Hydrophilicity gradient in covalent organic frameworks for membrane distillation
Hydrophilicity gradient in covalent organic frameworks for membrane distillation
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DOI：
10.1038/s41563-021-01052-w
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发表时间：
2021-07
期刊：
影响因子：
41.2
通讯作者：
Shuang Zhao;Chenghao Jiang;Jingcun Fan;S. Hong;Pei Mei;Ruxin Yao;Yilin Liu;Sule Zhang
中科院分区：
文献类型：
--
作者：
Shuang Zhao;Chenghao Jiang;Jingcun Fan;S. Hong;Pei Mei;Ruxin Yao;Yilin Liu;Sule Zhang
海水淡化有助于缓解世界面临的淡水危机。热驱动膜蒸馏是一种很有前途的方法，通过利用低品位的热量来净化来自各种盐水和污染源的水。然而，由于缺乏精确的结构控制，膜蒸馏膜的渗透性和润湿性有限。在这里，我们报告了一种策略，制造膜蒸馏膜组成的垂直对齐的通道与亲水性梯度工程缺陷的共价有机框架膜的亚胺键的去除。单个通道中的这种功能变化使得能够实现选择性的水输送途径和精确的液体-蒸气相变界面。除了具有抗污染和抗润湿能力之外，支撑层上的共价有机框架膜在85 °C进料和16 kPa绝对压力下显示出600 lm-2 h-1的通量，这几乎是用于脱盐的现有技术膜蒸馏膜的通量的三倍。研究结果对分子筛用梯度膜的发展有一定的促进作用。
Desalination can help to alleviate the fresh-water crisis facing the world. Thermally driven membrane distillation is a promising way to purify water from a variety of saline and polluted sources by utilizing low-grade heat. However, membrane distillation membranes suffer from limited permeance and wetting owing to the lack of precise structural control. Here, we report a strategy to fabricate membrane distillation membranes composed of vertically aligned channels with a hydrophilicity gradient by engineering defects in covalent organic framework films by the removal of imine bonds. Such functional variation in individual channels enables a selective water transport pathway and a precise liquid–vapour phase change interface. In addition to having anti-fouling and anti-wetting capability, the covalent organic framework membrane on a supporting layer shows a flux of 600 l m–2h–1with 85 °C feed at 16 kPa absolute pressure, which is nearly triple that of the state-of-the-art membrane distillation membrane for desalination. Our results may promote the development of gradient membranes for molecular sieving.