Recovery of gold (III) ions by thiourea- and urea-formaldehyde chelating resins

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) resins were synthesized and the recovery of Au3+ ions in aqueous solutions containing Cu2+ and Zn2+ ions by this chelating resins was studied.In the batch method studies with TF resin, the most appropriate acidic value for Au3+ adsorption was determined as 0.5 M HCl (pH=0.3) and Au3+ adsorption capasity of the resin was calculated as 29.67 mg Au3+/g. On the other hand, the optimum pH was 2 and Au3+ adsorption capacity was 17.54 mg Au3+/g with UF resin.Moreover the recovery and separation of Au3+ ions from Cu2+ and Zn2+ were examined by column method. In the column studies with TF, the adsorption capacities were found as 20.9 mg Au3+/g, 0.30 mg Cu2+/g and 0.002 mg Zn2+/g. On the other hand, the adsorption capacity with UF were 4.35 mg Au3+/g, 0.121 mg Cu2+ and 0.002 mg Zn2+/g. It was seen that Au3+ ions could be separated and recovered from Cu2+ and Zn2+ ions when TF resin was used. In addition the reusages of the resin were examined and it was seen that the resins were reusable.Keywords: Thiourea-formaldehyde, Urea-formaldehyde, Chelating resin, Gold(III) ions, Adsorption, Recovery