• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Applied Polymer Science >CHARACTERIZATION OF RELAXATION PHENOMENA AND PERMEATION BEHAVIORS IN SODIUM ALGINATE MEMBRANE DURING PERVAPORATION SEPARATION OF ETHANOL-WATER MIXTURE
【24h】

CHARACTERIZATION OF RELAXATION PHENOMENA AND PERMEATION BEHAVIORS IN SODIUM ALGINATE MEMBRANE DURING PERVAPORATION SEPARATION OF ETHANOL-WATER MIXTURE

机译：乙醇-水混合物渗透分离过程中海藻酸钠膜中弛豫现象和渗透行为的表征

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The pervaporation separation of a concentrated ethanol-water mixture with 90 wt % of ethanol content through a sodium alginate (SA) membrane was carried out to investigate both the relaxation process and permeation behavior of the membrane in pervaporation. From the swelling measurement of the membrane in 90 wt % of ethanol content of the aqueous solution, it was observed that SA has an excellent permselectivity toward water and a high solubility of water: about 1000 of sorption selectivity and 21 wt % of water content in the swollen membrane at 40 degrees C. Its excellent sorption properties could result in the outstanding pervaporation performance for the aqueous solution; higher than 10,000 of separation factors and 120-290 g/(m(2) h) of fluxes, depending on the operating temperature. However, a serious flux decline took place with operating time due to the occurrence of a significant relaxation process in SA. The flux decline was remarkable at the beginning stage and then mitigated with operating time. The fluxes were reduced by about 40-50% because of the relaxation process during the measurement. To analyze these phenomena in more detail, the hysteresis behavior of membrane performance along with an operation temperature cycle was investigated. During the heating process in the cycle, the relaxation process was important to affect membrane performance while the formation of excess stress in the membrane might be a crucial factor during the cooling process. It was postulated from the experimental observations that in the heating process an increase in flux with temperature is restricted by a more rapid relaxation process at a higher operation temperature, while in the cooling process, the excess stresses in the membrane are formed and accumulated in and near the transition zone and near the area in the membrane because of slower relaxational consolidation in unequilibrium cooling than in relaxational dilation in the heating process, resulting in flux more sensitive to temperature than in the heating process. These phenomena were found diminished as the relaxation time increased with aging time. The relaxation phenomena were discussed through an analysis on permeation activation energy data obtained from the pervaporation experiments. A qualitative model was established to describe the relaxational phenomena in the membrane material during the pervaporation process by using the basic principles of polymeric relaxation and the experimental observations obtained in this study. (C) 1996 John Wiley & Sons, Inc. [References: 19]
机译：通过藻酸钠（SA）膜对乙醇含量为90 wt％的浓乙醇-水混合物进行全蒸发分离，以研究膜在全蒸发过程中的弛豫过程和渗透行为。从在水溶液中乙醇含量为90 wt％的膜的溶胀测量中可以看出，SA对水具有极佳的渗透选择性和水的高溶解度：SA在水中的吸附选择性约为1000，水含量为21 wt％。膜在40摄氏度时溶胀。其优异的吸附性能可导致水溶液的出色的全蒸发性能;高于10,000的分离因子和120-290 g /（m（2）h）的助焊剂，具体取决于工作温度。但是，由于SA中发生了明显的弛豫过程，因此随着工作时间的推移，通量出现了严重下降。通量在开始阶段显着下降，然后随着运行时间而减轻。由于测量过程中的松弛过程，通量减少了约40-50％。为了更详细地分析这些现象，研究了膜性能的滞后行为以及操作温度循环。在循环的加热过程中，松弛过程对于影响膜性能非常重要，而膜中多余应力的形成可能是冷却过程中的关键因素。从实验观察中推测，在加热过程中，通量随温度的增加受较高工作温度下更快速的松弛过程所限制，而在冷却过程中，膜中的多余应力会形成并累积在膜中。由于在加热过程中非平衡冷却中的松弛固结要比松弛过程中的松弛膨胀慢，因此膜中过渡区附近和膜区域附近的热固结较慢，导致通量对温度的敏感性比加热过程中的敏感。发现这些现象随着弛豫时间随老化时间的增加而减小。通过分析从渗透蒸发实验获得的渗透活化能数据，讨论了弛豫现象。利用聚合物弛豫的基本原理和本研究获得的实验观察结果，建立了描述渗透过程中膜材料中弛豫现象的定性模型。 （C）1996 John Wiley＆Sons，Inc. [参考：19]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号