To investigate the transport of microplastics in mixed porous media, column experiments are conducted to investigate polystyrene nanoparticles (PSNPs) transport in saturated quartz sand (QS)-limestone (LT) porous media under different physicochemical conditions. The two-dimensional (2D) surface of DLVO interaction energy is calculated to quantify the continuous change of the DLVO energy barrier with ionic strength and predict the critical ionic strengths (CIS). Experimental results suggest the mobility of PSNPs is inhibited as the mass fraction of LT and grain size of PSNPs increases. However, PSNPs mobility is enhanced with initial concentration and flow velocity. Compared with monovalent cation (Na⁺), divalent cation (Ca²⁺) has a stronger charge shielding effect. Significantly, there is a significant correlation between the transport kinetic parameters of PSNPs and the DLVO energy barrier, which suggests 2D surface of DLVO interaction energy has a great applied potential in the prediction of nano-plastics behaviors in the natural subsurface environment.

为了研究微塑料在混合多孔介质中的传输，进行了柱实验来研究不同物理化学条件下饱和石英砂 (QS)-石灰石 (LT) 多孔介质中聚苯乙烯纳米粒子 (PSNP) 的传输。计算 DLVO 相互作用能的二维 (2D) 表面，以量化 DLVO 能垒随离子强度的连续变化，并预测临界离子强度 (CIS)。实验结果表明，随着 LT 的质量分数和 PSNPs 粒度的增加，PSNPs 的迁移率受到抑制。然而，PSNPs 的迁移率随着初始浓度和流速的增加而增强。与一价阳离子（Na ⁺）相比，二价阳离子（Ca ²⁺) 具有更强的电荷屏蔽作用。值得注意的是，PSNPs 的输运动力学参数与 DLVO 能垒之间存在显着相关性，这表明 DLVO 相互作用能的二维表面在预测天然地下环境中的纳米塑料行为方面具有巨大的应用潜力。