了解可生物降解和不可生物降解的微塑料与重金属的相互作用
Shuyue Yan1, Basanta Kumar Biswal1, Rajasekhar Balasubramanian2
1Department of Civil and Environmental Engineering, National University of Singapore, Singapore, 117576, Singapore.
概括
可生物降解的微塑料 (BMP) 比一些非生物降解的塑料 (NMP) 可以吸附更多的重金属. 在酸性条件下,BMPs还会更快地释放金属,这引发了毒性问题.
科学领域:
- 环境科学 环境科学
- 材料科学 材料科学 材料科学
- 化学 化学 化学
背景情况:
- 可生物降解的微塑料 (BMP) 被推广为非生物降解微塑料 (NMP) 的环保替代品.
- 然而,BMPs可以吸附重金属等环境污染物,可能增加它们的毒性.
- 了解重金属与BMP和NMP的相互作用对于环境风险评估至关重要.
研究的目的:
- 为了比较一个常见的BMP,聚乳酸 (PLA) 的重金属吸附能力,与三个NMP:聚乙烯 (PE),聚烯 (PP) 和聚乙烯 (PVC).
- 在这些微塑料上研究六种重金属 (Cd2+,Cu2+,Cr3+,Ni2+,Pb2+,和Zn2+) 的吸附特性和脱吸行为.
- 评估Langmuir异温和伪二次运动模型的适用性,用于描述微塑料上的重金属吸附.
主要方法:
- 研究了聚乳酸 (PLA),聚乙烯 (PE),聚烯 (PP) 和聚乙烯 (PVC) 微塑料吸收六种重金属的情况.
- 分析了吸附能力,等温和和运动模型 (Langmuir,伪二阶).
- 在酸性环境中进行了溶解试验,以评估金属释放.
主要成果:
- 重金属吸附能力按照以下顺序进行:PE > PLA > PVC > PP.
- (Cr3+) 在BMP和NMP两种测试重金属中表现出最强的吸附性.
- 与NMP相比,可生物降解的微塑料 (PLA) 在酸性条件下在6小时内释放出更高比例的吸附重金属 (54.6-62.6%),而NMP则在6小时内释放出更高的吸附重金属 (54.6-62.6%).
结论:
- 生物降解的微塑料,特别是PLA,可以积累大量的重金属,可能比一些非生物降解的塑料带来更大的环境风险.
- 吸附过程最好用兰格穆尔异热模型和伪二阶动力学来描述.
- 在酸性水生环境中,从BMP中释放的重金属的增加需要进一步研究它们的环境命运和生态影响.
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