Ion exchange method for the separation of lanthanides?

Answer 1

although the chemical behaviour of all lanthanide ions are almost identical there are slight quantative differences which vary systematically from la to lu . The hydrated radii of ln ions for instance with increase in the atomic number . It is found that the larger the hydrated radius of the ion the less strongly it is bound to the anionic site of an exchange resin . When a solution containing several lanthanides pass slowly through a column of a cation exchange resin the heavier members come through first . The separation can be enhanced by the use of complexing agents like citricacid or citrates. a cation exchange rein like dowex-1 is normally used for adsorption of lanthanide ions . The column is eluted with EDTA . The lanthanides are eluted in the reverse order of their atomic numbers . Polycarboxylates,lactates,hydroxy butyrate and alpha hydroxy carboxylates also can be used as elements . ion exchange method has been used for separation of lanthanides in kilogram quantities for commercial uses