Aging of microplastics increases their adsorption affinity towards organic contaminants
Aging of microplastics increases their adsorption affinity towards organic contaminants
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DOI：
10.1016/j.chemosphere.2022.134238
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发表时间：
2022-03-11
期刊：
影响因子：
8.8
通讯作者：
Perreault, Francois
中科院分区：
文献类型：
--
作者：
Bhagat, Kartik;Barrios, Ana C.;Perreault, Francois
当微塑料释放到环境中时，由于机械磨损和紫外线照射，其表面会发生风化。在本研究中，评估了风化高密度聚乙烯 (HDPE) 和聚丙烯 (PPE) 对两种模型污染物（菲和亚甲基蓝）的吸附，以了解微塑料的老化如何影响污染物吸附。在有或没有过氧化氢的情况下，使用紫外线照射，通过加速风化过程使微塑料老化。对原始和老化微塑料上的污染物进行了吸附等温线。老化微塑料对有机污染物的吸附比原始微塑料更高，其中亚甲基蓝的亲和力随老化增加最高，与原始颗粒相比增加了 4.7 倍，菲则增加了 1.9 倍。为了了解老化微塑料对污染物更高吸附的机制，通过傅里叶变换红外光谱、X 射线光电子能谱、zeta 电位、X 射线断层扫描和 Brunauer-Emmett-Teller 氪吸附分析来表征老化微塑料的比表面积和表面化学变化。这项研究的结果表明，微塑料的氧化可以增强有机污染物的吸附，这可能会增强它们作为水生食物链中污染物载体的作用。
When released in the environment, microplastics undergo surface weathering due to mechanical abrasion and ultraviolet exposure. In this study, the adsorption of two model contaminants, phenanthrene and methylene blue, by weathered high density polyethylene (HDPE) and polypropylene (PPE) was evaluated to understand how the microplastics' aging influences contaminant adsorption. Microplastics were aged through an accelerated weathering process using ultraviolet exposure with or without hydrogen peroxide. Adsorption isotherms were conducted for both contaminants on pristine and aged microplastics. The adsorption of organic contaminants was higher on aged microplastics than on pristine ones, with methylene blue having the highest affinity increase with aging at 4.7-fold and phenanthrene having a 1.9-fold increase compared to the pristine particles. To understand the mechanisms involved with higher adsorption of contaminants by aged microplastics, changes in the specific surface area and surface chemistry of aged microplastics were characterized by Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, zeta potential, X-ray tomography, and Brunauer-Emmett--Teller krypton adsorption analyses. The results of this study show that oxidation of microplastics can enhance the adsorption of organic contaminants, which may increase their role as vectors of contaminants in the aquatic food chain.