Thesis (M.Sc.)--Chulalongkorn University, 2009

The activated carbons were modified with various potentially gold binding reagents by impregnation technique and their extraction efficiencies toward gold were evaluated. Tetrabutyl ammonium iodide (TBA) was found to be the most effective adsorbent for gold in terms of both extraction efficiency and speed. Various parameters were optimized around the preparation and utilization of this modified carbon in both batch and column methods. Several interfering ions commonly found in gold waste samples were found to have absolutely no effects to the extraction of gold. The adsorption isotherm was studied but no definite relation to any model was established. The breakthrough curve was used to demonstrate the improvement in gold extraction of the TBA-impregnated carbon over a commercial activated carbon and determine the adsorption capacity. The breakthrough capacity of the TBA-carbon and the commercial carbon were 90.62 and 18.00 mg/g respectively. The TBA-carbon was successfully applied to the recovery of gold from a real industrial waste sample.