Graphene oxide (GO) membranes can purify wastewater due to their unique two-dimensional channels, but they are susceptible to mechanical damage during use, which reduces membrane performance. In this paper, EGO nanosheets were prepared by grafting ethylenediamine (EDA) small molecules onto GO at high temperatures and introducing aldehyde groups on the molecular chain of double aldehyde cellulose nanocrystals (DACNC), which reacted with reactive amino groups on the surface of the EGO nanosheets via a Schiff base reaction to create interlayer nanochannels in the composite membrane. The best performing EGO-DACNC24 composite membranes were prepared by adding different aldehyde substitution degrees and different amounts of DACNC to mediate the crosslinked interlayer nanochannels and network structure of the composite membranes. The water flux is more than 10 times that of pure GO membrane, and the rejection rate of dye molecules larger than 400 Da is always more than 99%. Excellent separation results are achieved after 120 h of operation due to the structural stability of the membrane resulting from chemical cross-linking. Damaged in practical applications, small amounts of added DACNC can achieve self-healing through the synergistic effect of dynamic Schiff base and hydrogen bonding interactions.

中文翻译：

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基于二醛纤维素纳米晶和乙二胺的GO纳滤膜的自修复特性有助于染料的高效分离

氧化石墨烯（GO）膜由于其独特的二维通道可以净化废水，但在使用过程中容易受到机械损坏，从而降低膜性能。本文通过在高温下将乙二胺（EDA）小分子接枝到GO上，并在双醛纤维素纳米晶（DACNC）分子链上引入醛基，与EGO表面的活性氨基反应，制备了EGO纳米片。通过希夫碱反应形成纳米片，在复合膜中形成层间纳米通道。通过添加不同的醛取代度和不同量的DACNC来调节复合膜的交联层间纳米通道和网络结构，制备了性能最佳的EGO-DACNC24复合膜。水通量是纯GO膜的10倍以上，对大于400Da的染料分子截留率始终保持在99%以上。由于化学交联产生的膜结构稳定性，运行 120 小时后可实现优异的分离结果。在实际应用中损伤时，少量添加DACNC可以通过动态席夫碱和氢键相互作用的协同作用实现自修复。