Selective Separation and Trace Determination of Hg(II) From Environmental Samples Using New Modifier

A. M. El-Menshawy and A.A. El-Asmy*

Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, Egypt, aelasmy@yahoo.com

  Abstract: A preconcentration method based on the sorption of Hg(II) on silica gel coated with 1- isatin-4-phenylthiosemicarbazone(HIPTSC) for its determination spectrophotometrically and/or by cold vapor atomic absorption spectrometry (CVAAS) has been developed. The sorbed Hg(II) was eluted with 0.1 moll⁻¹ HCl. The effect of pH, stirring time and eluent concentration on the recovery of Hg(II) was examined. The influence of some matrices individually or in combination on the recovery of Hg(II) was investigated using the developed method. The results showed that 500 µg ml⁻¹ each of K⁺, Cl⁻, NO₃⁻ and NH₄⁺; 350 µg ml⁻¹ each of CH₃COO⁻ and F⁻ ; and 200 µg ml⁻¹ each of Ca²⁺, Al³⁺, Mg²⁺, Ni²⁺,  Mn²⁺, Co²⁺, Cu²⁺, Fe³⁺, Zn²⁺, Pb²⁺ and Cd²⁺ did not interfere with the Hg(II)  sorption. At the optimum conditions, the recovery of Hg(II) was found > 98 %. The relative standard deviation and detection limit of the method were found to be < 1.0% and 5 ng ml⁻¹, respectively. The adsorption isotherm of Hg(II) was studied and the binding equilibrium constant and adsorption capacity were calculated to be 8.60 l mg^-1 and 14.005 mg g⁻¹, respectively. The proposed method was successfully applied for the determination of Hg(II) in  binary mixtures and environmental water samples.

Key words: Mercury(II); Silica gel; HIPTSC; adsorption isotherm; CVAAS.

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