Indirect Determination of Sulfide by Extraction Flotation Spectrophotometry of Copper(II) with Ammonium Sulfate-Ethanol-Water System

Abstract

A new extraction flotation spectrum method for indirect determination of trace amounts of sulfide by ammonium sulfate-ethanol-water system was developed. It showed that Cu(II) could combine with S 2 - into precipitate (CuS) which was floated in the surface of ethanol and water in the presence of ammonium sulfate. The sulfide can be indirectly determined by determining the flotation yield of Cu(II). The linear range from 2.4 x 10 - 8 to 3.2 x 10 - 6 g/mL and the detect limit of 2.0 x 10 - 8 g/mL was achieved. The results showed the determination of S 2 - was not affected by Pb(II), Zn(II), Cd(II), Fe(II), Co(II), Ni(II), Mn(II) and Cl - , Br - , I - , etc. In the paper, the method was successfully applied to the determination of a trace amount of sulfide in polluted water samples with the advantages of simplicity of equipment, rapidity, low cost, etc.