A combined experimental and molecular dynamics study revealed the role of oxygen debris (ODs) and functional groups on the nanofiltration performance of a graphene oxide (GO) membrane. A NaOH treatment removed ODs adsorbed onto the graphene oxide (DGO). COOH-decorated GO (CGO) was prepared by controlling the oxidation time of Hummer’s method, resulting in 45% of carbons with a COOH group. The water permeance of the prepared GO membrane without ODs was 1 order of magnitude greater than that of GO membranes in our experiments: 1.24, 1.59, and 14.7 L m^–2 h^–1 bar^–1 for GO, CGO, and DGO. However, the rejection of dye molecules below 1 nm in size was dramatically reduced without ODs, indicating that ODs play a critical role in rejecting molecules below 1 nm in size because of electrostatic and hydrogen bonding interactions and by narrowing the effective interlayer spacing, as noted in molecular simulations. Additionally, the CGO membrane displayed a similar separation performance compared to common GO membrane mainly decorated with OH and epoxy.

中文翻译：

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揭示氧气碎片和官能团在水通量和氧化石墨烯膜分子分离中的作用：结合实验和理论研究

结合实验和分子动力学研究，揭示了氧碎片（ODs）和官能团对氧化石墨烯（GO）膜的纳滤性能的作用。NaOH处理去除了吸附在氧化石墨烯（DGO）上的OD。通过控制悍马方法的氧化时间来制备装饰有COOH的GO（CGO），得到带有COOH基团的碳占45％。在我们的实验中，制备的不含OD的GO膜的透水性比GO膜的透水性大1个数量级：1.24、1.59和14.7 L m ^–2 h ^–1 bar ^–1适用于GO，CGO和DGO。但是，没有OD的情况下，染料分子尺寸小于1 nm的排斥率显着降低，这表明ODs在排斥尺寸小于1 nm的分子方面起着关键作用，这是由于静电和氢键相互作用以及通过缩小有效的层间间距而引起的，在分子模拟中。此外，与主要用OH和环氧装饰的普通GO膜相比，CGO膜表现出相似的分离性能。