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Fe_3O_4/Mn O2与Fe-Mn/Mn O2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Fe_3O_4与Fe-Mn具有相似的尖晶石类晶体结构,包覆Mn O2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Fe_3O_4包覆MnO_2的量更多、更均匀,进而使Fe-Mn/Mn O2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Fe_3O_4的17.5 mg·g-1(pH 5.5);包覆MnO_2以后,铜吸附性能显著增强,Fe-Mn/MnO_2最大铜吸附容量升高至58.2 mg·g-1(p H 5.5),为Fe_3O_4/MnO_2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Fe_3O_4/Mn O2与Fe-Mn/MnO_2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.
In order to reveal the relationship between the adsorption performance of adsorbents and their compositions,structure,and surface properties,the core-shell structured Fe_3O_4/ MnO_2 and Fe-Mn / MnO_2 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 Fe_3O_4 and Fe-Mn had spinel structure and no obvious crystalline phase change was observed after coating with MnO_2. The introduction of Mn might improve the affinity between the core and the shell,and therefore enhanced the amount and distribution uniformity of the MnO_2 coated.Consequently,Fe-Mn / MnO_2 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 p H 5. 5,compared with 17. 5mg·g^(-1)of Fe_3O_4. After coating,the maximal adsorption capacity of Fe-Mn / MnO_2 was increased to 58. 2 mg·g^(-1),which was 2. 6times as high as that of Fe_3O_4/ MnO_2 and outperformed the majority of magnetic adsorbents reported in literature. In addition,a specific adsorption of Cu occurred at the surface of Fe_3O_4/ MnO_2 or Fe-Mn / MnO_2 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.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第12期4531-4538,共8页
Environmental Science
基金
国家自然科学基金项目(51478457)
烟台市科学技术发展计划项目(2014ZH087)
关键词
壳核结构
磁性颗粒
吸附效能
表面性质
铜
core-shell structure
magnetic particle
adsorption performance
surface property
Cu
