A New Approach to Wastewater Remediation Based on Bifunctional Electrodes

• Published in: Environmental science & technology Vol. 43; no. 13; pp. 5100 - 5105
• Main Authors: Asmussen, Robert Matthew, Tian, Min, Chen, Aicheng
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2009
• Subjects: Applied sciences; Catalysis; Electrochemistry - methods; Electrodes; Exact sciences and technology; Microscopy, Electron, Scanning - methods; Nitrophenols - chemistry; Photochemistry - methods; Platinum - chemistry; Pollution; Remediation and Control Technologies; Time Factors; Titanium - chemistry; Waste Disposal, Fluid - methods; Water Pollutants - analysis; Water Purification - methods; Scanning electron microscopy; Pollutant behavior; Thermal decomposition; Waste treatment; Dispersive spectrometry; Modeling; Waste water; Electrocatalysis; Decontamination; Oxidation; Kinetics; Titanium oxide; Electrochemical reaction; Photooxidation; Catalyst; Photochemical degradation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es900582m

Here we report on a novel approach, the marriage of photocatalytic degradation and electrochemical oxidation, to wastewater remediation based on the use of bifunctional electrodes. To illustrate this innovative technique, TiO2/Ti/Ta2O5−IrO2 bifunctional electrodes were prepared using a facile thermal decomposition technique and employed in this study. The TiO2 photocatalyst was coated on one side of the Ti substrate, while the Ta2O5−IrO2 electrocatalytic thin film was coated on the other side. The fabricated bifunctional electrodes were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The performance of the bifunctional electrodes was tested using both 4-nitrophenol (4-NPh) and 2-nitrophenol (2-NPh) as model pollutants. Our study demonstrates that the prepared bifunctional electrodes exhibit high efficiency for both 4-NPh and 2-NPh degradation. In the degradation of 4-NPh a rate constant of 1.06 × 10−2min−1 was created and a rate constant of 1.93 × 10−2 min−1 was produced for 2-NPh by the combination of the photochemical and electrochemical oxidation on the novel bifunctional electrodes, quadruple the rate constant created by the individual photochemical and photoelectrochemical methods. The innovative approach described in this study provides a very promising and energy efficient environmentally friendly technology for water purification and waste effluent treatment.