a 2014

Sonochemical Precipitation of Lanthanide and Uranium Oxides

DOROSHENKO, Iaroslav, Jiří PINKAS a Michaela KUCHAŘOVÁ

Základní údaje

Originální název

Sonochemical Precipitation of Lanthanide and Uranium Oxides

Autoři

DOROSHENKO, Iaroslav (804 Ukrajina, domácí), Jiří PINKAS (203 Česká republika, garant, domácí) a Michaela KUCHAŘOVÁ (203 Česká republika, domácí)

Vydání

14th European Society of Sonochemistry Meeting, Avignon, France, 2014

Další údaje

Jazyk

angličtina

Typ výsledku

Konferenční abstrakt

Obor

10402 Inorganic and nuclear chemistry

Stát vydavatele

Francie

Utajení

není předmětem státního či obchodního tajemství

Kód RIV

RIV/00216224:14740/14:00073739

Organizační jednotka

Středoevropský technologický institut

Klíčová slova anglicky

Sonochemistry; Precipitation; Lanthanide oxides; Uranium oxide;
Změněno: 1. 12. 2014 01:33, prof. RNDr. Jiří Pinkas, Ph.D.

Anotace

V originále

There is an intensive research effort directed to finding suitable oxide ceramics for use as radioactive waste storage forms [1,2] and to finding new innovative methods of their preparation. A good example of these methods is rapidly developing application of sonochemistry. In this work we used non-radioactive nuclides as models for highly radioactive elements. For example, based on the charge analogy and similarities in ionic radii, we used La3+ for Am3+, Ce4+ for Pu4+ and UO22+ for PuO22+. We studied sonochemically driven synthesis of insoluble lanthanide and uranium containing precipitates from the selected metal precursors, such as metal acetylacetonates, in organic solvent – tetraglyme (tetraethylenglycol dimethylether, TGL). Sonolysis of a series of metal acetylacetonato complexes, M(acac)3, M = La, Ce, Pr, Nd, Eu, Gd, Dy, Er, and UO2(acac)2 was carried out in TGL under Ar atmosphere on a Sonics and Materials VXC system with 500 W input power and working frequency of 20 kHz. The precursors (0.50 g) were dissolved in 50 cm3 of a solvent, purged with Ar gas and cooled with a Julabo F 25-MP thermostat. Sonication was run for 8 hours under Ar atmosphere. The products were separated from the mother liquors by centrifugation on a Heraeus Labofuge 400 at 3000-3500 rpm. The precipitates were washed by isopropanol and hexane and left to dry in open air. After separation they can be easily transformed to the respective metal oxides by calcination. The products were characterized by ICP-OES elemental analysis for their metal content, by nitrogen adsorption/desorption isotherm for surface area. Thermal behavior of obtained samples was studied by TG/DSC analysis. Amorphous character of precipitates and resulting phase content after calcination at 1000 C during TG/DSC analysis were studied by PXRD analysis. The sonolysis of M(acac)n, n = 2, 3, in TGL provided amorphous powders with major bands in their IR spectra corresponding to a vas(COO) and vs(COO) vibration of acetates produced by the acac ligand decomposition. Some samples featured high surface areas up to 380 m2 g-1 measured by the BET analysis. Calcination of the powders to 1000 C during TG/DSC analysis in air and mixed atmosphere (90 % N2, 10 % air) led to the formation of U3O8, CeO2, Pr6O11, and other corresponding Ln2O3 oxides. Also efficiencies of metals precipitation from the mother liquor have been calculated using data from the ICP-OES and TG/DSC with PXRD, and obtained results were compared. In this case efficiency of metals precipitation up to the 95 % was observed.

Návaznosti

ED1.1.00/02.0068, projekt VaV
Název: CEITEC - central european institute of technology
GAP207/11/0555, projekt VaV
Název: Oxidy a fosforečnany kovů jako formy jaderného odpadu: studium sonochemického srážení, tepelných přeměn a rozpustnosti (Akronym: OPNW)
Investor: Grantová agentura ČR, Oxidy a fosforečnany kovů jako formy jaderného odpadu: studium sonochemického srážení, tepelných přeměn a rozpustnosti