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Effect of sodium dithionite on the surface composition of iron‐containing aquifer sediment
Author(s) -
Langell Marjorie A.,
Kadossov Evgueni,
Boparai Hardiljeet,
Shea Patrick
Publication year - 2009
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3122
Subject(s) - dithionite , sodium dithionite , sediment , x ray photoelectron spectroscopy , chemistry , environmental chemistry , iron sulfide , adsorption , environmental remediation , sulfide , composition (language) , sulfur , inorganic chemistry , contamination , geology , chemical engineering , paleontology , ecology , biochemistry , organic chemistry , engineering , biology , enzyme , linguistics , philosophy
AES, XPS and SIMS analyses were used to characterize the surface of Pantex aquifer sediment under pretreatment conditions previously shown to activate the sediment for remediation of the explosives‐contaminated aquifer. The untreated sediment contains detectable concentrations of iron, but the composition is heterogeneous and the nature of the iron at the surface is poorly defined. Treatment with dithionite (Na 2 S 2 O 4 ) produced Fe 3 O 4 ‐like material, as evidenced by characteristic Fe 2p XPS structure. Sediment treated with buffered dithionite (pH = 8.8) shows a higher Fe 2+ /Fe 3+ ratio and retains strongly adsorbed FeS‐like surface species even after copious washing with deionized water. The negative SIMS data indicate that, in the absence of the K 2 CO 3 buffer, the dithionite treatment places relatively little sulfur onto the surface, but requires the higher buffered pH to form sulfide and sulfates. Detection of Fe 3 O 4 and FeS on the sediment surface after dithionite treatment supports the effectiveness of this treatment in remediating contaminated aquifer sediment. SIMS and XPS indicate that treating with buffered dithionite also results in some loss of iron from the sediment surface. Copyright © 2009 John Wiley & Sons, Ltd.