Cation exchange techniques

Cation-exchange techniques, stability constant determination of Pu sulfate... 

Platinum was introduced on the activated support by a competitive cation exchange technique. An amount of 100 g of a 8 wt% Pt solution of platinumtetrammine hydroxide (Johnson Matthey) was added dropwise to a suspension of 40 g graphite in 800 ml 1 M ammonia (Merck p.a.) and stirred at ambient temperature for 24 hours. The catalyst was subsequently separated by filtration on a Millipore filter (HV 0.45m), washed with distilled water and dried in a vacuum oven at 373 K. The dried catalyst was reduced in flowing hydrogen at 573 K for 2 hours and stored under air before use. 

Carbendazim and thiophanate-methyl were determined in cabbage and onions (5,44). Au-tors et al. (44) used the cation-exchange technique for the HPLC determination. The preservatives were detected at 275 nm, and tetramethylammonium nitrate in nitric acid was used as mobile phase recoveries were 75% at a level of 0.08 mg/kg, when the determination limit of the method was 0.02 mg/kg. 

The pentaaqua cation [RuCl(OH2)5]2+ can be isolated in solution using cation exchange techniques.1887 It electronic spectrum1887 and rate of aquation (tj > 1 year) have been measured (cf. for [RuC16]3, aquation to [RuC15(OH2)]2 takes only a few seconds). Thus, cationic and neutral aquachlororuthenium(III) species are relatively substitutionally inert, compared to anionic species.2351... 

Wisniewski, J. and G. Wisniewska (1997). Application of electrodialysis and cation exchange technique to water and acid recovery. Environ. Protection Eng., 23, 3-4, 35-45. 

Following the introductions of the cation exchange technique for separation of amino acids (Moore and Stein, 1951) and the development of the first automatic amino acid analyser (Spackman et al., 1958), amino-acid analysis became routine in clinical and biological research. 

Pt and Pd supported on silica or active carbon are prepared by a cationic exchange technique, using an aqueous solution of platinum or palladium tetra-mine hydroxide, Pt(NH3)4(OH)2 and Pd(NH3)4(OH)2, following the procedure already described [94]. 

Ru supported on silica is prepared by grafting of triruthenium dodecacarbonyl RU3CO12 onto the support followed by decomposition in vacuo at 373 K to form metallic ruthenium particles covered by adsorbed CO. Adsorbed CO is then removed at 673 K in vacuo. The procedure was described by TheoUer et al. [95]. Ni/alumina is a commercial catalyst supplied by IFP. Ni supported on silica is prepared by the cationic exchange technique, using an aqueous solution of hex-amine nickel hydroxide Ni(NH3)6(OH)2, following the procedure already described [96]. Ir supported on silica is prepared by decomposition of Ir(Acac)3 absorbed on the silica surface, following the procedure already described [97]. 

The most common applications of cation exchange techniques for Pu are... 

Cation-exchange techniques have nevertheless been the most widely used for the separation of ions of the same charge. Mixtures of closely related trivalent ions especially have been successfully handled in this way. The sorption coefficients admittedly do not differ widely. They decrease slightly with decreasing ionic radius of [182,183], i.e. contrary to what would be expected from the simplest electrostatic argument. The reversal is due to the fact that hydration becomes more extensive as the ionic radius decreases. This means that the radius of the hydrated ion increases, with a consequent decrease of the sorbability. 

Cation-Exchange Techniques In Radio-chemistry. N AS-NS 113 [ 19711, 7.50 Chemical Yield Determinations In Radio-chemistry, NAS-NS-3111 [1967], 5.50 Detection and Measurement of Nuclear Radiation, NAS-NS-3105 [1961], 6.00 Liquid-Liquid Extraction with High-Molecular-Weight Amines, NAS-NS-3101... 

---