title: Isotope fractionation and spectroscopic analysis as an evidence of Cr(VI) reduction during biosorption.
abstract: This work investigates the mechanisms behind Cr(VI) biosorption/reduction on three biomaterials (brewers draff, grape waste and synthetic humic acid). Coupled Cr isotope analysis with ICP-OES, XPS and SEM was tested as a novel approach to study the reduction of Cr(VI) by the biomaterials. The Cr(VI) biosorption process was accompanied with heavier Cr isotopes enrichment in the remaining Cr(VI) fraction. A significant fractionation of Cr stable isotopes was observed with no significant pH effect; δ(53)Cr of the remaining fraction ranged from 0.2‰ to 1.9‰ while δ(53)Cr of the product (sorbed Cr) ranged from -1.2‰ to -2.8‰. The Rayleigh fractionation model fitted well the measured data and Cr isotope analysis provides thus an efficient tool to quantify Cr(VI) reduction by different biomaterials. In general, the sorption/reduction potential of the three studied biomaterials decreased in the following order: grape waste>humic acids>brewers draff.
authors.affiliation: Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6 - Suchdol, 165 21, Czech Republic. Electronic address: sillerovah@fzp.czu.cz.
authors.forename: Hana
authors.initials: H
authors.lastname: Šillerová
authors.forename: Vladislav
authors.initials: V
authors.lastname: Chrastný
authors.forename: Eva
authors.initials: E
authors.lastname: Čadková
authors.forename: Michael
authors.initials: M
authors.lastname: Komárek
mesh_terms: D000327:Adsorption; D005591:Chemical Fractionation; D002857:Chromium / Q000737:chemistry* / Q000378:metabolism; D052918:Environmental Restoration and Remediation / Q000379:methods; D007554:Isotopes / Q000737:chemistry*; D008956:Models, Chemical; D010084:Oxidation-Reduction
chemical_list: D007554:Isotopes; D002857:Chromium; C074702:chromium hexavalent ion
keywords: Biosorption; Chromium(VI); Isotope fractionation; Rayleigh fractionation model; Reduction