• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Separation and Purification Technology >Equilibrium concentrations in membrane contactors from non-linear distribution curves: Alkali picrates extraction with a calix[4]arene
【24h】

Equilibrium concentrations in membrane contactors from non-linear distribution curves: Alkali picrates extraction with a calix[4]arene

机译：非线性分布曲线中膜接触器中的平衡浓度：用杯[4]芳烃提取苦味碱

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 equilibrium concentrations in membrane contactors are investigated in closed system for the extraction of alkali metal picrates with the l,3-bis-benzo-crown-6-calix[4]arene in toluene (95%)-decanol (5%) in order to understand the extraction kinetics through the membrane. The modeling of the equilibrium distribution curves, which is carried out from the mass action law, allows the determination of the reaction equilibrium constant (K_(ex)). The presence of alkali chloride (0.1 M) in the initial aqueous phase changes the equilibrium concentrations: K_(ex) is 1.5 x 10~6 L~2 mol~(-2) for the cesium picrate extraction with cesium chloride while it is 3.75 x 10~6 L~2 mol~(-2) in the absence of cesium chloride. The calculation of the distribution coefficient (D) in the membrane contactor is carried out from global mass balances (operating line) and non-linear extraction isotherms. The experimental distribution coefficients are in agreement with the calculated values. The high ionic strength and hydrophilic character of chlorides in the aqueous phase lead to an increase of the picrate transfer and to a considerable increase of the distribution coefficient from 0.45 (C°_(aq) = 1.48 x 10~(-4) mol L~(-1)) for the cesium picrate extraction without cesium chloride to 170 (C°_(aq) = 1.7 x 10~(-4) mol L~(-1)) when cesium chloride is present. On the other hand, it appears that for high initial concentration in the aqueous phase (C°_(aq) > 7.0 x 10~(-4) mol L~(-1) for the cesium picrate) and in the presence of alkali chloride occurs the saturation of the organic phase with calixarene complex. This organic phase saturation inside the membrane pores generates a precipitate that slows down the transport kinetics.
机译：在密闭系统中研究了膜接触器中的平衡浓度，该条件用于在甲苯（95％）-癸醇（5％）中用l，3-双-苯并冠-6-杯芳烃[4]芳烃萃取碱金属苦味酸盐。为了了解通过膜的萃取动力学。根据质量作用定律对平衡分布曲线进行建模，可以确定反应平衡常数（K_（ex））。初始水相中存在碱金属氯化物（0.1 M）会改变平衡浓度：用氯化铯萃取苦味酸铯时K_（ex）为1.5 x 10〜6 L〜2 mol〜（-2），而其为3.75 x 10〜6 L〜2 mol〜（-2），无氯化铯。膜接触器中的分配系数（D）的计算是根据整体质量平衡（工作线）和非线性提取等温线进行的。实验分布系数与计算值一致。氯化物在水相中的高离子强度和亲水特性导致苦味酸盐转移增加，分配系数从0.45（C°（aq）= 1.48 x 10〜（-4）mol L -（-1））用于在不存在氯化铯的情况下将苦味酸铯萃取至170（C°（aq）= 1.7 x 10〜（-4）mol L〜（-1））（存在氯化铯时）。另一方面，对于水相中的高初始浓度（苦味酸铯，C°_（aq）> 7.0 x 10〜（-4）mol L〜（-1））来说似乎是高浓度的。氯化物发生与杯芳烃配合物的有机相饱和。膜孔内部的有机相饱和会产生沉淀，从而减慢传输动力学。

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