2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Non-Toxic Molybdenum as the Rolls-Royce nanoengines of the transition metal ions for the remediation of toxic sediments in harbours and urban waterways

M.R. Reda
CanadElectrochim, CA

Keywords:
Molybdenum, Oxidation number, harbours

Abstract:
Non-Toxic Molybdenum as the Rolls-Royce nanoengines of the transition metal ions for the remediation of toxic sediments in harbours and urban waterways. Part I : Preliminary Introduction to the basic chemistry. By M. Reda Independent Technical Consultant CanadElectrochem Reseach & Development 3080 Regional Road # 20 Cayuga, Ontario N0A1E0 Canada Corrosion555@canada.com In 1970, many of New England rivers, estuaries and harbors were environmental nightmares. Sewage and industrial wastes transformed New England waterways into waste dumps with almost no life at all, except perhaps noxious algae blooms. Rivers ran red, blue, or green depending on what dyes were used by mills upstream. New England region largest river, the Connecticut, was openly referred to as a .landscaped sewer.. It was no wonder many New England cities and towns turned their backs on their rivers and harbor fronts, paving them over or walling them from view. The purpose her is the remediation of toxic sediments in harbours and urban waterways by a simple cost effective method in order to try to restore the ecosystem for both short and long term durations. The purpose of this publication is to prove that the releasing of non toxic molybdenum ions (the Rolls-Royce nanoegines) have magic touch to clean up major pollutant both at the surface ( aerobic conditions), bottom water ( semi aerobic conditions) and the sediments (anaerobic conditions). Magnetic Susceptibility measurement of sediments samples taken from the bottom core samples had been used to measure the level of the presence of PAHs, trace metals and other priority pollutants in bottom core samples. Another objective is to show that the magic touch of Molybdenum ions will do its job without hydro dynamically disturbing the sediment bottom and thus releasing more pollutant to the water above the sediments. Molybdenum is unique in having well characterised aqueous ions in five different oxidation states. Molybdenum has a variable chemistry that no other transition metal element is able to match. Because of a wide range of structure and easy redox interconversion of aqueous ions ( Moz(X) where z and x can be any value between 1 and 6), this present different mechanistic aspects not previously encountered. Thanks to Prof. Geoffrey Sykes from University of New Castle upon Tyne from Scotland who had done many years of excellent works in the chemistry of Molybdenum ions at different pH. Based on the work of Sykes and others it will be shown how the different oxidation states of non toxic molybdenum which can be formed when released in the the Connecticut river can contribute to the removal of the pollutant. Molybdenum species present at or near surface (aerobic conditions) are different than those present inside the sediment( decompose for let us say few months).The ability of molybdenum ions in the 6 oxidation state for reaction with phosphate to produce molybdophosphate is used by marine chemist to measure phosphate concentration in ocean and river water. Molybdenum in the 6 oxidation state is an excellent catalyst for production of singlet oxygen from H2O2 (intentionally introduced for short time).Singlet oxygen is known for it ability to break double and triple bounds of organic compound. The ability of Mo(VI) for its redox reduction and Mo(III) ( anaerobic condition) for its redox oxidation of other metal ions present in the water and sediments are well known. According to Stiefle ( 1-The biochemistry of molybdenum and tungsten, Molybdenum and Tungsten:Their role in Biological Processes, 2002, 39, 1-29 and 2- Science, 272, 1599, 1996) Chemically molybdenum is versatile, forming compounds in a range of readily inter-convertible oxidation states, complex with many inorganic and organic ligands including physiologically important compounds, bi-nuclear and poly-nuclear species involving bridging ligands ( oxide, hydroxide, sulfide) or direct metal-metal bonds between molybdenum atoms and compounds in which the molybdenum coordinate number ranges from four to eight.The biochemical importance of molybdenum is due to its ability (a) to provide facile electron-transfer pathways, a consequence of the easy inter-convertibility of the different oxidation states,(b) to form bonds with nitrogen-, oxygen-, and sulfur- donors which are sufficiently strong to permit the existence of stable complexes but also sufficiently labile to permit facile ligand exchange reactions or change of molybdenum co-ordination number( as when interacting directly with a substrate according to P.C.H. Mitchell, Molybdenum: an outline of its chemistry and uses, ed. E.R. Barithwaite, J. Harber. Amestrdam ; Elsvier, 1994.). Thus releasing molybdenum ions in harbours and urban waterways will first acts on the pollutant present in the water ( and maybe) producing new chemicals which when precipitated at the bottom ( sediments) will act to on the sediments pollutant.


Nanotech 2008 Conference Program Abstract