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Journal of Thermal Analysis and Calorimetry
Authors: Hermi F. Brito, Jukka Hassinen, Jorma Hölsä, Högne Jungner, Taneli Laamanen, Mika Lastusaari, Marja Malkamäki, Janne Niittykoski, Pavel Novák, and Lucas C. V. Rodrigues

stimulated luminescence, results from the storage of energy to traps and its subsequent release induced by the thermal energy available at room temperature [ 1 ]. The most efficient persistent luminescence materials, i.e., CaAl 2 O 4 :Eu 2+ ,Nd 3+ and SrAl 2

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silicate host has been studied for a long time. In recent years, silicate phosphors have been reported by researchers [ 4 – 13 ]. In this article, MgAl 2 Si 2 O 8 : Mn 4+ , Eu 3+ , and MgAl 2 Si 2 O 8 : Mn 4+ , Yb 3+ -based phosphors were

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Abstract  

Line-broadening due to paramagnetic relaxation was observed in Mössbauer spectra of Eu2+ in glassy frozen solutions; such broadening may be used as an indicator of the state of dispersion of europium. It was demonstrated by the Mössbauer technique that Eu2+ was oxidized to Eu3+ by photoirradiation at >300 nm and that this oxidation reaction was induced by photoexcitation of the 320-nm band of Eu2+.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Xu, Q. L. Ning, X. Zhou, C. L. Chen, X. L. Tan, A. D. Wu, and X. Wang

Summary  

Effects of ionic strength and of fulvic acid on the sorption of Eu(III) on alumina were investigated by using a batch technique. The experiments were carried out at T=25±1 °C, pH 4-6 and in the presence of 1M NaCl. The results indicate that sorption isotherms of Eu(III) are linear at low pH values. The sorption-desorption of Eu(III) on alumina at pH 4.4 is reversible, but a sorption-desorption hysteresis is found at pH 5.0. Fulvic acid has an obvious positive effect on the sorption of Eu(III) on alumina at low pH values. The migration of Eu(III) in alumina was studied by using column experiments and 152+154Eu(III) radiotracer at pH 3.8. For column experiments, Eu(III) sorbed on alumina can be desorbed completely from the solid surface at low pH values. The findings are relevant to the evaluation of lanthanide and actinide ions in the environment.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Y. Suzuki, T. Nankawa, T. Yoshida, T. Ozaki, T. Ohnuki, A. J. Francis, S. Tsushima, Y. Enokida, and I. Yamamoto

Summary  

We have investigated the structure of Eu(III)-citrate complexes in aqueous solution and their degradability by Pseudomonas fluorescens. Analysis of 1:1, 1:2, and 1:5 Eu(III):citrate solutions at pH 7 by electrospray ionization mass spectrometry (ESI-MS) showed that the 2:2 Eu(III)-citrate complex is the predominant complex species at a low citrate/Eu(III) ratio, while at a high ratio, a 1:2 Eu(III)-citrate complex is formed preferably. Studies on the biodegradation of Eu(III)-citrate complex by P. fluorescens have shown that a 2:2 Eu(III)-citrate complex is resistent to degradation while a 1:2 complex transforms to a 2:2 complex with the degradation of excess citric acid.

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HCOO) 3 ·2H 2 O (where Ln(III) = Pr, Er), Ln(CCl 3 COO) 3 ·2H 2 O (where Ln(III) = Pr, Nd, Eu, Dy, Yb), [Nd(CCl 2 HCOO) 6 (H 2 O) 3 ] n · m H 2 O and Nd x Ln 1− x (CCl 3 COO) 3 ·2H 2 O. In 2003 year [Tb 2 (CH 3 COO) 6 (H 2 O) 4 ]·4H 2 O and [Tb 2 (CF 3

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–11. Horváth, J., Pálmai, O. & Németh, T., 1999. Expedite evaluation of the annual mineral N analyses. (In Hungarian) Gyakorlati Agrofórum. 10. (5)17–18. http://ec.europa.eu

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Abstract  

The batch method and the column method were simultaneously employed to study the sorption and desorption of Eu(III) on red earth as a function of pH (4.6–6), the presence of a well-characterized fulvic acid (FA) and the iron oxides content of red earth. The results from both methods were consistent qualitatively. The Eu(III) sorption showed significant dependences on pH and FA, the sorption was increased with increasing pH and by addition of FA to the solutions, while the iron oxides content of the red earth had a negative contribution to the sorption of Eu(III). Additionally, the sorption-desorption hysteresis of Eu(III) on red earth occurred at a pH range of 4.6–6. Therefore, the humic substance and high pH have a great tendency to immobilize Eu(III) on red earth.

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Abstract  

The kinetics of homogeneous electron exchange Eu3+/Eu2+ has been investigated in 1M HClO4, water+dimethylformamide (DMF) mixed solvent by using labeled europium. Non-monotonic variations of the electron exchange rate constants as a function of the solvent composition was observed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Sharayu Kasar, Sumit Kumar, Aishwarya Kar, K. Krishnan, N. Kulkarni, and B. Tomar

Abstract  

Sorption of Eu(III), an analogue of trivalent actinides (Am, Cm), by amorphous titania as well as different crystalline phases of titania, namely anatase and rutile, have been studied as a function of pH, using 154Eu (half life = 8.8 yrs, Eγ = 123,247 keV) as a radiotracer. The objective of this study was to investigate the effect of the crystalline phase of the titania on their sorption behaviour towards the metal ion. Amorphous titania was prepared by organic route and was converted into anatase and rutile by heating at elevated temperatures based on the differential thermal analysis studies. Eu(III) sorption by all forms of titania rises sharply with the pH of the suspension, with the sorption edge shifting to higher value in the order; amorphous < anatase < rutile. However, the normalization of the sorption data to the surface area of the sorbents resulted in the overlapping of the sorption curves for amorphous and anatase phases, with the data being higher for rutle in the lower pH region, indicating the effect of the crystal phase on sorption behaviour of Eu(III).

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