In this paper, the ion diffusion process through the graphene oxide (GO)/polyether sulfone(PES) membrane was probed by the electrochemical techniques. It was found that the GO/PES membrane exhibited lower rejection when feeding a solution with higher ion concentration. The calculated diffusion coefficient indicated that the Donnan repulsive interaction due to the GO platelets might play a key role in the rejection of GO/PES membrane. Computational calculation confirms that interlayer spacing shrinks less than 5% when increasing the solution concentration. These results suggest that compared with interlayer spacing, the Donnan repulsive interaction is more important for ion permeation during the concentration gradient‐driven diffusion. To investigate the detail of ion diffusion, electrochemical impedance spectroscopy (EIS) was utilized to probe the GO/PES membrane at initial immersing process. The EIS results showed an additional inductive loop at low frequency in the Nyquist plot at the initial diffusion stage, which would be more visible for the GO/PES membrane immersing at lower ion concentration. This inductive loop could be attributed to the uneven distribution of ions in GO/PES membrane, which is related to the cation‐adsorption capacity of GO.

中文翻译：

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通过氧化石墨烯/聚醚砜的膜渗透离子的研究

本文通过电化学技术探讨了通过氧化石墨烯（GO）/聚醚砜（PES）膜的离子扩散过程。发现当以更高的离子浓度进料溶液时，GO / PES膜表现出较低的排斥。计算的扩散系数表明，GO血小板引起的Donnan排斥相互作用可能在GO / PES膜的排斥中起关键作用。计算计算证实，当增加溶液浓度时，层间间距收缩小于5％。这些结果表明，与层间距相比，在浓度梯度驱动的扩散过程中，Donnan排斥相互作用对于离子渗透更为重要。为了研究离子扩散的细节，电化学阻抗谱（EIS）用于在初始浸没过程中探测GO / PES膜。EIS结果显示，在初始扩散阶段的奈奎斯特图中，低频处会出现一个附加的感应环路，这对于以较低离子浓度浸没的GO / PES膜将更为明显。这种感应回路可能归因于GO / PES膜中离子的不均匀分布，这与GO的阳离子吸附能力有关。