Characterization of Natural Enargite/Aqueous Solution Systems by Electrochemical Techniques
| Autor: | S. G. Real, Ricardo Schrebler, Humberto Gómez, Ricardo Córdova, Jorge Roberto Vilche |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Aqueous solution
Passivation Renewable Energy Sustainability and the Environment Chemistry Enargite Inorganic chemistry engineering.material Condensed Matter Physics Electrochemistry Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy Metal visual_art Electrode Materials Chemistry engineering visual_art.visual_art_medium Polarization (electrochemistry) |
| Zdroj: | Journal of The Electrochemical Society. 144:2628-2636 |
| ISSN: | 1945-7111 0013-4651 |
| Popis: | The electrochemical behavior of natural enargite electrodes in stirred and quiescent aqueous solutions covering a wide pH range was investigated using ac and dc electrochemical techniques. It is proposed that in the first stage of enargite oxidation the release of copper ions takes place and a copper‐depleted passivating film is formed on the electrode surface. At more positive potential the film becomes oxidized but depending on solution pH, a secondary passivation can be attained due to the precipitation of cupric arsenate. The electroreduction of enargite or a possible oxidized film formed during the preliminary treatment of the mineral surface initially releases S(II‐) species and generates a surface film containing and . At more negative potentials the electroreduction of to metallic As predominates. A dynamic system analysis carried out at pH 9.2 using electrochemical impedance spectroscopy gave additional information about the processes occurring on the enargite surface under anodic polarization. |
| Databáze: | OpenAIRE |
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