Selective solid-phase extraction of trace thallium with nano-Al2O3 from environmental samples

A novel sorbent, nano-Al2O3 was employed for the separation and preconcentration of thallium from aqueous solution in batch equilibrium experiments. It was found that the adsorption percentage of thallium ions was close to 100% at pH 4.5, and the desorption by 1.0 mL of 0.25 M HCl reached 99%. The adsorption equilibrium was well described by the Langmuir isotherm model with maximum adsorption capacity of 5.78 mg/g (20 +/- 0.1A degrees C). The enrichment factor values of Tl(III) was 25 for 25 mL sample. Detection limit of thallium (3 sigma, n = 11) equal to 0.8 mu g/mL and relative standard deviation (2.4%) were obtained. The method has been successfully applied to the determination of trace thallium in some environmental samples and the certified reference material polymetallic nodule (GBW07296) with satisfactory results.