sup 95 Mo NMR study of the interaction of heptamolybdate solutions with alumina and silica

Journal Article · Wed Jan 25 23:00:00 EST 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100339a069· OSTI ID:5361265

Sarrazin, P; Mouchel, B; Kasztelan, S ^[1]

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1. Universite des Sciences et Techniques de Lille Flandre-Artois, Villeneuve d'Ascq (France)

The characterization of molybdenum solutions inside the pores of {gamma}-alumina and silica during impregnation has been investigated by {sup 95}Mo NMR. This technique allows the identification of the different oxomolybdate species such as MoO{sub 4}{sup 2{minus}}, Mo{sub 7}O{sub 24}{sup 6{minus}}, Mo{sub 8}O{sub 26}{sup 4{minus}}, and SiMo{sub 12}O{sub 40}{sup 4{minus}} and the study of the dependence of their proportion versus the pH and the concentration of the solution alone or inside the pores of the support. It is shown that alumina leaves only MoO{sub 4}{sup 2{minus}} in the pore solution whatever the pH and concentration of the solution as a result of a basic buffer effect and a preferential adsorption of Mo{sub 7}O{sub 24}{sup 6{minus}}. In addition the amount of fixed molybdenum depends strongly on the pH of the solution, which influences the number of positively charged adsorbing centers on the alumina surface. A very different behavior is found for silica with a strong effect of the pH of the solution on the nature of the species present in the pore volume solution as molybdate, heptamolybdate, and silicomolybdic acid species are detected at different pH, whereas this parameter does not influence the amount of molybdenum adsorbed on this support. Comparison of different silicas demonstrates that {sup 95}Mo NMR is an in situ sensitive technique to characterize the adsorption properties of supports.

• OSTI ID: 5361265
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:2; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DISPERSIONS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERSTITIALS
ISOTOPES
MAGNETIC RESONANCE
MINERALS
MIXTURES
MOLYBDATES
MOLYBDENUM 95
MOLYBDENUM COMPOUNDS
MOLYBDENUM ISOTOPES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
REFRACTORY METAL COMPOUNDS
RESONANCE
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SOLUTIONS
SORPTION
SORPTIVE PROPERTIES
SPECTRA
STABLE ISOTOPES
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS