IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Root uptake and reduction of hexavalent chromium by aquatic macrophytes as assessed by high resolution X-ray emission
Autor/es:
F.R. ESPINOZA QUIÑONES; N. MARTIN; G. STUTZ; G. TIRAO; S.M. PALACIO; M.A. RIZZUTTO; A.N. MÓDENES; F.G. SILVA JR; N. SZYMANSKI; A.D. KROUMOV
Revista:
WATER RESEARCH
Editorial:
Elsevier Science B.V.
Referencias:
Lugar: Holanda; Año: 2009 vol. 43 p. 4159 - 4166
ISSN:
0043-1354
Resumen:
Aquatic macrophytes Salvinia auriculata, Pistia stratiotes and Eichhornia crassipes have been chosen to investigate the Cr(VI) reduced by root-based biosorption in chromium uptake experiment, using a high resolution XRF technique. These plants were grown in hydroponics medium supplied with non-toxic Cr concentrations during 27 days metal uptake experiment. The high-resolution Cr-Kβ fluorescence spectra for dried root tissues and Cr reference material (100% Cr, Cr2O3, and CrO3) were measured using an XRF spectrometer. For all species of aquatic plant treated with Cr(VI), the energy of Cr-Kβ2,5 line was shifted around 8 eV below the same spectral line identified to the Cr(VI) reference, but it is also near to the line identified to the Cr(III) reference. Moreover, there is a lack of the strong Cr-Kβ" line assigned to the Cr(VI) reference material within the Cr(VI)-treated plant spectra, suggesting the reduction of Cr(VI) for other less toxic oxidation state of Cr. As all Cr-Kβ spectra of root tissue species were compared, the peak energies and lineshape patterns of the Cr-Kβ2,5 line are coincident for the same aquatic plant specie, when they were treated with Cr(III) and Cr(VI). Based on the experimental evidences, the Cr(VI) reduction process has really happened during the metal biosorption by these plants.