Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, China.
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
Ecotoxicology. 2022 Jan;31(1):75-84. doi: 10.1007/s10646-021-02467-6. Epub 2021 Oct 26.
Additive metals are continuously released into the environment during the photo-degradation of plastics into microplastics, but this phenomenon has not been reported by many studies. Herein, we investigated the surface morphology changes along with the release of additive metals (Cr, Mn, Fe, Co, Cu, Zn, and Pb) during the degradation of three types of plastics, i.e., polypropylene (PP), polyethylene terephthalate (PET) and polyvinyl chloride (PVC), under UV light irradiation. FTIR results showed that 168 days of UV-irradiation led to the primary degradation of each plastic sample. The metal release could be found after 70 days UV-irradiation. The rate of metal release for the three plastics showed the following order: PP > PET ≈ PVC. In addition, the distribution and concentrations of the metals in the plastic could influence the release characteristics of each metal. Low release rate of Fe symbolized by the total metal release in the range of 4.28 ~10.27% as evident from the results of the primary degradation experiment, indicated the release of Fe occurring in the late stage of the plastic degradation or even in the microplastics-formation stage. As for the release of Co from PP, it was far lower than that of the other elements (0.35%), showing the same release characteristics as that of Fe. On the contrary, the release ratio of Pb from PP was 78.89% and was mainly concentrated in the early stage of the plastic degradation. The results help understanding the release behavior of the additive metals during the degradation of typical plastics under ultraviolet light irradiation.
在塑料光降解为微塑料的过程中，添加剂金属会不断释放到环境中，但许多研究并未报道这一现象。在此，我们研究了三种类型的塑料（聚丙烯（PP）、聚对苯二甲酸乙二醇酯（PET）和聚氯乙烯（PVC））在紫外光照射下降解过程中添加剂金属（Cr、Mn、Fe、Co、Cu、Zn 和 Pb）释放伴随的表面形貌变化。FTIR 结果表明，168 天的紫外光照射导致了每种塑料样品的初步降解。在 70 天的紫外光照射后可以发现金属释放。三种塑料的金属释放率表现出以下顺序：PP>PET≈PVC。此外，金属在塑料中的分布和浓度会影响每种金属的释放特性。Fe 的释放率较低，总金属释放量在 4.28%~10.27%范围内，这表明 Fe 的释放发生在塑料降解的后期甚至微塑料形成阶段。对于 PP 中 Co 的释放，其释放率远低于其他元素（0.35%），表现出与 Fe 相同的释放特征。相反，PP 中 Pb 的释放比例为 78.89%，主要集中在塑料降解的早期阶段。研究结果有助于理解在紫外光照射下典型塑料降解过程中添加剂金属的释放行为。
