Adsorption and pre-concentration of some metal ions from ethanol on silica gel modified with pyridinium ion

Abstract

Silica gel modified with pyridinium ions has been developed for the adsorption of metal ions from ethanol. This material was used to remove cobalt, copper, zinc, cadmium and mercury and can be employed for the pre-concentration of these metals by the column technique. These metals are eluted selectively from the column by a C₂H₅OH-H₂O binary mixture. For the elution mixture with a mole fraction of 0.5, the observed order is: Co ∼ Cd (ca. 96%) > Cu ∼ Zn (ca. 30%) > Hg (not eluted). All the metals, except Hg can be eluted quantitatively from the column with pure water. Mercury is recovered totally if an aqueous solution of 0.1 M HNO₃ is used as the eluent.