Zhang Honglong, Zhao Qiaoqiao, Zhong Kangbao, Bai Ruopeng, Dong Jiaojiao, Ma Jun, Zhang Jing, Strathmann Timothy J
School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, PR China.
Environ Sci Ecotechnol. 2024 Apr 20;21:100421. doi: 10.1016/j.ese.2024.100421. eCollection 2024 Sep.
Research efforts on permanganate (Mn(VII)) combined with redox-mediator (RM), have received increasing attention due to their significant performance for bisphenol-A (BPA) removal. However, the mechanisms underpinning BPA degradation remain underexplored. Here we show the overlooked interactions between RM and BPA during permanganate oxidation by introducing an RM-N-hydroxyphthalimide (NHPI). We discovered that the concurrent generation of MnO and phthalimide--oxyl (PINO) radical significantly enhances BPA oxidation within the pH range of 5.0-6.0. The detection of radical cross-coupling products between PINO radicals and BPA or its derivatives corroborates the pivotal role of radical cross-coupling in BPA oxidation. Intriguingly, we observed the formation of an NHPI-BPA complex, which undergoes preferential oxidation by Mn(VII), marked by the emergence of an electron-rich domain in NHPI. These findings unveil the underlying mechanisms in the Mn(VII)/RM system and bridge the knowledge gap concerning BPA transformation via complexation. This research paves the way for further exploration into optimizing complexation sites and RM dosage, significantly enhancing the system's efficiency in water treatment applications.
由于高锰酸盐（Mn(VII)）与氧化还原介质（RM）结合在去除双酚A（BPA）方面具有显著性能，相关研究工作日益受到关注。然而，BPA降解的潜在机制仍未得到充分探索。在此，我们通过引入RM- N-羟基邻苯二甲酰亚胺（NHPI），展示了在高锰酸盐氧化过程中RM与BPA之间被忽视的相互作用。我们发现，MnO和邻苯二甲酰亚胺氧基（PINO）自由基的同时生成在5.0 - 6.0的pH范围内显著增强了BPA的氧化。对PINO自由基与BPA或其衍生物之间自由基交叉偶联产物的检测证实了自由基交叉偶联在BPA氧化中的关键作用。有趣的是，我们观察到形成了一种NHPI - BPA络合物，它会被Mn(VII)优先氧化，其特征是NHPI中出现富电子域。这些发现揭示了Mn(VII)/RM体系的潜在机制，并填补了关于通过络合作用实现BPA转化的知识空白。这项研究为进一步探索优化络合位点和RM用量铺平了道路，显著提高了该体系在水处理应用中的效率。
