一锅法合成、表征及胺功能化磁铁矿纳米粒子对水溶液中Cr(VI)和Ni(II)离子的吸附研究：动力学、等温线及热力学研究
One-Pot synthesis, characterization and adsorption studies of amine-functionalized magnetite nanoparticles for removal of Cr (VI) and Ni (II) ions from aqueous solution: kinetic, isotherm and thermodynamic studies.
作者信息
Norouzian Baghani Abbas, Mahvi Amir Hossein, Gholami Mitra, Rastkari Noushin, Delikhoon Mahdieh
机构信息
Center for Water Quality Research, Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran ; Department of Environmental Health Engineering, School of Public Health Science, Tehran University of Medical Sciences, Tehran, Iran.
Department of Environmental Health Engineering, School of Public Health Science, Tehran University of Medical Sciences, Tehran, Iran ; Center for Solid Waste Research, Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
出版信息
J Environ Health Sci Eng. 2016 Jul 26;14:11. doi: 10.1186/s40201-016-0252-0. eCollection 2016.
BACKGROUND
Discharge of heavy metals such as hexavalent chromium (Cr (VI)) and nickel (Ni (II)) into aquatic ecosystems is a matter of concern in wastewater treatment due to their harmful effects on humans. In this paper, removal of Cr (VI) and Ni (II) ions from aqueous solution was investigated using an amino-functionalized magnetic Nano-adsorbent (Fe3O4-NH2).
METHODS
An amino-functionalized magnetic Nano-adsorbent (Fe3O4-NH2) was synthesized by compositing Fe3O4 with 1, 6-hexanediamine for removal of Cr (VI) and Ni (II) ions from aqueous solution. The adsorbent was characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), powder X-Ray Diffraction (XRD), and Vibrating Sample Magnetometry (VSM). Also, the effects of various operational parameters were studied.
RESULTS
According to our finding, Fe3O4-NH2 could be simply separated from aqueous solution with an external magnetic field at 30 s. The experimental data for the adsorption of Cr (VI) and Ni (II) ions revealed that the process followed the Langmuir isotherm and the maximum adsorption capacity was 232.51 mg g(-1) for Cr (VI) at pH = 3 and 222.12 mg g(-1) and for Ni(II) at pH = 6 at 298 °K. Besides, the kinetic data indicated that the results fitted with the pseudo-second-order model (R(2): 0.9871 and 0.9947 % for Cr (VI) and Ni (II), respectively. The results of thermodynamic study indicated that: standard free energy changes (ΔG(ɵ)), standard enthalpy change (ΔH(ɵ)), and standard entropy change (ΔS(ɵ)) were respectively -3.28, 137.1, and 26.91 kJ mol(-1) for Cr (VI) and -6.8433, 116.7, and 31.02 kJ mol(-1) for Ni (II). The adsorption/desorption cycles of Fe3O4-NH2 indicated that it could be used for five times.
CONCLUSIONS
The selected metals' sorption was achieved mainly via electrostatic attraction and coordination interactions. In fact, Fe3O4-NH2 could be removed more than 96 % for both Cr (VI) and Ni (II) ions from aqueous solution and actual wastewater.
背景
六价铬（Cr(VI)）和镍（Ni(II)）等重金属排放到水生生态系统中，因其对人类的有害影响，在废水处理中备受关注。本文研究了使用氨基功能化磁性纳米吸附剂（Fe3O4-NH2）从水溶液中去除Cr(VI)和Ni(II)离子。
方法
通过将Fe3O4与1,6-己二胺复合合成氨基功能化磁性纳米吸附剂（Fe3O4-NH2），用于从水溶液中去除Cr(VI)和Ni(II)离子。采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、粉末X射线衍射（XRD）和振动样品磁强计（VSM）对吸附剂进行表征。此外，还研究了各种操作参数的影响。
结果
根据我们的发现，Fe3O4-NH2在30秒内可通过外部磁场简单地从水溶液中分离出来。Cr(VI)和Ni(II)离子吸附的实验数据表明，该过程遵循朗缪尔等温线，在298°K时，pH = 3时Cr(VI)的最大吸附容量为232.51 mg g(-1)，pH = 6时Ni(II)的最大吸附容量为222.12 mg g(-1)。此外，动力学数据表明结果符合准二级模型（Cr(VI)和Ni(II)的R(2)分别为0.9871和0.9947）。热力学研究结果表明：Cr(VI)的标准自由能变化（ΔG(ɵ)）、标准焓变（ΔH(ɵ)）和标准熵变（ΔS(ɵ)）分别为-3.28、137.1和26.91 kJ mol(-1)，Ni(II)的分别为-6.8433、116.7和31.02 kJ mol(-1)。Fe3O4-NH2的吸附/解吸循环表明它可重复使用五次。
结论
所选金属的吸附主要通过静电吸引和配位相互作用实现。实际上，Fe3O4-NH2可从水溶液和实际废水中去除超过96%的Cr(VI)和Ni(II)离子。
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