Separation and preconcentration of gold using benzoylthiourea immobilized silica gel

In this thesis, trace amounts of gold have been determined by flame absorption spectrometry after separation and preconcentration by N,N-diphenyl -N'-4 flouro benzoylthiourea (DPFBT) impregnated silica gel. Benzoylthiourea impregnated silica was characterized by FT-IR spectrometry method. Sorption and desorption behaviors of gold with DPFBT impregnated silica under optimized conditions (pH, stirring time, desorption of metals, sorption capacities, volume of sample solution and flow rate, eluent solution, volume of eluent and flow rate) have been studied in batch or column process. The best desorption solution was determined as thiourea in HCl solution. The flow rates for loading and stripping were optimized to 1 mL/min. The prepared silica sorbent was successfully used for the separation and enrichment of Au(III), additionally which has a good chemical stability, high reusability and faster rate of equilibrium. The effects of alkaline metals, common anions and some heavy metal ions as interferences were discussed.Metal ion capacity of DPFBT/silica was calculated as 3,30 µmol Au(III)/g DPFBT/silica for gold. Preconcentration factors of 2 and 10 µg L-1 gold(III) solutions were determined as 26 and 20 respectively in the optimized conditions by GFAAS.Due to the selective procedure, the proposed method is presented as preconcentration method which is not need to any interference elimination process. Moreover, the applicability and accuracy of the proposed method have been investigated using synthetic and real samples.