Extraction method using thermo-responsive polymer : equilibrium analysis, and new enrichment technique for trace metals

使用热响应聚合物的萃取方法：平衡分析和痕量金属的新富集技术

• 批准号: 15550061
• 负责人: KIKUCHI Yoichi
• 金额: $ 2.37万
• 依托单位: Iwate University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15550061/
• 关键词: thermo-responsive polymer; PVME; extraction; preconcentration; tetraalkylammonium salts; copper; 海水; キレート抽出; 第四級アンモニウム塩; カドミウム; イオン対抽出

Some kind of water-soluble polymers, including poly (vinyl methyl ether)(PVME), in aqueous solutions exhibit a lower critical solution temperature (LCST)(for PVME around 308 K). They are water-soluble at low temperatures but their heating above the LCST results in phase separation. By the phase separation, certain hydrophobic substances in aqueous solution are efficiently incorporated into the polymer phase, and thus, such thermo-responsive polymers can be used as an extracting medium.In this study, the distribution equilibria of 8-quinolinolate metal chelates system and ion pairs of tetraalkylammonium salts system into temperature-induced separation phase of PVME have been investigated at 323 K. From an analysis of the distribution data, we can elucidate the distribution equilibria, and values of the extraction constant, K_<ex>. These results of polymer-mediated extraction were compared with those in conventional solvent extraction in order to clarify the natures of the polymer phase.Moreover, we have developed new preconcentration technique using themo-responsive polymer (PVME) for the determination of trace metal ions. As the model case of this technique, we established the optimum conditions for quantitave extraction of the ion pair of the copper-neocuproine chelate with picrate ion into the polymer phase having the very small volume. After dissolving the polymer phase in a small amount of acetone, the solution was analyzed by graphite AAS. This method was successfully applicable to the determination of copper in sea water.

一些水溶性聚合物，包括聚（乙烯基甲基醚）（PVME），在水溶液中表现出较低的临界溶解温度（LCST）（PVME约308 K）。它们在低温下是水溶性的，但加热到LCST以上会导致相分离。本文研究了323 K下8-羟基喹啉金属螯合物体系和四烷基铵盐离子对体系在PVME温度诱导分离相中的分配平衡。通过对分布数据的分析，我们可以阐明分布平衡和萃取常数K_（<ex>？）将聚合物介质萃取的结果与传统溶剂萃取的结果进行了比较，以阐明聚合物相的性质，并建立了一种新的热响应聚合物（PVME）富集技术，用于痕量金属离子的测定。作为该技术的模型，我们确定了苦味酸根离子与铜-新亚铜灵螯合物离子对定量萃取到体积很小的聚合物相中的最佳条件。在将聚合物相溶解在少量丙酮中之后，通过石墨AAS分析溶液。该方法已成功地应用于海水中铜的测定。