Separation of Pd Isotopes

A compilation of 17 procedures used for isolating radioactive Pd isotopes from a variety of target materials and a review of those chemical properties of Pd which might be useful for Pd separation are given by Hogdahl [139] a brief summary is also given in [99]. 

Most of the separation procedures are based on the precipitation [27, 68, 72, 76, 80, 89, 99, 110, 139, 158, 170] or extraction [11, 72, 81, 119, 122, 124, 139, 162] of the Pd dimethyl-glyoxime (DMG) complex. In combination with the commonly used scavenger precipitations of Fe, La, or Zr hydroxides and Ag halides quite high decontamination factors can be achieved (see for example procedure 1 below). The samples for counting are prepared using either Pd metal or insoluble Pd compounds, like DMG complex, sulfide, or iodide. 

The Pd-DMG complex is only very slightly soluble in water as well as in diluted HCl or HNOg and soluble in ammonia, CHClg, CCI4, or benzene. Se is apparently the main contamination in the Pd-DMG complex precipitated from fission product mixtures [99, 106, 139]. The complex can be destroyed with concentrated HNOg or aqua regia [99, 127, 139, 182]. 

Pd can also be precipitated with other organic reagents [139], however only two of them were used for radiochemical separations, namely salicylaldoxime [163] and a-furildiox-ime [190]. Other reagents used to precipitate Pd are S [109, 200], CN [139], and i [110]. The reduction of Pd was accomplished with Zn [99, 162], Mg [127], Cu [77, 91, 109], and by electroplating [81, 119]. The decontamination factor achieved by precipitation with Cu from fission product mixtures is quite high. Elemental Pd can also be coprecipitated with Te [158] or Se [139]. These precipitations can be used to recover small quantities of Pd from very dilute solutions. For this purpose the precipitation of PdS can also be used [139]. 

The separation of Pd from radioactive Ag can easily be achieved by just filtering the solution through a layer of inactive AgCl [36, 69] and Pd and Ag together are fixed In a precipitate of (Pd+Ag) cyanide [69]. Anion exchange was also applied for the purification of Pd [102, 110, 124, 139, 158, 170]. Lederer [181] developed a procedure based on paper chromatography. 

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