Polymeri Materials Laboratory, Chemistry and Materials Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan.
Organization for Marine Science and Technology, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan.
Sci Rep. 2023 Mar 14;13(1):4247. doi: 10.1038/s41598-023-31488-w.
Various tiny plastic particles were retrieved from the sea and studied using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis to prepare realistic reference microplastics (MP). Most of the MP exhibited a diameter of < 20 × 10 m and 0.1-0.2 molar ratios of oxygen to carbon atoms (O/C), indicating that they primarily comprised polyethylene (PE), polypropylene (PP), and polystyrene (PS). It took a long time to reproduce such O/C ratios in standard laboratory weathering methods. For example, degrading of 30 × 30 × 0.060 mm PP film required 75 days for the 0.1 ratio, even with an advanced oxidation process (AOP) using a sulfate radical anion (SO·) initiator in distilled water at 65 °C. However, seawater drastically improved the PP degradation performance of AOP under a weak acid condition to achieve the 0.1 ratio of PP film in only 15 days. The combination of seawater and the SO· initiator accelerated the degradation process and showed that the MP's size could be controlled according to the degradation time.
从海水中提取了各种微小的塑料颗粒，并使用扫描电子显微镜/能量色散 X 射线光谱（SEM/EDX）分析进行了研究，以制备现实的参考微塑料（MP）。大多数 MP 的直径<20×10 m，氧与碳原子的摩尔比（O/C）为 0.1-0.2，表明它们主要由聚乙烯（PE）、聚丙烯（PP）和聚苯乙烯（PS）组成。在标准实验室风化方法中，要重现这种 O/C 比值需要很长时间。例如，降解 30×30×0.060 毫米 PP 薄膜需要 75 天才能达到 0.1 的比值，即使在 65°C 的蒸馏水中使用硫酸盐自由基（SO·）引发剂进行高级氧化工艺（AOP）也是如此。然而，在弱酸条件下，海水极大地改善了 AOP 对 PP 的降解性能，仅 15 天即可使 PP 薄膜达到 0.1 的比值。海水和 SO·引发剂的结合加速了降解过程，并表明可以根据降解时间来控制 MP 的尺寸。
