Chemistry Departmental Seminar – Dr. Christian Ruby
About the event
Dr. Christian Ruby, Director of Research at Polytech Nancy, Université de Lorraine – France
Title: Structure and Reactivity of Iron Oxides: The Usefulness of Mössbauer Spectroscopy
Abstract: Among the different iron oxides present in the environment, mixed FeII-FeIII compounds play a specific role due to their high chemical reactivity. In particular, FeII-FeIII layered double hydroxide, most commonly called green rust (GR), was discovered for the first time in 1997 in a hydromorphic soil of the forest of Fougères (Britanny, France). Synthetic GR was shown to reduce a variety of inorganic pollutants, e.g. chromate or nitrate, and its ferric oxidation products adsorb phosphate anions very easily. GR and other mixed FeII-FeIII iron oxides such as magnetite are therefore promising materials for environmental applications concerning water and soil remediation [1]. Fougerite was also recently suspected by a group of American and French researchers to have played a role as a catalyzer for earth life [2].
In this talk, the Mössbauer Spectroscopy (MS) technique will be presented by using different examples concerning either the characterization and reactivity of GR or the bio-generation of magnetite. Recent results concerning the solid characterization of nano-zero-valent iron will also be presented. We will show that MS is a powerful technique to determine the speciation of iron (Fe0, FeII, FeIII) and to obtain quantitative information of the various iron-containing phases.
[1] M. Usman, J.M. Byrne, A Chaudhary, S Orsetti, K. Hanna, C. Ruby, A. Kappler, S.B. Haderlein, Magnetite and green rust: synthesis, properties, and environmental applications of mixed-valent iron minerals, Chemical Reviews 118 (7), 3251-3304.
[2] Duval Simon, Baymann Frauke, Schoepp-Cothenet Barbara, Trolard Fabienne, Bourrié Guilhem, Grauby Olivier, Branscomb Elbert, Russell Michael, Nitschke Wolfgang, 2019, Fougerite: the not so simple progenitor of the first cells, Interface Focus 92019006320190063