Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, Wuhan, China.
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, Wuhan, China; Shenzhen Institute of Huazhong University of Science and Technology, 518000, Shenzhen, China.
Chemosphere. 2018 Sep;207:41-49. doi: 10.1016/j.chemosphere.2018.04.160. Epub 2018 Apr 30.
Commercial β-MnO with a chemical formula of approximate MnMnO was used for mechanochemical (MC) oxidative degradation of decabromodiphenyl ether (BDE209). The ball milling process initiated the degradation of BDE209 on β-MnO, yielding a nearly complete degradation and debromination of BDE209 within 2 h. The use of β-MnO exhibited much higher MC debromination efficiency than that by using birnessite (δ-MnO, 40.2%), BiO (45.6%), CaO (65.3%), and persulfate (81.9%). It was demonstrated that the oxidative degradation of BDE209 was promoted by the redox half reactions of both Mn→ Mn and Mn→ Mn, but naturally existed Mn centers on the surface of β-MnO functioned as dominant reactive species at the initial stage of the MC degradation (often before the degradation efficiency of BDE209 achieved 50%). Moreover, the surface lattice oxygen of MnO, rather than O, played a key role in the debromination and mineralization of BDE209. The Mn sites on β-MnO not only easily accepted the electron of BDE209, but also promoted the mobility of lattice oxygen from the bulk to the surface for mineralizing BDE209. These results firstly highlighted the importance of Mn availability and oxygen mobility on the reactivity of manganese oxide for the MC oxidative degradation of organic pollutants.
商用β-MnO（化学式近似为 MnMnO）被用于机械化学（MC）氧化降解十溴二苯醚（BDE209）。球磨过程引发了 BDE209 在β-MnO 上的降解，在 2 小时内几乎完全降解和脱溴。与使用水钠锰矿（δ-MnO，40.2%）、BiO（45.6%）、CaO（65.3%）和过硫酸盐（81.9%）相比，β-MnO 的 MC 脱溴效率要高得多。结果表明，BDE209 的氧化降解是由 Mn→Mn 和 Mn→Mn 的氧化还原半反应共同促进的，但β-MnO 表面天然存在的 Mn 中心在 MC 降解的初始阶段（通常在 BDE209 的降解效率达到 50%之前）起到了主要的反应性物质的作用。此外，MnO 的表面晶格氧，而不是 O，在 BDE209 的脱溴和矿化中起着关键作用。β-MnO 上的 Mn 位点不仅容易接受 BDE209 的电子，而且还促进了晶格氧从体相到表面的迁移，从而矿化 BDE209。这些结果首次强调了 Mn 有效性和氧迁移性对于锰氧化物在 MC 氧化降解有机污染物中的反应性的重要性。
