The influence of amine structure on the mechanism of CO2 facilitated transport across amine-functionalized polymer membranes: An operando spectroscopy study
The influence of amine structure on the mechanism of CO2 facilitated transport across amine-functionalized polymer membranes: An operando spectroscopy study
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DOI：
10.1016/j.memsci.2023.122163
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发表时间：
2023-10
影响因子：
9.5
通讯作者：
Hui Xu;Sarah G. Pate;C. O'Brien
中科院分区：
文献类型：
--
作者：
Hui Xu;Sarah G. Pate;C. O'Brien
本文利用操作表面增强拉曼光谱（Sers）和原位透射傅里叶变换红外光谱（FTIR）研究了胺功能化聚合物膜中的胺结构（仲胺、叔胺、吡啶胺）对CO2跨膜传输机理的影响。具体地，通过测量膜的CO2渗透率/选择性并同时检测CO2传输中间体（例如，氨基甲酸盐，碳酸氢盐）在操作条件下使用Sers和FTIR光谱在膜中形成。虽然渗透测量表明，CO2移动通过一个促进运输机制的所有膜，operandoSERS andin-situFTIR结果表明，促进运输过程的分子水平的细节是高度敏感的胺官能团的结构。对于具有仲胺（PMVAm）和叔胺（PDVAm）的膜，CO2作为氨基甲酸盐和碳酸氢盐物质的混合物穿过膜。对于P4 VP，它具有吡啶胺基团，没有CO2衍生的中间体被检测到，这表明一个新的促进运输机制，涉及CO2和吡啶氮基团之间的弱相互作用，而不转化为氨基甲酸酯，碳酸氢盐，或其他中间物种的CO2。据我们所知，这种易化转运机制在文献中尚未报道。
The influence of the amine structure (secondary, tertiary, pyridinic) in amine-functionalized polymeric membranes on the mechanism of CO2transport across the membrane is investigated in this work usingoperandosurface enhanced Raman spectroscopy (SERS) andin-situtransmission FTIR spectroscopy. Specifically, the mechanism of CO2transport across poly-N-methyl-N-vinylamine (PMVAm), poly-N, N-dimethyl-N-vinylamine (PDVAm), and poly(4-vinylpyridine) (P4VP) membranes was investigated by measuring CO2permeances/selectivities of the membranes and simultaneously detecting CO2transport intermediates (e.g., carbamate, bicarbonate) formed in the membrane under operating conditions using SERS and FTIR spectroscopy. While permeation measurements suggest that CO2moves across all membranes via a facilitated transport mechanism,operandoSERS andin-situFTIR results suggest that the molecular-level details of the facilitated transport process are highly sensitive to the structure of the amine functional group. For membranes with secondary (PMVAm) and tertiary (PDVAm) amines, CO2moves across the membrane as a mixture of both carbamate and bicarbonate species. For P4VP, which has pyridinic amine groups, no CO2-derived intermediates were detected suggesting a new facilitated transport mechanism involving weak interactions between CO2and the pyridinic nitrogen group without transformation of CO2into carbamate, bicarbonate, or other intermediate species. Such a facilitated transport mechanism has not been reported in the literature to our knowledge.