State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China.
Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China.
J Contam Hydrol. 2023 Nov;259:104255. doi: 10.1016/j.jconhyd.2023.104255. Epub 2023 Oct 9.
Co-existence of microplastics, nanomaterials, and antibiotics may lead to intensified multifaceted pollution, which may influence their fate in soils. This study investigated the co-transport behavior of polystyrene microplastics (PS) and compound pollutants of graphene oxide (GO) and tetracycline (TC). Packed column experiments for microplastic with or without combined pollutants were performed in KCl (10 and 30 mM) and CaCl solutions (0.3 and 1 mM). The results showed transport of PS was facilitated at low ionic strengths and inhibited at high ionic strengths by GO with or without TC under examined conditions. Carrier effect of GO as well as the aggregation of PS in the presence of co-exiting GO or GO-TC could be the contributor. Although the existence of TC relieved the ripening phenomenon of PS and GO deposition due to enhanced electronegativity of sand media, the effect of GO on the PS transport has not been significantly impacted, indicating the dominant role of GO during cotransport process. Furthermore, the transport of PS was increased by TC owing to competition for deposition sites on sand surfaces. In turn, the transport of TC was mainly affected by PS whether graphene was present or not. The increase in electrostatic repulsive force (transport-promoting) and addition adsorption sites (transport-inhibiting) may be responsible for the observations. Our findings could improve understandings of complex environmental behaviors of microplastics and provide insight into investigation on cotransport of emerging contaminants under various conditions relevant to the subsurface environment.
共存的微塑料、纳米材料和抗生素可能导致强化的多方面污染，这可能会影响它们在土壤中的命运。本研究调查了聚苯乙烯微塑料 (PS) 与氧化石墨烯 (GO) 和四环素 (TC) 复合污染物的共输运行为。在 KCl（10 和 30 mM）和 CaCl 溶液（0.3 和 1 mM）中进行了带有或不带有组合污染物的微塑料填充柱实验。结果表明，在考察条件下，GO 无论是否存在 TC，均会在低盐度下促进 PS 的迁移，而在高盐度下抑制 PS 的迁移。GO 的载体效应以及 PS 在共存的 GO 或 GO-TC 存在下的聚集可能是其贡献的原因。尽管 TC 的存在由于砂介质的电负性增强而缓解了 PS 和 GO 沉积的老化现象，但 GO 对 PS 迁移的影响并未受到显著影响，这表明在共输运过程中 GO 起主导作用。此外，由于 TC 竞争砂表面的沉积位置，PS 的迁移增加。相反，TC 的迁移主要受 PS 的影响，无论是否存在石墨烯。增加静电斥力（促进迁移）和增加吸附位点（抑制迁移）可能是造成这种情况的原因。我们的研究结果可以提高对微塑料复杂环境行为的认识，并为研究与地下环境相关的各种条件下新兴污染物的共输运提供了新的思路。
