Zhang Xu, Wu Lixingzi, Han Xinle, Shi Yuzhi, Huang Jiwen, Ding Botao, Zhang Yanhao, Zhang Zhibin, Shi Yanfeng, Li Fulin
School of Municipal and Environmental Engineering, Shandong Jianzhu University, Ji'nan, 250101, China.
Water Resources Research Institute of Shandong Province, Ji'nan, 250013, China.
Chemosphere. 2025 Feb;370:143942. doi: 10.1016/j.chemosphere.2024.143942. Epub 2024 Dec 18.
Both perfluorooctanoic acid (PFOA) and polystyrene microplastics (PS-MPs) are emerging contaminants commonly found in aqueous environments. In co-contaminated areas, MPs may act as carriers for PFOA, complicating transport dynamics. However, information on their cotransport in porous media is limited. This study investigates the transport behaviors of PFOA and PS-MPs in saturated quartz sand columns under varying ionic strength (IS), cation type, and pH. Using the DLVO interaction energy theory and a mathematical model, we analyzed their cotransport. The results demonstrated that PS-MPs inhibited PFOA transport due to hydrophobic adsorption, reducing PFOA mobility. However, at pH 5, PS-MPs facilitated PFOA transport through competitive adsorption on sand surfaces. Conversely, PFOA significantly accelerated PS-MPs transport, likely due to electrostatic repulsion and reduced PS-MPs size. The promoting effect of PFOA on PS-MPs was similar in NaCl and CaCl solutions. It is noteworthy that under acidic conditions, the increased electrostatic attraction between PS-MPs and quartz sand leads to substantial adsorption of PS-MPs onto the quartz sand surface. Under these conditions, PFOA exerts almost no promoting effect on PS-MPs. This study showed that the coexistence of PS-MPs and PFOA would influence the mobility of each other in the saturated porous media. Overall, the findings from this work could greatly improve our understanding of cotransport behaviors and environmental risk of PS-MPs and PFOA.
全氟辛酸（PFOA）和聚苯乙烯微塑料（PS-MPs）都是在水环境中常见的新兴污染物。在共同污染区域，微塑料可能充当PFOA的载体，使迁移动力学变得复杂。然而，关于它们在多孔介质中共迁移的信息有限。本研究调查了在不同离子强度（IS）、阳离子类型和pH值下，PFOA和PS-MPs在饱和石英砂柱中的迁移行为。利用DLVO相互作用能理论和数学模型，我们分析了它们的共迁移。结果表明，PS-MPs由于疏水吸附抑制了PFOA的迁移，降低了PFOA的迁移率。然而，在pH值为5时，PS-MPs通过在砂表面的竞争吸附促进了PFOA的迁移。相反，PFOA显著加速了PS-MPs的迁移，可能是由于静电排斥和PS-MPs尺寸减小。PFOA对PS-MPs的促进作用在NaCl和CaCl₂溶液中相似。值得注意的是，在酸性条件下，PS-MPs与石英砂之间增加的静电吸引力导致PS-MPs大量吸附到石英砂表面。在这些条件下，PFOA对PS-MPs几乎没有促进作用。本研究表明，PS-MPs和PFOA的共存会影响它们在饱和多孔介质中的相互迁移率。总体而言，这项工作的发现可以极大地增进我们对PS-MPs和PFOA共迁移行为及环境风险的理解。
