Adsorption and Mutual Separation of Noble Metals Using Chitosan Modified by Propane Sultone

Chitosan modified by propane sultone (hereafter PSC) is prepared and the adsorption characteristics of noble metal ions are examined by using the chitosan resin. Gold, platinum and palladium are tried to separate in each other by using a glass column packed with PSC. Firstly, the chitosan derivative PSC having sulfonic group was prepared and crosslinked with ethylene glycol diglycidyl ether. IR spectra and elemental analyses were measured in order to evaluate the characteristics of PSC. Secondly, the adsorption and desorption experiments of the noble metals were carried out by a batch method and a continuous flow method using PSC. From the metal adsorption experiment in a batch method, it was found that the noble metals were adsorbed onto PSC through both sulfonic and amino groups. And thiourea dissolved in hydrochloric acid solution was found to be very effective to desorb the metals from PSC. In the separation of gold, platinum and palladium with PSC packed in the column, they were effectively separated by operating the column at pH 2.5. In the desorption step, 0.2 mol/dm 3 thiourea prepared using 0.1 mol/dm 3 hydrochloric acid made the adsorbed metals to desorb perfectly.