Selective solid phase extraction of mercury(II) by silica gel-immobilized-dithiocarbamate derivatives

A method is described for the selective extraction of mercury(II) from aqueous solutions as well as natural water samples, based on the use of four newly synthesized solid phase extractors via silica gel matrix-immobilized-iminodithiocarbamate derivatives (I-IV). The factors influencing the process of selective extraction of mercury(II) and 12 other metal ions were studied and evaluated as a function of pH of metal ion solution and equilibration shaking time. The values of metal capacity (mmol g(-1)) were determined for all metal ions and phases by the batch equilibrium technique. The four phases tested were found to exhibit excellent affinity towards selective extraction of mercury(II) in the presence of other interfering metal ions with the highest reported value corresponding to phase IV. Low interference of copper(II) ion was observed. The potential application of the four newly synthesized phases for the removal of mercury(II) from two natural water samples (drinking tap water and sea water) spiked with 100.0 and 5.0 mu g l(-1) of mercury(Il) was determined by the cold vapour atomic absorption technique and the results proved that excellent percent extraction of mercury(II) from both natural water samples (100 +/- 2%) by both phases III and IV was obtained with less or insignificant contributions by the matrix effects on the process of solid phase extraction of mercury(II). (C) 1999 Elsevier Science B.V. All rights reserved.