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Separation of copper(II) and aluminium(III) from fresh waters by solid phase extraction on a complexing resin column

The solid-phase extraction (SPE) of copper(II) and aluminium(III) from fresh waters on an ion-exchange complexing resin containing iminodiacetic groups (Chelex 100) has been examined. Quantitative recovery of the metal ions was related to the breakthrough profile that, for some samples, could not be evaluated directly. A method is suggested for evaluation, instead, of the sorption curves, on the basis of passing different volumes of sample through the column. This enables evaluation of important properties, for instance the central point of the breakthrough curve, V t . The column used was a small one, containing 0.10 g dry Chelex 100. The metal ion was eluted with a small volume of acid solution, 10 mL of 0.5 mol L -1 HNO 3 ; this resulted in good preconcentration factors. For copper(II) it was found that fresh waters of similar composition could have different V f in the same column. This was ascribed to different reaction coefficients (α M(I) ) of copper(II) in the considered samples, which affects V f . By use of the proposed SPE procedure it is possible to evaluate the reaction coefficient of copper(II). The values of α M(I) for two different drinking waters at pH 7.7 were found to be 3.70 x 10 12 and less than 4.40 x 10 11 . Similar results were obtained for aluminium(III).