光老化
化学
腐植酸
转化(遗传学)
水溶液
环境化学
化学工程
有机化学
生物化学
医学
皮肤病科
基因
工程类
肥料
作者
Fei Lian,Yaru Han,Yikang Zhang,Jiaqi Li,Binbin Sun,Zexuan Geng,Zhengyu Wang,Baoshan Xing
标识
DOI:10.1021/acs.est.2c09140
摘要
The colloidal stability of nanoplastics in aqueous solutions is greatly regulated by photoaging and dissolved organic matter (DOM). However, how the exposure order to sunlight and DOM modifies the environmental behavior of nanoplastics is seldomly determined. Here, with two different exposure orders, we investigated the impact of molecular-weight (MW)-fractionated humic acids (HAs) derived from biochar and the Suwannee River, respectively, on the aggregation of poly(ethylene terephthalate) nanoplastics (PET-NPs) in mono- and divalent electrolyte solutions. For exposure pattern (i) (photoaging followed by HA coating), photoaged PET-NPs had more oxidized surfaces and exhibited 22-320% higher binding affinity to HAs (especially the higher MW fractions) than the pristine counterparts, which greatly improved the dispersion of PET-NPs. For exposure pattern (ii) (HA coating followed by photoaging), HA-PET assemblies were formed, the dispersion of which increased with increasing irradiation time and was significantly higher than that of the samples in the exposure pattern (i) at the end of the experiment. This high dispersion of photoaged HA-PET assemblies was ascribed to the extra oxidation of PET by reactive oxygen species generated in the PET-HA interfaces during photoaging. These findings highlight the "active nature" of HA-PET assemblies, which provide new insight into the reaction of HA with nanoplastics beyond adsorption in the natural environment.
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