用消除夹带溶胀的新液膜法测定汞

A New Method of Avoiding Entrainment Swelling in Liquid Surfactant Membrane for the Determination of Trace Hg(Ⅱ)

夹带溶胀分为包裹溶胀和再液化溶胀,消除液膜操作中的夹带溶胀对液膜的工业化具有重要意义。文章从油膜和水膜的寿命出发,讨论了夹带溶胀形成的过程,结果表明,不论何种表面活性剂,油膜寿命均比水膜寿命高出20～88倍,把油滴分散到水中,上浮聚集后不发生乳化;把乳状液滴分散到水中,上浮聚集后不发生溶胀。这样本法的溶胀率大大低于搅拌池操作法的溶胀率。作者用这种消除夹带溶胀的新液膜法与火焰原子吸收法相结合测定汞,方法的精密度为19%～23%,回收率为998%～1011%,可富集测定ng·g-1级的汞。本方法已用于废水中汞的分析。

Entrainment swelling consists of occlusion swelling and reliquefaction swelling. Entrainment swelling is significant to industrialized liquid surfactant membrane in the process of operation. The present study based on the life-span of W/O emulsion and O/W emulsion discussed the process of forming entrainment swelling. The result shows that no matter what surface-active agent was used, the life-span of W/O emulsion is 20-88 times longer than that of O/W emulsion. After oil drop was dispersed in water, no swelling was discovered, thus, the ratio of swelling is less than that by other method. The new method of determination of trace mercury by avoiding entrainment swelling in liquid surfactant membrane and FAAS is described. The precision(RSD) and recovery are 1.9%-2.3% and 99.8%-101.1% respectively. Hg^2+ at ng·g^-1 level can be enriched and determined. This method can be used in the determination of trace mercury in waste water.