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 semiconductor manufacturing industry have been
reported using non-ionic 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 gold enriched solution. The results showed that
Bonlite BA304 and Purolite A-500 resin 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
A/R ratio of 8.33, and sorption capacity 53.6 mg gold/mL-resin. The mixture of acetone
and hydrochloric acid at volumetric ratio 9.0 could elute gold loaded on Purolite
A-500 resin to yield 10497 mg gold/L. The adsorption behavior of gold on Amberlite
XAD-7HP and Bonlite BA304 followed the both Langmuir and Freundlich isotherms.
In the case of Purolite A-500 resin, it followed suitably a Langmuir isotherm. Kinetic
data for gold adsorption on the three resins followed a second-order-rate.