Robust, readily scalable, high-flux graphene oxide (GO) mixed matrix composite membranes were developed for organic solvent nanofiltration. Hydroxylated polybenzimidazole was synthesized by N-benzylation of polybenzimidazole with 4-(chloromethyl)benzyl alcohol, which was confirmed by FTIR and NMR spectroscopy. Flat-sheet composite membranes comprising of polybenzimidazoles and 1 or 2 wt % GO were fabricated via conventional blade coating and phase inversion. Subsequently, GO was covalently anchored to the hydroxyl groups of the polymer using a diisocyanate cross-linking agent. The even distribution of GO in the membranes was mapped by visible-light microscopy. Hydroxylation and incorporation of GO in the polymer matrix increased the permeance up to 45.2 ± 1.6 L m^–2 h^–1 bar^–1 in acetone, nearly 5 times higher than the unmodified benchmark membrane. The enhancement in permeance from the addition of GO did not compromise the solute rejection. The composite membranes were found to be tight in seven organic solvents, having molecular weight cut-offs (MWCO) as low as 140 g mol^–1. Permeance increased with increasing solvent polarity, while rejection of a 420 g mol^–1 pharmaceutical remained over 93%. The covalent anchoring resulted in robust composite membranes that maintained constant performance over 14 days in a continuous cross-flow configuration.

中文翻译：

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用于高通量有机溶剂纳滤的稳健的共价交联聚苯并咪唑/氧化石墨烯膜

开发了用于有机溶剂纳米过滤的坚固，易于扩展的高通量氧化石墨烯（GO）混合基质复合膜。通过聚苯并咪唑与4-（氯甲基）苄醇的N-苄基化反应合成羟基化的聚苯并咪唑，这通过FTIR和NMR光谱证实。通过常规的叶片涂覆和相转化来制备包含聚苯并咪唑和1或2重量％的GO的平板复合膜。随后，使用二异氰酸酯交联剂将GO共价锚定在聚合物的羟基上。GO在膜中的均匀分布通过可见光显微镜法绘制。羟基化和GO在聚合物基质中的掺入将磁导率提高到45.2±1.6 L m ^–2 h ^–1丙酮中的bar ^–1，比未改性的基准膜高近5倍。加入GO可以提高渗透率，但不会影响溶质截留率。发现该复合膜在七种有机溶剂中是致密的，分子量截留值（MWCO）低至140 g mol ^–1。渗透率随溶剂极性的增加而增加，而420 g mol ^–1药物的排斥率仍然超过93％。共价锚定产生坚固的复合膜，该膜在连续错流配置下可在14天内保持稳定的性能。