负载乙基紫的微晶酚酞吸附富集-分光光度法测定水中痕量钒

Determination of Trace Vanadium in Nature Water Samples with Spectrophotometry After Separation/Preconcentration on Microcrystalline Phenolphthalein Modified by Ethyl Violet

建立了以微晶酚酞作为吸附剂分离富集环境水样中痕量钒的新方法。研究表明,当pH值在3.7～7.0时,溶液中以V3O39-存在形式为主的钒,与乙基紫阳离子(EV+)形成的离子缔合物(V3O93-).(EV+)3能被微晶酚酞定量吸附,在钒被富集的同时并能使其与常见阳离子Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)、Al(Ⅲ)、Cu(Ⅱ)、Hg(Ⅱ)、Pb(Ⅱ)、Mn(Ⅱ)、Fe(Ⅲ)、Cr(Ⅲ)等完全分离,且基本不受能与EV+形成离子缔合物的阴离子SO24-、NO3-、Br-、Cl-、I-、ClO4-的影响。分别在1.0L不同环境水样中加入5.00mL1.0×10-3mol/LEV+及1.0mL0.10mol/LHCl(调溶液pH值约为4.0)和5.00mL15.8%的酚酞乙醇溶液,搅拌约50min,能够使水样中的痕量钒得到很好的富集。富集因数达100～200倍,回收率在98.0%以上,RSD为1.1%～2.3%。

The paper presents a novel method for the separation and preconcentration of vanadium with microcrystalline phenolphthalein as the sorbent. Experiments indicated that vanadium existed in the main form of V3 O9^3- at pH 3.7 - 7. 0, and vanadium reacted with Ethyl Violet （ EV^＋ ） to form an ion-association complex （ V3 O9^3- ） · （ EV^＋ ） 3 which was quantificationally adsorbed on the surface of microcrystalline phenolphthalein. At the same time, vanadium（V） was completely separated from Co（Ⅱ）, Ni（Ⅱ）, Zn（Ⅱ）, Cd（Ⅱ）, AI（ Ⅲ ）, Cu（ Ⅱ ）, Hg（ Ⅱ ）, Pb（ Ⅱ ）, Mn（ Ⅱ ）, Fe（ Ⅲ ）, Cr（ Ⅲ ） and hardly affected by SO4^2-, NO3^-, Br^-, Cl^-, I^-, ClO4^-. After 5.00 mLofl. 0×10^-3 mol/LEV^＋, 1.00 mLof0.10 mol/LHCl（the pH of the solution was adjusted to about 4.0） and 5.00 mL of 15.8% phenolphthalein solution were added in 1.0 L environmental water sample, the mixture was stirred for 50 min, and trace vanadium（ V ） can be completely enriched in the process of stirring. The preconcentration factor can reach 100 - 200. The recovery of V（ V ） is beyond 98.0%. The relative standard deviation RSD is 1.1% - 2.3%. The method is simple and the result of determination of trace vanadium is satisfactory.