Understanding sorption mechanisms of uranium onto elemental iron, minerals and Shewanella putrefaciens surfaces in the presence of arsenic [Elektronische Ressource] / vorgelegt von Clement N'zau Umba-di-Mbudi

Clementine

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• Biologie

Informations

• Publié par: technische_universitat_bergakademie_freiberg
• Publié le: 01 janvier 2009
• Nombre de lectures: 32
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Understanding Sorption Mechanisms of Uranium onto
Elemental Iron, Minerals and Shewanella putrefaciens
Surfaces in the Presence of Arsenic




Der Fakultät fuer Geowissenschaften, Geotechnik und Bergbau

der Technische Universität Bergakademie Freiberg



genehmigte



DISSERTATION


Zur Erlangung des akademischen Grades


Doktor Ingenieur
(Dr.-Ing.)



Vorgelegt


von Clement N‘zau Umba-di-Mbudi
MSc Civil Hydrological Engineering

Geboren am 23.03.1960 in Boma/ Demokratische Republik von Kongo

Gutachter: Prof.Dr.rer.nat.Habil Broder Merkel (Freiberg, Deustchland)
Prof.Dr.-Ing.Habil Philippe Behra (Toulouse, France)



December 11, 2009
Abstract
The concomitant occurrence and reported discrepant behavior of uranium and arsenic in
water bodies is a major health and environmental concern. This study combined batch
and column experiments, hydrogeochemical simulations and XAFS spectroscopy to
uncover the exchange mechanisms governing uranium fate between water and scrap
metallic iron, minerals and Shewanella putrefaciens surfaces in the presence of arsenic.
The main results suggest that both water chemistry and the solid phase composition
influence uranium fate in the presence of arsenic. The importance of uranyl-arsenate
species as a major control of uranium behavior in the presence of arsenic is shown. The
toxicity of arsenic and the presence of nitrate are interpreted as limiting factors of the
enzymatic reduction of both toxins. Besides, XANES fingerprinting and EXAFS
modeling have confirmed precipitation/co-precipitation of uranyl-arsenates as a major
mechanism controlling uranium behavior in the presence of arsenic.

Kurzfassung
Das begleitende Auftreten und das berichtete diskrepante Verhalten des Urans und des
Arsens in den Wasserkörpern sind eine Hauptgesundheit und ein umweltisches Problem.
Diese Arbeit kombinierte Batch und Säule versuchen, hydrogeochemische Modellierung
und XAFS Spektroskopie, um die Austauscheinheiten freizulegen, die Uran Schicksal
zwischen Wasser und metallisches Eisen, Mineralien und shewanella putrefaciens
Oberflächen in Anwesenheit des Arsens auszurangieren regeln. Die Hauptresultate
schlagen vor, daß die Wasserchemie und der Aggregatzustandaufbau Urans Schicksal in
Anwesenheit des Arsens beeinflussen. Die Wichtigkeit der „Uranyl-arsenate― Spezies als
Hauptsteuerung des Urans Verhaltens in Anwesenheit des Arsens wird gezeigt. Die
Giftigkeit des Arsens und das Vorhandensein des Nitrats werden als Begrenzen von
Faktoren der enzymatischen Verkleinerung beider Giftstoffe gedeutet. Außerdem haben
XANES Fingerabdruck und EXAFS Modellierung fällung/mitfällung der „Uranyl-
arsenate― als Haupteinheit steuernden Urans Verhalten in Anwesenheit des Arsens
bestätigt.

Résumé
L'occurrence simultanée et le comportement divergent d'uranium et d'arsenic en milieu
aqueux constituent un problème majeur de santé publique et environnemental. Cette
étude a combiné les expériences en milieu fermé batch et en colonne, les simulations
hydrogéochimiques et la spectroscopie XAFS pour identifier les mécanismes d'échange
gouvernant le comportement d'uranium entre l'eau et le fer métallique, les minéraux et les
surfaces de Shewanella putrefaciens en présence d'arsenic. Les résultats principaux
suggèrent que la chimie de l'eau ainsi que la composition de la phase solide influencent le
comportement d'uranium en présence d'arsenic. L'importance d'espèces d'uranyl-arsenates
comme un contrôle majeur du comportement d'uranium en présence d'arsenic est
montrée. La toxicité d'arsenic et la présence du nitrate sont interprétées comme facteurs
limitant la réduction enzymatique des deux toxines. En plus, l‘analyse qualitative
XANES et la modélisation des spectres EXAFS ont confirmé la précipitation/co-
précipitation d'uranyl-arsenates comme un mécanisme majeur contrôlant le
comportement d'uranium en présence d'arsenic
i
Acknowledgements

First and foremost, I sincerely thank Prof.Dr.Habil. Broder J. Merkel for providing me
with the opportunity to carry out my graduate research under his supervision at the
Technische Universität Bergakademie Freiberg (TUBAF). From the inception of this
project, Prof. Merkel let me take initiatives and explore research avenues fully
independently. His encouragements and often very specific and critical suggestions have
been very helpful throughout. Thanks also to former and current academic, technical and
administrative staff of the department of Hydrogeology for their assistance as well as to
colleagues doctoral students of TUBAF for their friendship during my academic journey
in Germany.

I am equally and deeply indebted to Prof.Dr.Ing.HDR Philippe Behra of the Ecole
Nationale Supérieure des Ingénieurs en Arts Chimiques et Technologiques (ENSIACET)
at the Université de Toulouse for promptly accepting me to carry out part of my doctoral
research at the Laboratoire de Chimie Agro-Industrielle (LCA) of France. Prof. Behra‘s
guidance and fruitful discussions of my research have been very insightful. Through
Philippe, I also extend my gratitude to Prof. Elizabeth Boredon, the head of the LCA and
all her staff and to colleague thésards (Ph.D. students) for making my stay in Toulouse
enjoyable.

In Toulouse, my gratitude also goes to Dr. Laurence Girbal of the Centre de Bio-
ingénierie Gilbert Durand, Laboratoire de Biotechnologie-Bioprocédés of the Institut
National des Sciences Appliqueés (INSA) for her material Support and on discussions of
my experimental work. At the Laboratoire des Mécanismes et Transferts en Géologie
(LMTG) of the French National Scientific Research Center (CNRS), I particularly thank
Ir. Remi Freydier and Frederic Candaudap for their assistance on the around the clock
ICP-MS analyses of my samples at a very decisive moment of this project.

Back to Germany, I am grateful to Prof.Dr.Habil Michael Schlömann for giving me full
access to his ―Umwelt Mikrobiologie Labor‖ and guidance throughout. I am also thankful
ii to his assistants Dr. Margit Mau and Dr. Stefan Kaschabek, and the laboratory
technicians for fruitful discussions and support throughout.

Many thanks as well go to members of the XAFS family tree particularly to Dr. Jorg
Rothe, Dr. Melissa Denecke, Dr. Boris Brendenbach and Dr. Kathy Dardenne of the
Institut fuer Nukleare Entsorgung (INE) of the Forschungszentrum Karlsruhe (FZK).
Similarly, I also extend my gratitude to XAFS instructors Dr.HDR Andrea Scheinost and
Dr. Andre Rossberg of the Rossendorf Beamline in the European Synchrotron Light
source in Grenoble (France) and to Dr. A. Scheideger of the Swiss Light Source in
Vlingen (Switzerland). In this category are Dr. Mat Newville and Dr. Bruce Ravel of the
USA for their XAFS tutorials and for promptly responding to my EXAFS related
questions of their computer programs Athena and Artemis.

This work could not have been achieved without the financial help from British
Columbia government and the Federal government of Canada to cover part of my living
expenses in Germany. Thanks to these often anonymous administrative staff at the British
Columbia ministry of advanced education who professionally established the necessary
paper work including the signature of the memorandum of understanding with TUBAF to
allow me to get the education I wanted in Germany. My gratitude also goes to the
European commission COST ACTION 629, the Network of Excellence for actinide
Sciences-ACTINET, the Förderkreises Freiberger Geowissenschaften, the TUBAF PHD
program in Material, Environmental and Technology, the FZK‘s Institut fuer
Synkrotronstrahlung (ISS), the Metallaufbeiratung Zwickau and the Quarzwerke Frechen
for their respective financial and material support.

Last but not least, my gratitude goes to my extended family for gracefully coping with
my long academic journey in Germany and France. To you Lovely, thanks for your love,
understanding and support throughout this long journey. I do really hope in clos