Abstract:

Sodium percarbonate (SPC, Na₂CO₃·1.5H₂O₂), known as solid hydrogen peroxide, has garnered increasing attention in recent years. In this study, a nanotubular cobalt-nitrogen-carbon catalyst (Co-N-C) with abundant active sites was prepared using a simple method and utilized to activate SPC for the effective removal of tetracycline (TC). The morphology of the material was characterized using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The elemental distribution and valence state changes were analyzed using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The characterization results indicated that a nanotubular Co-N-C with abundant active sites was successfully synthesized. Under the conditions of a TC concentration of 10mg/L, SPC concentration of 2mmol/L, Co-N-C content of 0.2g/L and pH of 7, nearly 100% degradation of TC was achieved within 20 minutes. Radical quenching experiments and electron paramagnetic resonance (EPR) tests revealed that ·OH, ·CO₃^- and ·O₂^- were the primary active species for TC degradation in the Co-N-C/SPC system. Changes in the valence state of cobalt before and after the reaction, as well as the Co²⁺/Co³⁺ cycling process, facilitated the activation of SPC, and three-dimensional fluorescence spectroscopy analysis indicated that TC was degraded in the Co-N-C/SPC system.

Key words: sodium percarbonate, cobalt-nitrogen-carbon catalyst, tetracycline, kinetics, radical action

摘要：

过碳酸钠（SPC，Na₂CO₃·1.5H₂O₂）作为固体过氧化氢，近年来受到越来越多的关注。在此，通过简单的方法制备了具有丰富活性位点的纳米管状钴氮碳催化剂（Co-N-C），并用于活化SPC以有效去除四环素（TC）。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）对材料形貌进行表征。通过X射线粉末衍射仪（XRD）、傅里叶变换红外光谱仪（FTIR）和X射线光电子能谱（XPS）分析元素分布和价态变化。表征结果表明合成了具有丰富活性位点的纳米管状Co-N-C。在TC浓度10mg/L，SPC浓度为2mmol/L，Co-N-C含量为0.2g/L，pH为7的条件下，在20min内几乎实现了TC的100%降解。自由基淬灭实验和EPR测试表明Co-N-C/SPC系统中的 ·OH、·CO₃^-和·O₂^-为TC降解的主要活性物质。反应前后钴元素价态变化以及Co²⁺/Co³⁺循环过程促进了SPC的活化，三维荧光光谱分析表明TC在Co-N-C/SPC体系中被降解。

关键词: 过碳酸钠, 钴氮碳催化剂, 四环素, 动力学, 自由基作用