Electrochemical degradation of metronidazole from aqueous solutions using stainless steel anode coated with SnO2 nanoparticles: experimental design

Abstract

The optimization and modeling of the electrochemical process, which was conducted by using stainless steel electrode coated with SnO2 nanoparticles (nano-SnO2/SS) as anode, in the removal of metronidazole (MNZ) was carried out through the response surface methodology (RSM) involving a five-level central composite design (CCD). The nano-SnO2/SS anode was prepared using electrophoretic deposition (EPD) method. The interaction between four variables i.e. initial pH, current density, reaction time and electrolyte concentration was studied and modeled. The results of optimization showed that maximum MNZ removal efficiency was achieved at the optimum conditions: initial pH 7, current density15 mA/cm2, reaction time 100 min and electrolyte concentration 0.5 g/L. In optimum conditions, MNZ and COD removal efficiency were 85.1% and 34.48%, respectively. In addition, the statistical analysis of the results indicated that in the range studied, electrolyte concentration and pH had a significant effect on MNZ removal efficiency.