Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-601 74 Norrköping, Sweden.
RISE Research Institutes of Sweden, Bio- and Organic Electronics, Bredgatan 33, SE-602 21 Norrköping, Sweden.
Carbohydr Polym. 2022 Feb 15;278:118938. doi: 10.1016/j.carbpol.2021.118938. Epub 2021 Nov 26.
Ion selective membranes are at the heart of energy conversion and harvesting, water treatment, and biotechnologies. The currently available membranes are mostly based on expensive and non-biodegradable polymers. Here, we report a cation-selective and low-cost membrane prepared from renewable nanocellulose and 1,2,3,4-butanetetracarboxylic acid which simultaneously serves as crosslinker and source of anionic surface groups. Charge density and structure of the membranes are studied. By using different degrees of crosslinking, simultaneous control over both the nanochannel structure and surface charge concentration is achieved, which in turn determines the resulting ion transport properties. Increasing negative charge concentration via higher crosslinker content, the obtained ion conductivity reaches up to 8 mS/cm (0.1 M KCl). Optimal ion selectivity, also influenced by the solution pH, is achieved at 20 wt% crosslinker addition (with ion conductivity of 1.6 mS/cm). As regular ~1.4 nm nanochannels were formed at this composition, nanofluidic contribution to ion transport is likely.
离子选择性膜是能量转换和收集、水处理和生物技术的核心。目前可用的膜大多基于昂贵且不可生物降解的聚合物。在这里，我们报告了一种由可再生纳米纤维素和 1,2,3,4-丁烷四羧酸制备的阳离子选择性和低成本膜，该膜同时用作交联剂和阴离子表面基团的来源。研究了膜的电荷密度和结构。通过使用不同程度的交联，可以同时控制纳米通道结构和表面电荷浓度，从而决定了离子传输性能。通过增加更高交联剂含量来增加负电荷浓度，获得的离子电导率高达 8 mS/cm（0.1 M KCl）。通过添加 20 wt%的交联剂（离子电导率为 1.6 mS/cm），可以达到最佳的离子选择性，这也受到溶液 pH 值的影响。在这种组成下形成了规则的约 1.4nm 纳米通道，因此很可能对离子传输有纳滤流的贡献。
