Effect of Chloride and Suwannee River Fulvic Acid on Cu Speciation: Implications to Cu Redox Transformations in Simulated Natural Waters
| Autor: | Shikha Garg, Christopher J. Miller, A. Ninh Pham, T. David Waite, Guowei Xing |
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| Rok vydání: | 2020 |
| Předmět: |
media_common.quotation_subject
Kinetics Inorganic chemistry chemistry.chemical_element 010501 environmental sciences 01 natural sciences Chloride Redox chemistry.chemical_compound Rivers medicine Environmental Chemistry Benzopyrans Reactivity (chemistry) Hydrogen peroxide 0105 earth and related environmental sciences media_common Hydrogen Peroxide General Chemistry Copper 6. Clean water Bioavailability Speciation chemistry Oxidation-Reduction medicine.drug |
| Zdroj: | Environmental Science & Technology. 54:2334-2343 |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/acs.est.9b06789 |
| Popis: | Copper is a critical trace nutrient and, at higher concentrations, a toxicant in natural waters, with the relative rates of transformation between the Cu(I) and Cu(II) oxidation states being key to its speciation, bioavailability, and toxicity. While the influence of chloride (Cl-) and natural organic matter on Cu speciation and associated redox transformations has been studied separately, their combined influence on Cu speciation and Cu redox transformations has not been examined. As such, in this study, we investigate the impact of Cl- and Suwannee River fulvic acid (SRFA) on Cu(II) reduction and Cu(I) oxidation kinetics at pH 8.2. SRFA plays a dual role in providing Cu(II) reducing moieties as well as Cu ligating sites. Our results indicate that the SRFA-bound Cu(II) is less reactive than the inorganic Cu(II), and the SRFA-bound Cu(I) being much more rapidly oxidized than the inorganic Cu(I). The presence of Cl- weakens Cu(II) binding by SRFA, thereby increasing the reactivity of Cu(II). Similarly, weakening of Cu(I) binding by SRFA and concomitant binding of Cu(I) by Cl- stabilizes Cu(I). Our results further show that continuous formation of hydrogen peroxide occurs in the presence of Cu(II), SRFA, and Cl- in air-saturated solution with the presence of H2O2 enhancing the dynamic nature of the system. |
| Databáze: | OpenAIRE |
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