Macías Mariana, Rodríguez de San Miguel Eduardo
Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Mexico City 04510, Mexico.
Membranes (Basel). 2023 May 12;13(5):512. doi: 10.3390/membranes13050512.
The synthesis and optimization of polymeric inclusion membranes (PIMs) for the transport of Cd(II) and Pb(II) and their separation from Zn(II) in aqueous saline media are presented. The effects of NaCl concentrations, pH, matrix nature, and metal ion concentrations in the feed phase are additionally analyzed. Experimental design strategies were used for the optimization of PIM composition and evaluating competitive transport. Synthetic seawater with 35% salinity, commercial seawater collected from the Gulf of California (Panakos), and seawater collected from the beach of Tecolutla, Veracruz, Mexico, were employed. The results show an excellent separation behavior in a three-compartment setup using two different PIMs (Aliquat 336 and D2EHPA as carriers, respectively), with the feed phase placed in the central compartment and two different stripping phases placed on both sides: one solution with 0.1 mol/dm HCl + 0.1 mol/dm NaCl and the other with 0.1 mol/dm HNO. The selective separation of Pb(II), Cd(II), and Zn(II) from seawater shows separation factors whose values depend on the composition of the seawater media (metal ion concentrations and matrix composition). The PIM system allows S(Cd) and S(Pb)~1000 and 10 < S(Zn) < 1000, depending on the nature of the sample. However, values as high as 10,000 were observed in some experiments, allowing an adequate separation of the metal ions. Analyses of the separation factors in the different compartments in terms of the pertraction mechanism of the metal ions, PIMs stabilities, and preconcentration characteristics of the system are performed as well. A satisfactory preconcentration of the metal ions was observed after each recycling cycle.
介绍了用于在盐水介质中传输Cd(II)和Pb(II)并将它们与Zn(II)分离的聚合物包容膜（PIMs）的合成与优化。此外，还分析了进料相中NaCl浓度、pH值、基质性质和金属离子浓度的影响。采用实验设计策略来优化PIMs的组成并评估竞争性传输。使用了盐度为35%的合成海水、从加利福尼亚湾采集的商业海水（帕纳科斯）以及从墨西哥韦拉克鲁斯州特科卢特拉海滩采集的海水。结果表明，在三室装置中使用两种不同的PIMs（分别以Aliquat 336和D2EHPA作为载体）时，分离行为良好，进料相置于中间隔室，两侧分别放置两种不同的反萃相：一种是含有0.1 mol/dm HCl + 0.1 mol/dm NaCl的溶液，另一种是含有0.1 mol/dm HNO的溶液。从海水中选择性分离Pb(II)、Cd(II)和Zn(II)，其分离因子的值取决于海水介质的组成（金属离子浓度和基质组成）。PIM系统可实现S(Cd)和S(Pb)~1000，10 < S(Zn) < 1000，具体取决于样品的性质。然而，在一些实验中观察到高达10,000的值，从而能够充分分离金属离子。还根据金属离子的萃取机制、PIMs的稳定性以及系统的预富集特性，对不同隔室中的分离因子进行了分析。在每个循环周期后，观察到金属离子有令人满意的预富集效果。
