Application of modified nanoclay as a sorbent for separation and preconcentration trace amounts of Tl+ ions

A procedure has been proposed for separation and preconcentration of trace amounts of thallium. It is based on the adsorption of thallium (I) ions onto organo nanoclay loaded with 1-(2-pyridylazo)-2-naphthol (PAN). Thallium (I) ions were quantitatively retained on the column in the pH range of 3.5-6.0, whereas quantitative desorption occurs with 5.0 mL of 5% ascorbic acid and thallium was determined by flame atomic absorption spectrometry. Linearity was maintained between 0.66 ng mL-1-15.0 μg mL-1 in initial solution. Detection limit was 0.2 ng mL-1 in initial solution and preconcentration factor was 150. Eight replicate determinations of 2.0 μg mL-1 of thallium in final solution gave a relative standard deviation of ±1.48%. Various parameters such as the effect of pH, breakthrough volume and interference of a large number of anions and cations have been studied and the proposed method was used to determine thallium (I) ions in water and standard samples. Determination of thallium ions in standard sample showed that the proposed method have good accuracy.

Keywords:

Preconcentration , Nanoclay , Thallium determination