Highly efficient removal of Cr(VI) from water with nanoparticulated zerovalent iron: Understanding the Fe(III)–Cr(III) passive outer layer structure
| Autor: | G. Zampieri, V. Nahuel Montesinos, Graciela Custo, Marta I. Litter, Ana G. Leyva, S. Bengió, E. Beatriz Halac, Natalia Quici |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
Passivation XPS ANALYSIS General Chemical Engineering Inorganic chemistry chemistry.chemical_element Industrial and Manufacturing Engineering Chromium symbols.namesake chemistry.chemical_compound X-ray photoelectron spectroscopy Environmental Chemistry Reactivity (chemistry) Hexavalent chromium NANOSCALE ZEROVALENT IRON Zerovalent iron Aqueous solution Otras Ciencias Químicas Ciencias Químicas General Chemistry chemistry RAMAN SPECTROSCOPY symbols HEXAVALENT CHROMIUM Raman spectroscopy CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | Chemical Engineering Journal. 244:569-575 |
| ISSN: | 1385-8947 |
| Popis: | Nanoscale zerovalent iron (nZVI) particles were successfully employed for Cr(VI) removal from aqueous solutions at pH 3. It was found that the capacity of the system increases with increasing nZVI dosage. Starting at 300. μM, a complete Cr(VI) conversion was achieved in 30. min with a Fe:Cr(VI) molar ratio (MR) of 3, and 45% conversion with MR= 1 over the same period of time. The material exhibited an enhanced reactivity in comparison with other previously tested similar materials. The proposed mechanism involves an initial reduction of Cr(VI) to Cr(III) by reaction with Fe0 or Fe(II) on the particle surface or in solution (secondary pathway), followed by an arrest on Cr(VI) removal attributed to the passivation of the surface of the nanoparticles. Passivation was confirmed by Raman and X-ray photoelectron spectroscopies (XPS). Furthermore, XPS analysis demonstrated that Cr(III) is the only Cr species present in the external layer of the nanoparticles after the reaction. Raman analysis and XPS measurements performed after mild sputtering showed that nZVI exposed to Cr(VI) presented a structure, from outside to inside, of hydroxychromites→magnetite→Fe0. © 2014 Elsevier B.V. Fil: Montesinos, Victor Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina Fil: Quici, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina Fil: Halac, Emilia Beatriz. Comisión Nacional de Energía Atómica; Argentina Fil: Leyva de Guglielmino, Ana Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Custo, Graciela Susana. Comisión Nacional de Energía Atómica; Argentina Fil: Bengió, Silvina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Zampieri, Guillermo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina Fil: Litter, Marta Irene. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín; Argentina |
| Databáze: | OpenAIRE |
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