【作者】 陈淑芳；

【导师】 赵临远；

【作者基本信息】 广西师范大学 ， 无机化学， 2008， 硕士

【摘要】 白炭黑是一类重要的精细无机化工产品,呈细小粒子状,用途广泛。但经过认真深入分析,我们认为白炭黑在用做橡胶补强剂、油墨、涂料填料、牙膏磨擦剂(更准确地称为牙膏用二氧化硅)时,起作用的仅仅分别是它的表层、表层很薄的一部分和表面上一些突起的棱角,而粒子内部很大的一部分是不发挥作用的。据此,我们设想制备一种粒子,具有核-壳复合结构,内部(核)为廉价矿物,而外表(壳)的组成、结构、性能等与白炭黑粒子表层相近。这样的新产品(我们称为ASNS,amorphous silica with novel particle structure),定能在某些应用中替代现有产品,创造很大的经济效益和社会效益。对于这样一个项目的开发,艰难程度可想而知。产于桂林北部的辉沸石,纯度高,储量大,为世界罕见。本研究组在前期研究工作中发现,控制条件可以使辉沸石和酸的反应仅限于发生在颗粒表层。我们认为,对辉沸石颗粒表层进行精心改造,能够得到ASNS。本论文首先对文献中各种铝硅酸盐与酸反应的研究成果进行了认真总结,充分了解可能使用的药剂的种类、处理的方式和条件等,以供借鉴。在系统、深入考察由辉沸石制备ASNS的条件之前,提出它的一项重要技术指标,即辉沸石颗粒表层转化程度的量度—表层转化率。为了快速、准确地测定这一指标,很好地服务于新产品研制,并为未来新产品生产中质量检测和控制做好准备(所获得的方法将构成未来新产品技术规范、企业标准的重要组成部分),又提出对这一类产品的表征方法进行创新,以探针分子吸附法测定辉沸石颗粒表层转化产物(PSTS,product of surface layer transformation of stilbite)的表层转化率(表层转化率为100%的PSTS才有可能是ASNS)。该方法的理论依据为:辉沸石和无定形SiO2对直径大于0.62nm的分子的吸附限于发生在外表面上,渗透到内层的很少或者基本可忽略不计,根据二者对不同染料分子吸附量的差异,探索出了一种简易、快速、可靠的检测方法。本论文的主要工作如下:1.深入研究了无定形SiO2对甲基橙、亚甲基蓝、结晶紫的吸附过程。结果表明,无定形SiO2基本不吸附甲基橙。由于亚甲基蓝和结晶紫都是阳离子型染料,使得无定形SiO2对亚甲基蓝、结晶紫的吸附较容易发生,都能在10min左右迅速达到吸附平衡,并有较大的吸附量。2.在同样实验条件下研究了辉沸石对甲基橙、亚甲基蓝、结晶紫的吸附。结果表明:辉沸石在中性及碱性条件基本不吸附甲基橙,只有在酸性条件下才吸附甲基橙,并且随pH的增大吸附量增加。辉沸石吸附甲基橙是一个较缓慢的过程,大约需2h达到吸附平衡。辉沸石和无定形SiO2对亚甲基蓝、结晶紫的吸附量相当,都有较大吸附,但辉沸石对二者的吸附平衡时间较长,吸附亚甲基蓝需150min,结晶紫需90min才能达到平衡。3.经盐酸和高温处理过的辉沸石比天然辉沸石更容易吸附甲基橙。20℃时,天然辉沸石对初始浓度为20mg/L,pH为4.5的甲基橙的吸附量为1.43mg/L,同样条件下预处理过的辉沸石的吸附量可增大到3.48mg/L。4.最终确定以甲基橙为探针分子。温度为20℃,吸附剂都为0.2g,甲基橙溶液的初始浓度为20mg/L,溶液pH值都为1,无定形SiO2对甲基橙的吸附量q′= 0;辉沸石对甲基橙的吸附量q°= 2.13mg/g。将q′、q°代入转化率公式得: x = (2.13- q) / 2.13只需在同样条件下测定PSTS对甲基橙的吸附量q,即可求得辉沸石颗粒的表层转化率。更多还原

【Abstract】 The silica is a kind of important fine inorganic product of chemical industry, assumes the tiny granule shape, the versatility. But under the earnest thorough analysis, when the silica uses to make the rubber strengthening agent, the printing ink, the coating padding, the toothpaste to rub the liniment (is called toothpaste accurately with silicon dioxide), we think it has an effect merely respectively on its surface layer, the surface layer very thin part or the edges and corners of the surface, but very major part of the interior does not play a role. According to the above, we conceive prepare one kind of granule, which has the nucleus - shell composite construction, whose interior (nucleus) is the inexpensive mineral, but the composition, the structure, the performance etc of the outer surface (shell) is similar with the silica. Such new product (we call it ASNS, amorphous silica with novel particle structure), may substitute the existing product in certain applications, and create very great economic efficiency and the social efficiency. Regarding this kind of project development, it can be imagined the difficult degree.The stilbite produced in the northern of Guilin, is rare in the world with its high purity, big reserves. In the earlier period research work, this study team discovered that the response of the stilbite and the acid is only restricted in occuring in the pellet surface layer when we control the requirement. We believed that we can obtain ASNS by making the careful transformation to the stilbite pellet surface layer. The present paper first summarizes the research results of the reaction of each kind of aluminosilicate and the acid, the full understanding possibly using the medicament type, the processing way and the condition and so on, to supply for reference. Before we research the condition systematically and deeply by prepareing ASNS with the stilbite, we propose its important technical specification, namely the measurement degree stilbite pellet surface layer transformation― surface layer conversion rate. In order to determinate this target fast and accuratly, serve well the new product development, and prepare well for the quality detection and the control (the method will be an important component of the future new product technology standard, enterprise standard), we also proposed an innovation to this kind of product’s attribute method, which propose the adsorption method of probe molecule to determinate the surface conversion rate of the stilbite particle(PSTS, product of surface layer transformation of stilbite). When the surface layer conversion rate is 100%, PSTS only then has possibility been ASNS.The theoretical foundation of this thesis is that the stilbite and amorphous SiO2 adsorpt the molecular whose diameter is bigger than 0.62nm limited to occur in the outside surface, seeped very few to the inner layer. Regarding this we have studied the adsorption relations between the two particle and many kinds of dye intermolecular. According to the difference of the adsorptive capacity, we have explored a simple, fast and reliable examination method.The prime task is as follows:1 We have researched the adsorption process of amorphous SiO2 to methyl orange, methylene blue, gentian violet. The result indicated that amorphous SiO2 basic does not adsorb the methyl orange. But it adsorbs the methylene blue and the gentian violet easily for the methylene blue and the gentian violet are the positive ion dye members. It also can achieve the adsorption equilibrium rapidly about 10min, and has a big adsorptive capacity.2 We have also discussed the adsorption process of stilbite to methyl orange, methylene blue and the gentian violet under the same experimental condition. The result indicats that: the stilbite basic does not adsorb the methyl orange in the neutrality and the alkalinity condition, but adsorbs the methyl orange in the acidic condition. And the adsorptive capacity will increase when the pH increase under the acidic condition. The adsorption process of stilbite to methyl orange is a slow process, which probably needs 2h to achieve the adsorption equilibrium. The adsorptive capacity of stilbite or amorphous SiO2 to the methylene blue and the gentian violet is equivalent. Both of them adsorb greatly, but the adsorption equilibrium time is long, while the methylene blue needs 150min, the gentian violet needs 90min to be able to achieve balanced.3 The stilbite after the treatment of the hydrochloric acid and the high temperature adsorbs the methyl orange more easier than the natural stilbite. When the initial density is 20mg/L, the pH is 4.5, and the temperature is 20℃, the natural stilbite’s adsorptive capacities to methyl orange is 1.43mg/L, and the pretreated stilbite’s adsorptive capacity may increase to 3.48mg/L under the same condition. 4 We finally determine to take methyl orange as the probe molecule. When the temperature is 20℃, the quality of absorbent is 0.2g, the initial density of methyl orange solution is 20mg/L, and the pH is 1, the adsorptive capacity of amorphous SiO2 to methyl orange is q ’ = 0, while the adsorptive capacity of Stilbite to methyl orange is q°= 2.13mg/g. Take the q ’ and q°into the conversion rate formula: x = (2.13- q) / 2.13Only to need determine the adsorptive capacity q of the product PSTS under the similar condition, then we will obtain the surface conversion rate of the stilbite particles.更多还原