Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China; College of New Energy and Environment, Jilin University, Changchun 130021, China; Institute of Water Resources and Environment, Jilin University, Changchun 130021, China.
Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China; College of New Energy and Environment, Jilin University, Changchun 130021, China; Institute of Water Resources and Environment, Jilin University, Changchun 130021, China.
Chemosphere. 2024 Sep;363:142833. doi: 10.1016/j.chemosphere.2024.142833. Epub 2024 Jul 11.
In this study, we examined the aging characteristics of polyethylene (PE) and polylactic acid (PLA) microplastics (MPs), examining the adsorption behaviors and mechanisms concerning Cd(II) and Cr(VI) under both single and binary systems. The results revealed that aging treatment changed the physicochemical properties of MPs. The aging mechanisms of PLA and PE MPs were shown to be similar by the 2D-FTIR-COS study. These mechanisms involve the formation of oxygen-containing functional groups through the combination of carbon chain breakdown and oxygen. Aged MPs had a greater ability to adsorb metal ions than pristine MPs, with PLA MPs outperforming PE MPs. After 30 days of aging, Cd(II) adsorption increased by 40.61 % and 25.49 % for PE and PLA MPs, respectively, while Cr(VI) adsorption increased by 37.50 % and 69.29 %, respectively. The adsorption ability of PE and PLA MPs with Cd(II) or Cr(VI) under binary systems was less than that under single systems, with Cd(II) exhibiting more adsorption competitiveness than Cr(VI). Humic acid (HA), ionic species and strength, solution pH, and adsorption of Cd(II) and Cr(VI) were found to be significantly correlated. Further investigation into the adsorption mechanisms of Cd(II) and Cr(VI) on PE and PLA MPs revealed that pore-filling, electrostatic interactions, complexation, and hydrogen bonding play important roles in the adsorption process. The study's conclusions are crucial for assessing the risk associated with concurrent contamination by metal ions and microplastics.
在这项研究中，我们考察了聚乙烯（PE）和聚乳酸（PLA）微塑料（MPs）的老化特征，研究了在单一和二元体系中 Cd(II)和 Cr(VI)的吸附行为和机制。结果表明，老化处理改变了 MPs 的物理化学性质。二维傅里叶变换红外相关光谱（2D-FTIR-COS）研究表明，PLA 和 PE MPs 的老化机制相似。这些机制涉及通过碳链断裂和氧的结合形成含氧官能团。老化后的 MPs 比原始 MPs 具有更强的金属离子吸附能力，其中 PLA MPs 优于 PE MPs。经过 30 天的老化，PE 和 PLA MPs 对 Cd(II)的吸附分别增加了 40.61%和 25.49%，而对 Cr(VI)的吸附分别增加了 37.50%和 69.29%。在二元体系中，PE 和 PLA MPs 对 Cd(II)或 Cr(VI)的吸附能力均低于单一体系，Cd(II)的吸附竞争能力强于 Cr(VI)。发现腐殖酸（HA）、离子种类和强度、溶液 pH 值以及 Cd(II)和 Cr(VI)的吸附之间存在显著相关性。进一步研究了 Cd(II)和 Cr(VI)在 PE 和 PLA MPs 上的吸附机制，结果表明，孔填充、静电相互作用、络合和氢键在吸附过程中起着重要作用。该研究的结论对于评估金属离子和微塑料共存污染的风险至关重要。
