Introduction of α-MnO2 nanosheets to NH2 graphene to remove Cr6+ from aqueous solutions
Introduction of α-MnO2 nanosheets to NH2 graphene to remove Cr6+ from aqueous solutions
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DOI：
10.1039/c5ra04545b
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发表时间：
2015-05
期刊：
影响因子：
3.9
通讯作者：
Li Zhang;Yaxi Tian;Yaopeng Guo;Hui Gao;Haizhen Li;Shiqiang Yan
中科院分区：
文献类型：
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作者：
Li Zhang;Yaxi Tian;Yaopeng Guo;Hui Gao;Haizhen Li;Shiqiang Yan
制备并表征了α-MnO2-NH2-RGO杂化物的平面结构，并用于去除水溶液中的六价铬离子（Cr6+）。利用傅里叶变换红外光谱（FTIR）、x射线衍射（XRD）、透射电镜（TEM）和布鲁诺尔-埃米特-泰勒（BET）理论对新型吸附剂进行了表征。研究了Cr6+吸附效率与Cr6+溶液pH、接触时间和温度的关系。结果表明，吸附量与pH值密切相关，Freundlich等温模型最能描述吸附平衡。对Cr6+的最大吸附量为371 mg g−1。动力学吸附符合准二级动力学模型，表明吸附机理为对非均相材料的物理或化学吸附。得到了吸附过程的热力学参数，结果表明吸附过程是自发的、放热的。经过5次循环后，α-MnO2-NH2-RGO的吸附量仍可高达81%。因此，这些发现表明α-MnO2-NH2-RGO可以作为Cr6+的优秀吸附剂。
The planar structure of the designed α-MnO2–NH2–RGO hybrid was prepared and characterized and used to remove hexavalent chromium ions (Cr6+) from aqueous solutions. The characterization of the novel adsorbent was carried out using the Fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and the Brunauer–Emmett–Teller (BET) theory. Cr6+ adsorption efficiency was investigated as a function of the pH of Cr6+ solution, contact time and temperature. The results showed that the adsorption capacity strongly depended on the pH and that the adsorption equilibrium data were best described by the Freundlich isothermal model. The maximum sorption capacity towards Cr6+ was 371 mg g−1. The kinetic adsorption was fitted to the pseudo-second-order kinetics model and it indicated that the adsorption mechanism is physical or chemical sorption on heterogeneous materials. The thermodynamic parameters were obtained, and the results showed that the adsorption process is spontaneous and exothermic. The adsorption capacity of α-MnO2–NH2–RGO can remain as high as 81% after five usage cycles. As a result, these findings propose that α-MnO2–NH2–RGO could be used as an outstanding adsorbent for Cr6+.