Aas Determination of Some Trace Heavy Metals in Lake Van Water After Preconcentration by Complexation With Surface Functional Groups on Activated Carbon

Abstract

The adsorption of some trace heavy metals on a granulated, pure and activated carbon (Riedel-de Haen, 18002) was characterized assuming that it takes place by formation of complexes with functional groups, present in the activated carbon. The concentrations were determined for each element in aqueous suspension at constant acidity. An atomic absorption spectrometric method for the determination of the trace heavy metals (Zn, Pb, Cd, Cr, Ni, Cu, Co, Bi, Mn) in Lake Van water and that of the rivers flowing into the lake has been developed after adsorption of their diethyldithiocarbamate (DEDTC) complexes on activated carbon. Complexes were adsorbed on the adsorbent at pH 3.2 +/- 0.1. Trace heavy metal ions were elueted with 20 ml of 1 M HNO3 and determined by flame atomic absorption spectrometry (FAAS). Under optimum conditions, the trace heavy metal ions in aqueous samples were concentrated about 50-fold by column treatment and recovery rates of the investigated metals were in the range 79-106%.