| 题名 | 有机物优先透过渗透汽化膜的制备与应用 |
| 作者 | 祝振洲 |
| 学位类别 | 硕士 |
| 答辩日期 | 2010-06-04 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 万印华 |
| 关键词 | 渗透汽化 膜分离 有机物优先透过 响应曲面 有机物废水 |
| 其他题名 | Preparation and application of organophilic pervaporation membranes |
| 学位专业 | 生物化工 |
| 中文摘要 | 由于化石能源短缺，生物能源尤其是燃料乙醇发展需求日益旺盛。有机物优先透过渗透汽化技术由于具有低能耗，可原位分离发酵液中的乙醇等优点成为研究的热点。本文针对目前有机物优先透过渗透汽化膜对乙醇分离因子普遍不高的问题，采用改性疏水沸石填充聚二甲氧基硅氧烷(Polydimethylsiloxane, PDMS)的方法，制备了有机物优先透过渗透汽化杂化膜和复合膜，运用响应曲面法对复合膜操作条件进行了优化，并初步研究了自制杂化膜在有机废水分离中的应用。主要研究内容及结果如下： (1)制备了对乙醇—水体系分离因子较高的杂化膜。采用硅烷偶联剂，乙烯基三甲氧基硅烷，对疏水沸石进行改性，将偶联剂基团反应到沸石表面，改善了沸石在PDMS中的分散，提高了沸石的填充量，从而增加了沸石填充PDMS膜对乙醇—水溶液的分离效果，渗透汽化实验表明，改性沸石制备的杂化膜比未改性沸石制备的杂化膜对质量分数为5%的乙醇—水体系中乙醇分离因子可由16.0提高到29.5，增加了84%。 (2)以聚丙烯腈超滤膜为底膜，杂化膜制备配方为基础配方，制备了有机物优先透过渗透汽化复合膜。渗透汽化实验表明催化剂用量和膜厚对改性沸石填充PDMS复合膜的分离性能有较大影响。随着催化剂用量增加，膜的分离因子先增加后减小，渗透通量先减小后增加。随着分离层厚度减小，膜的分离因子减小，渗透通量增大。利用响应曲面法研究了操作温度和循环流速对膜的分离性能的影响，结果表明温度的影响最显著，循环流速的影响次之。得到最优操作条件：温度为59.8°C,循环流速为30.0 L/h，此时通量(J)和分离因子(α)均能取得较高值J=242.8 g/(m2·h)，α=20.6。 (3)以苯酚—水体系和乙酸乙酯—水体系为分离对象，考察了原料液浓度和渗透汽化温度对自制渗透汽化杂化膜分离性能的影响。由于溶解度参数不同，杂化膜对乙酸乙酯的选择透过性大于苯酚。随着原料液浓度增加，膜对苯酚分离因子降低，通量增加，膜对乙酸乙酯—水体系中乙酸乙酯的分离因子增加，通量增加；随着渗透汽化操作温度升高，膜对苯酚的分离因子降低，通量增加，膜对乙酸乙酯的分离因子增加，总通量增加。 |
| 英文摘要 | Demand on the development of bio-fuels, especially the fuel alcohol, has been increasing dramatically due to the depletion and insufficient supply of fossil energy. Organophilic pervaporation technology has drawn a great deal of attention of scientists and engineers, because of its serious advantages such as low energy consumption and in-situ separation of ethanol from fermentation broth. In this thesis, efforts were made to increase the separation factor towards ethanol of organophilic pervaporation membranes which are not high enough now. Hydrophobic silicatelite-1 particles were surface modified and used to fill in polydimethylsiloxane (PDMS) to prepare ethanol permselective pervaporation hybrid membrane. Composite membrane was prepared based on the preparation method of hybrid membrane and surface response methodology was used to optimize the pervaporation operating conditions using the composite membrane. Hybrid membrane was also used to separate model organic waste water. The results were summarized as follows: (1) Hybrid membrane with high separation factor towards ethanol was prepared. Hydrophobic silicalite-1 particles were surface modified by silane coupling agent, vinyltrimethoxysilane (VTMS). The Framework of the silicalite-1 was not affected after modification, and VTMS reacted successfully with chemical groups on silicalite-1. With VTMS modified silicalite-1, the amount of the silicalite-1 filled in PDMS was increased, therefore, the separation factor of the hybrid membrane for 5wt% ethanol-water system was increased by 84% (from 16 to 29.5) as compared with the membrane made from unmodified silicalite-1. The mechanical property of the hybrid membrane was also improved. (2) Organophilic pervaporation composite membrane was prepared and the pervaporation operation conditions were optimized. Organophilic pervaporation composite membrane was prepared using PAN as supporting substrate. Pervaporation experiments showed that the amount of the catalyst used and the thickness of the selective layer could significantly affect the properties of the membrane. With the increase of the catalyst used, the separation factor increased first and then decreased, while the total flux decreased first and then increased. With the decrease of the thickness of the selective layer, the separation factor decreased and the total flux increased. Surface response methodology was used to examine the effect of the pervaporation temperature and feed flow rate on the separation performance of the composite membrane. It was found that temperature could affect more significantly on separation factor and total flux than flow rate. The optimized temperature and flow-rate were found to be 59.8 °C and 30.0 L/h, respectively. Under these operating conditions, a permeate flux of 242.8 g/(m2·h) and a separation factor of 20.6 were obtained. (3) In application of model organic waste water containing phenol or ethyl acetate using organophilic pervaporation hybrid membrane, the effect of feed concentration and pervaporation temperature on membrane separation properties was investigated. Because of the different solubility parameters of different substances, the separation ability towards ethyl acetate was better than phenol. For acetate-water system, with the increase of the feed concentration and temperature, the separation factor and the total flux increased, simultaneously. For phenol-water system, the increase of the feed concentration and the pervaporation temperature could result in the increase of the total flux and the decrease of the separation factor. |
| 公开日期 | 2013-09-17 |
| 页码 | 65 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1514]  |
| 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 | 祝振洲. 有机物优先透过渗透汽化膜的制备与应用[D]. 北京. 中国科学院研究生院. 2010. |
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