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成本低廉和无二次污染的“绿色”合成纳米材料是发展原位纳米环境修复技术的前沿研究课题之一.本文以绿茶提取液为还原剂和稳定剂进行“绿色”合成纳米铁,探讨在不同的气氛下“绿色”合成的纳米铁颗粒的主要成分,以期为调控合成纳米铁系材料提供基础研究.首先,利用扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线光电子能谱分析(XPS)和傅里叶变换红外光谱(FTIR)等表征手段对不同反应气氛下合成的纳米铁颗粒的表面微观形貌、尺寸和价态结构进行分析.结果发现,在通入N2情况下,合成的纳米铁颗粒粒径为(84.7±11.5)nm,其主要成分以纳米零价铁为主;在通入空气情况下,合成的纳米铁粒径为(117.8±26.2)nm,其主要成分是纳米零价铁、氧化铁和四氧化三铁的混合物;通入O2时,合成的纳米铁粒径为(141.2±26.3)nm,其主要成分以四氧化三铁为主.其次,评价在不同气氛条件下合成纳米铁颗粒对去除亚甲基蓝(MB)的反应活性.结果表明,在反应温度313 K下降解初始浓度为50 mg·L-1的MB溶液,反应5 min时已达到平衡,通入N2合成的纳米铁降解MB,去除率高达98.7%,而通入O2合成的纳米铁反应效率低,对MB的去除率仅为65.3%.最后,从以上发现提出不同气氛下可以调控“绿色”合成的铁系纳米材料成分,从而导致不同的纳米修复环境中污染物的能力.
Low cost and no secondary pollution “green ” synthetic nanomaterials is one of the frontier research topics in the development of in situ nanotechnology environmental repair technology.In this paper, green tea extract is used as reducer and stabilizer to synthesize nano Iron to explore the main components of “green ” synthesized nano-iron particles under different atmosphere, in order to provide basic research for the regulation of the synthesis of nano-iron materials.Firstly, using scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy ), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the surface morphology, size and valence structure of the nano-iron particles synthesized under different reaction atmospheres. , The size of the synthesized nano-iron particles is (84.7 ± 11.5) nm, with the main component of the nano-zero-valent iron; the particle size of the synthesized nano-iron is (117.8 ± 26.2) nm, the main component is a mixture of nano-zero-valent iron, iron oxide and ferroferric oxide; the diameter of the synthesized nano-iron is (141.2 ± 26.3) nm when O2 is introduced, and its main component is tris Iron-based.Secondly, the evaluation of the synthesis under different atmosphere conditions The results showed that the MB solution with initial concentration of 50 mg · L-1 was degraded at 313 K and the equilibrium reached 5 min after the reaction, leading to N2 synthesis Iron degraded MB, the removal rate of up to 98.7%, while the introduction of O2 synthesis of nano-iron reaction efficiency is low, MB removal rate of only 65.3% .Finally, from the above findings suggest that under different atmosphere can control the “green” synthesis Iron-based nanomaterials contribute to the ability of different nanometers to repair contaminants in the environment.