Application of xanthine functionalized resin in speciation of chromium in natural water

Department of Chemistry, University of Burdwan. Golapbag, Burdwan-713 104, West Bengal. India

E-mail : arabindakdas@rediffmail.com; debasishbanerjebu@yahoo.com Fax : 91-342-2557938

Manuscript received 26 October 2005, revised 1 February 2006, accepted 7 February 2006

Separation and preconcentration of two forms of chromium viz. Cr^III and Cr^VI in natural ,water was carried out applying a resin containing xanthine moiety anchored onto polystyrene-divinylbenzene (8%) by azo (-N=N-) function. The maximum exchange capacity of Cr^III was found to be 0.6718 mmol g^-1 at pH 6.5 and that for Cr^VI was 1.1324 mmol g-1 at pH 1.0. The sorption of both Cr^III and Cr^VI onto resin follows a second order kinetics with rate constant values of 0.0-'7 and 0.410 mmol^-1 min^-1 for Cr^III and Cr^VI respectively. The two species Cr^III and Cr^VI arceluted completely by 3 M aud 4 M HCl respectively. The detection limits of 4.3 and 5.1 µg ml^-1 for Cr^III and Cr^VI were achieved. The optimum llow rate, sample breakthrough volume of column operation for Cr^III and Cr^VI species were found to be 1.2 ml min^-1 and 3000 ml respectively. Finally the developed method using this resin was applied for determination of these two species in synthetic binary mixtures, natural water samples and validated comparing with results using previously developed method.