Hu Jinyuan, Lim Fang Yee, Hu Jiangyong
Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore.
Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore.
Water Res. 2023 Apr 1;232:119628. doi: 10.1016/j.watres.2023.119628. Epub 2023 Jan 16.
The fact that 94% of microplastics (MPs) ubiquitous in the environment are subject to natural weathering makes the aging study currently a research hotspot. This review summarized the physicochemical characteristics of MPs undergoing natural and artificial aging and evaluated current analytical methods used in aging studies. Besides, the differences in photoaging and aging induced by advanced oxidation processes (AOPs) were discussed, leading to a conclusion that AOPs composed of oxidant and ultraviolet (UV) irradiation can better facilitate the alteration of MPs compared to UV irradiation alone. In addition, the environmental behavior of aged MPs was outlined and their adsorption properties for organics and metals were highlighted as a result of combined effects of hydrophobic, π-π, diffusion, and hydrogen bond interaction. Furthermore, the mechanisms of photoaging and AOPs-initiated aging were analyzed, mainly the role of reactive oxygen species (ROS) and environmentally persistent free radicals (EPFRs). Finally, the applications of two-dimensional correlation spectroscopy (2D-COS) and three-dimensional fluorescence spectra using excitation emission matrix-parallel factor analysis (EEM-PARAFAC) were discussed for the aging process analysis. This overview plays an important role in explaining the aging characteristics of MPs and provides a theoretical foundation for further investigations into their toxicity and removal.
环境中普遍存在的微塑料（MPs）有94%会经历自然老化，这一事实使得老化研究成为当前的一个研究热点。本综述总结了经历自然老化和人工老化的微塑料的物理化学特性，并评估了老化研究中目前使用的分析方法。此外，还讨论了光老化和高级氧化过程（AOPs）诱导的老化之间的差异，得出的结论是，与单独的紫外线照射相比，由氧化剂和紫外线（UV）照射组成的AOPs能更好地促进微塑料的变化。此外，概述了老化微塑料的环境行为，并强调了由于疏水、π-π、扩散和氢键相互作用的综合影响，它们对有机物和金属的吸附特性。此外，分析了光老化和AOPs引发的老化机制，主要是活性氧（ROS）和环境持久性自由基（EPFRs）的作用。最后，讨论了二维相关光谱（2D-COS）和使用激发发射矩阵-平行因子分析（EEM-PARAFAC）的三维荧光光谱在老化过程分析中的应用。本综述在解释微塑料的老化特性方面发挥了重要作用，并为进一步研究其毒性和去除提供了理论基础。
