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1、西安科技大学 硕士学位论文 Pickering乳液的制备及应用研究 姓名：刘登卫 申请学位级别：硕士 专业：化学工艺 指导教师：贺拥军 2011 论文题目：Pickering 乳液的制备及应用研究 专 业：化学工艺 硕 士 生：刘登卫 (签名) 指导教师：贺拥军 (签名) 摘 要 Pickering乳液是以固体粒子替代传统化学乳化剂制得的热力学和动力学均稳定的 分散体系。Pickering乳液由于其成本低、无毒和环保等特性，在食品、医药和化妆品等 领域具有重要的应用价值。本文以固体粒子为乳化剂制备了稳定的Pickering乳液，考察 了影响Pickering乳液形成和稳定性的因素，并研究了Pi
2、ckering乳液作为分离介质的应用 性能。 采用Stber法制备了SiO2粒子，用直接沉淀法制备了ZnO粒子和MgO粒子，利用晶 相生长逐层包覆的方法制备了SiO2/ZnO复合粒子，讨论了反应物浓度、滴加方式和滴加 速度等因素对固体粒子形貌和分散性的影响。SEM测试表明，SiO2粒子分散性良好，平 均粒径约为300 nm； ZnO粒子呈针状结构， 平均直径为20 nm； ZnO在SiO2表面分布不均， 改变锌盐溶液的浓度和滴加速度，可以得到ZnO组分含量不同的SiO2/ZnO复合粒子； MgO粒子有球形和立方晶形结构，平均粒径约为100 nm。FTIR检测表明，SiO2、ZnO、 SiO2/
3、ZnO和MgO粒子表面均有大量的羟基。XRD分析证明，MgO结晶度较高。 以 SiO2、ZnO、SiO2/ZnO 和 MgO 粒子为乳化剂，制备了 O/W 型 Pickering 乳液， 考察了固体粒子种类、复合粒子组分含量、油水体积比、连续相中电解质和表面活性剂 等因素对乳液稳定性的影响。以三氯甲烷为油相时，基于 SiO2和 ZnO 制备的乳液很不 稳定，而 SiO2/ZnO 和 MgO 均能得到稳定的乳液，且 SiO2/ZnO 中 ZnO 组分含量越高， 乳液滴越小。在 MgO 稳定的三氯甲烷/水乳液中，增加油水体积比，乳液稳定性下降， 但没有发生相转变。 当连续相中电解质浓度增加时， 乳
4、液稳定性下降， 且 Na2CO3比 NaCl 的作用强。给 MgO 稳定的三氯甲烷/水乳液中加入表面活性剂，乳液滴变小且更稳定； 给表面活性剂稳定的三氯甲烷/水乳液中加入固体粒子， 乳液滴平均直径增大而稳定性也 增加。 以 SiO2/ZnO 稳定的三氯甲烷-苯乙烯/水乳液为介质， 进行了静态和动态分离甲基紫 的研究。在静态分离下，Pickering 乳液在 30 min 内就趋于分离饱和，温度对分离效果 的影响不大，而增加乳液量和增大甲基紫水溶液浓度可以提高乳液分离能力，分离前后 乳液滴的形貌变化不大。在动态分离下，增加 Pickering 乳液量、降低甲基紫溶液进水 浓度和流速，可以延长穿透
5、时间和提高乳液分离能力，分离后乳液滴发生了凹陷、扁平 等变形。 以 MgO 稳定的三氯甲烷/水乳液为介质，进行了苯胺的静态和动态分离。在静态分 离下，Pickering 乳液在 10 min 以就达到了最大分离量，增加乳液量和分离级数，分离 效率提高；增大 MgO 用量，分离效率先增大后减小。单级分离效率低于 70%，三级分 离效率超过 98%，分离前后乳液滴的形貌变化不大。在动态分离下，增加乳液用量、减 小进水流速和进水浓度，穿透时间延长。 关 键 词：固体粒子；Pickering乳液；稳定性；甲基紫；苯胺；分离 研究类型：基础研究 Subject : Study on the Prepar
6、ation and Application of Pickering Emulsions Specialty ：Chemical Technology Name ：Liu Dengwei (Signature) Instructor ：He Yongjun (Signature) ABSTRACT As a thermodynamic and dynamic stability system, solid-stabilized emulsions are stabilized by solid particles as emulsifiers instead of traditional ch
7、emical surfactants, which are often called Pickering emulsions. Because of low cost, non-toxic and environmental, Pickering emulsions play an important role in food, pharmaceutical and cosmetics et al. In this paper, Pickering emulsions stabilized by single and composite particles were prepared, the
8、 factors influenced the stability of Pickering emulsions were discussed, and the application in separation process of Pickering emulsions was investigated. Using Stber method, SiO2 particles were prepared by hydrolysis reaction of tetraethoxysilane (TEOS). ZnO and MgO particles were prepared by dire
9、ct precipitation method. SiO2/ZnO composite particles were prepared with a layer by layer method by coating ZnO on the surface of SiO2 particles. SEM showed that SiO2 particles were dispersed well and spherical with an average diameter of 300 nm, ZnO particles were needle-like morphology with an ave
10、rage size of 20 nm, MgO particles had both spherical and dubic crystal structure with an average diameter of 100 nm, ZnO were uneven distributed on the surface of SiO2 and different components composite particles could be prepared by changing the concentration of zinc salt solution and the drops of
11、liquid speed. FTIR showed that a large number of hydroxyl groups on the surface of SiO2, ZnO, SiO2/ZnO and MgO. XRD confirmed MgO had a high degree of crystallization. The oil-in-water Pickering emulsions stabilized by SiO2, ZnO, SiO2/ZnO and MgO particles as emulsifiers were prepared, and the facto
12、rs of solid particles type, component content of composite particles, oil-water ratio, electrolyte in continuous phase and surfactants on the formation and stability of the emulsions were investigated. The results showed that the emulsions stabilized by SiO2/ZnO and MgO were very stable, but by SiO2
13、 and ZnO were not while chloroform as oil phase. The stability of Pickering emulsions stabilized by MgO decreased when oil-water ratio increased, but no phase inversion occurred. The stability decreased when electrolyte concentration was high, and Na2CO3 was stronger than NaCl. The droplets became s
14、maller and much more stable when surfactants were added in the emulsions stabilized by MgO particles as emulsifier and chloroform as oil, and joined solid particles to the chloroform in water emulsions stabilized by surfactants, the size and the stability of the droplets were increased. The static a
15、nd dynamic separation of methyl violet based on the chloroform-styrene in water emulsions stabilized by SiO2/ZnO particles. The results showed that Pickering emulsions tended to separation saturation with in 30 min, but temperature had little influence, the separation efficiency could be improved by
16、 increasing the amount of emulsions and the concentration of methyl violet on the static separation, and the droplets changed little before and after separation. The penetration time extended and the separation ability of methyl violet increased when increasing the amount of the emulsions, decreasing the concentration of methyl violet and flow rate, and the droplets changed depression, flat and so on. The stat
