title: A reinvestigation of EXAFS and EPR spectroscopic measurements of chromium(VI) reduction by coir pith.
abstract: New measurements using extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR) techniques are consistent with Cr in the Cr(III) oxidation state as the main product from the adsorption of Cr(VI) on coir pith. These confirm the previous X-ray measurements, but differ from the results of previous EPR studies, which indicated that Cr(V) was the main form of Cr. The reason for this discrepancy is the presence of a broad signal from Cr(III) in an unsymmetrical environment that was missed previously; the Cr(V) component is in fact only a minor reaction product. As a result of this problem with spectral acquisition and interpretation, some simple recommendations are presented for conducting EPR investigations on natural systems.
authors.affiliation: Department of Environmental Science, Faculty of Science and Technology, Suan Dusit Rajabhat University, 10300, Thailand.
authors.forename: Parinda
authors.initials: P
authors.lastname: Suksabye
authors.forename: Niramon
authors.initials: N
authors.lastname: Worasith
authors.forename: Paitip
authors.initials: P
authors.lastname: Thiravetyan
authors.forename: Akira
authors.initials: A
authors.lastname: Nakajima
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Goodman
mesh_terms: D002857:Chromium / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D010084:Oxidation-Reduction; D013057:Spectrum Analysis / Q000379:methods*; D014965:X-Rays
chemical_list: D002857:Chromium