磁性煤系高岭石纳米材料的制备及对Cr(Ⅵ)的吸附

    Preparation of Magnetic Coal-measure Kaolinite Nanomaterials and Adsorption of Cr(Ⅵ)

    • 摘要: 这是一篇矿物材料领域的论文。为开发煤伴生矿产资源高岭石高值化利用技术,以洗选固废产物煤矸石/煤泥为原料,采用间接插层-液相剥片法制备煤系高岭石纳米材料(Coal-measure Kaolinite Nanomaterials,CKN),在此基础上以化学沉淀法制备磁性煤系高岭石纳米材料(Magnetic Coal-measure Kaolinite Nanomaterials,MCKN),通过XRD、SEM、BET等表征分析了MCKN的物理化学性质,并对不同质量比(m(Fe3O4)∶m(CKN)=1∶3;1∶4;1∶5;1∶6;1∶7)MCKN吸附Cr(Ⅵ)的行为进行探讨。结果表明:Fe3O4与CKN的质量比为1∶ 5的MCKN对Cr(Ⅵ)的吸附效果较佳;MCKN磁分离效果良好,在第5次吸附解吸后对Cr(Ⅵ)的吸附率仍能保持在87%以上;CKN形态较完整,表面光滑,呈多层结构,部分形成纳米管状结构,但仍然有一部分以片状结构存在;添加了Fe3O4后,MCKN表面变粗糙,有明显的30~40 nm颗粒状覆着,表明MCKN的成功制备;CKN的比表面积高于煤系高岭石,而MCKN的比表面积约为CKN的2倍;MCKN对Cr(Ⅵ)的吸附符合准二级动力学模型,为化学吸附,吸附等温线符合Langmuir模型,饱和吸附容量为17.26 mg/g,且吸附是吸热自发的过程。综上,采用煤系高岭石制备的MCKN具有良好的吸附Cr(Ⅵ)的性能,且便于磁性回收重复利用,可作为工业应用中以废治废的潜在材料。

       

      Abstract: This is an article in the field of mineral materials. In order to develop the high-value utilization technology of coal associated mineral resources kaolinite, coal-measure kaolinite nanomaterials(CKN) were prepared by indirect intercalation-liquid phase exfoliation method using coal gangue/slime, which is a solid waste product from washing, as raw materials. On this basis, the magnetic coal-measure kaolinite nanomaterials (MCKN) were prepared by chemical precipitation method, and the physical and chemical properties of MCKN were analyzed by XRD, SEM, BET, etc, and the different quality the ratio (m(Fe3O4): m(CKN)=1: 3, 1: 4, 1: 5, 1: 6, 1: 7) MCKN adsorption of Cr (Ⅵ) behavior was discussed. The results show that MCKN with a mass ratio of Fe3O4 to CKN of 1:5 has the best adsorption effect on Cr(Ⅵ), MCKN has a good magnetic separation effect, and the adsorption rate of Cr(Ⅵ) can still be maintained after the fifth adsorption and desorption above 87%. CKN has a relatively complete morphology, a smooth surface, and a multilayer structure, some of which form nanotube structures, but some of them still exist in sheet-like structures. After loading Fe3O4, the surface of MCKN becomes rough, with an obvious 30~40 nm granular coating, indicating the successful preparation of MCKN, and the specific surface area of MCKN is higher than that of coal- measure kaolinite, while the specific surface area of MCKN is about twice that of CKN. The adsorption of Cr(Ⅵ) by MCKN conforms to the quasi-second-order kinetics, the model is chemical adsorption. The adsorption isotherm conforms to the Langmuir model, the saturated adsorption capacity is 17.26 mg/g, and the adsorption is an endothermic spontaneous process. In summary, the coal-measure kaolinite MCKN has good adsorption performance of Cr(VI), and is convenient for magnetic recovery and reuse, and can be used as a potential material for waste treatment in industrial applications.

       

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