三种体系萃取分离-液闪测定海水中234Th的比较研究

本文对TOA萃取剂萃取钍适宜的操作条件及萃取溶剂进行了试验,提出了TOA/苯萃取234Th的最佳条件: 在 1cm3含 234Th的 6mol/dm3 HNO3 溶液中,用体积比为 0. 5的TOA/苯溶液 2cm3 萃取,然后用 2cm3 1. 0mol/dm3 H2SO4反萃取,最高萃取率达 94%.对TOA/苯、TBP/煤油和TTA/苯这 3种萃取体系的萃取效率及其影响因素、萃取机理、成本等做了比较,认为 3种体系各有利弊,但均可有效地应用于相关的海洋学研究中.

Comparative study on separation of 234 Th in sea water with three extraction systems and determination using liquid scintillation spectrometer

A new method was established that ()~(234)Th in seawater was separated and purified by the anion-exchange combined trioctylamine (TOA)/benzene extraction, and then determined by the ultra low level liquid scintillation spectrometer(LSS) and the best extraction conditions were found. 1 cm~3 6 mol/dm~3 HNO_3 solution containing ()~(234)Th was extracted by TOA/benzene (volume ratio equal 0.5) for 1 min, then back-extracted with 1.0 mol/dm~3 H_2SO_4 for 1 min. Adding Mg(NO_3)_2 or (Al(NO_3)_3) to solution extracted would enhance about 10% extraction efficiency, and the highest efficiency was 94%.Three extraction systems, i.e., TOA/benzene, thenoyltrifluoroacetone(TTA)/benzene,and tributyl phosphate(TBP)/kerosene, could extract ()~(234)Th successfully, but their mechanisms differed. TBP extraction was based on simple physical partition, TTA system was extracted by formation of hydrophobe, and TOA system was extracted by formation of pseudosalt. Compared these extraction systems on feasible extraction procedure, efficiency and cost in detail, we considered that three systems can all be used to determine ()~(234)Th in seawater.