活性炭吸附-差示脉冲阳极溶出伏安法测定硫酸渣提取液中痕量铊

Determination of trace thallium in extraction solution from sulfuric acid slag by activated carbon adsorption-differential pulse anodic stripping voltammetry

研究了活性炭吸附-差示脉冲阳极溶出伏安法测定复杂基体（二种硫酸渣逐级提取液）中痕量铊的方法。讨论了伏安图的形成、测定底液和pH值的选择，研究了直接测定和分离测定（分离方式选择、有机物去除）的相态和方法。结果表明：炉底渣和沉灰渣的水相、粘土相和铁锰相提取液中的铊均可直接测定，炉底渣和沉灰渣有机相、碳酸盐相、硫化物相和硅酸盐相提取液中的铊用活性炭吸附分离，并用50～60℃ 50g／L的（NH4）2C2O4解吸，去除有机物后也可测定。本方法检出限为0．5μg／L，千倍浓度的9种阳离子共存或万倍浓度的8种阳离子单独存在时均不干扰。方法用于硫酸渣逐级提取液中铊的测定，结果同ICP—MS法的结果相一致。

A method for determination of trace thallium in sequential extraction solution with complicated matrix and from two kinds of sulfuric acid slags by activated carbon adsorption-differential pulse anodic stripping voltammetry was studied. The formation of voltammetry graph, base solution and the choice of pH were discussed. The phase state and method for both direct and separated determination , including the choice of separation form and removal of organic matter, were investigated. The results showed that thallium in extracted solution of water phase, clay phase ,iron and manganese phase of slag and dreg could all be determined directly. Thallium in extracted solution of organic phase ,carbonate phase,sulfide phase and silicate phase of slag and dreg can also be determined after it is adsorpted by activated carbon and then desorpted with 50 g/L （NH4）2 C204 at 50-60℃ to remove organic substances. The detection limit of this method was 0.5μg/L. There was＇t any interference in the solution containing 1 000 fold amount of nine coexisting cations and 10 000 fold amount of eight single cations. The method has been applied to the determination of thallium in sequential extracted solution of sulfuric acid slag , and the results are in good agreement with those obtain by ICP-MS.