The mode of action of iron(III) uptake from sulfate solutions by the commercial extractant CYANEX®272, bis(2,4,4-trimethylpentyl)phosphinic acid, has been studied using conventional solvent extraction methods, together with ³¹P{¹ H} NMR spectroscopy, electrospray ionisation mass spectrometry, and DFT calculations that have not previously been used to analyse the content of the ISOPAR M water-immiscible phase. The maximum Fe-loading recorded was 177% of the theoretical maximum, based on the formation of an Fe(III) complex [Fe(L)₃] with a 1:3 molar ratio of Fe to phosphinate (L). Inductively coupled plasma optical emission spectroscopy (ICP-OES) indicates that sulfate or hydrogen sulfate ions are co-extracted in a 1:2 molar ratio with iron across the whole of the Fe-loading range, which helps to account for the loadings being greater than 100% of the theoretical value. ³¹P{¹ H} NMR spectroscopy indicates that the limiting factor in Fe-loading is the availability of uncomplexed CYANEX®272 (sulfate is present in large excess). In contrast to the behaviour of Co(II) and Zn(II) extraction by CYANEX®272, there is no evidence for the formation of polymeric Fe(III) complexes and highly viscous solutions at high metal loadings. The identity of the extracted species is likely to be a polynuclear Fe(III) sulfate complex.

使用常规溶剂萃取方法和³¹ P { ¹  H一起研究了商业萃取剂CYANEX®272双（2,4,4-三甲基戊基）次膦酸从硫酸盐溶液中吸收铁（III）的作用方式。} NMR光谱法，电喷雾电离质谱法和DFT计算以前没有用于分析ISOPAR M与水不混溶相的含量。基于Fe（III）络合物[Fe（L）₃的形成，记录的最大Fe负载量为理论最大值的177％Fe与次膦酸酯（L）的摩尔比为1：3。电感耦合等离子体发射光谱法（ICP-OES）表明，在整个Fe负载范围内，硫酸根或硫酸氢根离子与铁以1：2摩尔比共萃取，这有助于说明负载较大超过理论值的100％。³¹ P { ¹ 1 H NMR光谱表明，铁负载的限制因素是未络合的272的可用性（存在大量硫酸盐）。与CYANEX®272提取Co（II）和Zn（II）的行为相反，没有证据表明在高金属负载下会形成聚合Fe（III）配合物和高粘度溶液。所提取物质的身份可能是多核硫酸铁（Ⅲ）配合物。