotubes (Pd/MWCNTs) electrode. The Pd/MWCNTs electrode was characterized using scanning electronic microscopy, X-ray diffraction, and cyclic voltammetry (CV). The Pd/MWCNTs electrode was used as the cathode and a platinum wire was used as the anode for the CV experiment. The various electrolysis parameters that affect the degradation of diclofenac, including feed concentration, applied voltage, pH, supporting electrolyte concentration, and electrolysis time were investigated. The Pd/MWCNTs electrode demonstrated the best performance compared with that of the graphite and MWCNTs electrodes and achieved a removal efficiency of 90.6% after 2 h. The electrochemical reduction degradation followed pseudo-first-order kinetics. Finally, two possible degradation pathways were proposed based on the degradation products identified using high performance liquid chromatography-mass spectrometry (HPLC-MS).