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 Preparation and Application of Pickering
Emulsions
Specialty ：Chemical Technology
Name ：Liu Dengwei
The static and dynamic separation of aniline was carried out with Pickering emulsions as separation media. The results showed that Pickering emulsions reached to the maximum capacity, with increasing the amount of emulsions and the extraction stages, the static extraction efficiency increased, increasing MgO particles, the extraction efficiency raised first and then decreased, and the static extraction efficiency of single-stage was 70%, while that of three-stages exceeded 98%. The dynamic extraction behavior of aniline from aqueous solution was similar to that of adsorption procedure in fixed bed, with the increase of the volume amount of Pickering emulsions, the decrease of inlet rate and initial aniline concentration, the dynamic extraction efficiency increased, the penetration time was prolonged and the droplets had large deformation.
(Signatature)
ABSTRACT
As a thermodynamic and dynamic stability system, solid-stabilized emulsions are stabilized by solid particles as emulsifiers instead of traditional chemical 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 factors influenced the stability of Pickering emulsions were discussed, and the application in separation process of Pickering emulsions was investigated.
The static and 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 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.
Using Stöber method, SiO2 particles were prepared by hydrolysis reaction of tetraethoxysilane (TEOS). ZnO and MgO particles were prepared by direct 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 average 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 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.
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。
The oil-in-water Pickering emulsions stabilized by SiO2, ZnO, SiO2/ZnO and MgO particles as emulsifiers were prepared, and the factors 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 and ZnO were not
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
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