Abstract Metal-organic frameworks (MOFs) have attracted extensive attention in catalysis and adsorption fields due to the large surface area and tunable pore structure, however MOFs have not been so broadly exploited for water treatment primarily due to their low water stability and hydrophilicity. In this study, a kind of MOFs, poly(acrylic acid) (PAA) modified UiO-66-NH2 (UiO-66-NH2@PAA), was first synthesized and used to fabricate membranes via vacuum-assisted self-assembly process. Owing to the high water adsorption ability of MOF, abundant hydrophilic, negatively-charged carboxyl groups and high surface roughness, the membranes exhibited high hydrophilicity and underwater superoleophobicity, and thus better antifouling performance. Owing to the ionization and deionization ability of carboxyl groups, the membranes exhibited good stability in the pH range from 1 to 11. Owing to the existence of chemical and hydrogen bond interactions, the membranes exhibited improved multicycle stability. Accordingly, the MOF membranes exhibited high separation efficiency for oil/water emulsion (rejection > 99.9%). Under optimum conditions, the pure water flux was 2330 L m−2 h−1 bar−1 and the flux recovery ratio (FRR) after 3 cycles separation of oil/water emulsion maintained over 80%, manifesting great potential of MOF membranes in oil/water separation.

中文翻译：

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用于油水分离的具有水下超疏油性的自组装 MOF 膜

摘要 金属有机骨架材料（MOFs）由于具有较大的表面积和可调的孔结构，在催化和吸附领域引起了广泛关注，但主要由于其低的水稳定性和亲水性，MOFs在水处理中并没有得到如此广泛的应用。在这项研究中，首先合成了一种 MOF，聚（丙烯酸）（PAA）改性的 UiO-66-NH2（UiO-66-NH2@PAA），并用于通过真空辅助自组装工艺制造膜。由于MOF的高吸水能力、丰富的亲水性、带负电荷的羧基和高表面粗糙度，膜​​表现出高亲水性和水下超疏油性，从而具有更好的防污性能。由于羧基的电离和去离子能力，该膜在 1 到 11 的 pH 范围内表现出良好的稳定性。由于存在化学和氢键相互作用，膜表现出改善的多循环稳定性。因此，MOF 膜对油/水乳液表现出很高的分离效率（拒绝率 > 99.9%）。在最佳条件下，纯水通量为2330 L m-2 h-1 bar-1，油水乳液分离3次循环后通量回收率（FRR）保持在80%以上，显示出MOF膜在油中的巨大潜力/水分离。