The fabrication of 3D hierarchical flower-like δ-MnO2@COF nanocomposites for the efficient and ultra-fast removal of UO22+ ions from aqueous solution
The fabrication of 3D hierarchical flower-like δ-MnO2@COF nanocomposites for the efficient and ultra-fast removal of UO22+ ions from aqueous solution
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DOI：
10.1039/d0en00793e
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
Xin Zhong;Zhipeng Lu;Wen Liang;Xiaojie Guo;Baowei Hu
中科院分区：
文献类型：
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作者：
Xin Zhong;Zhipeng Lu;Wen Liang;Xiaojie Guo;Baowei Hu
在此，通过采用简单的超声处理工艺将δ-晶体二氧化锰（δ-MnO2）纳米花与共价有机骨架（COF，TpPa-1）集成，构建了互穿3D花状δ-MnO2@TpPa-1复合材料。通过 SEM、TEM-EDX、XRD、FT-IR、pHpzc、XPS 和 N2 吸附-解吸研究对 δ-MnO2@TpPa-1 的物理化学性质进行了表征。 UO22+离子在δ-MnO2和δ-MnO2@TpPa-1上的吸附动力学证实了伪二阶模型的存在。等温实验结果表明，Langmuir 模型提供了更好的拟合，说明了 UO22+ 离子在 δ-MnO2 和 δ-MnO2@TpPa-1 上的自发、吸热和单层化学吸附过程。由于静电引力和内球表面络合，在pH 6.5和298 K下，UO22+离子在δ-MnO2和δ-MnO2@TpPa-1上的最大吸附水平分别为499.41 mg g−1和1147.773 mg g−1。含氧基团在 U-O 键和共价 Mn-O-U 键的形成中发挥着重要作用，使 δ-MnO2@TpPa-1 成为从溶液中消除放射性核素的优异吸附剂。
Herein, interpenetrating 3D flower-like δ-MnO2@TpPa-1 composites were suitably constructed though the integration of δ-crystal manganese dioxide (δ-MnO2) nano-flowers with a covalent organic framework (COF, TpPa-1) via adopting a simple ultrasonication process. The physicochemical properties of δ-MnO2@TpPa-1 were characterized via SEM, TEM-EDX, XRD, FT-IR, pHpzc, XPS, and N2 adsorption–desorption studies. The kinetics of UO22+-ion adsorption onto δ-MnO2 and δ-MnO2@TpPa-1 confirmed the existence of a pseudo-second-order model. The results of isothermal experiments showed that the Langmuir model provided a better fit, illustrating a spontaneous, endothermic, and monolayer chemisorption process for UO22+ ions onto δ-MnO2 and δ-MnO2@TpPa-1. The maximum adsorption levels of UO22+ ions onto δ-MnO2 and δ-MnO2@TpPa-1 were 499.41 mg g−1 and 1147.773 mg g−1, respectively, at pH 6.5 and 298 K, owing to electrostatic attraction and inner-sphere surface complexation. Oxygen-containing groups played essential roles in the formation of U–O bonds and covalent Mn–O–U bonds, making δ-MnO2@TpPa-1 an excellent adsorbent for radionuclide elimination from solution.