Shi Yanqi, Huang Hexinyue, Zheng Lezhou, Tian Yechao, Gong Zhimin, Wang Jiahao, Li Wentao, Gao Shixiang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210093, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210093, China.
Sci Total Environ. 2023 Dec 1;902:166584. doi: 10.1016/j.scitotenv.2023.166584. Epub 2023 Aug 25.
The nonwoven PET fabrics are chemically, mechanically and thermally treated fiber aggregate without weaving, knitting or braiding, which could be used as a base to make polyurethane (PU) synthetic leather through a series of processing. Our research systematically compared the photoaging behaviors of pure non-woven PET base fabric (NPET-P) and PU synthetic leather (nonwoven PET-base fabrics with PU coating, NPET-U), and their possibilities for microplastic fibers (MPFs) generation and chemical transformation in water. NPET-U was photoaged to a higher oxidation degree with higher O/C ratios and more distinct changes in chemical structures. The amount of MPFs released from NPET-U (1.98 × 10 g/fibers) was significantly lower than that from NPET-P (4.76 × 10 g/fibers) after 360 h light irradiation (p value <0.05) with a slower degradation rate and delayed MPFs release. The lengths and diameters of released MPFs from NPET-U varied within a smaller range than that from NPET-P exposed to UV light irradiation. Natural sunlight aging of fabrics for 365 days was found to be equivalent to approximately 85.3-127.2 h UV aging in the laboratory, which indicated the lab accelerated experiments was extraordinarily intense to simulate natural sunlight aging. Furthermore, abundant calcium and sulfur-contained chemicals were detected in original fabrics and the leachate of 360 h light-aged fabrics using the inductively coupled plasma optical emission spectrometer (ICP-OES). The organic components of the leachate were separated according to their molecular weight with the changes of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and the UV response over aging time. UV stimulation aggravated the role of plastic polymers as disinfection by-product (DBP) precursors. Nevertheless, although NPET-U could produce more nitrogen-contained chemicals, it had similar formation potentials of nitrogen-containing DBPs as NPET-P. The discussion lucubrated the potential risks of the production of MPFs and chemical release in the leachate with regard to combined plastic pollution.
非织造聚酯（PET）织物是未经编织、针织或编织的化学、机械和热处理纤维聚集体，可作为基础材料，通过一系列加工制成聚氨酯（PU）合成革。我们的研究系统地比较了纯非织造PET基布（NPET-P）和PU合成革（带有PU涂层的非织造PET基布，NPET-U）的光老化行为，以及它们在水中产生微塑料纤维（MPF）和化学转化的可能性。NPET-U光老化后氧化程度更高，具有更高的O/C比和更明显的化学结构变化。光照360小时后，NPET-U释放的MPF量（1.98×10 g/纤维）明显低于NPET-P（4.76×10 g/纤维）（p值<0.05），降解速率较慢且MPF释放延迟。NPET-U释放的MPF的长度和直径变化范围比暴露于紫外线照射的NPET-P小。发现织物在自然阳光下老化365天相当于实验室中约85.3-127.2小时的紫外线老化，这表明实验室加速实验在模拟自然阳光老化方面非常强烈。此外，使用电感耦合等离子体发射光谱仪（ICP-OES）在原始织物和光照360小时的织物渗滤液中检测到大量含钙和含硫化学品。根据渗滤液中溶解有机碳（DOC）、溶解有机氮（DON）的变化以及老化时间的紫外线响应，按分子量分离渗滤液的有机成分。紫外线刺激加剧了塑料聚合物作为消毒副产物（DBP）前体的作用。然而，尽管NPET-U可以产生更多的含氮化学品，但它与NPET-P具有相似的含氮DBP形成潜力。该讨论深入探讨了在综合塑料污染方面MPF产生和渗滤液中化学物质释放的潜在风险。
