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MOSSBAUER SPECTROSCOPY IN STUDYING OF SYNTHESIS AND
ENVIRONMENTAL APPLICATIONS OF FERRATE(VI)
Virender K. Sharmaa, Libor Machalab, Karolina Siskovab, Radek Zborilb
aCenter
of Ferrate Excellence and Chemistry Department, Florida Institute of
Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA
bRegional
Centre of Advanced Technologies and Materials, Departments of
Experimental Physics and Physical Chemistry, Faculty of Science, Palacky
University, Slechtitelu 11, 78371 Olomouc, Czech Republic
In recent years, iron in the +6 oxidation state, commonly called ferrate(VI) (FeVIO42-, Fe(VI))
has been of great interest because of its dual role as a non-chlorine disinfectant/oxidant and a
subsequent coagulation/precipitation as ferric hydroxide in water treatment. Solid-state
reactions and/or alkaline melting present Fe(VI) synthetic approaches, which may enable a
large scale production of ferrate(VI) compound.
57
Fe Mössbauer spectroscopy very well
discerns between different oxidation states of iron atoms and thus can be used for
identification and quantification of the high-valent iron compounds. Fe(VI) behave as strong
and selective oxidizing agents therefore they are also used in various environmentally friendly
applications, e.g. waste water purification and removal of metals.
In this context, in-situ
Mössbauer experiments are presented as a powerful tool to directly monitor chemical
transformations of the ferrate samples as well as their reactions with other compounds.
Moreover rapid mixing and freezing technique enables to investigate solution reactions too.
In the presentation, examples will be given to demonstrate the applications of 57Fe Mössbauer
spectroscopy to understand mechanisms of the oxidative reactions of the ferrates with
pollutants such as metal cyanides, arsenic, and nitrogen-containing pollutants. In the reaction
of ferrate(VI) with metal cyanides, Fe(VI) oxidizes the cyanide to cyanate with the formation
of iron(III) oxyhydroxides differing in particle size, crystal structure, and surface area. Most
of the metals produced from the reaction could be removed completely from the water.
Results of Mössbauer spectroscopy of the iron(III) oxyhydroxides will be presented.
Presenting author: Professor Virender K. Sharma
Address: Center of Ferrate Excellence, Florida Tech, Melbourne, Florida, USA
FAX: 001-321-674-8951
E-mail: [email protected]