纳米铁的绿色合成及其在环境中的应用研究进展

纳米铁（零价铁及铁氧化物）比表面积大、还原能力强、反应活性高，是一种良好的环境功能材料。传统的纳米铁合成方法中，物理方法对反应所需仪器设备要求较高，化学方法使用的还原剂具有毒性，绿色合成方法能够有效克服传统方法的不足之处。本文首先根据合成途径、纳米铁的类型介绍了利用植物和微生物对纳米零价铁（nZVI）及纳米铁氧化物（IONPs）进行绿色合成的方法，同时论述了制备的纳米铁所表现的特征（如形貌、尺寸、聚集倾向、等电位点）。随后总结了纳米铁通过不同反应机制（吸附、还原、催化氧化）去除环境有机、无机污染物（染料、芳香族化合物、硝酸盐、重金属）的应用。最后指出了纳米铁在绿色合成与实际应用过程中存在的挑战性问题及解决方法，以期为纳米铁今后的深入研究和大规模的工业生产应用提供参考依据。

Green synthesis of Fe nanoparticles and their environmental applications

Fe nanoparticles (zero-valent iron and iron oxide) have been regarded as an excellent type of environmental functional material with enormous surface area, outstanding reduction property and high reaction activity. However, in the common synthesis methods of Fe nanoparticles, the physical method usually requires extensive use of equipment for the reaction, and the reducing agent used in the chemical method is toxic, while the green synthesis method can effectively overcome the deficiencies of the conventional method. In this paper, methods were first introduced based on green synthesis of nanoscale zerovalent iron particles (nZVI) and iron oxide nanoparticles (IONPs) by plants and microorganisms in terms of the synthetic route and the type of Fe nanoparticles. Meanwhile, the characteristics (e.g. morphology, size, aggregation tendency, point of zero charges) of the prepared Fe nanoparticles were also discussed. Subsequently, the application of Fe nanoparticles to remove environmental organic and inorganic pollutants (e.g., dyes, aromatic compounds, nitrate, heavy metals) by different reaction mechanisms (adsorption, reduction, catalytic oxidation) was summarized. Finally, the existing challenges in the process of green synthesis and practical application of Fe nanoparticles and their solutions were pointed out, to provide a reference for the future research and large-scale industrial production of Fe nanoparticles.