Fe3O4@SA/Ce微球的表征及对染料的吸附特性

以天然高分子化合物海藻酸钠(sodium alginate,SA)为骨架,结合磁性Fe₃O₄和稀土铈离子Ce(Ⅲ)通过溶液反应制备出一种新型的磁性海藻酸铈复合微球(Fe₃O₄@SA;Ce).采用X射线衍射(XRD)、孔结构比表面积分析(BET)、扫描电子显微镜(SEM)、红外光谱(FT-IR)及振动样品强磁计(VSM)对Fe₃O₄@SA;Ce的结构进行了表征,并以直接桃红12B(direct red 12B,DR 12B)和直接橙S(direct orange S,DO S)两种染料为吸附对象,探讨了Fe₃O₄@SA;Ce的吸附剂性能、吸附动力学和热力学.结果表明,Fe₃O₄@SA;Ce对室温下自然pH染料溶液中DR 12B和DO S均表现出良好的吸附效果,吸附量分别可达464 mg·g^-1和730 mg·g^-1.在不同温度下(298、313、328 K),Fe₃O₄@SA;Ce对DR 12B和DO S的吸附过程均可用拟二级吸附动力学方程准确描述.通过等温吸附研究,发现Fe₃O₄@SA;Ce对两种染料的等温吸附较好地符合Freundlich模型.各种表征结果表明,SA与Ce(Ⅲ)和Fe₃O₄交联反应后生成的Fe₃O₄@SA;Ce凝胶球表面有大量深浅不一的褶皱沟纹,形貌发生了显著变化.作为一种绿色环保、制备方法简单、可高效吸附的磁性高分子复合吸附剂,Fe₃O₄@SA;Ce对高浓度染料具有很好的吸附效果,期望能够在染料废水处理中得到广泛应用.

Characterization of Fe3O4@SA/Ce microspheres and their adsorption characteristics for direct dyes

A new type of magnetic composite microspheres(Fe₃O₄@SA;Ce)was prepared by a solution method with natural polymer sodium alginate(SA),magnetic Fe₃O₄and rare earth cerium ion Ce(Ⅲ).Fe₃O₄@SA;Ce was characterized by X-ray diffraction(XRD),Brunauer-Emmett-Teller(BET),scanning electron microscopy(SEM),Fourier transform infrared spectrometry(FT-IR)and vibrating sample magnetometry(VSM).The adsorption properties,adsorption kinetics and thermodynamics of direct red 12B(DR 12B)and direct orange S(DO S)were investigated in detail.The results showed that Fe₃O₄@SA;Ce had good adsorbing effect on DR 12B and DO S in natural pH dye solution at room temperature,and the adsorption capacity reached 464 mg·g^-1and 730 mg·g^-1,respectively.The adsorption process of the Fe₃O₄@SA;Ce for DR 12B and DO S could be described by a pseudo-second-order adsorption kinetic equation at different temperatures(298,313 and 328 K).It was found that the isothermal adsorption of Fe₃O₄@SA;Ce for the two dyes was in accordance with the Freundlich model.The morphology of the Fe₃O₄@SA;Ce gel changed significantly,and the surface showed a large number of folds and different depth grooves after the cross-linking reaction of SA with Ce(Ⅲ)and Fe₃O₄.Fe₃O₄@SA;Ce is a new type of magnetic polymer gel ball adsorbents with a simple fabrication process and high efficiency adsorption,and could be used as a feasible adsorbent for the treatment of high concentration dye wastewater.