Insight into the Photodegradation of Microplastics Boosted by Iron (Hydr)oxides
Insight into the Photodegradation of Microplastics Boosted by Iron (Hydr)oxides
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DOI：
10.1021/acs.est.2c07824
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发表时间：
2022-12-06
影响因子：
11.4
通讯作者：
Zhu, Lingyan
中科院分区：
文献类型：
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作者：
Ding, Ling;Guo, Xuetao;Zhu, Lingyan
铁（氢）氧化物作为一种天然矿物积极参与有机污染物的转化，但其对微塑料（MPs）光化学过程的影响仍存在很大的知识空白。这项研究首次研究了两种普通塑料材料聚乙烯（PE）和聚丙烯（PP）在模拟太阳光照射下由铁（氢）氧化物（针铁矿和赤铁矿）介导的降解情况。两种铁（氢）氧化物均显着促进 MP（特别是 PP）的降解，其中针铁矿的效果比赤铁矿更大，这与铁（氢）氧化物产生的羟基自由基（（OH）-O-中心点）有关。在光照射下，表面Fe(II)相催化产生H2O2并促进Fe2+的释放，导致随后的光驱动芬顿反应，产生大量(OH)-O-中心点。当铁（氢）氧化物被不同浓度的NaF修饰时，表面Fe（II）的活性以及Fe2+的释放大大降低，从而显着抑制（OH）-O-中心点的形成和MP降解。值得注意的是，表面羟基（特别是相当于FeOH）通过调节Fe物种的活性来影响（OH）-O-中心点的反应动力学。这些发现揭示了铁（氢）氧化物在影响 MP 光降解方面的独特影响和内在机制。
Iron (hydr)oxides as a kind of natural mineral actively participate in the transformation of organic pollutants, but there is a large knowledge gap in their impacts on photochemical processes of microplastics (MPs). This study is the first to examine the degradation of two ordinary plastic materials, polyethylene (PE) and polypropylene (PP), mediated by iron (hydr)oxides (goethite and hematite) under simulated solar light irradiation. Both iron (hydr)oxides significantly promoted the degradation of MPs (particularly PP) with a greater effect by goethite than hematite, related to hydroxyl radical ((OH)-O-center dot) produced by iron (hydr)oxides. Under light irradiation, the surface Fe(II) phase catalyzed the production of H2O2 and promoted the release of Fe2+, leading to the subsequent light-driven Fenton reaction which produced a large amount of (OH)-O-center dot. As the iron (hydr)oxides were modified with NaF at various concentrations, the activity of the surface Fe(II) as well as the release of Fe2+ were greatly reduced, and thus the (OH)-O-center dot formation and MP degradation were depressed remarkably. It is worth noting that the surface hydroxyl groups (especially equivalent to FeOH) affected the reaction kinetics of (OH)-O-center dot by regulating the activity of Fe species. These findings unveil the distinct impacts and intrinsic mechanisms of iron (hydr)oxides in influencing the photodegradation of MPs.