Abstract
Adsorption gel for metal ions was prepared from wastepaper by immobilizing primary amino groups by means of chemical modification. From the elemental analysis of the gel, it was found to contain a functional group as high as 4.1 mol/kg-dry gel. Adsorption behaviors for some base metals such as copper (II) and chromium (III and VI) in the pH region as well as precious metals such as gold (III), palladium (II) and platinum (IV) from hydrochloric acid were examined and compared with commercially available weakly basic anion exchange resin. Concerning the adsorption of base metals from the pH region, the order of the selectivity among metals tested was as follows: copper (II) >chromium (VI) >iron (III) >>zinc (II) >chromium (III) . On the other hand, gold (III), palladium (II) and platinum (IV) were quantitatively adsorbed over the whole concentration region of hydrochloric acid, while iron (III) and zinc (II) were not practically adsorbed. The selectivity to precious metals of the gel was found to be higher than that of the anion exchange resin. The maximum adsorption capacities for palladium (II), platinum (IV) and copper (II) were 1.6, 1.1 and 0.48 mol/kg-dry gel, respectively.
