Electrochemical degradation of metronidazole-containing wastewater using Ni-foam as an electrode

Abstract

This study uses commercially available Ni-foam (NiF) as an anode for the electrochemical degradation of metronidazole (MNZ) in the aqueous phase. The electrode was characterized by Scanning electron microscopy to analyze the 3D layered crisscross network structure of NiF, which facilitates an electrochemical activity for MNZ degradation. Crystalline phases were analyzed by XRD, and metal oxidation states were analyzed by XPS for the characterization of NiF. Electrochemical oxidation tests were performed using NiF electrodes for the degradation of MNZ in the aqueous phase. Various experiments were conducted to study the effect of process parameters, such as current density, initial concentration of MNZ, solution pH, etc., on MNZ degradation. Cyclic voltammetry study confirmed that Ni present in NiF favored through electrochemical oxidation of MNZ at potential; Experimental data exhibit that a higher removal rate of MNZ was attained under the optimized condition (initial concentration: 100 ppm; pH: 5; current density: 40 mA/cm2) in the 180 min electrolysis time and ICE was 23 % initially and then decreased with time. The stability of NiF as an electrode was accessed through an accelerated service lifetime test and repeated cyclic test of the used electrode after regeneration, indicating the NiF can be used up to 10 cycles without significant loss in removal % efficiency of MNZ.