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Adsorption of Selenium and Strontium on Goethite: EXAFS Study and Surface Complexation Modeling of the Ternary Systems

Nie, Zhe 1; Finck, Nicolas ORCID iD icon 1; Heberling, Frank ORCID iD icon 1; Pruessmann, Tim ORCID iD icon 2,3; Liu, Chunli; Lützenkirchen, Johannes ORCID iD icon 1
1 Institut für Nukleare Entsorgung (INE), Karlsruher Institut für Technologie (KIT)
2 Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)
3 Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

Knowledge of the geochemical behavior of selenium and strontium is critical for the safe disposal of radioactive wastes. Goethite, as one of the most thermodynamically stable and commonly occurring natural iron oxy-hydroxides, promisingly retains these elements. This work comprehensively studies the adsorption of Se(IV) and Sr(II) on goethite. Starting from electrokinetic measurements, the binary and ternary adsorption systems are investigated and systematically compared via batch experiments, EXAFS analysis, and CD-MUSIC modeling. Se(IV) forms bidentate inner-sphere surface complexes, while Sr(II) is assumed to form outer-sphere complexes at low and intermediate pH and inner-sphere complexes at high pH. Instead of a direct interaction between Se(IV) and Sr(II), our results indicate an electrostatically driven mutual enhancement of adsorption. Adsorption of Sr(II) is promoted by an average factor of 5 within the typical groundwater pH range from 6 to 8 for the concentration range studied here. However, the interaction between Se(IV) and Sr(II) at the surface is two-sided, Se(IV) promotes Sr(II) outer-sphere adsorption, but competes for inner-sphere adsorption sites at high pH. ... mehr

Postprint §
DOI: 10.5445/IR/1000068765
Veröffentlicht am 13.06.2022
DOI: 10.1021/acs.est.6b06104
Zitationen: 50
Web of Science
Zitationen: 44
Zitationen: 45
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Katalyseforschung und -technologie (IKFT)
Institut für Nukleare Entsorgung (INE)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2017
Sprache Englisch
Identifikator ISSN: 0013-936X, 1520-5851
KITopen-ID: 1000068765
HGF-Programm 32.01.01 (POF III, LK 01) Grundl. Unters. - Geochemie v. Actiniden
Erschienen in Environmental science & technology
Verlag American Chemical Society (ACS)
Band 51
Heft 7
Seiten 3751-3758
Nachgewiesen in Dimensions
Web of Science
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