| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Research Abstract |
In order to clarify the factors controlling the interactions between actinides and naturally occurring substances, sorption of Np(V) on various hydrous oxides and complexation of Np(V) with various organic substances have been investigated.
(1) Various iron and aluminum hydrous oxides (oxides, oxyhydroxides, hydroxides and amorphous hydrous oxides) have been obtained as crushed minerals, precipitates from alkaline solutions and thermally treated/aged precipitates, and characterized by thermal analysis, X-ray diffraction analysis, surface-area determination based on BET adsorption isotherm and acid-base titration. Sorption of Np(V) on these hydrous oxides have been investigated as a function of pH and sieved particle sizes and discussed in terms of their crystal form, crystallinity and surface conditions.
(2) The stability constants of Np(V) complexes with various aliphatic and aromatic carboxylates have been obtained in 1.0 M NaClO_4 at 25ﾟC by solvent extraction method using thenoyltrifluoroacetone and 1,10-phenanthroline in isoamylalcohol. Ligand acids investigated are: hydroxycarboxylates, dicarboxylates, nitrogen-containing carboxylates such as aminoacids and IDA, NTA and EDTA. The stabilities of these complexes are discussed in connection with their structures.
|
