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Selective pre-concentration and solid phase extraction of mercury(II) from natural water by aluminaloaded ammonium pyrrolidine dithiocarbamate phases

Ali Moghimi

Alumina phase loaded with ammoniumpyrrolidine dithiocarbamate (APDC )were synthesized based on chemical binding and physical adsorption approaches. The stability of a chemically modifiedAPDC especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of alumina immobilized APDC phase. The application of this alumina for sorption of a series of metal ions was performed by using different controlling factors such as the pH ofmetal ion solution and the equilibration shaking time by the static technique. This difference was interpreted on the basis of selectivity incorporated in these sulfur containing alumina phases. Hg(II) was found to exhibit the highest affinity towards extraction by these alumina phases. The pronounced selectivitywas also confirmed fromthe determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for mercury(II) to occur by alumina immobilizedAPDC phase. The potential applications of alumina immobilizedAPDC phase for selective extraction of mercury(II) to occur from aqueous solutionwere successfully accomplished aswell as pre- concentration of lowconcentration ofHg(II) (22 pg ml-1) from natural tap water with a pre-concentration factor of 200 for Hg(II) off-line analysis by cold vapor atomic absorption analysis.