中文摘要：

采用共沉淀硝酸盐氧化法合成了不同掺杂量的钒掺杂磁铁矿（Fe3-xVxO4,x〈0.4）,并运用化学分析、X射线衍射（XRD）、BET比表面积测试、傅立叶变换红外光谱（FTIR）以及N2和空气气氛下的热重-差示扫描量热分析（TG-DSC）等手段对合成的Fe3-xVxO4进行了结构表征.结果显示,合成的Fe3-xVxO4为立方晶系尖晶石结构,钒离子主要类质同像替换八面体位上的Fe3＋.合成的Fe3-xVxO4是纳米级的磁性材料,晶粒尺寸为28～35nm.钒掺杂作用增加了磁铁矿的表面羟基量.吸附实验结果表明,在中性pH下,Fe3-xVxO4对亚甲基蓝的饱和吸附量随钒掺杂量的增加明显增大,其吸附等温线符合Langmuir方程.Fe3-xVxO4对亚甲基蓝的吸附反应主要在前25min内完成,动力学曲线符合准二级动力学方程.此外,提高溶液的pH有利于Fe3-xVxO4对亚甲基蓝的吸附.

英文摘要：

A series of vanadium-doped magnetite（Fe3-x VxO4,x 0.4） synthesized by an oxidation-precipitation method,were characterized using chemical analysis,X-ray diffraction（XRD）,fourier transform infrared spectroscopy（FTIR）,as well as thermogravimetric and differential scanning calorimetry（TG-DSC） analyses.The obtained results show that the synthetic Fe3-x VxO4 has spinel structure while vanadium mostly replaces Fe3 ＋ in the octahedral sites.The synthetic Fe3-xVxO4 is magnetic material,with crystal size ranging from 28 to 35 nm.The substitution of vanadium in the magnetite structure increases the amount of surface hydroxyls.The experimental adsorption results indicate that,in neutral pH condition,the maximum adsorption capacities of Fe3-xVxO4 increase obviously with the increase of vanadium concentration in magnetite while the adsorption isotherm complies well with the Langmuir model.The adsorption of methylene blue（MB） on Fe3-xVxO4 can get equilibrium in the first 25 min,supporting a pseudosecond order equation.Moreover,the rise of the solution pH value results in an increase of the adsorption capability of MB on Fe3-x VxO4.