PRECONCENTRATION OF COPPER(II) AND ARSENIC(III) DIETHYLDITHIOCARBAMATES ON SILICA CHEMICALLY-MODIFIED WITH HEXADECYL GROUPS

Sorption of copper(II) and arsenic(III) as diethyldithiocarbamate (DED TC) complexes, which are formed in flow on silica chemically modified with hexadecyl groups, was studied. The pH range of the maximum sorpti on was determined. The recovery of complexes was studied as a function of the flow rate of solutions, the length of the mixer, and the conce ntrations of reactants. For copper, the ratio between the components o f the adsorbed complex was found (Cu : DEDTC = 1 : 2), and the conditi onal equilibrium constant at pH 7 was calculated. A procedure for dete rmining copper that includes preconcentration and subsequent atomic-ab sorption determination in eluates was proposed. Under the optimum cond itions, sorption of arsenic(III) was no higher than 80%.