With the wide applications of graphene nanoplatelets (GNPs) in the industries, more concerns are raised about the effectiveness of filtration technology to control GNPs release during manufacturing and handling processes. Accurate prediction of the capture efficiency of airborne GNPs is significant to avoid occupational exposure. Herein, the aerodynamic property and filtration mechanisms of airborne GNPs with plate-like shape and folded structure were studied. Different equivalent diameters of GNPs (aerodynamic diameter d, mobility diameter d) were derived and used to describe diverse mechanisms in the filtration model. The capture efficiency of plate-like GNPs and sphere-like NaCl particles was measured with Nuclepore membranes and nanofibrous membranes to assess the particle shape effect during filtration. The plate-like GNPs showed higher capture efficiency due to the larger interception length. SEM measurement showed that not only planar GNPs, GNPs with folded structure also occurred due to the large lateral size to thickness ratio and strong mechanical stimulation in the atomization process. For GNPs with aerodynamic diameter of 0.5 – 0.9 μm, the capture efficiency for folded GNPs decreased by 20 – 30% according to the analytical calculation. In addition, the effects of membrane structural parameters (Nuclepore membrane pore radius, fiber diameter, solidity) on the quality factor () were systematically analyzed to evaluate the overall filtration performance. This study not only elucidates the effect of plate-like shape and folded structure on the aerodynamics of airborne GNPs, but also contributes to better design of Nuclepore and nanofibrous membranes to improve the filtration performance of plate-like particles.

中文翻译：

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板状折叠结构空气飞行石墨烯纳米片的气动性能及过滤评价


随着石墨烯纳米片（GNP）在工业中的广泛应用，人们越来越关注过滤技术在制造和处理过程中控制 GNP 释放的有效性。准确预测空气中 GNP 的捕获效率对于避免职业暴露具有重要意义。在此，研究了具有板状和折叠结构的机载GNPs的气动特性和过滤机制。推导出 GNP 的不同当量直径（空气动力学直径 d、流动直径 d）并用于描述过滤模型中的不同机制。使用 Nuclepore 膜和纳米纤维膜测量板状 GNP 和球状 NaCl 颗粒的捕获效率，以评估过滤过程中颗粒形状的影响。由于拦截长度较大，板状 GNP 显示出更高的捕获效率。 SEM测量表明，不仅是平面GNP，由于雾化过程中横向尺寸与厚度之比大以及强烈的机械刺激，也出现了具有折叠结构的GNP。根据分析计算，对于气动直径为0.5 – 0.9 μm的GNP，折叠GNP的捕获效率下降了20 – 30%。此外，系统分析了膜结构参数（Nuclepore膜孔径、纤维直径、密实度）对品质因数（）的影响，以评价整体过滤性能。这项研究不仅阐明了板状形状和折叠结构对空气中GNPs空气动力学的影响，而且有助于更好地设计核孔和纳米纤维膜，以提高板状颗粒的过滤性能。