Mao Zhou, Wu Qingzhi, Wang Min, Yang Yushi, Long Jia, Chen Xiaohui
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
Department of Prosthetic, School of Stomatology, Wuhan University, Wuhan, 430079, People's Republic of China.
Nanoscale Res Lett. 2014 Sep 16;9(1):501. doi: 10.1186/1556-276X-9-501. eCollection 2014.
A series of nanocomposites consisting of zero-valent iron nanoparticles (ZVI NPs) encapsulated in SiO2 microspheres were successfully synthesized through a successive two-step method, i.e., the wet chemical reduction by borohydride followed by a modified Stöber method. The as-synthesized nanocomposites were characterized using X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer, and inductively coupled plasma-atomic emission spectrometer. The catalytic performance of SiO2-encapsulated ZVI nanocomposites for the degradation of organic dyes was investigated using methylene blue (MB) as the model dye in the presence of H2O2. The results showed that the degradation efficiency and apparent rate constant of the degradation reaction were significantly enhanced with increased ZVI NPs encapsulated in SiO2 microspheres, whereas the dosage of H2O2 remarkably promoted degradation rate without affecting degradation efficiency. The content-dependent magnetic property ensured the excellent magnetic separation of degradation products under an external magnet. This strategy for the synthesis of SiO2-encapsulated ZVI NPs nanocomposites was low cost and easy to scale-up for industrial production, thereby enabling promising applications in environmental remediation.
通过连续两步法成功合成了一系列由包裹在二氧化硅微球中的零价铁纳米颗粒（ZVI NPs）组成的纳米复合材料，即先用硼氢化物进行湿化学还原，然后采用改进的Stöber法。使用X射线衍射、场发射扫描电子显微镜、振动样品磁强计和电感耦合等离子体原子发射光谱仪对合成的纳米复合材料进行了表征。以亚甲基蓝（MB）为模型染料，在过氧化氢存在的条件下，研究了二氧化硅包裹的ZVI纳米复合材料对有机染料的催化降解性能。结果表明，随着包裹在二氧化硅微球中的ZVI NPs数量增加，降解反应的降解效率和表观速率常数显著提高，而过氧化氢的用量显著促进了降解速率，且不影响降解效率。含量依赖的磁性确保了在外部磁场下对降解产物的优异磁分离。这种合成二氧化硅包裹的ZVI NPs纳米复合材料的策略成本低且易于放大用于工业生产，从而在环境修复方面具有广阔的应用前景。
