The characterisation by luminescence spectroscopy of uranium(VI) incorporated into zeolites and aluminas

Abstract

Luminescence spectroscopy of solids at 77 K has been used to characterise the uranium(VI) species incorporated into a-alumina, g-alumina and zeolites Y and ZSM-20 by adsorption from solution and into ZSM-5 by chemical synthesis. With uranyl adsorbed from nitrate solutions onto a-and g-aluminas, the luminescence measurements show the dominant uranium species is schoepite, UO 3´x H 2 O, in agreement with results from X-ray diffraction and Raman spectroscopy. With uranyl acetate, there are indications that a crystalline acetate species is also present. With zeolite-Y and ZSM-20, the main species is a dimer. In addition, some monomeric [UO 2 (H 2 O) 5 ] 21 is also present. With ZSM-5, although this is not observed in X-ray diffraction, the luminescence spectrum shows the presence of a species, similar to the schoepite seen with the aluminas. It is suggested that this may be due both to closely related polymeric species, and to uranyl anions, such as [UO 2 (OH) 4 ] 22 and [UO 2 (OH) 3 ] 2 .

Physical Aspects of Radiation-Induced Processes on SiO2, γ-Al2O3, Zeolites, and Clays

“…The quenching of the luminescence of the Cu + by O 2 can be used to assess the distribution of Cu + in the zeolite . Other studies with UO 2 2+ have looked at energy transfer. , It was found that the efficiency of the energy transfer depended on the apparent dimensionality of the zeolite . For zeolite A with surface-bound UO 2 2+ , the transfer of energy to Eu 3+ was high at 93%, whereas UO 2 2+ on the inner surface of X and Y gave only an efficiency of energy transfer of 40%.…”

“…Inorganic cations have been exchanged into zeolite and their emission characteristics used to comment on the zeolite. − For Ag + in zeolites Y and X, the luminescence is similar to that of Ag + in rare gas matrices, and the spectrum shifts with the Si/Al ratio as a consequence of the charge density and polarizability of the Ag + environment. Cuprous ion (Cu + ) is readily produced from Cu 2+ adsorbed in zeolites.…”

Characterization of Uranium in Archived 2H Evaporator Scale

“…47 Other U XAFS-based characterization studies that were designed to precipitate zeolites in the presence of micro M levels of U(VI) have been conducted. 48 These studies indicated that the U that precipitated during the formation of the zeolite (specifically, sodalite) was present in multiple forms such as uranyl oxide/oxide hydrates and silicates in addition to some uranate (as opposed to strictly uranyl) forms of U(VI).…”

Polyacrylamide–clinoptilolite/Y-zeolite composites: Characterization and adsorptive features for terbium

“…Although, the usability of Z and YZ in adsorption procedures have been proved with a number of investigations ( [8][9][10][11][12][13][14][15][16] for Z, and [17][18][19][20][21][22][23] for Y-zeolite), further researches require for enhancement of adsorptive features and practical usage of zeolites, since the aggregation and coagulation of mineral particles under varying conditions of temperature and electrolytes lead variations in flow properties of these minerals. This is an undesired feature for their practical use as adsorbents since it may result in e.g.…”