γ-Fe_2O_3/膨胀石墨复合材料吸附废水中六价铬的应用研究

Application ofγ-Fe_2O_3/Expanded Graphite to Cr(Ⅵ) Adsorption from Wastewater

介绍了采用溶胶凝胶法合成新型的复合材料-磁性的γ-Fe_2O_3膨胀石墨(MEG)复合材料。通过采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)以及X-光电子能谱仪(XPS)对该复合材料MEG进行了表征,结果表明MEG中γ一Fe_2O_3的粒径约为50nm,而且其中γ一Fe_2O_3和膨胀石墨通过C=O相互作用。复合材料MEG作为新型的六价铬吸附剂,通过吸附时间、初始溶液的pH值以及再生性对该吸附过程进行了考察。结果表明:在40 min内MEG吸附六价铬的过程基本达到平衡;在初始溶液的pH为3.5时,MEG对六价铬的最大吸附量可以达到16.4mg/g;而且该复合材料MEG重复使用3次后吸附效果基本没有下降。因此,复合材料MEG对于废水中六价铬的处理有选择性吸附作用,而且初始溶液的pH值对其吸附过程起着重要作用。

A novel composite material, maghemite （Y-Fe203）/expanded graphite （MEG）, was prepared by sol-gel method. MEG was characterized by scanning electron microscope （SEM）, transmission electron microscopy （TEM）, powder X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, which suggested that the particle size of Y/-Fe2O3 in MEG was about 50 nm and Y/-Fe203 and expanded graphite was coordinated by C： O. MEG, as a novel adsorbent for Cr （Ⅵ ）, was investigated by time, solution pH and the regeneration of adsorbent. Results showed that the adsorption process could reach adsorption equilibrium within 40rain. The maximum adsorbing capacity for Cr（Ⅵ ） could be 16.4 mg/g at pH 3.5. MEG could be reused three times without the adsorption effect reducing. Therefore MEG presents the selective action for the adsorption of Cr（ Ⅵ ） from wastewater, and pH value of initial solution has an important role in the adsorption process.