Study Of Adsorption Of Organic Acids In Different Medium Environment On Weakly Basic Resin By Potentiometric Method

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.