光老化微塑料上的含硫持久性自由基和反应物质：识别和形成机制,Environmental Science & Technology

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光老化微塑料上的含硫持久性自由基和反应物质：识别和形成机制
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2023-06-01 , DOI: 10.1021/acs.est.3c01310
Wenjun Jiang ₁ , Kecheng Zhu ₁ , Haonan Ma ₁ , Jinbo Liu ₁ , Chi Zhang ₁ , Yunchao Dai ₁ , Hanzhong Jia ₁

Affiliation

元素组成可能会影响与光老化微塑料相关的持久自由基（PFR）和活性物质（RS）的形成；但目前仍缺乏相关研究。本研究系统地研究了模拟阳光下含硫微塑料（S-MPs）上PFRs和RS的形成、演化和类型。电子顺磁共振检测和功率饱和曲线分析在每种光老化聚苯硫醚（PPS）和聚砜（PSF）上分离出三种不同的 PFR。结合表征和密度泛函理论计算的结果，在辐照的S-MPs上观察到的PFR被分类为具有相邻S原子的氧中心自由基（即硫氧自由基）、氧中心自由基和硫中心自由基，其中PPS上的硫氧自由基是苯硫酚类自由基，PSF上的氧中心自由基和硫中心自由基分别被鉴定为苯磺酸类自由基和苯磺酰类自由基。此外，光老化 S-MP 上 PFR 的潜在前体分子片段，包括采用热解-气相色谱/质谱和液相色谱-质谱联用技术检测对甲苯亚磺酸和苯磺酸。有趣的是，除了活性氧以外，在辐照的S-MP 上还观察到活性硫(SO ₃^{•– )，其主要来自}^• OH 和磺酰基自由基的反应。这些结果对于评估大气中 S-MP 的潜在风险具有重要意义。

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Sulfur-Containing Persistent Free Radicals and Reactive Species on Photoaged Microplastics: Identification and the Formation Mechanism

The elemental composition may affect the persistent free radical (PFR) and reactive species (RS) formation associated with photoaging microplastics; however, a relevant study is still lacking. This study systematically investigated the formation, evolution, and types of PFRs and RS on sulfur-containing microplastics (S-MPs) under simulated sunlight. Electron paramagnetic resonance detection and power saturation curve analysis isolated three different PFRs on each photoaging poly(phenylene sulfide) (PPS) and polysulfone (PSF). Combining the results of characterization and density functional theory calculation, these observed PFRs on the irradiated S-MPs were classified as oxygen-centered radicals with an adjacent S atom (namely, thio–oxygen radicals), oxygen-centered and sulfur-centered radicals, where the thio–oxygen radicals on PPS were benzenethiol-like radicals, and oxygen-centered radicals and sulfur-centered radicals on PSF that were identified as benzenesulfonic-like radicals and phenyl sulfonyl-like radicals, respectively. Moreover, potential precursor molecule fragments of PFRs on the photoaging S-MPs, including p-toluenesulfinic acid and benzenesulfonic acid, were detected by pyrolysis-gas chromatography/mass spectrometry and liquid chromatography-mass spectrometry. Interestingly, reactive sulfur species (SO₃^•–) was also observed on irradiated S-MPs in addition to reactive oxygen species, which was mainly derived from the reaction of ^•OH and sulfonyl radicals. These results have implications for assessing the potential risks of atmospheric S-MPs.

更新日期：2023-06-01

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