Reduction and sorption of chromium by Fe(II)-bearing phyllosilicates: chemical treatments and X-ray absorption spectroscopy (XAS) studies
| Autor: | Maria Franca Brigatti, Ziyu Wu, Gabriele Giuli, Augusto Marcelli, Cristina Lugli, Giannantonio Cibin, Annibale Mottana, Eleonora Paris |
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| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
X-ray absorption spectroscopy
Aqueous solution Extended X-ray absorption fine structure fillosilicati Chemistry XAS Inorganic chemistry adsorbimento Soil Science chemistry.chemical_element Structural formula cromo chemistry.chemical_compound Chromium Montmorillonite Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Hexavalent chromium Chlorite Water Science and Technology |
| Zdroj: | Scopus-Elsevier |
| Popis: | The reduction of hexavalent chromium species in aqueous solutions by interaction with Fe(lI)- bearing solid surfaces was studied using a 0.96 l0 3 M Cr(VI) solution and iron-rich clays with different Fe(lI)/Fe(III) ratios, layer charge, and exchange properties, i.e., chlorite, corrensite, and montmorillonite. Experimental studies demonstrated that Fe(lI)-bearing phyllosilicates reduce aqueous Cr(VI) ions at acidic pH. Chlorite and corrensite, owing to the high Fe(II)/Fe(III) ratio, are electrochemically reactive, as rapid Cr(VI) reduction indicated. In contrast, montmorillonite showed minimum to nil reactivity towards Cr(VI). Furthermore, corrensite, which is high in both Fe(II)~'e(III) ratio and exchange capacity, adsorbs the greatest amount of chromium. X-ray absorption spectroscopy at A1, Mg, Fe, and Cr K-edges was used to investigate the adsorbed chromium species. The montmorillonite sample, unaffected by treatment with Cr(VI) solution, displays no change at any investigated edge. Edge shape and energy also do not change for the Mg and A1 spectra in corrensite, and changes are minor in chlorite. By contrast, the Fe K-edge changes both in chlorite and corrensite, and indicates an increase of Fe(III) in treated samples at the expense of pre-existing Fe(II). Cr K-edge spectra show that chlorite and corrensite sorb Cr(III), which implies its reduction from Cr(VI) in the interacting solution. |
| Databáze: | OpenAIRE |
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