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电位法研究弱碱性树脂在不同介质环境中吸附有机酸的行为

Study of Adsorption of Organic Acids in Different Medium Environment on Weakly Basic Resin by Potentiometric Method

【作者】 王培秋

【导师】 陈炳稔;

【作者基本信息】 华南师范大学 , 高分子化学与物理, 2003, 硕士

【摘要】 本论文以D354弱碱性阴离子交换树脂为吸附剂,在不同的介质环境中(加入盐或葡萄糖作为第三组分),吸附低浓度的甲酸、乙酸、丙酸、丁酸、苯甲酸及其衍生物,采用电位法对吸附过程进行在线跟踪,利用固—液界面吸附动力学方程,求取表观吸附速率常数。着重研究D354树脂与有机酸在三元体系中的固—液吸附行为,结合盐效应理论,讨论了LiCl、NaCl、KCl、LiBr、NaBr、KBr、MgCl2、BaCl2、SrCl2九种外加盐及葡萄糖对吸附速率的影响,寻找其吸附过程的规律,为树脂吸附有机酸的工业化生产,设计最佳工艺条件提供有价值的参数。 实验结果表明: 1.利用电位法对D354弱碱性阴离子交换树脂吸附有机酸的固—液吸附体系的吸附行为进行追踪,实验相对偏差小于4%,符合固—液吸附体系的实验要求。 2.弱碱性阴离子交换树脂吸附低浓度有机酸的过程是遵循单分子层吸附机理的。 3.外加盐对D354弱碱性阴离子交换树脂吸附低浓度有机酸起到加速作用,外加盐作为第三组分的三元体系的吸附速率大于二元体系的吸附速率。 4.吸附速率随着外加盐浓度的增大而增大,且加入2-1价的盐(MgCl2、BaCl2、SrCl2)的三元体系的吸附速率大于加入1-1价的盐(Licl、NaCl、KCl)三元体系的吸附速率。 5.盐的浓度和酸的活度系数之间存在良好的线性关系,用盐效应理论能够对这一现象进行较好的解释:盐的加入主要起盐析作用,盐的浓度越大,盐析作用越强,盐析常数ks值越大,活度系数越大,因此吸附过程的吸附速率加快。

【Abstract】 In this thesis, adsorption of low concentration organic acids such as formic acid, acetic acid, propane acid, and butanoic acid, benzoic acid and its derivate in different medium environment (salt or glucose was added as a third component) on weakly basic anion exchanger (D354) as adsorbent was studied. By potentiometric method, we could trace the adsorption process on-line. The apparent adsorption rate constant kt was calculated by the solid-liquid interface dynamics equation. In ternary system, the solid-liquid adsorption behavior of weakly basic anion exchanger (D354) and organic acids in ternary system was particularly researched. With the salt effect theory, the influence of medium (LiCl, NaCl, KC1, LiBr, NaBr, KBr, MgCl2, BaCl2, SrCl2 ) concentration on adsorption rate was discussed and the regularity of adsorption process was found. Valuable theory parameter will be provided for the industrialized production of the adsorption of organic acids on resin and the design of the optimal conditions for industrial art.The experiment results indicated that:1. The adsorption behavior in a solid-liquid system was traced by potentiometric method, the relative deviation was less than 4%, which was in accordance with the experimental requirement of solid-liquid adsorption system.2. The adsorption process of low concentration organic acids on weakly basic anion exchanger obeyed monolayer adsorption mechanism.3. The added salt had acceleration effect on the adsorption of organic acids in low concentration onto weakly basic anion exchanger (D354). The adsorption rate in ternary system was larger than that in binary system in case of added salt as a third component.4. The adsorption rate increased with an increase of the salt concentration. The adsorption rate of divalent salt (MgCl2,BaCl2,SrCl2 ) in a ternary system was larger than that of monovalent salt (LiCl, NaCl, KC1) in the same system.5.A good linear relationship is found between the concentration of the salt and the activity coefficient of acid. A good explanation can be given by salt effect theory; the addition of salt serve as salting-out. The larger of salt concentration, the stronger of salting-out, and then the larger of salting-out constant ks, the larger of activity coefficient, and the quicker of the adsorption rate.

  • 【分类号】O647.3
  • 【被引频次】1
  • 【下载频次】143
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