Au(III) Selective Adsorption of Quaternary Ammonium-Silica Hybrid in Au/Cu System

Adsorption of Au(III) has been studied for an Au/Cu binary system on quaternary ammonium-silica hybrid material (HAKS) in a batch system. HAKS used has 91,478 Ǻ pore diameter and has been synthesized by methylation reaction of amino-silica hybrid (HAS). Adsorbed metal ions were analyzed by AAS spectrophotometer and materials which have been interacted with the Au(III) were characterized by XRD. Adsorption of Au(III) was carried out as function of pH, contact time, and adsorbate concentration. Adsorption kinetics was determined by pseudo second order, Langmuir-Hinshelwood and Santosa model, while the adsorption isotherm is analyzed by the Langmuir and Freundlich models. Selective adsorption of Au(III) in binary Au/Cu system on HAS and HAKS is effective at pH 3. Adsorption kinetics studies showed that the adsorption of Au(III) on HAS and HAKS fits to pseudo second order model with adsorption rate constant of 31.89 and 2.08mg g-1 min-1. Both materials show a linear plot of Langmuir isotherm models with adsorption capacity on HAKS lower (7.09mg/g) than on HAS (63.25mg/g). HAKS also showed no higher selectivity coefficient for Au(III) toward Cu(II) than the HAS.