School of Chemistry and Material Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210046, China.
Department of Engineering and Technology, Jiangsu Institute of Commerce, Nanjing 211168, China.
J Environ Sci (China). 2021 Jan;99:10-20. doi: 10.1016/j.jes.2020.06.003. Epub 2020 Jun 23.
Nitrogen-rich graphitized carbon microspheres (NGCs) with hierarchically porous were constructed by self-assembly. Under different heat treatment conditions, the structure, morphology and properties of NGCs were studied by using multiple characterization techniques. The results showed that the chemical microenvironments (e.g. surface chemistry, degree of graphitization and defective, etc.) and microstructures properties (e.g. morphology, specific surface area, particle size, etc.) could be delicately controlled via thermal carbonization processes. The degradation of ofloxacin (OFLX) by NGCs activated peroxymonosulfate (PMS) was studied systematically. It was found that the synergistic coupling effect between optimum N or O bonding species configuration ratio (graphitic N and C=O) and special microstructure was the main reason for the enhanced catalytic activity of NGC-800 (calcination temperature at 800°C). Electron paramagnetic resonance (EPR) experiments and radical quenching experiments indicated that the hydroxyl (OH), sulfate (SO) and singlet oxygen (O) were contributors in the NGC-800/PMS systems. Further investigation of the durability of chemical structures and surface active sites revealed that undergo N bonding species configuration reconstruction and cannibalistic oxidation during PMS activation reaction. The used NGC-800 physicochemical properties could be recovered by heat treatment to achieve the ideal catalytic performance. The findings proposed a valuable insight for catalytic performance and controllable design of construction.
富氮石墨化碳微球（NGCs）通过自组装构建，具有分级多孔结构。在不同的热处理条件下，采用多种表征技术研究了 NGCs 的结构、形貌和性能。结果表明，通过热碳化过程可以精细调控化学微环境（例如表面化学、石墨化程度和缺陷等）和微观结构特性（例如形态、比表面积、粒径等）。系统研究了 NGCs 活化过一硫酸盐（PMS）降解氧氟沙星（OFLX）的性能。研究发现，最佳 N 或 O 键合物种结构比（石墨 N 和 C=O）与特殊微观结构之间的协同耦合效应是 NGC-800（在 800°C 下煅烧）增强催化活性的主要原因。电子顺磁共振（EPR）实验和自由基猝灭实验表明，羟基（OH）、硫酸根（SO）和单线态氧（O）是 NGC-800/PMS 体系中的贡献者。进一步研究化学结构和表面活性位的耐久性表明，在 PMS 活化反应中经历 N 键合物种结构重构和自噬氧化。通过热处理可以恢复用过的 NGC-800 的物理化学性质，以实现理想的催化性能。研究结果为催化性能和可控设计提供了有价值的见解。
