Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 40249, Taiwan.
Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan.
Sci Total Environ. 2024 Nov 15;951:175537. doi: 10.1016/j.scitotenv.2024.175537. Epub 2024 Aug 14.
This study extensively explored the adsorption behavior of heavy metals (Pb, Ni, Cu, Zn, and Cd) onto microplastics (MPs). The particle sizes of MPs ranged from 0.149 to 0.25 mm. The microplastics were generated from commercial products manufactured from both conventional (polyethylene (PE) bottle, polystyrene (PS) spoon, and polyethylene terephthalate (PET) egg carton) and biodegradable (polylactic acid (PLA) spoon, and polylactic acid (PLA) egg carton) plastics. The study also considered the influence of solution pH on the adsorption capacity of heavy metals. Regarding the adsorption potential for Cu, the ranking was as follows: PLA-egg (1408 μg·g) > PLA-spoon (735 μg·g) > PE-bottle (315 μg·g) > PET-egg (283 μg·g) > PS-spoon (237 μg·g). PLA MPs showed the highest adsorption capacity due to the lower thermal stability and higher presence of surface oxygen functional groups. Moreover, the adsorption capacities of the five metals onto PLA-spoon and PLA-egg decreased in the following order: Pb (1785 μg·g) > Zn (1267 μg·g) > Cd (748 μg·g) > Cu (735 μg·g) > Ni (722 μg·g), and Pb (1520 μg·g) > Ni (1412 μg·g) > Cu (1408 μg·g) > Zn (1118 μg·g) > Cd (423 μg·g), respectively. The SEM-EDS, FTIR and XPS results demonstrated that surface oxygen-containing functional groups play an important role during the adsorption process. This study extended its analysis to quantify the metal content of the post-adsorption MPs, revealing uneven adsorption of heavy metals onto the MPs. This implies that the diversity of commercial plastic products may result in significant variations in their ability to adsorb heavy metals, underscoring the importance of effectively managing discarded commercial plastic products.
本研究广泛探讨了重金属（Pb、Ni、Cu、Zn 和 Cd）在微塑料（MPs）上的吸附行为。MPs 的粒径范围为 0.149 至 0.25mm。微塑料由商业产品产生，这些商业产品由传统塑料（聚乙烯（PE）瓶、聚苯乙烯（PS）勺和聚对苯二甲酸乙二醇酯（PET）蛋盒）和可生物降解塑料（聚乳酸（PLA）勺和聚乳酸（PLA）蛋盒）制成。该研究还考虑了溶液 pH 值对重金属吸附能力的影响。就 Cu 的吸附潜力而言，排名如下：PLA-egg（1408μg·g）>PLA-spoon（735μg·g）>PE-bottle（315μg·g）>PET-egg（283μg·g）>PS-spoon（237μg·g）。PLA MPs 表现出最高的吸附能力，因为其热稳定性较低，表面含氧官能团较多。此外，五种金属在 PLA 勺和 PLA 蛋上的吸附能力按以下顺序降低：Pb（1785μg·g）>Zn（1267μg·g）>Cd（748μg·g）>Cu（735μg·g）>Ni（722μg·g），Pb（1520μg·g）>Ni（1412μg·g）>Cu（1408μg·g）>Zn（1118μg·g）>Cd（423μg·g）。SEM-EDS、FTIR 和 XPS 结果表明，表面含氧官能团在吸附过程中起着重要作用。本研究进一步分析了吸附后 MPs 中的金属含量，结果表明重金属在 MPs 上的吸附不均匀。这意味着商业塑料产品的多样性可能导致其吸附重金属的能力存在显著差异，这凸显了有效管理废弃商业塑料产品的重要性。
