Abstract
Individual adsorption of bismuth and copper on hydrous lead dioxide was investigated. Using differential pulse polarographic (d.p.p.) method to determine the metal ion concentrations before and after adsorption, the effects of hydrogen ion and metal ion concentrations and stirring time on the adsorption were evaluated. In acidic solution (pH 12), about 100 % adsorption of bismuth (0.4 mg) and about 0 % adsorption of copper (0.1 mg) on hydrous lead dioxide (HLD, 0.12 g calculated as PbO2·2 H2O) were observed with stirring from one to five hours. The adsorption capacity of HLD to bismuth was about 0.02 g Bi/g HLD. And then the possibility of separating bismuth {(5400) μg} from the solution (500 ml) containing copper (<30 g) by the coprecipitation was investigated. HLD collecting bismuth was dissolved with sodium oxalate, followed by addition of the supporting electrolyte containing sodium citrate, ethylenediaminetetraacetic acid and potassium nitrate. The solution was adjusted to pH 5.05.5 and filled up to 50 ml. Bismuth in the solution was analyzed by using d.p.p. method. The recovery of bismuth was about 100 % without interference from much copper and other coexistent elements, which were As(III), As(V), Sb(III), Sb(V), Fe(III) and Sn(II). This method was applied for the determination of bismuth in a copper metal standard sample, and bismuth amount shown in Table 3 was obtained. From these results, bismuth amount in the order of 10-5 % in a copper metal could be determined without laborious procedures.
