Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Department of Municipal and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Haidian District, Beijing 100044, China.
Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Department of Municipal and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Haidian District, Beijing 100044, China.
J Hazard Mater. 2022 Mar 15;426:128111. doi: 10.1016/j.jhazmat.2021.128111. Epub 2021 Dec 21.
In the study, an efficient '1 + 1 > 2' synergistic coupling system driven by visible light consisting of mesoporous g-CN (MCN) and persulfate (PS)was constructed. The free radical transformation, electron transfer and non-covalent interaction between the MCN layer and PS in the system were explored via experiments and DFT calculations. The similarity for the fate of the seven β-lactam antibiotics with typical structures in the oxidation system was studied systematically in depth. First, the consistencies and differences of the seven antibiotics were summarized from three aspects: three-dimensional structures, electron cloud distributions, and the vulnerable sites. Notably, the selective differential degradation of β-lactam antibiotics in the MCN/PS system was speculated to be related with the molecular ionization potential (MIP), as a key index to describe the difficulty of oxidation. The distribution relationship between MIP and the oxidation kinetic constant (K) was explored and showed the following trend: a higher MIP indicates a weaker ability to provide electrons, and this leads to a greater resistance to oxidative degradation. In total, four main oxidation pathways of β-lactam antibiotics were systematically summarized combining HPLC-QTOF-MS and the simplified Fukui function calculation. The toxicity assessment of intermediate products provided by the T.E.S.T software of USEPA also shows a decreasing trend in the oxidation process. In the end, the superior practicability and stability of the MCN/PS system was verified by complex environment simulation and cyclic test. This research clarified the selective differential degradation mechanism of β-lactam antibiotics and provided a possible idea for the effective removal of refractory organic pollutants in water.
在这项研究中，构建了一种由介孔 g-CN（MCN）和过硫酸盐（PS）组成的高效可见光驱动的“1+1＞2”协同耦合体系。通过实验和 DFT 计算，探讨了体系中 MCN 层与 PS 之间的自由基转化、电子转移和非共价相互作用。系统深入地研究了具有典型结构的七种β-内酰胺抗生素在氧化体系中的命运相似性。首先，从三个方面总结了七种抗生素的异同：三维结构、电子云分布和易损部位。值得注意的是，推测 MCN/PS 体系中β-内酰胺抗生素的选择性差异降解与分子电离势（MIP）有关，MIP 是描述氧化难度的关键指标。探索了 MIP 与氧化动力学常数（K）之间的分布关系，结果表明以下趋势：较高的 MIP 表明提供电子的能力较弱，这导致对氧化降解的抵抗力更大。总之，结合 HPLC-QTOF-MS 和简化的 Fukui 函数计算，系统总结了β-内酰胺抗生素的四种主要氧化途径。USEPA 的 T.E.S.T 软件提供的中间产物的毒性评估也显示出在氧化过程中呈下降趋势。最后，通过复杂环境模拟和循环试验验证了 MCN/PS 体系的优越实用性和稳定性。这项研究阐明了β-内酰胺抗生素的选择性差异降解机制，为水中难处理有机污染物的有效去除提供了一种可能的思路。
