Non-selective rapid electro-oxidation of persistent, refractory VOCs in industrial wastewater using a highly catalytic and dimensionally stable IrPd/Ti composite electrode. (September 2018)

• Record Type: Journal Article
• Authors: Cho, Wan-Cheol; Poo, Kyung-Min; Mohamed, Hend Omar; Kim, Tae-Nam; Kim, Yul-Seong; Hwang, Moon Hyun; Jung, Do-Won; Chae, Kyu-Jung
• Is Part Of: Chemosphere. Volume 206(2018)
• Page Start: 483
• Page End: 490
• Publication Date: 2018-09
• Subjects: Volatile organic compounds -- Electro-oxidation -- Dimensionally stable anode -- Platinum group metal -- Palladium -- Chloroform; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.05.060
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Volatile organic compounds (VOCs) are highly toxic contaminants commonly dissolved in industrial wastewater. Therefore, treatment of VOC-containing wastewater requires a robust and rapid reaction because liquid VOCs can become volatile secondary pollutants. In this study, electro-oxidation with catalytic composite dimensionally stable anodes (DSAs)—a promising process for degrading organic pollutants—was applied to remove various VOCs (chloroform, benzene, toluene, and trichloroethylene). Excellent treatment efficiency of VOCs was demonstrated. To evaluate the VOC removal rate of each DSA, a titanium plate, a frequently used substratum, was coated with four different highly electrocatalytic composite materials (platinum group metals), Ir, IrPt, IrRu, and IrPd. Ir was used as a base catalyst to maintain the electrochemical stability of the anode. Current density and electrolyte concentration were evaluated over various ranges (20–45 mA/cm 2 and 0.01–0.15 mol/L as NaCl, respectively) to determine the optimum operating condition. Results indicated that chloroform was the most refractory VOC tested due to its robust chemical bond strength. Moreover, the optimum current density and electrolyte concentration were 25 mA/cm 2 and 0.05 M, respectively, representing the most cost-effective condition. Four DSAs were examined (Ir/Ti, IrPt/Ti, IrRu/Ti, and IrPd/Ti). The IrPd/Ti anode was the most suitable for treatment of VOCs presenting the highest chloroform removal performance of 78.8%, energy consumption of 0.38 kWh per unit mass (g) of oxidized chloroform, and the least volatilized fraction of 4.4%. IrPd/Ti was the most suitable anode material for VOC treatment because of its unique structure, high wettability, and high surface area. Graphical abstract: Image 1 Highlights: DSAs composite electrodes were investigated for electro-oxidation of VOCs. Both of VOCs' oxidization and volatilization were evaluated to maximum treatment. Energy consumption was calculated as a key-factor for electro-oxidation. IrPd/Ti achieved the highest removal efficiency compared to other electrodes. Current density and electrolyte concentration were adapted for proper operation.