Search Results

You are looking at 1 - 10 of 277 items for :

  • "Molybdenum" x
  • All content x
Clear All
Acta Veterinaria Hungarica
Authors: András Bersényi, Erzsébet Berta, István Kádár, Róbert Glávits, Mihály Szilágyi, and Sándor Fekete

Anke, M., Masaoka, T., Groppel, B., Zervas, G. and Arnhold, W. (1989): The influence of sulphur, molybdenum and cadmium exposure on the growth of goat, cattle and pigs. Arch. Anim. Nutr., Berlin, 1-2 , 221

Restricted access

Allen, R. M., Chatterjee, R., Madden, M. S., Ludden, P. W., Shah, V. K. (1994) Biosynthesis of the iron molybdenum cofactor of nitrogenase. Crit. Rev. Biotechnol. 14 , 225

Restricted access
Acta Biologica Hungarica
Authors: M. Anke, M. Seifert, Sylvia Holzinger, R. Müller, and U. Schäfer

Anke, M. (2004) Molybdenum. In: Merian, E., Anke, M., Ihnat, M., Stoeppler, M. (eds) Elements and their Compounds in the Environment . 2 nd ed., Wiley-VCH Verlag, Weinheim, pp. 1007

Restricted access

Abstract  

The isotopic compositions of molybdenum in six uranium-rich samples from the Oklo Zone 9 natural reactor were accurately measured by thermal ionization mass spectrometry. The samples were subjected to an ion exchange separation process that removed the isobaric elements zirconium and ruthenium, with high efficiency and a low blank. Molybdenum possesses seven isotopes of which 92,94,96Mo are unaffected by the fission process, enabling the raw data to be corrected for isotope fractionation by normalising to 92Mo/96Mo, and to use 94Mo to correct for the primordial component in each of the fission-produced isotopes. This enables the relative fission yields of Mo to be calculated from the isotopic composition measurements, to give cumulative fission yields of 1:0.941:0.936:1.025 for 95,97,98,100Mo, respectively. These data demonstrate that the most important nuclear process involved in reactor Zone 9 was the thermal neutron fission of 235U. The consistency of the relative cumulative fission yields of all six samples from different locations in the reactor, implies that Mo is a mobile element in the uraninite comprising Zone 9, and that a significant fraction of molybdenum was mobilized within the reactor zone and probably escaped from Zone 9, a conclusion in agreement with earlier published work.

Restricted access

Abstract  

This paper describes the studies on the extraction of molybdenum (VI) from aqueous nitric acid medium by (2-ethylhexyl) phosphonic acid, mono (2-ethylhexyl) ester (PC-88A). The extraction affecting parameters such as concentration of HNO3 in aqueous feed, effect of concentration of extractants, effect of diluents, and molybdenum concentration in the aqueous phase are investigated to optimize the extraction conditions for the quantitative separation of molybdenum from nitric acid medium. With increase of HNO3 concentration in aqueous phase, percentage extraction was found to be decreased in all the cases. Percentage extraction of molybdenum increases with increase in PC-88A concentration till the 0.15 M of PC88A, and after that it becomes constant. Kerosene and n-dodecane was found to be most suitable diluents. Among the various strippants used 0.2 M (w/v) solution of Na2CO3 and 0.2 M (w/v) solution (NH4)2CO3 are found to be the equally suitable for stripping of molybdenum from the loaded organic phase. The stripping of molybdenum from loaded organic layer by various reagents followed the order: (NH4)2CO3 >Na2CO3 >0.1 M sodium salt of EDTA >2 M NaOH >8 M HNO3. The optimized process conditions are employed to extract molybdenum (VI) from actual Davies–Gray waste as well as from diluted high level waste generated in the purex stream. More than 94% Mo(VI) was extracted from radioanalytical as well as from high level waste of purex process and quantitative recovery was achieved in both the cases when 0.2 M sodium carbonate was used as stripping agent.

Restricted access
Acta Alimentaria
Authors: M. Anke, M. Seifert, W. Arnhold, S. Anke, and U. Schäfer

. Elements and their compounds in the environment 2004 Anke, M. (2004b): Molybdenum. —in: Merian, E., Anke, M

Restricted access

The biological and toxicological importance of molybdenum in the environment and in the nutrition of plants, animals and man

Part IV: The molybdenum intake of adults with mixed and vegetarian diets in Germany and Mexico (duplicate portion studies)

Acta Alimentaria
Authors: M. Anke, S. Holzinger, M. Seifert, R. Müller, and U. Schäfer

2004 Anke, M. (2004b): Molybdenum. —in: Merian, E., Anke, M., Ihnat, M. & Stoeppler, M. (Eds) Elements and their compounds in the

Restricted access
Acta Alimentaria
Authors: M. Seifert, W. Dorn, R. Müller, S. Holzinger, and M. Anke

2004 Anke, M. (2004b): Molybdenum. —in: Merian, E., Anke, M., Ihnat, M. & Stoeppler, M. (Eds) Elements and their compounds in the

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: E. Skwarek, S. Khalameida, W. Janusz, V. Sydorchuk, N. Konovalova, V. Zazhigalov, J. Skubiszewska-Zięba, and R. Leboda

Introduction Vanadium pentoxide, molybdenum trioxide, and their mixed compositions with different metal ratio are used as numerous catalysts of hydrocarbons’ partial oxidation and oxidative dehydrogenation [ 1 , 2 ]. This

Restricted access

Introduction Molybdenum is a chemical element from the group d of transition metals. The free element, which is a silvery metal, has the sixth highest melting point of any element. It readily forms hard, stable carbides and

Restricted access