SEPARATION AND PRECONCENTRATION OF GOLD USING MULTIWALLED CARBON NANOTUBES AS SOLID-PHASE EXTRACTION ADSORBENT

Modified multi walled carbon nanotubes were used as a solid sorbent for separation and preconcentration trace amounts of Au (III) ions. The sorption of Au3+ ions was quantitative in pH range of 2.0-5.0, whereas quantitative desorption occurs instantaneously with 5.0 mL of 2.0 mol L-1 Na2S2O3. The eluted solution was aspirated directly into the flame of atomic absorption spectrometry (FAAS). The proposed method permitted a large enrichment factor of 94. The precision of the method was ±1.11% (n=10, c=2.0 μg mL-1) and the limit of detection (3Sbl) was 0.15 ng mL-1. The calibration curve for Au3+ is linear between 0.53 ng mL-1 to 36.0 μg mL-1 in initial or 0.05 to 36.0 μg mL-1 in final solution with a correlation coefficient of 0.9999 (R2). The influences of the experimental parameters including sample pH, sample flow rate, eluent volume and eluent flow rate, sample volume, and interference of some ions on the recoveries of the gold ions were investigated. The proposed method was applied for preconcentration and determination of gold in different water samples

Keywords:

Carbon nanotubes , Preconcentration , Sorbent , Gold determination introduction