Assembly of Defect-Free Microgel Nanomembranes for CO2 Separation.
Assembly of Defect-Free Microgel Nanomembranes for CO2 Separation.
复制标题
用于二氧化碳分离的无缺陷微凝胶纳米膜的组装。
DOI：
--
复制
发表时间：
2021
影响因子：
9.5
通讯作者：
I. Taniguchi
中科院分区：
文献类型：
--
作者：
Y. Hoshino;Tomohiro Gyobu;Kazushi Imamura;A. Hamasaki;Ryutaro Honda;Ryoga Horii;Chie Yamashita;Y. Terayama;Takeshi Watanabe;S. Aki;Yida Liu;J. Matsuda;Y. Miura;I. Taniguchi
开发坚固而薄的CO2分离膜，允许快速和选择性地渗透CO2，对于重新平衡全球碳循环至关重要。水凝胶由于其可调的化学性质和对溶质的特别高的扩散系数而成为有吸引力的膜材料。然而，它们的脆弱性阻碍了适用于气体分离的薄的无缺陷膜的制造。在这里，我们报告的组装无缺陷的水凝胶纳米膜的CO2分离。这样的膜可以通过将胶体水凝胶微粒（微凝胶）的水性悬浮液涂覆到平坦的、粗糙的或微图案化的多孔载体上来制备，只要孔是亲水性的并且孔径小于微凝胶的直径即可。微凝胶颗粒的可变形性使得能够从变形的15 nm厚的盘状颗粒自主组装无缺陷的30-50 nm厚的膜层。显微镜分析证实，毛细力驱动的水渗透到孔中有助于在孔上组装无缺陷的致密水凝胶层。虽然干燥的膜没有显示出显着的CO2渗透性，即使在胺基团的存在下，渗透性显着增加时，膜充分水合形成水凝胶。该结果表明膜中的自由水对于实现碳酸氢根离子的快速扩散的重要性。由含胺微凝胶颗粒组成的水凝胶纳米膜显示出对燃烧后气体的选择性CO2渗透（850 GPU，αCO2/N2 = 25）。掺杂胺的含酸微凝胶膜对燃烧后气体（1010 GPU，αCO2/N2 = 216）和直接空气捕获（1270 GPU，αCO2/N2 = 2380）表现出高度选择性的CO2渗透。本文报道的成膜机理将提供洞察软物质的自组装。此外，通过可变形微凝胶的自主组装来制造水凝胶纳米膜的通用策略将能够大规模制造高性能分离膜，从而允许从燃烧后气体和大气中低成本地捕获碳。
The development of robust and thin CO2 separation membranes that allow fast and selective permeation of CO2 will be crucial for rebalancing the global carbon cycle. Hydrogels are attractive membrane materials because of their tunable chemical properties and exceptionally high diffusion coefficients for solutes. However, their fragility prevents the fabrication of thin defect-free membranes suitable for gas separation. Here, we report the assembly of defect-free hydrogel nanomembranes for CO2 separation. Such membranes can be prepared by coating an aqueous suspension of colloidal hydrogel microparticles (microgels) onto a flat, rough, or micropatterned porous support as long as the pores are hydrophilic and the pore size is smaller than the diameter of the microgels. The deformability of the microgel particles enables the autonomous assembly of defect-free 30-50 nm-thick membrane layers from deformed ∼15 nm-thick discoidal particles. Microscopic analysis established that the penetration of water into the pores driven by capillary force assists the assembly of a defect-free dense hydrogel layer on the pores. Although the dried films did not show significant CO2 permeance even in the presence of amine groups, the permeance dramatically increased when the membranes are adequately hydrated to form a hydrogel. This result indicated the importance of free water in the membranes to achieve fast diffusion of bicarbonate ions. The hydrogel nanomembranes consisting of amine-containing microgel particles show selective CO2 permeation (850 GPU, αCO2/N2 = 25) against post-combustion gases. Acid-containing microgel membranes doped with amines show highly selective CO2 permeation against post-combustion gases (1010 GPU, αCO2/N2 = 216) and direct air capture (1270 GPU, αCO2/N2 = 2380). The membrane formation mechanism reported in this paper will provide insights into the self-assembly of soft matters. Furthermore, the versatile strategy of fabricating hydrogel nanomembranes by the autonomous assembly of deformable microgels will enable the large-scale manufacturing of high-performance separation membranes, allowing low-cost carbon capture from post-combustion gases and atmospheric air.