Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
Water Res. 2014 Apr 1;52:92-100. doi: 10.1016/j.watres.2013.12.041. Epub 2014 Jan 8.
In this study we comparatively investigate the removal of humic acids with Fe@Fe2O3 core-shell nanowires under anoxic and oxic conditions. The products of humic acids after reacting with Fe@Fe2O3 core-shell nanowires under anoxic and oxic conditions were carefully examined with three-dimensional excitation emission matrix fluorescence spectroscopy and gas chromatography mass spectrometry. It was found that humic acids were removed by Fe@Fe2O3 core-shell nanowires via adsorption under anoxic condition. Langmuir adsorption isotherm was applicable to describe the adsorption processes. Kinetics of humic acids adsorption onto Fe@Fe2O3 core-shell nanowires was found to follow pseudo-second-order rate equation. By contrast, the oxic removal of humic acids with Fe@Fe2O3 core-shell nanowires involved adsorption and subsequent oxidation of humic acids because Fe@Fe2O3 core-shell nanowires could activate molecular oxygen to produce reactive oxygen species to oxidize humic acids. This subsequent oxidation of humic acids could improve the oxic removal rate to 2.5 times that of anoxic removal, accompanying with about 8.4% of mineralization. This study provides a new method for humic acids removal and also sheds light on the effects of humic acids on the pollutant removal by nano zero-valent iron.
在本研究中，我们比较研究了在缺氧和有氧条件下，用 Fe@Fe2O3 核壳纳米线去除腐殖酸的情况。在缺氧和有氧条件下，腐殖酸与 Fe@Fe2O3 核壳纳米线反应后的产物，用三维激发发射矩阵荧光光谱法和气相色谱质谱法进行了仔细的考察。结果发现，在缺氧条件下，腐殖酸通过吸附被 Fe@Fe2O3 核壳纳米线去除。Langmuir 吸附等温线适用于描述吸附过程。腐殖酸在 Fe@Fe2O3 核壳纳米线上的吸附动力学符合准二级速率方程。相比之下，在有氧条件下，腐殖酸与 Fe@Fe2O3 核壳纳米线的去除涉及腐殖酸的吸附和随后的氧化，因为 Fe@Fe2O3 核壳纳米线可以激活分子氧产生活性氧物种来氧化腐殖酸。腐殖酸的这种后续氧化可以将有氧去除率提高到缺氧去除率的 2.5 倍，同时伴有约 8.4%的矿化。本研究为腐殖酸的去除提供了一种新方法，也为纳米零价铁去除污染物时腐殖酸的影响提供了一些启示。
