Zhu Jiani, Wang Lei, Wang Jin, Wang Fudi, Tian Mengtao, Zheng Shuchang, Shao Ning, Wang Lele, He Miaolu
Research Institute of Membrane Separation Technology of Shaanxi Province, Key Laboratory of Membrane Separation of Shaanxi Province, School of Environmental & Municipal Engineering, Xi'an University of Architecture and Technology, No. 13 Yan Ta Road, Xi'an 710000, China.
ACS Nano. 2020 Nov 24;14(11):15306-15316. doi: 10.1021/acsnano.0c05649. Epub 2020 Nov 13.
Two-dimensional (2D) membranes exhibit exceptional properties in molecular separation and transport, which reveals their potential use in various applications. However, ion sieving with 2D membranes is severely restrained due to intercalation-induced swelling. Here, we describe how to efficiently stabilize the lamellar architecture using Keggin Al polycations as pillars in a TiCT membrane. More importantly, interlayer spacing can be easily adjusted with angstrom precision over a wide range (2.7-11.2 Å) to achieve selective and tunable ion sieving. A membrane with narrow -spacing demonstrated enhanced selectivity for monovalent ions. When applied in a forward osmosis desalination process, this membrane exhibited high NaCl exclusion (99%) with a fast water flux (0.30 L m h bar). A membrane with wide -spacing showed notable selectivity, which was dependent on the cation valence. When it was applied to acid recovery from iron-based industrial wastewater, the membrane showed good H/Fe selectivity, which makes it a promising substitute for traditional polymeric membranes. Thus, we introduce a possible route to construct 2D membranes with appropriate structures to satisfy different ion-sieving requirements in diverse environment-, resource-, and energy-related applications.
二维（2D）膜在分子分离和传输方面表现出卓越的性能，这揭示了它们在各种应用中的潜在用途。然而，由于插层诱导的膨胀，二维膜的离子筛分受到严重限制。在这里，我们描述了如何在TiCT膜中使用Keggin型铝聚阳离子作为支柱来有效稳定层状结构。更重要的是，层间距可以在很宽的范围内（2.7 - 11.2 Å）以埃级精度轻松调节，以实现选择性和可调谐的离子筛分。具有窄间距的膜对单价离子表现出增强的选择性。当应用于正向渗透脱盐过程时，该膜表现出高的NaCl截留率（99%）和快速的水通量（0.30 L m⁻² h⁻¹ bar⁻¹）。具有宽间距的膜表现出显著的选择性，这取决于阳离子的价态。当应用于从铁基工业废水中回收酸时，该膜表现出良好H⁺/Fe²⁺选择性，这使其成为传统聚合物膜的有前途的替代品。因此，我们引入了一条构建具有适当结构的二维膜的可能途径，以满足在不同环境、资源和能源相关应用中不同的离子筛分要求。
