【摘要】：Al2O3納米材料由于具有高比表面積、好的熱穩(wěn)定性、高介電常數(shù)、低成本等特性,在吸附劑、催化劑、催化劑載體、功能陶瓷、復合材料增強劑和新結(jié)構(gòu)材料合成等諸多領域都有廣泛的應用。而Al2O3納米材料的性質(zhì)和應用很大程度上依靠它的形貌和結(jié)構(gòu),所以近些年,合成具有特殊微結(jié)構(gòu)的形貌可控的Al2O3納米材料已受到許多學者關注,不同形貌的Al2O3納米材料也被相繼報道,如,Al2O3纖維、納米棒、納米針、納米片、納米球、花狀等。本文以傳統(tǒng)水熱法為基礎,通過改變原材料、表面活性劑種類,調(diào)節(jié)水熱溫度、保溫時間、水解速度等條件,合成了不同形貌的Al2O3納米粉體,并以剛果紅作為模擬污染物,研究了所制備的樣品的吸附性能。(1)以Al(NO3)3·9H2O作為鋁源,尿素為添加劑,聚乙二醇(PEG)為表面活性劑,采用傳統(tǒng)水熱法成功合成了純度較高的麥穗狀Al2O3納米粉體,煅燒不同溫度來分析熱處理過程中樣品晶相的轉(zhuǎn)變,同時研究了水熱保溫時間對產(chǎn)物形貌和微結(jié)構(gòu)的影響,并以此推理麥穗狀超級結(jié)構(gòu)形成的可能機理。結(jié)果表明隨著保溫時間的增加,先是自組裝過程進一步進行,之后,奧斯特瓦爾德熟化過程的發(fā)生導致麥穗狀結(jié)構(gòu)完全崩塌。吸附性能測試表明,樣品對有機污染物有很好的去除效果。(2)無任何表面活性劑輔助的情況下,采用傳統(tǒng)水熱法,僅以Al(NO3)3·9H2O和尿素為原料,通過改變其水熱保溫時間制備出不同形貌的Al2O3納米粉體。實驗結(jié)果表明水熱過程中保溫時間對產(chǎn)物的形貌有很大影響,并對比性研究了有表面活性劑和無表面活性劑時樣品可能的不同生長機理。吸附性能測試表明無表面活性劑輔助合成的Al2O3納米粉體對有機污染物也具有很好的去除能力。(3)利用陰陽離子雙水解原理,使用Na Al O2與Al(NO3)3·9H2O、Al Cl3·6H2O、Al2(SO4)3·18H2O為原材料,合成三種尺寸可控的Al2O3納米粉體,其形貌分別為四邊形納米薄片組成的線團狀、納米棒、不規(guī)則納米片。在這種合成策略中,Al3+和Al O2-相互促進作用,使鋁源的水解反應能在真正意義上快速達到完全,縮短了反應時間,同時,整個反應過程也避免調(diào)節(jié)p H值。相較于傳統(tǒng)的水熱法,這種策略更適合工業(yè)量化生產(chǎn)。(4)使用有機鋁源C9H2 1Al O3為原材料,不需要任何其它添加劑,通過傳統(tǒng)水熱法合成了六邊形Al2O3納米薄片。實驗結(jié)果表明,嘗試使用不用的鋁源可以獲得不同結(jié)構(gòu)的Al2O3納米材料。吸附性能測試結(jié)果表明,最終的樣品依然對有機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.
【學位授予單位】：陜西科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ133.1;TB383.1

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本文編號：2276549