title: Electrochemical decolorization of dye wastewater by surface-activated boron-doped nanocrystalline diamond electrode.
abstract: Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes (EAOPs) to treat it. Surface activation of the electrode used in such treatment is an important factor determining the success of the process. The performance of boron-doped nanocrystalline diamond (BD-NCD) film electrode for decolorization of Acid Yellow (AY-36) azo dye with respect to the surface activation by electrochemical polarization was studied. Anodic polarization found to be more suitable as electrode pretreatment compared to cathodic one. After anodic polarization, the originally H-terminated surface of BD-NCD was changed into O-terminated, making it more hydrophilic. Due to the oxidation of surface functional groups and some portion of sp(2) carbon in the BD-NCD film during anodic polarization, the electrode was successfully being activated showing lower background current, wider potential window and considerably less surface activity compared to the non-polarized one. Consequently, electrooxidation (EO) capability of the anodically-polarized BD-NCD to degrade AY-36 dye was significantly enhanced, capable of nearly total decolorization and chemical oxygen demand (COD) removal even after several times of re-using. The BD-NCD film electrode favored acidic condition for the dye degradation; and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species.
authors.affiliation: Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan, Chinese Taipei; Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan, Chinese Taipei. Electronic address: 7chchen@itri.org.tw.
authors.forename: Chienhung
authors.initials: C
authors.lastname: Chen
authors.affiliation: Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan, Chinese Taipei.
authors.forename: Ervin
authors.initials: E
authors.lastname: Nurhayati
authors.affiliation: Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan, Chinese Taipei. Electronic address: okok830@gmail.com.
authors.forename: Yaju
authors.initials: Y
authors.lastname: Juang
authors.affiliation: Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan, Chinese Taipei. Electronic address: cphuang@mail.nctu.edu.tw.
authors.forename: Chihpin
authors.initials: C
authors.lastname: Huang
mesh_terms: D057919:Biological Oxygen Demand Analysis; D001895:Boron; D004396:Coloring Agents / Q000032:analysis / Q000737:chemistry*; D018130:Diamond; D004563:Electrochemistry; D004566:Electrodes; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D001895:Boron; D004396:Coloring Agents; D018130:Diamond; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Acid Yellow (AY-36); Azo dye; Boron-doped NCD; Electrochemical polarization; Electrooxidation; Surface activation