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Detailed understanding of metal adsorption on clay minerals obtained by combining atomistic simulations and X-ray absorption spectroscopy

Applicant Daehn Rainer
Number 156412
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Other disciplines of Environmental Sciences
Start/End 01.01.2015 - 31.12.2018
Approved amount 266'805.00
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All Disciplines (2)

Discipline
Other disciplines of Environmental Sciences
Geochemistry

Keywords (5)

Atomistic; EXAFS; Clays; Adsorption ; Simulations

Lay Summary (German)

Lead
Tonminerale sind überwiegend wasserhaltige Aluminiumsilikate, die durch Verwitterungsprozesse, übersättigte Bodenlösungen oder durch hydrothermale Prozesse entstanden sind. Eine herausragende Eigenschaft von Tonmineralien ist, dass sie unter nahezu neutralen pH Bedingungen (pH 5-7) dauerhaft Schadstoffe an sich binden können. Um Vorhersagen über den Transport von Schadstoffen in der Umwelt treffen zu können ist ein detailliertes Verständnis an der Wasser-Ton-Grenzfläche unabdingbar. Röntenabsorptionsspektroskopie ist im Umweltbereich die weitverbreitetste analytische Methode, da sie Messungen auch kleinster Schadstoffmengen erlaubt. Die Analyse dieser Daten kann dann genaue Aussagen über die gebildeten Oberflächenkomplexe machen. Die neuesten Entwicklungen auf dem Gebiet der Computertechnik machen es nun auch möglich, die Aufnahme von Schadstoffen an Tonmineralien zu berechnen.
Lay summary

Ziel des Forschungsprojektes ist es, ein grundlegendes Verständnis über die Aufnahme von Schadstoffen an verschiedenen Tonmineralien zu gewinnen. Diese Studie wird sich auf zwei Schichtsilikate, den Illit und Montmorillonit, konzentrieren. Es handelt sich dabei um dreischichtige Tonmineralien, bestehend aus einer Aluminium-Oktaeder-Schicht, umgeben von zwei Silikat-Tetraederschichten. Die untersuchten Schadstoffe, wie z. B. Ni(II), Fe(II), Fe(III), Th(IV) and U(VI), decken die drei- bis sechs-wertigen Oxidationszustände ab. Resultate aus der Röntenabsorptionsspektroskopie werden mit molekularen Rechnungen verglichen werden.

Direct link to Lay Summary Last update: 27.10.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
Characterization of Structural Iron in Smectites — An Ab Initio Based X-ray Absorption Spectroscopy Study
Kéri Annamária, Dähn Rainer, Krack Matthias, Churakov Sergey V. (2019), Characterization of Structural Iron in Smectites — An Ab Initio Based X-ray Absorption Spectroscopy Study, in Environmental Science & Technology, 53(12), 6877-6886.
Combined XAFS Spectroscopy and Ab Initio Study on the Characterization of Iron Incorporation by Montmorillonite
Kéri Annamária, Dähn Rainer, Krack Matthias, Churakov Sergey V. (2017), Combined XAFS Spectroscopy and Ab Initio Study on the Characterization of Iron Incorporation by Montmorillonite, in Environmental Science & Technology, 51(18), 10585-10594.
Combined X-ray microanalytical study of the Nd uptake capability of argillaceous rocksNd uptake study by combined X-ray microanalysis
Kéri Annamária, Osán János, Fábián Margit, Dähn Rainer, Török Szabina (2016), Combined X-ray microanalytical study of the Nd uptake capability of argillaceous rocksNd uptake study by combined X-ray microanalysis, in X-Ray Spectrometry, 45(1), 54-62.

Collaboration

Group / person Country
Types of collaboration
Mineralogy/University of Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
9th MECC Talk given at a conference Combined ab initio and XAFS spectroscopy study on the characteristics of metal uptake by clay minerals 17.09.2018 Zagreb, Croatia Daehn Rainer; Krack Matthias; Churakov Sergey; Kéri Annamaria Gabriella;
Goldschmidt 20 Talk given at a conference Combined ab initio and XAFS spectroscopy study on the characteristics of metal uptake by clay minerals 12.08.2018 Boston, United States of America Kéri Annamaria Gabriella; Daehn Rainer; Churakov Sergey; Krack Matthias;
7th Clay Conference Talk given at a conference Characteristics of iron uptake by montmorillonite combining ab initio calculations and XAFS spectroscopy studies 24.09.2017 Davos, Switzerland Churakov Sergey; Krack Matthias; Kéri Annamaria Gabriella; Daehn Rainer;
ICC16 Talk given at a conference Characteristics of iron uptake by montmorillonite combining ab initio calculations and XAFS spectroscopy studies 17.07.2017 Granada , Spain Krack Matthias; Daehn Rainer; Churakov Sergey; Kéri Annamaria Gabriella;
EMC2016 Talk given at a conference Combined ab initio and EXAFS spectroscopy study on the characteristics of iron uptake by clay minerals 11.09.2016 Rimini , Italy Churakov Sergey; Daehn Rainer; Kéri Annamaria Gabriella; Krack Matthias;
XAFS16 Poster Competitive metal adsorption on montmorillonite investigated by combining X-ray absorption spectroscopy and atomistic simulations 23.08.2015 Karlsruhe, Germany Daehn Rainer; Krack Matthias; Kéri Annamaria Gabriella; Churakov Sergey;


Associated projects

Number Title Start Funding scheme
165548 Dissolution, growth and toxic ion uptake at phyllosilicate surfaces: Coupling atomistic interactions at the mineral-water interface with Kinetic Monte Carlo model. 01.01.2017 Project funding (Div. I-III)
164017 Environmental Atomic Force Microscope 01.03.2016 R'EQUIP
171018 Alkali-silica reaction in concrete 01.05.2017 Sinergia

Abstract

Clay minerals can irreversibly bind metals in waste and soil matrices under mildly acidic to basic pH conditions. The prediction of the faith of contaminants in the geosphere requires a profound and detailed knowledge of the processes at the clay-water interface. It has been demonstrated that the combination of wet chemistry experiments and advanced X-ray absorption spectroscopy (XAS) techniques is the most promising approach to investigate environmental systems. The data analysis of extended X-ray absorption fine structure (EXAFS) spectra allows in the best cases to unequivocally determine the nature of surface complexes formed at clay mineral edge sites. With advances in computational sciences it has become possible to perform molecular simulations, which can be used for the interpretation of EXAFS data for surface adsorbed species on surfaces of clay minerals. In the proposed study at least two clay minerals will be investigated, montmorillonite and illite. Both have in common that they are dioctahedral smectite 2:1 clay minerals. Their structure consists of an octahedral sheet (consisting mainly of Al atoms) attached to two tetrahedral sheets (consisting mainly of Si atoms). In dioctahedral clays two of the three octahedral positions are filled. Whereas in montmorillonite isomorphic substitution occurs predominantly in the octahedral layers, illite is exhibiting isomorphic substitution primarily in the tetrahedral sheets. Therefore, the aim of this doctoral study is to understand the retention mechanism of environmentally relevant elements, covering various oxidation states from III to VI on most common clay minerals, montmorillonite and illite, based on molecular simulations and spectroscopic measurements. More specifically the adsorption of Ni(II), Fe(II), Fe(III), Th(IV) and U(VI) onto clay mineral edge sites will be investigated to gain a deep understanding of the faith of these elements in the geosphere. The combined interpretation of the modelling results and the XAS experiment is challenging due to potentially limited accuracy of the data. An innovative approach should be developed for the systematic improvement of the simulation results and their comparison with the experiments.
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