Abstract
Collection of cobalt (II), nickel (II), copper (II), zinc(II), cadmium (II), mercury (II), and lead (II) with xanthated Sephadex (X-Sephadex) was invstigated by the batch system involving various salt solutions. Each metals were collected with X-Sephadex completely from 1 M solution of sodium nitrate, sodium chloride, and sodium bromide. Although mercury and copper were collected completely from 1×10-1 M and 1×10-2 M EDTA solution, respectively, the other metals were seriously affected by the presence of EDTA and the collection yields were lowered even by 1×10-5 M EDTA. Based on these findings, the separation of mercury and lead was carried out as follows. From 500 ml sample solution containing 5.00×10-4 mmol each of these metals, mercury was collected by stirring with 0.1 g of the X-Sephadex at pH 1.5. The X-Sephadex collecting mercury was filtered and then lead was collected with another fresh X-Sephadex from the filtrate after adjusting to pH 5.2. The respective X-Sephadex collecting mercury and lead was washed with water and the metals were dissolved with 10 ml of conc. hydrochloric acid for determination by atomic absorption. The separation of mercury or copper from other metals such as cobalt, nickel, cadmium, and lead was also successful by the similar procedure. The separation of copper and cadmium by the column system was carried out as follows. Both 5.00×10 -4mmol of copper and cadmium were collected together by passing 500 ml sample solution at pH 6.36.5 through a column packed with 0.2 g of X-Sephadex. Cadmium was eluted with 1×10-2 M EDTA solution and then copper was dissolved with a hot mixture of 30 % hydrogen peroxide (0.5 ml) and 18 N sulfuric acid (2 ml). Similarily, quantitative separation of copper from lead and mercury from cadmium was also achieved.
