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Neumann J, Lessing J, Lee SS, Stubbs JE, Eng PJ, Demnitz M, Fenter P, Schmidt M. Y(III) Sorption at the Orthoclase (001) Surface Measured by X-ray Reflectivity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:266-276. [PMID: 36562683 DOI: 10.1021/acs.est.2c06703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Interactions of heavy metals with charged mineral surfaces control their mobility in the environment. Here, we investigate the adsorption of Y(III) onto the orthoclase (001) basal plane, the former as a representative of rare earth elements and an analogue of trivalent actinides and the latter as a representative of naturally abundant K-feldspar minerals. We apply in situ high-resolution X-ray reflectivity to determine the sorption capacity and molecular distribution of adsorbed Y species as a function of the Y3+ concentration, [Y3+], at pH 7 and 5. With [Y3+] ≥ 1 mM at pH 7, we observe an inner-sphere (IS) sorption complex at a distance of ∼1.5 Å from the surface and an outer-sphere (OS) complex at 3-4 Å. Based on the adsorption height of the IS complex, a bidentate, binuclear binding mode, in which Y3+ binds to two terminal oxygens, is proposed. In contrast, mostly OS sorption is observed at pH 5. The observed maximum Y coverage is ∼1.3 Y3+/AUC (AUC: area of the unit cell = 111.4 Å2) for all the investigated pH values and Y concentrations, which is in the expected range based on the estimated surface charge of orthoclase (001).
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Affiliation(s)
- Julia Neumann
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Jessica Lessing
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
| | - Sang Soo Lee
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
| | - Peter J Eng
- Center for Advanced Radiation Sources, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
- James Franck Institute, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
| | - Maximilian Demnitz
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
| | - Paul Fenter
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Moritz Schmidt
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
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Rodionova AA, Petrov VG, Vlasova IE. Sorption of Np, Pu, Am, Sr, Cs on the Mineral Phases of the Rocks of the Nizhnekansky Granitoid Massif under Conditions of Underground Repositories for Radioactive Wastes. RADIOCHEMISTRY 2022. [DOI: 10.1134/s106636222206011x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Demnitz M, Schymura S, Neumann J, Schmidt M, Schäfer T, Stumpf T, Müller K. Mechanistic understanding of Curium(III) sorption on natural K-feldspar surfaces. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:156920. [PMID: 35753478 DOI: 10.1016/j.scitotenv.2022.156920] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/29/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
To assess a reliable safety case for future deep underground repositories for highly active nuclear waste the retention of radionuclides by the surrounding host rock must be understood comprehensively. Retention is influenced by several parameters such as mineral heterogeneity and surface roughness, as well as pore water chemistry (e.g., pH). However, the interplay between those parameters is not yet well understood. Therefore, we present a correlative spectromicroscopic approach to investigate sorption of the actinide Cm(III) on: 1) bulk K-feldspar crystals to determine the effect of surface roughness and pH (5.5 and 6.9) and 2) a large feldspar grain as part of a complex crystalline rock system to observe how sorption is influenced by the surrounding heterogeneous mineralogy. Our findings show that rougher K-feldspar surfaces exhibit increased Cm(III) uptake and stronger complexation. Similarly, increasing pH leads to higher surface loading and stronger Cm(III) binding to the surface. Within a heterogeneous mineralogical system sorption is further affected by neighboring mineral dissolution and competitive sorption between mineral phases such as mica and feldspar. The obtained results express a need for investigating relevant processes on multiple scales of dimension and complexity to better understand trivalent radionuclide retention by a potential repository host rock.
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Affiliation(s)
- Maximilian Demnitz
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Stefan Schymura
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Research Site Leipzig, Permoserstraße 15 04318 Leipzig, Germany.
| | - Julia Neumann
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Moritz Schmidt
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Thorsten Schäfer
- Friedrich-Schiller-Universität Jena, Institute for Geosciences, Burgweg 11, 07749 Jena, Germany.
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Katharina Müller
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
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