研究了三乙醇胺(TEA)水溶液在电解质作用下的相分离及其通过形成TEA-Fe3+配合物实现三乙醇胺相对Fe3+的萃取,萃取过程将萃取剂和萃取溶剂合二为一。同时还讨论了表面张力、溶液提升率对火焰原子吸收光谱法(FAAS)测定三乙醇胺相中铁的影响。建立了TEA-K2HPO4-H2O双水相萃取、FAAS测定铁的新方法:在试液中加入1 mL三乙醇胺(1+1)和5 g K2HPO4后以水定容为10 mL,离心分离后用FAAS测定三乙醇胺相中的铁。线性范围20~240μg/L,检出限6.1μg/L(S/N=3),已用于自来水和井水中铁的萃取。
The phase separation of triethanolamine(TEA) solution in the presence of electrolytes and then extraction of iron in the solution into TEA-rich phase based on the formation of TEA-Fe3+ complex were developed.The triethanolamine was served as both extractant and extraction solvent in the extraction.The effect of surface tension and uptake rate on the determination of iron in TEA-rich phase by flame atomic absorption spectrometry(FAAS) was discussed at the same time.The suitable system for iron extraction was TEA-K2HPO4-H2O,in which iron mainly partitioned into the TEA-rich phase.Phase systems were prepared in a 10 mL graduated centrifuge tube by adding 1 mL of triethanolamine(1+1) and 5 g of dipotassium hydrogen phosphate,then being diluted to 10 mL with doubly-distilled water and centrifuged to facilitate phase separation.Linear calibration graph was obtained in the concentration range of 20~240 μg/L with a detection limit of 6.1 μg/L(S/N=3).The method was applied to extraction of iron in tap water and well water with satisfactory results.