Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China.
Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China.
J Hazard Mater. 2017 Sep 15;338:428-436. doi: 10.1016/j.jhazmat.2017.05.044. Epub 2017 May 25.
Manganese oxides exhibit an excellent microwave absorption performance that could increase the degradation efficiency of organic pollutants in contaminated water. Incorporation of various transition metals into manganese oxides could bring about changes in their crystal structure and improve their physicochemical performance. In this work, a better microwave absorption material was obtained by adjusting and controlling the electron spin magnetic moments of Fe-doped birnessite. The powder X-ray diffraction, inductive coupled plasma emission spectrometer, X-ray photoelectron spectroscopy, and network analyses were performed to characterize the crystal structure, chemical composition, valence and content of the elements, and the microwave absorption performance of the obtained samples. Doping Fe into birnessite resulted in little changes to their crystal structure. The narrow energy spectrum of Fe (2p) revealed that the doped Fe was in the form of Fe (III) in birnessite structure. As the content of Fe (III) increased, the content of Mn (III) decreased accordingly. Substitution of Mn (III) by Fe (III) in the birnessite crystal lattice, confirmed by combining the characterization analyses with structure refinements for each doped sample, increased the overall numbers of unpaired electrons in birnessite structure, resulting in a higher electron spin magnetic moment and better microwave response. Compared with the non-doped sample, Fe-doped birnessite improved the efficiency of tetracycline degradation, which proved that Fe-doped birnessite indeed had better response towards the microwave, and thus, could be utilized for better removal of organic pollutants under microwave irradiation.
锰氧化物表现出优异的微波吸收性能，能够提高受污染水中有机污染物的降解效率。将各种过渡金属掺入锰氧化物中可以改变其晶体结构并提高其物理化学性能。在这项工作中，通过调整和控制掺铁叶琳石的电子自旋磁矩，获得了一种更好的微波吸收材料。采用粉末 X 射线衍射、电感耦合等离子体发射光谱仪、X 射线光电子能谱和网络分析对所得样品的晶体结构、化学成分、价态和含量以及微波吸收性能进行了表征。掺杂 Fe 对叶琳石的晶体结构影响很小。Fe（2p）的窄能谱表明，掺杂的 Fe 以 Fe（III）的形式存在于叶琳石结构中。随着 Fe（III）含量的增加，Mn（III）的含量相应减少。通过结合每个掺杂样品的特征分析和结构精修，证实了 Fe（III）取代叶琳石晶格中的 Mn（III），增加了叶琳石结构中未配对电子的总数，从而产生更高的电子自旋磁矩和更好的微波响应。与未掺杂样品相比，掺铁叶琳石提高了四环素的降解效率，这证明掺铁叶琳石确实对微波有更好的响应，因此可以在微波辐射下更好地去除有机污染物。
