Adsorption of Pb(II) Using Magnetic Titanate Nanotubes Prepared via Two‐Step Hydrothermal Method
Adsorption of Pb(II) Using Magnetic Titanate Nanotubes Prepared via Two‐Step Hydrothermal Method
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DOI：
10.1002/clen.201300582
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发表时间：
2014-07
影响因子：
1.7
通讯作者：
Lei Zhang;Xin Wang;Huan Chen;Fang Jiang
中科院分区：
文献类型：
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作者：
Lei Zhang;Xin Wang;Huan Chen;Fang Jiang
采用两步水热法制备了磁性钛酸盐纳米管（MTNTs），并将其用作吸附剂吸附水中的Pb（II）。通过N2吸附-脱附分析、透射电子显微镜、粉末X射线衍射、振动样品磁强计、zeta电位分析、X射线光电子能谱（XPS）和傅里叶变换红外光谱（FT-IR）对MTNTs进行了表征。结果表明，CoFe 2 O 4是在水热过程中形成的，并被注入到纳米管的缠结网络中。MTNTs的饱和磁化强度为9.20 emu g-1，这使得MTNTs可以在外部磁场中容易地恢复。MTNTs对Pb（II）的吸附速度非常快，符合准二级动力学模型。此外，Pb（II）的吸附强烈依赖于pH值，MTNTs对Pb（II）的最大吸附容量在pH 5.0时达到442.5 mg g−1。FT-IR和XPS分析表明，MTNTs对Pb（II）的吸附机理为层间Na+/H+离子交换。此外，负载Pb（II）的MTNTs可以用饱和EDTA-2Na溶液在pH 2.5再生，吸附剂可以重复使用。
Magnetic titanate nanotubes (MTNTs) have been prepared by a two-step hydrothermal method and used as adsorbents for the removal of Pb(II) from aqueous solution. The MTNTs are characterized by N2 adsorption–desorption analysis, transmission electron microscopy, powder X-ray diffraction, vibrating sample magnetometer, zeta potentials analysis, X-ray photoelectron spectra (XPS), and Fourier transform infrared (FT-IR) spectroscopy. The results indicate that CoFe2O4 is formed in the hydrothermal process and implanted into the entangled network of nanotubes. The saturation magnetization of MTNTs is 9.20 emu g−1, which makes MTNTs can be readily recovered in an external magnetic field. The adsorption of Pb(II) over MTNTs is very fast and follows the pseudo-second-order kinetic model. Additionally, Pb(II) adsorption is strongly pH dependent and the maximum adsorption capacity of MTNTs for Pb(II) reaches 442.5 mg g−1 at pH 5.0. FT-IR and XPS analysis suggest that the adsorption mechanism of MTNTs is ionic exchange between Pb(II) and Na+/H+ in the interlayer of nanotubes. Furthermore, Pb(II)-loaded MTNTs can be regenerated by saturated EDTA-2Na solution at pH 2.5 and the adsorbents can be used repeatedly.