纳米β-FeOOH对水中Cr(VI)吸附性能的研究

羟基氧化铁由于其较高的表面电荷和较大的比表面积,对重金属离子具有良好的吸附性能,本文采用三种不同的制备方法制得羟基氧化铁(FeOOH),对制得的样品进行了X-射线衍射(XRD)和透射电子显微镜(TEM)表征,并分别用比表面积分析仪和电泳仪测得产品的比表面积和zeta电位。XRD图谱分析结果表明三种产品均为β-FeOOH,而TEM分析结果表明,三种方法得到的β-FeOOH均为纳米级,其形貌分别为长六方形、梭形和纺锤形。所得三种β-FeOOH分别用于吸附模拟水样中Cr(Ⅵ),研究结果表明,三种方法制得的β-FeOOH以加入有机大分子壳聚糖制得的产品(S3)的吸附效果最好。由S3吸附Cr(Ⅵ)的吸附等温实验得出,在293K、303K和313K时,其对Cr(Ⅵ)的饱和吸附量分别为15.45mg／g, 16.87mg／g和18.48mg／g。K_F值随温度升高而不断增大,表明S3对Cr(VI)的吸附过程为吸热反应。

Removal of Cr (VI) from aqueous solutions by nano β-FeOOH

Iron oxybydroxide (FeOOH) has good performance for adsorption of heavy metal ions because of its high surface charge and large surface area. Three different methods were used to synthesize FeOOH. The identities of FeOOH were verified by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface area of the nanoparticle was measured by a surface area analyzer, and the zeta potential of the nanoparticle was obtained by a zeta potential analyzer. The XRD peaks of these three crystallites well matched with the standard β-FeOOH. The TEM images showed that they were nano-scaled, and the morphologies were rectangle, shuttle and spindle, respectively. The three kinds of β-FeOOH were used to conduct adsorption experiments to investigate their adsorption capacity of Cr(Ⅵ) in the simulated water. The result of the adsorption experiments showed that β-FeOOH which synthesized with organic macromolecules had high removal efficiency for Cr(Ⅵ) in comparison with other samples. Adsorption isotherm studies indicated that the adsorption capacities of β-FeOOH were 15.45mg/g, 16.87 mg/g and 18.48mg/g at 293 K, 303 K and 313 K, respectively. An increase in the values of K_F with the increasing temperature indicated that the adsorption was an endothermic process.