可控形貌氧化铝的制备及吸附性能的研究
发布时间：2018-10-17 11:43
【摘要】：Al2O3纳米材料由于具有高比表面积、好的热稳定性、高介电常数、低成本等特性,在吸附剂、催化剂、催化剂载体、功能陶瓷、复合材料增强剂和新结构材料合成等诸多领域都有广泛的应用。而Al2O3纳米材料的性质和应用很大程度上依靠它的形貌和结构,所以近些年,合成具有特殊微结构的形貌可控的Al2O3纳米材料已受到许多学者关注,不同形貌的Al2O3纳米材料也被相继报道,如,Al2O3纤维、纳米棒、纳米针、纳米片、纳米球、花状等。本文以传统水热法为基础,通过改变原材料、表面活性剂种类,调节水热温度、保温时间、水解速度等条件,合成了不同形貌的Al2O3纳米粉体,并以刚果红作为模拟污染物,研究了所制备的样品的吸附性能。(1)以Al(NO3)3·9H2O作为铝源,尿素为添加剂,聚乙二醇(PEG)为表面活性剂,采用传统水热法成功合成了纯度较高的麦穗状Al2O3纳米粉体,煅烧不同温度来分析热处理过程中样品晶相的转变,同时研究了水热保温时间对产物形貌和微结构的影响,并以此推理麦穗状超级结构形成的可能机理。结果表明随着保温时间的增加,先是自组装过程进一步进行,之后,奥斯特瓦尔德熟化过程的发生导致麦穗状结构完全崩塌。吸附性能测试表明,样品对有机污染物有很好的去除效果。(2)无任何表面活性剂辅助的情况下,采用传统水热法,仅以Al(NO3)3·9H2O和尿素为原料,通过改变其水热保温时间制备出不同形貌的Al2O3纳米粉体。实验结果表明水热过程中保温时间对产物的形貌有很大影响,并对比性研究了有表面活性剂和无表面活性剂时样品可能的不同生长机理。吸附性能测试表明无表面活性剂辅助合成的Al2O3纳米粉体对有机污染物也具有很好的去除能力。(3)利用阴阳离子双水解原理,使用Na Al O2与Al(NO3)3·9H2O、Al Cl3·6H2O、Al2(SO4)3·18H2O为原材料,合成三种尺寸可控的Al2O3纳米粉体,其形貌分别为四边形纳米薄片组成的线团状、纳米棒、不规则纳米片。在这种合成策略中,Al3+和Al O2-相互促进作用,使铝源的水解反应能在真正意义上快速达到完全,缩短了反应时间,同时,整个反应过程也避免调节p H值。相较于传统的水热法,这种策略更适合工业量化生产。(4)使用有机铝源C9H2 1Al O3为原材料,不需要任何其它添加剂,通过传统水热法合成了六边形Al2O3纳米薄片。实验结果表明,尝试使用不用的铝源可以获得不同结构的Al2O3纳米材料。吸附性能测试结果表明,最终的样品依然对有机污染物有很好的去除能力。
[Abstract]:Due to its high specific surface area, good thermal stability, high dielectric constant and low cost, Al2O3 nanomaterials are found in adsorbent, catalyst carrier, functional ceramics, etc. Composite reinforcements and new structural materials have been widely used in many fields. However, the properties and applications of Al2O3 nanomaterials depend largely on their morphology and structure. In recent years, many scholars have paid close attention to the synthesis of Al2O3 nanomaterials with special microstructure and controllable morphology. Al2O3 nanomaterials with different morphologies have also been reported, such as Al2O3 fibers, nanorods, nanowires, nanometers, nanospheres, flowers and so on. Based on the traditional hydrothermal method, different morphologies of Al2O3 nanocrystals were synthesized by changing raw materials, kinds of surfactants, adjusting hydrothermal temperature, holding time and hydrolysis speed. Congo red was used as the simulated pollutant. The adsorption properties of the prepared samples were studied. (1) Al (NO3) 3 9H2O was used as aluminum source, urea as additive, polyethylene glycol (PEG) as surfactant, and high purity Al2O3 nanocrystalline powder was successfully synthesized by hydrothermal method. The transformation of crystal phase during heat treatment was analyzed by calcination at different temperatures, and the effect of hydrothermal holding time on the morphology and microstructure of the product was studied, and the possible mechanism of the formation of superstructure in wheat panicle was deduced. The results show that with the increase of the holding time, the self-assembly process is carried out further, and then the ripening process of Osterwald leads to the complete collapse of the panicle structure of wheat. The adsorption performance test showed that the sample had a good removal effect on organic pollutants. (2) without any surfactant, the traditional hydrothermal method was used, only Al (NO3) 3 9H2O and urea were used as raw materials. Al2O3 nanocrystalline powders with different morphologies were prepared by changing the hydrothermal holding time. The experimental results show that the holding time has a great influence on the morphology of the product during hydrothermal process, and the different growth mechanisms of the samples with and without surfactants are comparatively studied. The adsorption performance test showed that the Al2O3 nano-powders synthesized with non-surfactant also had good removal ability to organic pollutants. (3) using Na Al O 2 and Al (NO3) 39H 2O 3 Al Cl3 6H 2O Al 2 (SO4) 3 18H2O as raw materials, Na Al O 2 and Al (NO3) 39 H 2O 3 H 2O Al 2 (SO4) 3 18H2O were used as raw materials. Three kinds of Al2O3 nanocrystalline powders with controllable size were synthesized, and their morphologies were composed of quadrilateral nanocrystals, nanorods and irregular nanowires, respectively. In this kind of synthesis strategy, Al3 and Al O _ 2- promote each other, so that the hydrolysis reaction of aluminum source can be achieved rapidly and the reaction time can be shortened. At the same time, the whole reaction process also avoids adjusting pH value. Compared with traditional hydrothermal method, this strategy is more suitable for industrial quantification production. (4) hexagonal Al2O3 nanocrystals were synthesized by conventional hydrothermal method using organic aluminum source C9H2 1Al O3 as raw material and without any other additives. The experimental results show that Al2O3 nanomaterials with different structures can be obtained by using unneeded aluminum sources. The results of adsorption test show that the final sample still has a good removal capacity for organic pollutants.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ133.1;TB383.1
本文编号：2276549
[Abstract]:Due to its high specific surface area, good thermal stability, high dielectric constant and low cost, Al2O3 nanomaterials are found in adsorbent, catalyst carrier, functional ceramics, etc. Composite reinforcements and new structural materials have been widely used in many fields. However, the properties and applications of Al2O3 nanomaterials depend largely on their morphology and structure. In recent years, many scholars have paid close attention to the synthesis of Al2O3 nanomaterials with special microstructure and controllable morphology. Al2O3 nanomaterials with different morphologies have also been reported, such as Al2O3 fibers, nanorods, nanowires, nanometers, nanospheres, flowers and so on. Based on the traditional hydrothermal method, different morphologies of Al2O3 nanocrystals were synthesized by changing raw materials, kinds of surfactants, adjusting hydrothermal temperature, holding time and hydrolysis speed. Congo red was used as the simulated pollutant. The adsorption properties of the prepared samples were studied. (1) Al (NO3) 3 9H2O was used as aluminum source, urea as additive, polyethylene glycol (PEG) as surfactant, and high purity Al2O3 nanocrystalline powder was successfully synthesized by hydrothermal method. The transformation of crystal phase during heat treatment was analyzed by calcination at different temperatures, and the effect of hydrothermal holding time on the morphology and microstructure of the product was studied, and the possible mechanism of the formation of superstructure in wheat panicle was deduced. The results show that with the increase of the holding time, the self-assembly process is carried out further, and then the ripening process of Osterwald leads to the complete collapse of the panicle structure of wheat. The adsorption performance test showed that the sample had a good removal effect on organic pollutants. (2) without any surfactant, the traditional hydrothermal method was used, only Al (NO3) 3 9H2O and urea were used as raw materials. Al2O3 nanocrystalline powders with different morphologies were prepared by changing the hydrothermal holding time. The experimental results show that the holding time has a great influence on the morphology of the product during hydrothermal process, and the different growth mechanisms of the samples with and without surfactants are comparatively studied. The adsorption performance test showed that the Al2O3 nano-powders synthesized with non-surfactant also had good removal ability to organic pollutants. (3) using Na Al O 2 and Al (NO3) 39H 2O 3 Al Cl3 6H 2O Al 2 (SO4) 3 18H2O as raw materials, Na Al O 2 and Al (NO3) 39 H 2O 3 H 2O Al 2 (SO4) 3 18H2O were used as raw materials. Three kinds of Al2O3 nanocrystalline powders with controllable size were synthesized, and their morphologies were composed of quadrilateral nanocrystals, nanorods and irregular nanowires, respectively. In this kind of synthesis strategy, Al3 and Al O _ 2- promote each other, so that the hydrolysis reaction of aluminum source can be achieved rapidly and the reaction time can be shortened. At the same time, the whole reaction process also avoids adjusting pH value. Compared with traditional hydrothermal method, this strategy is more suitable for industrial quantification production. (4) hexagonal Al2O3 nanocrystals were synthesized by conventional hydrothermal method using organic aluminum source C9H2 1Al O3 as raw material and without any other additives. The experimental results show that Al2O3 nanomaterials with different structures can be obtained by using unneeded aluminum sources. The results of adsorption test show that the final sample still has a good removal capacity for organic pollutants.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ133.1;TB383.1
【参考文献】
相关期刊论文 前1条
1 杜淼;孙中溪;;纳米氧化铝制备方法研究进展[J];无机盐工业;2005年12期
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