Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, Guangzhou University, Guangzhou, 510006, China; School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, Guangdong, 510006, China.
Water Res. 2019 Apr 15;153:200-207. doi: 10.1016/j.watres.2019.01.011. Epub 2019 Jan 21.
In this study, a manganese(IV) oxide-mediator (MnO-mediator) system for the abatement of sulfonamide antibiotics was evaluated. Two simple model humic constituents, syringaldehyde (SA) and acetosyringone (AS), could promote the transformation of sulfonamides at pH 5-8. Two additional potential mediators, tannic acid and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS), had negligible enhancement on the transformation of sulfonamides by MnO. The enhancing effect was attributed to the reaction of the oxidized mediator (i.e., phenoxy radical or benzoquinone-like compounds) produced from the oxidation of the mediators by MnO with SMX. Thereby cross-coupling products from sulfamethoxazole (SMX) with oxidized SA were formed in the MnO-SA system, which was confirmed by liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry. Coexisting metal ions (i.e., Ca(II), Mg(II) and Mn(II)) showed inhibitory effects in the order of Mn(II)> Ca(II)> Mg(II). For repetitive runs of the MnO-SA-SMX system, MnO lost its oxidative capacity due to the sorption of Mn(II) on the reactive sites of the MnO surface. A full regeneration of partially deactivated MnO by oxidation of the sorbed Mn(II) with Mn(VII) could be achieved.
在这项研究中，评估了一种锰(IV)氧化物-介体（MnO 介体）体系来去除磺胺类抗生素。两种简单的模型腐殖质成分，丁香醛（SA）和乙酰丁香酮（AS），可以在 pH 值为 5-8 的条件下促进磺胺类抗生素的转化。另外两种潜在的介体，鞣酸和 2,2'-联氮-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS），对 MnO 转化磺胺类抗生素几乎没有增强作用。这种增强作用归因于介体被 MnO 氧化产生的氧化介体（即酚氧基自由基或苯醌类似物）与 SMX 反应。因此，在 MnO-SA 体系中形成了来自磺胺甲恶唑（SMX）与氧化 SA 的交叉偶联产物，这通过液相色谱/电喷雾电离-三重四极杆质谱得到了证实。共存的金属离子（即 Ca(II)、Mg(II)和 Mn(II)）的抑制作用顺序为 Mn(II)>Ca(II)>Mg(II)。对于 MnO-SA-SMX 体系的重复运行，由于 Mn(II)在 MnO 表面的反应性位点上的吸附，MnO 失去了氧化能力。通过用 Mn(VII)氧化吸附的 Mn(II)可以实现部分失活的 MnO 的完全再生。
