Comparative studies on the adsorption of Au(III) from waste rinse water of semiconductor industry using various resins

Comparative studies on the adsorption of gold from waste rinse water (Au 178.3 mg/L and trace Cu, Ni, Zn, Sn, etc) of the semiconductor manufacturing industry have been reported using nonionic Amberlite XAD-7HP, strong base Bonlite BA304, and Purolite A-500. Batch and column studies were carried out to optimize various process parameters such as contact time, acidity of solution, and resin dose for gold adsorption from waste rinse water and elution to get a gold-enriched solution. The results showed that Bonlite BA304 and Purolite A-500 resins could exchange gold easily at high acidity whereas Amberlite XAD-7HP adsorbs gold effectively at low acidity (adjusted pH = 0). Purolite A-500 was found to be the most suitable resin as it adsorbed 99.6% gold at an A/R ratio of 8.33 and a sorption capacity of 53.6 mg gold/mL resin. The mixture of acetone and hydrochloric acid at a volumetric ratio of 9.0 could elute gold loaded on Purolite A-500 resin to yield 10,497 mg gold/L. The adsorption behavior of gold on Amberlite XAD-7HP and Bonlite BA304 followed both the Langmuir and Freundlich isotherms. In the case of the Purolite A-500 resin, it followed suitably a Langmuir isotherm. Kinetic data for gold adsorption on the three resins followed a second-order rate.