Evaluation of FTO-BaTiO3/NiTiO3 electrode towards sonoelectrochemical degradation of emerging pharmaceutical contaminants in water

Abstract

Water treatment aimed at removing pharmaceutical contaminants in water has gained global attention, arising from the decline in water quality. Sonoelectrochemical (SEC) degradation technique is an emerging method that has shown a good prospect for the removal of these contaminants from water. We hereby report the use of SEC degradation for the mineralization of zidovudine (ZVD) and paracetamol (PCM) in water using fluorine-doped tin oxide-barium titanate/nickel titanate (FTO-BaTiO3/NiTiO3) electrode. The titanate-based (BaTiO3 and NiTiO3) nanoparticles were successfully synthesized and characterized using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectrometer (EDS). The FTO/BaTiO3/NiTiO3 electrode was prepared by drop-casting a slurry of the BaTiO3/NiTiO3 composite on an FTO glass. The electrode was characterized electrochemically with chronoamperometry, linear sweep voltammetry, and electrochemical impedance spectroscopy techniques. At optimum conditions of 2.0 V bias potential, 40 W ultrasound power and 10 mm electrode-probe distance, degradation efficiencies of 68.10% and 57.86% were obtained upon applying FTO/BaTiO3/NiTiO3 electrode for SEC degradation of ZVD and PCM, respectively within 180 min. In addition, 38.35% total organic carbon removal from the bulk solution containing the pharmaceuticals was also obtained. Positive synergistic indexes and energy consumption of 0.247 kWh g-1 of TOC obtained also indicate that combining sonolysis and electrochemical oxidation was beneficial and economical for the performance of SEC degradation for the removal of the targeted pharmaceutical contaminants in water. This work hereby confirms that electrodes prepared from the combination of titanate-based materials can be beneficial for improving the SEC degradation of pharmaceutical and other recalcitrant organic pollutants in water.