| 题名 | 微分散液滴稳定性和反应选择性调控规律及其应用研究 |
| 作者 | 吴勇 |
| 学位类别 | 博士 |
| 答辩日期 | 2011-11-28 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 刘会洲 |
| 关键词 | 微分散 液/液体系 界面电荷 反应选择性 陶瓷膜 |
| 其他题名 | Regulation of Stability and Reaction Selectivity for Liquid-Liquid Micro-dispersed Systems and Its Application |
| 学位专业 | 化学工艺 |
| 中文摘要 | 液/液微分散技术作为化工过程中一种新兴的技术，在实验研究和工业应用上都有很好的前景，特别是在微流体、生物医学、纳米材料等领域。本论文通过极性溶剂、pH、离子强度等来调控液/液微分散液滴的界面电荷，同时利用改进团聚模型评价液/液微分散体系的微观混合性能，进一步应用微分散技术对青霉素G进行连续反萃的研究。研究内容主要包括以下四个方面： (1) 通过无表面活性剂的制备方法获得稳定的正十二烷/水乳液，考察了极性溶剂、pH和盐溶液等对界面电荷的影响，结果表明，乳化液滴直径可以通过正十二烷和亲水性溶剂的比例进行调控。当正十二烷与亲水溶剂相的摩尔比为0.00072~0.073，形成105 nm~453 nm的液滴，多分散指数小于0.2，通过实验获得亨利函数值计算分散液滴的表面电位。当离子强度在0.1 mM~1 mM范围内，表面电位明显下降。此外，通过改变液滴表面亲水性和官能团调控十二烷液滴的界面电荷，亲水溶剂对表面电位的影响从小到大的顺序是甲醇<乙醇<1-丙醇<丙酮<乙腈。 (2) 液/液微分散法制备粒径可控均一的三辛胺液滴并利用电泳淌度预测三辛胺液滴的分散聚并性能，考察了极性溶剂、pH、离子类型、表面活性剂对电泳淌度的影响。结果表明，三辛胺液滴的电泳淌度随着pH升高而增大，极性溶剂对电泳淌度影响排序是甲醇<乙醇<1-丙醇<丙酮。离子型表面活性剂对电泳淌度影响与自身价态有关，非离子型表面活性剂则与其原子的亲核性有关。在甲醇作为分散剂的情况下，三辛胺等电点是pI=5.4，在等电点附近离子强度影响不明显。 (3) 陶瓷膜液/液微分散过程具有良好互溶两相的混合性能，通过利用碘酸钾和碘化钾反应体系研究了陶瓷膜液/液体系的微观混合效率。考虑到轴向反应物的浓度梯度，耦合串联全混流模型和团聚模型确定微观混合时间与离集指数的关系。采用微观混合时间对比研究膜孔尺寸、渗透通量、内件、雷诺数对陶瓷膜分散微观混合效率的影响。结果表明，在同一渗透压差下，减小膜孔尺寸能够提高陶瓷膜反应器的微观混合效率。增加渗透通量、主体相流量和引入湍流内件进一步强化陶瓷膜反应器的微观混合效率，微观混合时间可以在0.7 ms到300 ms之间进行自由调控。耦合内件的陶瓷膜反应器的微观混合效率影响顺序是空管<圆柱形内件<螺旋内件 |
| 英文摘要 | As one new kind of chemical process, liquid-liquid micro-dispersion technology has good prospects on experimental research and industrial applications, especially in areas such as micro-fluidics, bio-medicine and nano-materials. This dissertation focused on studying interface potential of liquid-liquid micro-dispersion by means of polar solvents, pH and ionic strength etc., using the improved incorporation model to evaluate micro-mixing performance of liquid-liquid dispersion system, and applying the liquid-liquid micro-dispersion technology to stripping of penicillin G. The main results were as follows: (1) The stable dodecane/water emulsion droplets were prepared via a surfactant-free method. Interface potential can be tuned by polar solvent, pH and ionic strength. The droplet size was tuned from 105 nm to 453 nm when the molar ratio of disperser to dodecane was from 0.00072 to 0.073, and the polydispersity index was less than 0.2. The interface potential of dodecane/water was mainly changed by ionic strength at the range from 0.1 mM to 1 mM. In addition, polar solvent was also able to control interface potential. The order of interface potential is methanol < ethanol < 1-propanol < acetone < acetonitrile. The polar solvent plays a leading role in controlling interface charge. (2) Electrophoretic mobility of trioctylamine by a simple dispersive liquid-liquid emulsification was measured without any surfactants. The dispersing agents are four polar solvents (methanol, ethanol, 1-propanol, and acetone). To identify the chief factor in electrophoretic mobility, the effects of ionic strength, ion type, and surfactants were also investigated. The results indicated that pH and the hydrophilicity of organic solvent in aqueous phase affected significantly. As pH value increased, the electrophoretic mobility of trioctylamine droplets increased. The isoelectric point of trioctylamine droplets was approximately 5.4 and was not influenced by ionic strength. (3) Micromixing efficiency in a ceramic membrane reactor by using turbulence promoters was studied with iodide-iodate test reaction. Due to concentration gradient along with the ceramic membrane, an improved incorporation model coupled with a continuous stirred tank reactor in series model was established to determine the ratio of micromixing time to segregation index. Decreasing membrane pore diameter has significant influence on micromixing efficiency under the same transmembrane pressure drop. In addition, both increasing permeation flow rate or bulk flow rate and decreasing membrane pore size was able to enhance micromixing efficiency. The introduction of turbulence promoters can further intensify the micromixing efficiency of the reactor. The micromixing efficiency of ceramic membrane reactor with turbulence promoter was observed in a sequence of cylindrical insert < helical insert < KenicsTM static mixer insert. The micromixing time of the reactor was in the range from 0.7 ms to 300 ms. Judged by its performance, ceramic membrane reactor might be a promising reactor for fast reaction systems. (4) A ceramic membrane micro-extractor, employed for continuous re-extraction of penicillin G, was studied systematically. Re-extraction efficiency and degradation rate of penicillin G were extensively examined by superficial Reynolds number, phase ratio of oil to water, initial concentration of penicillin G and membrane pore size. To further understand and quantitatively analyze the re-extraction behavior, a resistance-in-series model was developed to predict the re-extraction efficiency of membrane micro-dispersion at steady-state conditions. The main factors affecting the re-extraction efficiency of penicillin G were superficial Reynolds number and phase ratio. The re-extraction efficiency of penicillin G reached 99% or above when superficial Reynolds number was more than 934 and phase ratio was less than 0.08. Meanwhile, the degradation rate of penicillin G decreased to 0.5% when superficial Reynolds number was 934. Compared with the re-extraction performance of the batch extractor, less residence time was needed and the degradation rate decreased more than 50%. According to the model, the theoretical re-extraction efficiency was in good agreement with experimental data. |
| 语种 | 中文 |
| 公开日期 | 2013-09-24 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1753]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 吴勇. 微分散液滴稳定性和反应选择性调控规律及其应用研究[D]. 中国科学院研究生院. 2011. |
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