Graphene oxide (GO) membranes enabled by subnanosized diffusion channels are promising to separate small species in membrane distillation (MD). However, the challenge of effectively excluding small volatiles in MD persists due to the severe swelling and subsequent increase in GO interlamination spacing upon direct contact with the hot feed. To address this issue, we implemented a design in which a polymer is confined between the GO interlaminations, creating predominantly 2D nanochannels centered around 0.57 nm with an average membrane pore size of 0.30 nm. Compared to the virginal GO membrane, the polymer-intercalated GO membrane exhibits superior antiswelling performance, particularly at a high feed temperature of 60 °C. Remarkably, the modified membrane exhibited a high flux of approximately 52 L m^–2 h^–1 and rejection rates of about 100% for small ions and 98% for volatile phenol, with a temperature difference of 40 °C. Molecular dynamics simulations suggest that the sieving mechanisms for ions and volatiles are facilitated by the narrowed nanochannels within the polymer network situated between the 2D nanochannels of GO interlaminations. Concurrently, the unrestricted permeation of water molecules through the multinanochannel GO membrane encourages high-flux desalination of complex hypersaline wastewater.

中文翻译：

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工程多纳米通道聚合物插层氧化石墨烯膜用于膜蒸馏中严格的挥发物筛分


由亚纳米级扩散通道实现的氧化石墨烯（GO）膜有望在膜蒸馏（MD）中分离小物质。然而，由于与热进料直接接触后GO层间间距严重膨胀和随后增加，有效排除MD中小挥发物的挑战仍然存在。为了解决这个问题，我们实施了一种设计，其中聚合物被限制在 GO 层间之间，主要创建以 0.57 nm 为中心的二维纳米通道，平均膜孔径为 0.30 nm。与原始GO膜相比，聚合物插层GO膜表现出优异的抗溶胀性能，特别是在60℃的高进料温度下。值得注意的是，在温差为 40 °C 的情况下，改性膜表现出约 52 L m ^–2 h ^–1的高通量，对小离子的截留率约为 100%，对挥发性苯酚的截留率约为 98%。分子动力学模拟表明，位于 GO 层间结构二维纳米通道之间的聚合物网络内的狭窄纳米通道促进了离子和挥发物的筛分机制。同时，水分子通过多纳米通道GO膜的不受限制的渗透促进了复杂高盐废水的高通量脱盐。