浮选萃取分光光度法测定痕量硅酸盐的研究

硅酸盐在盐酸介质中，与过量的钼酸铵形成ａ－硅钼杂多酸，在有机溶剂苯的存在下，可将过量的ＴＭＢ（３，３′，５，５′－四甲基联苯胺）氧化形成黄色的ＴＭＢ＾２＋亚胺盐，并形成离子缔合物，同时浮选分离进入苯层，再用萃取剂二甲亚砜－甲酸从苯反萃取。在４５８ｎｍ波长下有最大吸收，表观摩尔吸光系数为１．２６＊１０＾５Ｌ．同，在０．０２－１ｍｇ．Ｌ＾－１范围内Ｓｉ的含量符合比尔定律，线性相关系数ｒ为０．９９９５，可用于废水中硅酸盐的测定。该方法集富集与测定于一体，具有灵敏度高，选择性好，方便、快速的特点。

Flotation and Extraction Spectrophotometric Determination of Trace Silicate in Water

In HCl solution, silicate reacted with molybdate ammonium to produce silicomolibdic, then a yellow compound which was produced from the oxidation of TMB was simultaneously isolated to benzene phase by flotation and then isolated to dimethylsulfoxideformic acid by extraction. The compound gives a high absorption at 458 nm. The apparent molar absorptivity is 1.26 x 10(5) L.mol-1.cm-1. In the range of 0.02-1 mg.L-1 Si obeys Beer's law. The proposed method which combines with enrichment and measurement is simple, rapid, selective and convenient to determine silicate in water with satisfied results.