Non-selective rapid electro-oxidation of persistent, refractory VOCs in industrial wastewater using a highly catalytic and dimensionally stable Ir–Pd/Ti composite electrode

Wan Cheol Cho, Kyung Min Poo, Hend Omar Mohamed, Tae Nam Kim, Yul Seong Kim, Moon Hyun Hwang, Do Won Jung, Kyu Jung Chae

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

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, Ir–Pt, Ir–Ru, and Ir–Pd. 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/cm2 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/cm2 and 0.05 M, respectively, representing the most cost-effective condition. Four DSAs were examined (Ir/Ti, Ir–Pt/Ti, Ir–Ru/Ti, and Ir–Pd/Ti). The Ir–Pd/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%. Ir–Pd/Ti was the most suitable anode material for VOC treatment because of its unique structure, high wettability, and high surface area.

Original languageEnglish
Pages (from-to)483-490
Number of pages8
JournalChemosphere
Volume206
DOIs
Publication statusPublished - 2018 Sep

Keywords

  • Chloroform
  • Dimensionally stable anode
  • Electro-oxidation
  • Palladium
  • Platinum group metal
  • Volatile organic compounds

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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