NUKLEONIKA 2006, 51(Suppl. 1):s79-s82
Andrzej Deptuła1, Wiesława Łada1, Tadeusz Olczak1, Andrzej G. Chmielewski2
1 Department of Nuclear Methods of Material Engineering,
Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
2 IDepartment of Nuclear Methods in Process Engineering,
Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
Various kinds of active alumina supports were obtained by the Institute of Nuclear Chemistry and
Technology (INCT) sol-gel process in the following steps: (1) preparation of alumina sols by extraction
of nitrates with Primene JMT from aluminium nitrate solution; (2) gelation to spherical particles
(with diameter < 100 mm) by extraction of water from sol emulsion in
2-ethyl-1-hexanol; (3) sometimes conversion of NO3- stabilized gel to OH-
form by reaction with ammonia; (4) calcination of gels to g-Al2O3
with specific surface area > 100 m2/g at 500°C. The powders were then impregnated with
chloroplatinic acid and recalcined at 500°C. Catalysts were also prepared by direct gelation of
alumina sol containing hydroplatinic acid followed by steps (3) and (4). Pt/Al2O3
catalysts were used for the reduction of 1 M UO2(NO3)2-
0.5 M HCOOH solution with hydrogen at atmospheric pressure. The course of the reduction was controlled
analytically and by measuring the U(VI)/U(IV) redox potential. It was concluded that the catalysts
obtained by impregnation of the supports prepared from nitrate stabilized gels exhibit the best
activity and stability.