Generator of Actinium-228 and a Study of the Sorption of Actinium by Carbon Nanomaterials

A method has been developed for isolation of Ac-228 from aged samples of natural Th-232. Macroscopic amounts of the thorium bulk (20 g) were separated by its extraction by a solution of di(2-ethylhexyl)phosphoric acid in toluene from 4 M HNO3 solutions, with microamounts of Ra-228 and Ac-228 remaining in the aqueous phase. Ac-228 was selectively extracted from the resulting solution by the method of extraction chromatography on a column with RE resin sorbent, and Ra-228 quantitatively remained in the 4 M HNO3 eluate. Ac-228 was washed out of the column with 0.05 M HNO3, it could be used as a radioisotope for research purposes. After the accumulation of the daughter Ac-228 the solution of Ra-228 in 4 M HNO3 was repeatedly passed through an identical column. The resulting Ac-228 was used in the study to examine its sorption on commercial and modified carbon nanomaterials (CNMs) instead of the difficultly accessible Ac-225. It is shown that the application of CNMs as carriers of actinium isotopes for nuclear medicine purposes is promising.