核-壳纳米复合材料制备及含铬重金属处理

Preparation Study of Core-Nanoshell Composite Materials and Treatment of Chromium-Containing Heavy Metals

采用一步固相法,制备出以富铁空心微珠为基、稀土掺杂纳米铁氧体为壳的核-壳型纳米复合材料.对所制备样品进行X射线衍射(XRD)、扫描电子显微镜(SEM)和磁性能的表征.结果表明成功制备了核-壳型纳米复合材料,样品的晶粒粒径为30 nm,复合材料两相的交换耦合作用增强,剩磁与矫顽力有所改善,提高了复合材料对重金属阳离子的吸附.采用原子吸收光谱法研究了该复合材料对Cr3+离子的吸附性能,确定了最佳吸附条件.在最佳工艺条件下,该复合材料对含铬重金属的吸附率达到98%以上,有较好的吸附能力,适于推广使用.

A core-nanoshell composite materials doped with La were prepared by a solid-state reaction method. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with La. The sam- ples were characterized by X-ray diffraction analysis, scanning electron microscope and vibrating sample mag- netometer. The results show that the core-nanoshell composite materials were prepared successfully, the grain- size of the sample is about 30 nm. The analysis indicate that the exchange-coupling interaction happens be- tween ferrite of the magnetic fly-ash hollow cenosphere and nanosized ferrite coating. With improved rema- nence and coercivity, the adsorption capacity of heavy metal ions of the composite material is increased. The adsorption behaviors of Cr3 ＋ ions were studied by atomic adsorption spectrometry. Under the optimum condi- tions, the adsorption rate of the composite material for chromium metal reaches over 98%.