Abstract Graphene quantum dots (GQDs), a new type of carbon-based nanoparticles are widely used in scientific applications in the recent years. With the size less than 10 nm, and the strong hydrophilic characteristics GQDs exhibit high mobility in the environment, and can easily transmit to the groundwater environment. Hence, a good understanding of the transport behaviors of GQDs in porous media can provide guidance for assessment and prediction of its environmental risks. Saturated packed column experiments were conducted to investigate the effect of ionic strength (IS,1 and 100 mM), pH (4,7 and 9) and initial concentration (9 and 18 mg L−1) on the fate and transport of GQDs in saturated porous media. Advection-dispersion-reaction model with the second-order kinetics simulated the process well. The retention of GQDs was promoted with increased ionic strength in sand column, which could be explained with classic filtration and XDLVO theories. The increase of pH slightly reduced the GQDs deposition in saturated porous media, due to that there were no secondary minima in XDLVO calculation, and GQDs still showed high mobility. Higher input concentration slightly increased the GQDs retention due to the ripening process. The recovery rate of GQDs were more than 90 % in the environment with low salt content, exhibiting extremely high migration capacity.

中文翻译：

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石墨烯量子点 (GQD) 在饱和多孔介质中的传输

摘要 石墨烯量子点（GQDs）是一种新型的碳基纳米粒子，近年来被广泛应用于科学领域。粒径小于10 nm，亲水性强的GQDs在环境中表现出很高的迁移率，很容易传输到地下水环境中。因此，深入了解 GQDs 在多孔介质中的输运行为可以为其环境风险的评估和预测提供指导。进行饱和填充柱实验以研究离子强度（IS,1 和 100 mM）、pH（4,7 和 9）和初始浓度（9 和 18 mg L-1）对 GQDs 在饱和多孔介质。具有二级动力学的对流-弥散-反应模型很好地模拟了该过程。GQDs 的保留随着砂柱中离子强度的增加而提高，这可以用经典过滤和 XDLVO 理论来解释。由于 XDLVO 计算中没有二次极小值，pH 的增加略微减少了 GQDs 在饱和多孔介质中的沉积，并且 GQDs 仍然表现出较高的迁移率。由于成熟过程，较高的输入浓度略微增加了 GQDs 保留。GQDs在低盐环境中的回收率超过90%，表现出极高的迁移能力。由于成熟过程，较高的输入浓度略微增加了 GQDs 保留。GQDs在低盐环境中的回收率超过90%，表现出极高的迁移能力。由于成熟过程，较高的输入浓度略微增加了 GQDs 保留。GQDs在低盐环境中的回收率超过90%，表现出极高的迁移能力。