纳米氧化钛固相萃取环境样品中的铊

Solid-Phase Extraction of Thallium with Nano-TiO2 from Environmental Samples

研究了纳米TiO2对铊的固相萃取性能,考察了吸附的最佳pH值和吸附容量。实验表明,在最佳pH条件下,铊定量、快速地被吸附在纳米TiO2上,275,293,313 K时最大吸附容量分别为3.44 mg g-1,4.10 mg g-1,4.88 mg g-1,等温吸附线呈现可逆的Langmuir吸附形式。标准吸附自由能变ΔGθ为负值,表明该过程属自发的吸热反应。被吸附在纳米TiO2上的Tl(Ⅲ)能采用100℃水浴恒温10分钟定量洗脱,回收率达到98.24%。铊的检出限为0.49μg L-1,相对标准偏差(RSD%)为6.2%,该方法可应用于实际水样和多金属结核样品GBW07296中铊的测定。

The adsorption behavior of nano-TiO2 towards Thallium （TI） was investigated. The test included effect of pH on adsorption ra-tio, and adsorption capacity. Under the optimum conditions, TI （Ⅲ） ions could be adsorbed and recovered quantitatively. The maxi-mum adsorption capacity of thallium ions on nano-TiO2 was 3.44 mg g^-1, 4.10 mg g^-1, and 4.88 mg g^-1 at 275, 293 and 313 K, respec-tively. The Langmuir model could describe the adsorption of nano-TiO2 to TI （Ⅲ） ions successfully over the whole range of concentration studied. The negative value ofA G eshowed the adsorptions of TI （ Ⅲ ） by nano-Ti02 were a spontaneous process. For the elution of TI （lU）, the desorption percentage reached to 98.24% by the 100~C water bath heating 10 rain. Detection limits （3 ~ ） of 0.49 p, g L-~, relative standard deviation of 6.2% level were obtained. The methixt has been successfully applied for determination of trace elements thal-lium in some environmental samples and the certified reference material （GBW07296） .