Currently, layered graphene oxide (GO) membranes have gained considerable attention due to their high separation efficiency in water treatment. However, a molecular-level separation mechanism remains elusive due to the complex irregular stacking feature of GO nanoscale flakes in actual GO membranes. Most existing molecular simulation studies using idealized GO membrane models might largely ignore the membrane structural heterogeneity. In this work, a molecular simulation protocol was applied to construct a non-idealized amorphous GO membrane model, and its structural morphology and property fit well with the realistic GO membranes. For the first time, the actual structure-oriented GO membrane model was used to study the separation behavior of heavy metal ions from aqueous solutions. The effects of the stacking structures and morphologies for the amorphous membranes on the water permeation and ion rejection were investigated. The constituent GO flakes with varied sheet sizes and oxidization degrees were considered. Our simulations demonstrate that the GO-based amorphous membranes with different-sized GO sheets can exhibit distinct ion rejection mechanisms and water penetration behavior. This finding has not been observed in previous idealized membrane models. Our simulation study provides novel insight into the separation mechanisms and improves the microscopic understanding of layered GO membranes.

目前，层状氧化石墨烯（GO）膜由于其在水处理中的高分离效率而备受关注。然而，由于实际 GO 膜中 GO 纳米级薄片的复杂不规则堆叠特征，分子水平的分离机制仍然难以捉摸。大多数现有的使用理想化 GO 膜模型的分子模拟研究可能在很大程度上忽略了膜结构的异质性。在这项工作中，应用分子模拟协议构建了一个非理想化的无定形GO膜模型，其结构形态和性能与现实的GO膜非常吻合。首次使用实际结构取向的 GO 膜模型研究重金属离子从水溶液中的分离行为。研究了无定形膜的堆叠结构和形态对水渗透和离子排斥的影响。考虑了具有不同片材尺寸和氧化程度的组成 GO 薄片。我们的模拟表明，具有不同尺寸 GO 片材的 GO 基无定形膜可以表现出不同的离子排斥机制和水渗透行为。在以前的理想化膜模型中没有观察到这一发现。我们的模拟研究为分离机制提供了新的见解，并提高了对分层 GO 膜的微观理解。我们的模拟表明，具有不同尺寸 GO 片材的 GO 基无定形膜可以表现出不同的离子排斥机制和水渗透行为。在以前的理想化膜模型中没有观察到这一发现。我们的模拟研究为分离机制提供了新的见解，并提高了对分层 GO 膜的微观理解。我们的模拟表明，具有不同尺寸 GO 片材的 GO 基无定形膜可以表现出不同的离子排斥机制和水渗透行为。在以前的理想化膜模型中没有观察到这一发现。我们的模拟研究为分离机制提供了新的见解，并提高了对分层 GO 膜的微观理解。