El-Mehalmey Worood A, Safwat Youssef, Bassyouni Mohamed, Alkordi Mohamed H
Center for Materials Science, Zewail City of Science and Technology, October Gardens, 6th of October, Giza 12578, Egypt.
ACS Appl Mater Interfaces. 2020 Jun 17;12(24):27625-27631. doi: 10.1021/acsami.0c06399. Epub 2020 Jun 4.
Despite the large number of reports on the utilization of highly microporous solids, most relevant are metal-organic frameworks (MOFs), in different demanding applications, the successful hybridization of MOFs and moldable polymer matrices into flexible, water-permeable membranes exhibiting strong entanglement of the MOF and the polymer matrix properties is still lacking. We describe herein an efficient pathway to construct a mixed-matrix membrane (MMM) comprising a water-stable metal-organic framework (UiO-66-NH), as the active sorbent, and cellulose acetate (CA), as the polymer matrix, to construct a flexible membrane for water treatment applications. The MOF@CA MMM demonstrated superior performance in terms of exceptional removal of organic dyes (both cationic and anionic species) as well as hexavalent Cr ions, compared to the control CA membrane. The recorded high uptake of the MOF@CA MMM for this wide array of contaminants demonstrated the accessibility of the MOF nanocages immobilized within the MMM, in contrast to the common perception that the polymer matrix might act as a physical barrier to block the accessibility of the MOF cages. The negative surface charge of the matrix exerted a notable action to affect the diffusion of the negatively charged contaminants to reach the active sorbent filler. Moreover, the formed membrane demonstrated high durability and recyclability with no detected loss of performance over numerous cycles. This approach outlines the ability to formulate one of the most water-stable MOFs, as exceptional microporous sorbent, into a usable membrane form compatible with real-life applications.
尽管有大量关于高微孔固体利用的报道，其中最相关的是金属有机框架（MOF），但在不同的苛刻应用中，仍缺乏将MOF与可模塑聚合物基体成功杂化，形成具有MOF与聚合物基体性能强缠结的柔性、透水膜的方法。我们在此描述了一种构建混合基质膜（MMM）的有效途径，该膜包含作为活性吸附剂的水稳定金属有机框架（UiO - 66 - NH）和作为聚合物基体的醋酸纤维素（CA），用于构建用于水处理应用的柔性膜。与对照CA膜相比，MOF@CA MMM在出色去除有机染料（阳离子和阴离子物种）以及六价铬离子方面表现出卓越性能。MOF@CA MMM对如此广泛的污染物具有高吸附量，这表明固定在MMM中的MOF纳米笼具有可及性，这与通常认为聚合物基体可能作为物理屏障阻碍MOF笼可及性的观点相反。基体的负表面电荷对影响带负电荷污染物扩散以到达活性吸附剂填料起到了显著作用。此外，所形成的膜表现出高耐久性和可回收性，在多个循环中未检测到性能损失。这种方法概述了将最具水稳定性的MOF之一，作为出色的微孔吸附剂，制成与实际应用兼容的可用膜形式的能力。
