Sonoelectrochemical oxidation of sulfamethoxazole in simulated and actual wastewater on a piezo-polarizable FTO/BaZr(x)Ti((1−x))O(3) electrode: reaction kinetics, mechanism and reaction pathway studies

The sonoelectrochemical (SEC) oxidation of sulfamethoxazole (SMX) in simulated and actual wastewater on FTO/BaZr((0.1))Ti((0.9))O(3), FTO/BaZr((0.05))Ti((0.95))O(3) and FTO/BaTiO(3) electrodes is hereby presented. Electrodes from piezo-polarizable BaZr((0.1))Ti((0.9))O(3), BaZr((0.05))Ti((0.95))O(3), and BaTiO(3) materials were prepared by immobilizing these materials on fluorine-doped tin dioxide (FTO) glass. Electrochemical characterization performed on the electrodes using chronoamperometry and electrochemical impedance spectroscopy techniques revealed that the FTO/BaZr((0.1))Ti((0.9))O(3) anode displayed the highest sonocurrent density response of 2.33 mA cm(−2) and the lowest charge transfer resistance of 57 Ω. Compared to other electrodes, these responses signaled a superior mass transfer on the FTO/BaZr((0.1))Ti((0.9))O(3) anode occasioned by an acoustic streaming effect. Moreover, a degradation efficiency of 86.16% (in simulated wastewater), and total organic carbon (TOC) removal efficiency of 63.16% (in simulated wastewater) and 41.47% (in actual wastewater) were obtained upon applying the FTO/BaZr((0.1))Ti((0.9))O(3) electrode for SEC oxidation of SMX. The piezo-polarizable impact of the FTO/BaZr((0.1))Ti((0.9))O(3) electrode was further established by the higher rate constant obtained for the FTO/BaZr((0.1))Ti((0.9))O(3) electrode as compared to the other electrodes during SEC oxidation of SMX under optimum operational conditions. The piezo-potential effect displayed by the FTO/BaZr((0.1))Ti((0.9))O(3) electrode can be said to have impacted the generation of reactive species, with hydroxyl radicals playing a predominant role in the degradation of SMX in the SEC system. Additionally, a positive synergistic index obtained for the electrode revealed that the piezo-polarization effect of the FTO/BaZr((0.1))Ti((0.9))O(3) electrode activated during sonocatalysis combined with the electrochemical oxidation process during SEC oxidation can be advantageous for the decomposition of pharmaceuticals and other organic pollutants in water.