State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China.
Environ Sci Technol. 2024 Apr 16;58(15):6835-6842. doi: 10.1021/acs.est.3c10497. Epub 2024 Apr 3.
Artificial ion channel membranes hold high promise in water treatment, nanofluidics, and energy conversion, but it remains a great challenge to construct such smart membranes with both reversible ion-gating capability and desirable ion selectivity. Herein, we constructed a smart MXene-based membrane via -phenylenediamine functionalization (MLM-PPD) with highly stable and aligned two-dimensional subnanochannels, which exhibits reversible ion-gating capability and ultrahigh metal ion selectivity similar to biological ion channels. The pH-sensitive groups within the MLM-PPD channel confers excellent reversible Mg-gating capability with a pH-switching ratio of up to 100. The mono/divalent metal-ion selectivity up to 1243.8 and 400.9 for K/Mg and Li/Mg, respectively, outperforms other reported membranes. Theoretical calculations combined with experimental results reveal that the steric hindrance and stronger PPD-ion interactions substantially enhance the energy barrier for divalent metal ions passing through the MLM-PPD, and thus leading to ultrahigh mono/divalent metal-ion selectivity. This work provides a new strategy for developing artificial-ion channel membranes with both reversible ion-gating functionality and high-ion selectivity for various applications.
人工离子通道膜在水处理、纳流控和能量转换等领域具有广阔的应用前景，但构建具有可逆离子门控能力和理想离子选择性的智能膜仍然是一个巨大的挑战。在此，我们通过 - 苯二胺功能化（MLM-PPD）构建了一种智能 MXene 基膜，具有高度稳定且排列整齐的二维亚纳米通道，表现出类似于生物离子通道的可逆离子门控能力和超高金属离子选择性。MLM-PPD 通道内的 pH 敏感基团赋予了出色的可逆 Mg 门控能力，pH 切换比高达 100。单/二价金属离子选择性分别高达 1243.8 和 400.9，优于其他报道的膜。理论计算结合实验结果表明，空间位阻和更强的 PPD-离子相互作用显著增加了二价金属离子通过 MLM-PPD 的能垒，从而导致超高的单/二价金属离子选择性。这项工作为开发具有可逆离子门控功能和高离子选择性的人工离子通道膜提供了新策略，可应用于各种领域。
