摘要

微塑料已成为全球关注的新兴污染物。散装塑料可以降解形成直至纳米级（<100nm）的较小颗粒，这被称为纳米塑料。由于它们的高表面积，纳米塑料可以非常有效地结合疏水化学品，当这种纳米塑料被生物群吸收时增加它们的危害。本研究报告了多环芳烃（PAHs）在淡水中对70 nm聚苯乙烯的吸附分布系数，以及PAH吸附等温线，其环境现实水溶液浓度为10（-5）μg/ L至1μg/ L.使用动态光散射评估纳米聚苯乙烯聚集态。吸附等温线是非线性的，等温线下端的分布系数非常高，值高达10（9）L / kg。从平面PAHs和芳族聚合物聚苯乙烯表面之间的π-π相互作用解释了高和非线性吸附，并且高于微米级聚苯乙烯。纳米聚苯乙烯聚集体尺寸的减少对吸附没有显着影响，这表明PAHs可以到达原始纳米颗粒上的吸附位点，而不管聚集状态如何。用C18聚二甲基硅氧烷预萃取纳米聚苯乙烯降低了PAHs的吸附，这可以通过除去纳米聚苯乙烯中最疏水的部分来解释。

Microplastic has become an emerging contaminant of global concern. Bulk plastic can degrade to form smaller particles down to the nanoscale (<100 nm), which are referred to as nanoplastics. Because of their high surface area, nanoplastic may bind hydrophobic chemicals very effectively, increasing their hazard when such nanoplastics are taken up by biota. The present study reports distribution coefficients for sorption of polycyclic aromatic hydrocarbons (PAHs) to 70 nm polystyrene in freshwater, and PAH adsorption isotherms spanning environmentally realistic aqueous concentrations of 10(-5)  μg/L to 1 μg/L. Nanopolystyrene aggregate state was assessed using dynamic light scattering. The adsorption isotherms were nonlinear, and the distribution coefficients at the lower ends of the isotherms were very high, with values up to 10(9) L/kg. The high and nonlinear sorption was explained from π-π interactions between the planar PAHs and the surface of the aromatic polymer polystyrene and was higher than for micrometer-sized polystyrene. Reduction of nanopolystyrene aggregate sizes had no significant effect on sorption, which suggests that the PAHs could reach the sorption sites on the pristine nanoparticles regardless of the aggregation state. Pre-extraction of the nanopolystyrene with C18 polydimethylsiloxane decreased sorption of PAHs, which could be explained by removal of the most hydrophobic fraction of the nanopolystyrene. 

https://www.ncbi.nlm.nih.gov/pubmed/26588181