Bai Lihua, Liang Sijia, Li Hongjian, Wang Chao, Wu Xinda, Xu Min, Shi Jiaqi, Zhu Fengxiao, Chen Wei, Gu Cheng
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China.
Key Laboratory of Environmental Remediation and Ecological Health (Ministry of Industry and Information Technology), Jiangsu Province Ecology and Environment Protection Engineering Research Center of Groundwater Pollution Prevention and Control, Jiangsu Environmental Engineering Technology Co., Ltd., Nanjing 210019, Jiangsu, China.
Environ Sci Technol. 2025 Jan 21;59(2):1388-1398. doi: 10.1021/acs.est.4c11206. Epub 2025 Jan 10.
Beyond their roles in adsorbing and transporting pollutants, microplastics (MPs) and nanoplastics (NPs), particularly polystyrene variants (PS-M/NPs), have emerged as potential accelerators for the transformation of coexisting contaminants. This study uncovered a novel environmental phenomenon induced by aged PS-M/NPs and delved into the underlying mechanisms. Our findings revealed that the aged PS-M/NP particles significantly amplified the photodegradation of common cephalosporin antibiotics, and the extent of enhancement was tightly correlated to the molecular structures of cephalosporin antibiotics. Notably, the results confirmed that the hydroxyl radical (OH•) acted as the primary agent to drive the accelerated degradation. Furthermore, in-depth analysis utilizing Fourier transform infrared spectroscopy, batch adsorption experiments, and theoretical calculations underscored that the structure-dependent enhancement stemmed from the specific hydrogen bonding sites, rather than mere adsorption capacity. Specifically, the -OOH group (hydroperoxyl group) on the PS surface exhibited a greater potential to generate OH• compared to the -OH group. Therefore, cephalosporins that formed hydrogen bonds with -OOH moieties on the aged PS surfaces, as opposed to -OH, would experience a more pronounced degradation enhancement. Thus, the unique interaction pattern between contaminants and PS-M/NPs transforms aged PS into a selective reactor, facilitating the targeted degradation of pharmaceuticals in aquatic ecosystems.
除了在吸附和运输污染物方面的作用外，微塑料（MPs）和纳米塑料（NPs），特别是聚苯乙烯变体（PS-M/NPs），已成为共存污染物转化的潜在促进剂。本研究发现了一种由老化的PS-M/NPs引起的新环境现象，并深入探讨了其潜在机制。我们的研究结果表明，老化的PS-M/NP颗粒显著增强了常见头孢菌素抗生素的光降解，增强程度与头孢菌素抗生素的分子结构密切相关。值得注意的是，结果证实羟基自由基（OH•）是驱动加速降解的主要因素。此外，利用傅里叶变换红外光谱、批量吸附实验和理论计算进行的深入分析强调，结构依赖性增强源于特定的氢键位点，而非仅仅是吸附能力。具体而言，PS表面的-OOH基团（氢过氧基团）比-OH基团表现出更大的产生OH•的潜力。因此，与-OH相比，与老化PS表面的-OOH部分形成氢键的头孢菌素将经历更显著的降解增强。因此，污染物与PS-M/NPs之间独特的相互作用模式将老化的PS转化为一个选择性反应器，促进了水生生态系统中药物的靶向降解。
