Selective Adsorption of Gd3+ on a Magnetically Retrievable Imprinted Chitosan/Carbon Nanotube Composite with High Capacity

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• 作者：Kai Li ; Qiang Gao ; Gayatri Yadavalli ; Xiang Shen ; Hanwu Lei ; Bo Han ; Kaisheng Xia ; Chenggang Zhou
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：September 30, 2015
• 年：2015
• 卷：7
• 期：38
• 页码：21047-21055
• 全文大小：492K
• ISSN：1944-8252

文摘

A novel magnetic imprinting nanotechnology for selective capture of Gd³⁺ from a mixed solution of rare earth ions was developed by simply adding Gd³⁺-imprinted chitosan/carbon nanotube nanocomposite (IIP-CS/CNT) and silica-coated magnetite nanoparticle (SiO₂@Fe₃O₄). The IIP-CS/CNT was prepared for the first time via a facile 鈥渟urface deposition鈥揷rosslinking鈥?method, exhibiting a well-defined coating structure. Interestingly, the neighboring IIP-CS/CNT monomers were held together as bundles, like a network, containing abundant interstitial spaces. When IIP-CS/CNT and SiO₂@Fe₃O₄ were dispersed in a mixed solution of rare earth ions, the magnetic SiO₂@Fe₃O₄ submicrospheres would be trapped in or adhere to the IIP-CS/CNT network, leading to the magnetization of IIP-CS/CNT; meanwhile, Gd³⁺ ions could be selectively captured by the magnetized IIP-CS/CNT. Saturation adsorption capacity for Gd³⁺ was up to 88 mg g^鈥? at 303.15 K, which is significantly higher than the Gd³⁺ adsorption capacities for the reported rare earth ion-imprinted adsorbents over recent years. The selectivity coefficients relative to La³⁺ and Ce³⁺ were 3.50 and 2.23, respectively, which are very similar to those found for other reported CS-based imprinted materials. Moreover, the imprinted adsorbents could be easily and rapidly retrieved by an external magnetic field without the need of additional centrifugation or filtration, greatly facilitating the separation process. Test of reusability demonstrated that the magnetized IIP-CS/CNT could be repeatedly used without any significant loss in binding capacity. Overall, this work not only provides new insights into the fabrication of magnetic imprinted CS-based composite, but also highlights its application for selective adsorption toward rare earth ions.