纳米介孔材料SBA-15和MCFs吸附亚甲基蓝和酸性红G的比较研究

发布时间：2018-06-08 01:34

本文选题：SBA-15 + MCFs　；参考：《长春理工大学》2017年硕士论文

【摘要】：本研究利用水热合成法制备出SBA-15和MCFs分子筛,通过化学分析,低温氮气吸附-解吸附等温线,粉末X-射线衍射(XRD),透射电镜(TEM),扫描电镜(SEM)和傅里叶变换红外光谱(FT-IR)对SBA-15和MCFs的表面、孔隙结构等进行表征。用合成的SBA-15和MCFs对亚甲基蓝、酸性红G染料溶液进行吸附,通过实验得出SBA-15和MCFs吸附亚甲基蓝和酸性红G的最佳吸附条件以及最大吸附量,SBA-15对亚甲基蓝的最大吸附量为223 mg/g,SBA-15对酸性红G的最大吸附量是3.532 mg/g,MCFs对亚甲基蓝的最大吸附量是215.5 mg/g,MCFs对酸性红G的最大吸附量是3.053mg/g。SBA-15和MCFs吸附亚甲基蓝和酸性红G的动力学符合准二阶动力学方程。通过Langmuir和Freundlich吸附等温线模型对结果进行分析,SBA-15和MCFs吸附亚甲基蓝和吸附酸性红G的吸附体系符合Freundlich吸附等温线模型。吸附过程中的吉布斯自由能变化00ΔG,可以判断吸附过程是自发进行的。吸附过程中的焓变小于零,说明吸附过程是放热反应,熵变的负值表明吸附过程是熵减少的过程。对吸附后的复合材料通过化学分析、粉末XRD、SEM、TEM、FT-IR、低温N2吸附-解吸附等一系列方法进行了表征,表征结果表明吸附后的复合材料仍然保留原介孔材料的骨架结构,但复合材料有序度降低。吸附后,复合材料的平均孔径、总孔容和比表面积均比吸附前介孔材料的要降低,表明吸附后介孔材料孔道被部分填充、堵塞,这说明染料分子包合在了介孔孔道中。对比吸附前后介孔体积的变化可以算出介孔材料SBA-15每个孔平均吸附6.67×10~(20)个亚甲基蓝分子,介孔材料MCFs每个孔平均吸附2.56×10~(21)个亚甲基蓝分子。
[Abstract]:SBA-15 and MCFs molecular sieves were prepared by hydrothermal synthesis. The isotherms of adsorption and desorption of low temperature nitrogen were obtained by chemical analysis. The surface and pore structures of SBA-15 and MCFs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Methylene blue and acid red G dye solution were adsorbed by synthetic SBA-15 and MCFs. The optimum adsorption conditions of SBA-15 and MCFs for methylene blue and acid red G and the maximum adsorption capacity of SBA-15 for methylene blue are obtained. The maximum adsorption capacity of SBA-15 for acid red G is 3.532 mg / g MCFs for methylene blue. The maximum adsorption capacity of acid red G is 3.053 mg / g SBA-15 and 3.053 mg / g SBA-15, respectively. The kinetics of adsorption of methylene blue and acid red G by MCFs accords with the quasi-second-order kinetic equation. The results were analyzed by Langmuir and Freundlich adsorption isotherms. The adsorption systems of SBA-15 and MCFs for methylene blue and acid red G were fitted to Freundlich adsorption isotherm model. The Gibbs free energy of the adsorption process varies by 00 螖 G, which can be judged to be spontaneous. The enthalpy of the adsorption process is smaller than zero, which indicates that the adsorption process is an exothermic reaction, and the negative value of entropy change indicates that the adsorption process is a process of entropy reduction. The adsorbed composites were characterized by a series of methods, such as chemical analysis, powder XRDX SEMMOTEMT-IR, low temperature N2 adsorption and desorption. The results showed that the adsorbed composites still retained the skeleton structure of the original mesoporous materials. However, the order degree of the composites decreased. After adsorption, the average pore size, total pore volume and specific surface area of the composites were lower than those of the mesoporous materials before adsorption, indicating that the mesoporous materials were partially filled and blocked after adsorption, which indicated that the dye molecules were encapsulated in the mesoporous channels. By comparing the changes of mesoporous volume before and after adsorption, it can be calculated that the mesoporous material SBA-15 adsorbs an average of 6.67 脳 10 ~ (-1) methylene blue molecules per pore, and MCFs an average of 2.56 脳 10 ~ (10) (21) methylene blue molecules per pore.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;TQ424.25

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