Hul Gabriela, Okutan Hande, Le Coustumer Philippe, Ramseier Gentile Stéphan, Zimmermann Stéphane, Ramaciotti Pascal, Perdaems Pauline, Stoll Serge
Department F.-A. Forel for Environmental and Aquatic Sciences, Institute for Environmental Sciences, University of Geneva, 1205 Geneva, Switzerland.
Ecole Doctorale, Université de Bordeaux Montaigne, 33607 Pessac, France.
Nanomaterials (Basel). 2024 Mar 15;14(6):529. doi: 10.3390/nano14060529.
Information about the influence of surface charges on nanoplastics (NPLs) transport in porous media, the influence of NPL concentrations on porous media retention capacities, and changes in porous media adsorption capacities in the presence of natural water components are still scarce. In this study, laboratory column experiments are conducted to investigate the transport behavior of positively charged amidine polystyrene (PS) latex NPLs and negatively charged sulfate PS latex NPLs in quartz sand columns saturated with ultrapure water and Geneva Lake water, respectively. Results obtained for ultrapure water show that amidine PS latex NPLs have more affinity for negatively charged sand surfaces than sulfate PS latex NPLs because of the presence of attractive electrical forces. As for the Geneva Lake water, under natural conditions, both NPL types and sand are negatively charged. Therefore, the presence of repulsion forces reduces NPL's affinity for sand surfaces. The calculated adsorption capacities of sand grains for the removal of both types of NPLs from both types of water are oscillating around 0.008 and 0.004 mg g for NPL concentrations of 100 and 500 mg L, respectively. SEM micrography shows individual NPLs or aggregates attached to the sand and confirms the limited role of the adsorption process in NPL retention. The important NPL retention, especially in the case of negatively charged NPLs, in Geneva Lake water-saturated columns is related to heteroaggregate formation and their further straining inside narrow pores. The presence of DOM and metal cations is then crucial to trigger the aggregation process and NPL retention.
关于表面电荷对纳米塑料（NPLs）在多孔介质中传输的影响、NPLs浓度对多孔介质保留能力的影响以及在天然水成分存在下多孔介质吸附能力的变化，相关信息仍然匮乏。在本研究中，进行了实验室柱实验，分别研究带正电荷的脒基聚苯乙烯（PS）乳胶NPLs和带负电荷的硫酸根PS乳胶NPLs在分别用超纯水和日内瓦湖水饱和的石英砂柱中的传输行为。超纯水实验结果表明，由于存在吸引力，脒基PS乳胶NPLs比硫酸根PS乳胶NPLs对带负电荷的砂表面具有更强的亲和力。至于日内瓦湖水，在自然条件下，NPLs类型和砂均带负电荷。因此，排斥力的存在降低了NPLs对砂表面的亲和力。对于100和500 mg/L的NPLs浓度，计算得出的砂粒从两种类型的水中去除两种类型NPLs的吸附容量分别在0.008和0.004 mg/g左右波动。扫描电子显微镜图像显示单个NPLs或聚集体附着在砂上，并证实了吸附过程在NPLs保留中的作用有限。在日内瓦湖水饱和柱中，尤其是带负电荷的NPLs，重要的NPLs保留与异质聚集体的形成及其在窄孔内的进一步过滤有关。DOM和金属阳离子的存在对于引发聚集过程和NPLs保留至关重要。
