Investigation of chelating dye impregnated resins for the selective adsorption and separation of trace metals from aqueous solutions
The preparation and characterisation of novel, high efficiency chelating sorbents which were suitable for the preconcentration and separation of trace metals from complex matrices using a single column has been described. Hydrophilic and hydrophobic substrates in the form of cellulose and polystyrene resins were modified with chelating dyes by either covalent bonding or physical adsorption respectively. Large particle size polystyrene resins were used for preliminary investigations of dye loading and metal retaining capacities. After crushing resins to an intermediate particle size, capacity factors (k' values) and metal retaining capacities of four resins were determined. One resin, MN200, was chosen for further investigations after crushing to a small particle size. A study of analytical separations and selectivities on the small particle size dye impregnated MN200, for a range of dyes, was used to determine the suitability for analytical and preparative applications. The selectivity and separating ability of the unmodified resin was also investigated. Three specific preparative and analytical applications were chosen which would exploit the metal separating capabilities of the modified or unmodified resins. The first of these studies was applied to the isolation of strontium from calcium, rubidium and barium in gypsum samples. The second involved the separation and determination of trace bismuth in lead and the third described the separation and determination of thorium and uranium from a complex metal containing matrix.