Dynamic sorption and desorption of gold using Spheron DEAE as sorbent

Abstract

The dynamic sorption and desorption of gold was studied using Spheron DEAE, a macroreticular hydroxyethyl methacrylate-ethylenedimethacrylate copolymer with chemically bonded diethylaminoethyl groups, as the sorbent. Factorial experiments were designed to optimize the composition of the mobile phase (H+ and Cl- ions); as a result, hydrochloric acid was used in a concentration of 0.01 mol l-1. Thiourea solution (0.4 mol l-1) in 0.25M hydrochloric acid served as the eluent: the gold sorbed was eluted completely in seven column volumes. A column of 1 cm3 volume retained gold quantitatively from 0.5 l of solution containing the metal in a concentration of 1 mg l-1 (5 μmol l-1); the recovery of gold by elution was 99% and the degree of concentration of gold with respect to the influent was a hundred. A method is worked out for a direct photometric determination of gold in the thiourea eluates, based on the decomposition of thiourea with hydrogen peroxide.