Transport of carboxylate salts of varying chain lengths in crosslinked polyether membranes
Transport of carboxylate salts of varying chain lengths in crosslinked polyether membranes
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DOI：
10.1016/j.memsci.2024.122584
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发表时间：
2024-03-18
影响因子：
9.5
通讯作者：
Beckingham，Bryan S.
中科院分区：
文献类型：
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作者：
Mazumder，Antara;Heist，Alexandra;Beckingham，Bryan S.
各种链长的羧酸根阴离子是许多应用中的重要分子，如CO2还原，膜生物反应器等。此外，羧酸根阴离子普遍存在于生物分子中，如氨基酸，脂肪酸等。因此，了解不同链长的羧酸根在聚合物材料中的传输行为是重要的，既作为一个基本现象，也为应用设计材料。在这里，我们通过测量一系列聚合物膜的渗透性（P）和总分配系数（K）来表征四种模型羧酸盐-甲酸钠盐（NaOFm），乙酸钠盐（NaOAc），丙酸钠盐（NaOPr），和丁酸盐（NaOBu）-在不同的上游盐浓度（0.1-1 M）或一系列基于聚乙二醇二丙烯酸酯（PEGDA）的膜，其具有1）不同的预聚合水含量; 2）变化的不带电侧链共聚单体（聚乙二醇甲基丙烯酸酯，PEGMA），和3）变化的带电共聚单体）2-丙烯酰胺基-2-甲基-1-丙磺酸，AMPS）。根据溶液扩散模型方程（P双键K × D）、实验获得的渗透率和总分配系数计算了四种盐在膜中的扩散系数。对于这些膜中的大多数，NaOFm的渗透性比其他三种羧酸盐（NaOAc、NaOPr和NaOBu）高得多，似乎是由于较低的链长和由此较小的水合直径。就总分配系数而言，未观察到基于尺寸的趋势。例如，NaOBu的总分配系数（K）通常是四种中最大的，并且在较高的上游盐浓度（1 M）下，四种盐的总分配系数的值收敛。由此，我们得出结论，羧酸盐通过这些基于PEGDA的无孔致密膜的传输主要是由动力学而不是吸附驱动的。
Carboxylate anions of various chain lengths are important molecules for many applications such as CO2reduction, membrane-based bioreactors, etc. Also, carboxylate anions are ubiquitous in biological molecules such as amino acids, fatty acids, etc. Therefore, understanding the transport behavior of carboxylates of different chain lengths in polymer materials is important both as a fundamental phenomenon but also for designing materials for applications. Here, we characterized transport behavior by measuring the permeability (P), and total partition coefficient (K) for a series of polymer membranes for four model carboxylate salts—sodium salts of formate (NaOFm), acetate (NaOAc), propionate (NaOPr), and butanoate (NaOBu)—at varied upstream salt concentrations (0.1–1 M) or a series of polyethylene glycol diacrylate (PEGDA)-based membranes with 1) varying pre-polymerization water content; 2) varying uncharged side chain comonomer (polyethylene glycol methacrylate, PEGMA), and 3) varying charged comonomer)2-acrylamido-2-methyl-1-propanesulfonic acid, AMPS). Also, diffusivity values of the four salts through the membranes have been calculated based on the solution diffusion model equation (Pdouble bondK × D), experimentally obtained permeability, and total partition coefficients. For a majority of these membranes, NaOFm's permeability is much higher than the other three carboxylate salts (NaOAc, NaOPr, and NaOBu) seemingly due to the lower chain length and thereby smaller hydrated diameter. In terms of total partition coefficient, a size-based trend is not observed. For example, NaOBu's total partition coefficient (K) is generally the largest among the four, and at higher upstream salt concentrations (1 M), the values of the total partition coefficients of the four salts converge. From this we conclude that the carboxylate salt transport through these PEGDA-based non-porous dense membranes to be primarily driven by kinetics and not sorption.