【作者】 赵西丹；

【导师】 杨延钊；

【作者基本信息】 山东大学 ， 应用化学， 2010， 硕士

【摘要】 微乳液是由表面活性剂、助表面活性剂(通常为醇类)、油(通常为碳氢化合物)和水(或电解质水溶液)在适当的比例下自发形成的外观为透明或半透明,粒径在10～200 nm之间,具有超低界面张力(通常约为10-2mN·m-1)热力学稳定的乳状液体系。本文主要研究了微乳液的性质及其在金属离子镓和铝之间分离萃取方面的应用。首先,我们以十六烷基三甲基溴化铵为表面活性剂,以正戊醇为助表面活性剂,以正庚烷为油相和盐酸溶液制备了热力学稳定的W／O型微乳液体系。通过稀释法估算了微乳液各种结构参数和醇转移的界面自由能；发现微乳液形成后随含水量的增加,水内核半径Rw直线增加,平均聚集数N减小,颗粒总数Nd增加,形成自由能减小,微乳液变得不稳定。制备了微乳液拟三元相图,考察了微乳液各成分对微乳液结构和性质的影响,并在微乳液中引入表面活性剂磷酸三丁酯,制作了拟三元相图,发现磷酸三丁酯使微乳液的三相区大幅变小,使微乳液更加稳定。通过对微乳液电导率的变化的测定,验证了磷酸三丁酯对微乳液稳定性的作用,同时验证了此W／O型微乳液的为渗滤导电机理。然后,在对微乳液性质的研究基础上,分别利用阴离子和阳离子表面活性剂,制备了两种稳定的微乳液。用两种微乳液进行了萃取镓的研究,考察了萃取时间、水油比、萃取剂浓度、料液盐酸浓度等等因素对萃取的影响。发现两种微乳液有其相似点,如萃取速度快,对酸度敏感等；但由于表面活性剂性质差别很大,导致了微乳液的很多不同之处,阳离子表面活性剂制备的微乳液,相对由阴离子表面活性剂制备的微乳液来说,需要更长的时间来达到萃取平衡,萃取效果也相对较差,两种微乳液萃取镓的最佳条件也不同。最后,利用阳离子表面活性剂十六烷基三甲基溴化铵制备的微乳液,进行了微乳液分离金属镓和铝的研究。该微乳液由于磷酸三丁酯的加入,在萃取过程中具有很强的稳定性,可以保持在较大的水油比下也不会破乳。通过考察各种影响萃取的因素对萃取率的影响,我们得出了最佳萃取条件；在最优条件下,微乳液对镓和铝具有非常好的选择性。对富集了镓的微乳液,进行了反萃实验,结果表明,大部分镓可被反萃到低浓度盐酸溶液中,该微乳液成地功实现了镓和铝的分离。更多还原

【Abstract】 Microemulsion is a kind of thermodynamically stable dispersion systems, which is consisted of a surfactant, a cosurfactan, organic solvent and water. Usually microemulsion is transparent or translucent, the diameter of microemulsion varies from 10nm to 200nm, and the interfacial tension of micromulsion is very low (about 10-2 mN·m-1). In this paper, the study is focused on microemulsion’s characteristic and application on the extraction of gallium and aluminum.First, a new stable W/O microemulsion was made from cetyltrimethylammonium bromide (CTAB), n-pentanol, n-heptane and HCl solution. Dilution method was used to estimate some paraters of the micromeulson, and it was found that with the increase of water uptake of the formed microemulsion, Rw increased linearly, N and the free energy decreased, and the microemulsion became unstable. The pseudo-ternary diagram of the microemulsion was prepared to study the structures and forms of different kinds of microemulsion, and tributyl phosphate (TBP) was introduced to stabilize the microemulsion. The conductivity of the microemulsions was surveyed to verify the effect of TBP on the stability of microemulsion, and the study on the influence of water content to the conductivity proved that this W/O microemulsion is percolation conductive.Second, on the basis of the study on microemulsion’property, two kind of microemulsions were made of cationic surfactant and anionic surfactant, respectively. The study of different factors like time, volume ratio, the concentration of extractant and acidity were carried out, the result showed that the trends of extraction rate of some factors on these two kinds of microemulsion were the same, but the nature of the surfactant determined that there were many differences, the micromulsion made of cationic surfactant spent more time to arrive at the equilibrium, and the extraction rate is lower than that made of anionic surfactant. The best conditions of the extraction were different for two kinds of microemulsions.Last, the cationic surfactant Cetyl trimethylammonium bromide (CTAB) was chosen to organize a microemulsion, and the separation of gallium and aluminum was studied. The factors which influnced the extraction rate were surveyed, and the best condition for the extraction was obtained. On the optimal condition, the selectivity of microemulsion on gallium and aluminum was very well; for the microemulsion that was enriched with gallium, a back-extraction was carried out and most gallium was extracted to the HCl solution. The separation of gallium and aluminum was successfully achieved finally.更多还原