High-valent iron-oxo species on pyridine-containing MWCNTs generated in a solar-induced H2O2 activation system for the removal of antimicrobials. (June 2021)

• Record Type: Journal Article
• Authors: Xia, Yun; Li, Nan; Lu, Wangyang; Wang, Wentao; Yao, Yuyuan; Zhu, Zhexin; Xu, Tiefeng; Gu, Yan; Chen, Wenxing
• Is Part Of: Chemosphere. Volume 273(2021)
• Publication Date: 2021-06
• Subjects: High-valent iron-oxo species -- Pyridine-containing MWCNTs -- Solar-induced -- H2O2 activation -- Antimicrobials; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.129545
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The overuse of antimicrobials has resulted in serious damage to the ecosystem and human health. Therefore, the development of an efficient, stable, and reusable catalyst to eliminate antimicrobials under mild conditions is highly desired. Drawing inspiration from the metabolism of drugs by the enzymes in the human body, such as heme catalase, we developed a simulated enzyme catalyst, perchloride iron phthalocyanine (FePcCl16 ), immobilized on pyridine-modified multiwalled carbon nanotubes (FePcCl16 -Py-MWCNTs). In the catalyst, FePcCl16 worked as the active site, and the axial fifth ligand, 4-aminopyridine, was introduced to cleave H2 O2 heterolytically. Inspired by the reaction mechanism of heme catalase and H2 O2, the catalytic system was designed based on FePcCl16 -Py-MWCNTs for oxidizing 4-chloro-3, 5-dimethylphenol (PCMX) by H2 O2 activation. The results showed that the catalytic activity of the system was significantly increased under simulated solar light irradiation, which can promote electron transfer for heterolytic cleavage of H2 O2 . The enzyme-like catalyst achieved much higher catalytic activity than the Fenton reaction when the pH was close to neutral. It turned out that the main active species was high-valent iron-oxo (Fe(Ⅳ) = O) rather than hydroxyl radial (OH) or superoxide radical (O2 − ), different from most mechanisms. Ultraperformance liquid chromatography-high-definition mass spectrometry showed that the substrate was degraded to small molecule acids by Fe(Ⅳ) = O active species and further mineralization indicated by total organic carbon. The catalytic system exhibited highly efficient, stable, recyclable catalytic performance under mild conditions and did not cause secondary pollution to the environment. This study of a simulated enzyme catalytic system offers important insight into sewage treatment. Graphical abstract: Image 1 Highlights: FePcCl16 -Py-MWCNTs prepared by axial coordination as enzyme-like catalyst. Pyridine-functionalized multi-walled carbon nanotubes contributed to the catalysis of enzyme. The enzyme-like catalytic system exhibited a high photocatalytic activity. Solar light irradiation induced H2 O2 activation. Antimicrobials degradation by high-valent iron-oxo species in the catalytic system.