Time-resolved XANES speciation studies of chromium on soils during simulated contamination.
Time-resolved synchrotron X-ray absorption near edge structure (XANES) spectroscopy was used to study changes of chromium speciation in soils upon soil-water interaction. The time resolution was 30-45 min. In a flow-column apparatus operated near the synchrotron beamline, two different types of soil were treated with potassium-dichromate solution, and soil samples were taken and directly analysed by XANES. The results provide insight into different equilibrium times of a few hours, depending on the type of soil. The XANES speciation analyses, based on a model comprising insoluble Cr(III) and Cr(VI) compounds, show how the fate of Cr species on soils can be followed close to real-time. Since the method allowed the soils to be investigated close to real-time, sampling in the field and preservation before analysis were made redundant. This study benefits the development of corresponding in situ remediation techniques.
Kappen
P
P
Centre for Materials and Surface Science and Department of Physics, La Trobe University, Kingsbury Drive, Bundoora, Victoria 3086, Australia. p.kappen@latrobe.edu.au
Welter
E
E
Beck
P H
PH
McNamara
J M
JM
Moroney
K A
KA
Roe
G M
GM
Read
A
A
Pigram
P J
PJ
D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D011192:Potassium Dichromate / Q000737:chemistry; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D013997:Time Factors
D012989:Soil Pollutants; D012996:Solutions; D002857:Chromium; D011192:Potassium Dichromate