Distribution coefficient cation-exchange resin

The ratio of the distribution coefficients of pertechnetate and perrhenate is about 1.6 to 2, comparable to adjacent rare earth metals. Technetium and rhenium may be separated by ion-exchange chromatography. However, efficient separations require some care and tend to be slow. On the other hand, cation exchange resins adsorb technetiiun only to a negligible extent so that pertechnetate can be rapidly separated from cationic elements . 

Ka and Ke are the distribution coefficients of the two species present in equation (4.2). Using a cation exchange resin, a similar situation can be described. 

The distribution coefficient increases from La3+ to Lu3+ and then decreases with increasing Z. When citrate ion is used as eluant the elution sequence is the reverse of the order for cation exchange resins [50]. 

Fig. 42. Volume distribution coefficient of the elements vs HCl concentration for Dowex 50 X 4 cation exchange resin. Tracer concentrations of the elements were used for the most part.

Adachi S,WatanabeT,KohashiM.Role of swelling pressure on the distribution coefficient of maltool-igosaccharide in a cation-exchange resin. Agric Biol Chem 1989 53(12) 3203-8. 

Adachi S, Mkuno T, Matsuno R. Concentration-dependence of the distribution coefficient of maltooligosaccharides on a cation-exchange resin. J Chromatogr A 1995 708(2) 177—83. 

Consider a cation exchange resin in an aqueous solution containing Na2S04. Obtain the selectivity of the resin for the sodium cation over the sulfate anion if the activity based distribution coefficient of the anion between the resin and the external solution is 0.001. (Ans. 31, 630.)... 

The lonsiv ion exchange resins are extraction technologies used to separate radionuclides from alkaline wastewater in the presence of competing cations. These resins include lonsiv IE-910 and lonsiv IE-911, which are manufactured using a new class of crystalline silicotitanates (CSTs) invented by researchers from Sandia National Laboratory (SNL) and Texas A M University. CSTs demonstrate high distribution coefficients in acidic, neutral, and alkaline solutions with high concentrations of competitive ions such as sodium and potassium. The affinity of CSTs for strontium in neutral or alkaline wastes is also high. 

F W. E. Strelow and H. Sondorp, Distribution coefficients and cation-exchange selcctivitics of elements with AG50W-X8 resins in perchloric acid, Talama, 19, 1113,1972. 

The selectivity of sulfonated ion-cxchange resins for metal cations is often expressed qualitatively in terms of elution orders. Numerical selectivity data for cations are limited [3-5]. Strelow and co-workers [6-8] published comprehensive lists of distribution coefficients for metal ions with perchloric acid and other mineral acid eluents. However, their data are for sulfonated gel resins of high exchange capacity. 

Cation exchange chromatography The key step in this procedure is the direct transfer of the initial 0.1 N HCl Ga eluate to a cation exchanger. Due to high distribution coefficients, Ga is quantitatively adsorbed on only about 50 mg of the resin directly from the generator eluate. This effect also occurs with higher concentrations of HCl, e.g., 0.6 N HCl, as used for SnOa-based Ge/ Ga generators. Low volumes of 0.4-1.0 mL of hydrochloric acid/acetone mixtures... 

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