微纳米分级有序介孔硅酸镁的制备与性能研究

发布时间：2018-01-14 02:25

本文关键词：微纳米分级有序介孔硅酸镁的制备与性能研究　出处：《内蒙古大学》2017年硕士论文　论文类型：学位论文

【摘要】：硅酸镁具有独特的晶体结构和高比表面积的多孔性,可以提供特异的分子场作用力,形成多种类型的吸附中心,在吸附分离领域中有巨大的应用潜力。如何提高硅酸镁的比表面积和孔体积进而提高其吸附性能,已成为该领域的研究重点。本文通过水热法来构筑微纳米分级介孔硅酸镁,研究其对染料分子和铅离子的吸附性能,主要研究内容如下:1.微纳米分层结构硅酸镁利用介孔二氧化硅SBA-15为模板,以氯化镁为镁源,通过牺牲辅助模板-水热法制备出微纳米分层结构硅酸镁。结果表明:硅酸镁具有微纳米复合结构,表面是由纳米片组成,片的厚度约为12nm,硅酸镁的比表面积为411 m~2/g,孔体积为0.45 cm~3/g,平均孔径为4.18 nm。微纳米分层结构硅酸镁对亚甲基蓝(MB)和罗丹明B(RhB)的最大吸附量分别为353 mg/g和227mg/g,吸附过程符合准二级动力学方程,吸附符合朗缪尔吸.附等温模型。2.微纳米有序介孔硅酸镁通过蔗糖填充和碳化工艺,获得碳填充的介孔氧化硅SBA-15(C@SBA-15),并将其作为辅助模板和硅源,通过水热技术制备出微纳米有序介孔硅酸镁。结果表明:硅酸镁具有二维六方相介孔结构,微米结构是由纳米孔道和表面的纳米片构成,比表面积为283 m2/g,平均孔径为7.39 nm,孔体积为0.53 cm3/g,纳米片的厚度约为44 nm。微纳米有序介孔硅酸镁对MB的一次和二次吸附量分别为341 mg/g和203 mg/g,表现出较高的吸附容量、优异的重复利用效率和稳定性;对铅离子最大吸附量为417 mg/g。吸附过程满足准二级动力学方程和朗缪尔吸附等温模型,可以用韦伯-莫里斯内扩散模型描述。3.单分散微纳米介孔硅酸镁对含有表面活性剂的SBA-15进行原位碳化,获得分散性良好的C@SBA-15,并以此为模板和硅源,同时加入分散剂PEG200,通过牺牲辅助模板-水热法制备出单分散微纳米介孔硅酸镁。结果表明:硅酸镁的表面和沿着内部孔道都充满了片状结构,构成分散性良好的微纳米复合结构硅酸镁,其比表面积为424 m2/g,平均孔径大小为50 nm,孔体积为0.53 cm3/g;对MB的最大吸附量为208.5 mg/g,吸附过程符合准二级吸附动力学,吸附容量可以用朗缪尔等温吸附模型分析。实验表明这种以介孔氧化硅材料为模板和硅源制备的微纳米介孔硅酸镁具有较高的比表面积和大的孔体积,制备方法简单易操作,对有机阴离子染料和重金属离子有很强的吸附作用,并且作为吸附剂可以多次循环使用,是一种性能优异的吸附材料。
[Abstract]:Magnesium silicate has unique crystal structure and high surface area porosity, which can provide specific molecular field force and form a variety of adsorption centers. It has great application potential in the field of adsorption and separation. How to improve the specific surface area and pore volume of magnesium silicate and improve its adsorption performance. In this paper, micro and nano-sized mesoporous magnesium silicate was constructed by hydrothermal method to study the adsorption properties of dye molecules and lead ions. The main contents of the study are as follows: 1. The micro and nano layered magnesium silicate uses mesoporous silica SBA-15 as template and magnesium chloride as magnesium source. Magnesium silicate was prepared by sacrificial assisted template-hydrothermal method. The results show that magnesium silicate has a micro-nano composite structure, and the surface is composed of nanochips, the thickness of which is about 12 nm. The specific surface area of magnesium silicate is 411mg / g and the pore volume is 0.45 cm~3/g. The average pore size is 4.18 nm. The maximum adsorption capacity of microlayered magnesium silicate for methylene blue blue (MBB) and Rhodamine Bhh (RhB) is 353 mg/g and 227 mg / g, respectively. The adsorption process accords with the quasi-second-order kinetic equation and the adsorption accords with Langmuir sorption. 2. The ordered mesoporous magnesium silicate is filled with sucrose and carbonized by sucrose. Carbon filled mesoporous silicon oxide SBA-15 was obtained and used as an auxiliary template and silicon source. The results show that magnesium silicate has two-dimensional hexagonal mesoporous structure and micron structure is composed of nano-pore and surface nanochip. The specific surface area is 283m2 / g, the average pore size is 7.39nmand the pore volume is 0.53 cm3/g. The thickness of nanocrystalline was about 44 nm. The primary and secondary adsorption capacities for MB were 341 mg/g and 203mg / g, respectively, showing a high adsorption capacity. Excellent reuse efficiency and stability; The maximum adsorption capacity of lead ion is 417 mg / g. The adsorption process meets the quasi-second-order kinetic equation and Langmuir adsorption isotherm model. Weber-Morrisnay diffusion model can be used to describe .3.Mono-dispersed micro-mesoporous magnesium silicate in situ carbonization of SBA-15 containing surfactants to obtain a good dispersion of CSBA-15. It is used as template and silicon source, and dispersant PEG200 is added at the same time. The monodisperse micro-mesoporous magnesium silicate was prepared by sacrificial assisted template-hydrothermal method. The results showed that the surface and inner channels of magnesium silicate were filled with flake structure. Magnesium silicate with good dispersibility has a specific surface area of 424 m2 / g, an average pore size of 50 nm and a pore volume of 0.53 cm / g. The maximum adsorption capacity of MB was 208.5 mg / g, and the adsorption process was in accordance with the quasi-second-order adsorption kinetics. The adsorption capacity can be analyzed by Langmuir isothermal adsorption model. The experimental results show that the micromesoporous magnesium silicate prepared by using mesoporous silica as template and silicon source has high specific surface area and large pore volume. The preparation method is simple and easy to operate, has strong adsorption on organic anionic dyes and heavy metal ions, and can be used as adsorbent for many times, so it is a kind of excellent adsorption material.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ132.2;TB383.1

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