| 铜在壳核结构磁性颗粒上的吸附:效能与表面性质的关系 |
| 摘要点击 3486 全文点击 1553 投稿时间：2015-06-19 修订日期：2015-08-04 |
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| 中文关键词 壳核结构 磁性颗粒 吸附效能 表面性质 铜 |
| 英文关键词 core-shell structure magnetic particle adsorption performance surface property Cu |
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| 中文摘要 |
| 为了揭示吸附剂的吸附效能与其组成、结构及表面性质之间的关系,本研究对两种壳核结构磁性颗粒Fe3O4/MnO2与Fe-Mn/MnO2的形貌特征、表面性质进行了系统表征,并对铜在磁性颗粒表面的吸附行为与机制进行了详细研究. 表征结果表明磁核Fe3O4与Fe-Mn具有相似的尖晶石类晶体结构,包覆MnO2后,晶体结构均未发生明显变化. 但Mn的引入,增强了磁核与外壳间的结合作用,Fe-Mn比Fe3O4包覆MnO2的量更多、更均匀,进而使Fe-Mn/MnO2具有更高的比表面积与更低的等电点. 吸附实验结果表明,Fe-Mn的最大铜吸附容量33.7 mg ·g-1(pH 5.5)高于Fe3O4的17.5 mg ·g-1(pH 5.5); 包覆MnO2以后,铜吸附性能显著增强,Fe-Mn/MnO2最大铜吸附容量升高至58.2 mg ·g-1(pH 5.5),为Fe3O4/MnO2的2.6倍,且优于多数文献报道的磁性吸附剂. 机制研究表明铜在Fe3O4/MnO2与Fe-Mn/MnO2的表面发生了特性吸附,形成了内层表面络合物. 综上所述,磁性颗粒的吸附效能与其组成成分、形貌结构及表面性质之间具有显著的相关性. |
| 英文摘要 |
| In order to reveal the relationship between the adsorption performance of adsorbents and their compositions, structure, and surface properties, the core-shell structured Fe3O4/MnO2 and Fe-Mn/MnO2 magnetic particles were systematically characterized using multiple techniques and their Cu adsorption behaviors as well as mechanism were also investigated in details. It was found that both Fe3O4 and Fe-Mn had spinel structure and no obvious crystalline phase change was observed after coating with MnO2. The introduction of Mn might improve the affinity between the core and the shell, and therefore enhanced the amount and distribution uniformity of the MnO2 coated. Consequently, Fe-Mn/MnO2 exhibited a higher BET specific surface area and a lower isoelectric point. The results of sorption experiments showed that Fe-Mn had a higher maximal Cu adsorption capacity of 33.7 mg ·g-1 at pH 5.5, compared with 17.5 mg ·g-1 of Fe3O4. After coating, the maximal adsorption capacity of Fe-Mn/MnO2 was increased to 58.2 mg ·g-1, which was 2.6 times as high as that of Fe3O4/MnO2 and outperformed the majority of magnetic adsorbents reported in literature. In addition, a specific adsorption of Cu occurred at the surface of Fe3O4/MnO2 or Fe-Mn/MnO2 through the formation of inner-sphere complexes. In conclusion, the adsorption performance of the magnetic particles was positively related to their compositions, structure, and surface properties. |
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