Weak Acid Resin Research Articles

Equilibres ioniques obtenus entre un echangeur d'ions et une solution de polyelectrolytes, faibles et de meme signe de charge

When an equilibrium is established between an ion exchange resin and a solution of polyelectrolyte of the same sign of charge (without added salt), there is no co-ion in the resin phase. It is shown that, for a weak acid resin in equilibrium with a solution of a strong acid polyelectrolyte completely neutralized by a monovalent counter-ion M +, the graph pH - p M = f( α), where α represents the degree of neutralization of the resin, is independent of the concentration of polyelectrolyte. These results have been verified for a highly swollen ion exchange gel. A weak resin in equilibrium with a solution of a weak polyelectrolyte gives a system in which the counter-ion is distributed between the two phases. The equilibrium partition can be calculated using a set of equations resembling those for buffer solutions. Experimental verifications have been obtained. The possible developments are discussed.

A model for the thermal regeneration of ion-exchange resins, Part I

A theoretical model has been developed to describe the thermal regeneration of ion-exchange resins in the Sirotherm process1-10 for desalting water. It assumes that the thermal effect is primarily due to the large increase that occurs in the ionization of water when the temperature is raised. The hydrogen and hydroxyl ions compete with salt for exchange sites in the resins and for that reason water, itself, acts as a regenerating acid and base. ��� Calculations have been made of the equilibrium conditions, column behaviour, and titration behaviour of mixtures of weak-acid and weak-base resins with aqueous solutions of 1 : 1 and 2 : 2 electrolytes, assuming the systems to obey Donnan's equilibrium relationship. There is satisfactory agreement between the calculated and observed effects of both temperature and pressure.

Rubidium‐Sodium Exchange on a Weak Acid Resin as Influenced by Ionic Strength

AbstractChanges in the selectivity coefficient, Ks, for Na‐Rb exchange on IRC, a weak acid resin with carboxylic functional groups, were observed when the concentration of the external solution was increased from 10‐3M to 10‐1M. These ionic strength effects on Ks were interpreted in terms of an ion pair‐diffuse double layer model. Increasing Ks favoring Rb over Na with increasing ionic strength may be attributed to an increasing fraction of adsorbed ions in the ion‐pair form.

Electrochemically Controlled Ion Exchange: I . Mechanism

The results of coulometric and mass balance analyses have been used to elucidate the mechanism of this demineralization process. Essentially, undissociated fixed groups (e.g., weak acid or weak base) that are ionized as a result of the electrochemical reactions partake in an ion exchange process. The properties of weak acid and weak base ion exchange resins are incorporated into the electrodes. The simultaneous removal of anions and cations is undertaken in neutral solution. Regeneration of the electrodes is accomplished by polarity reversal.

Interaction between diacetylchitobiose methyl glycoside and lysozyme as studied by NMR spectroscopy

This chapter focuses on vertebrate lysozymes, particularly hen egg-white (HEW) lysozyme. Lysozymes of other types generally are distinguishable from HEW lysozyme in having higher molecular weights and somewhat different enzymic activities. Lysozyme is small and basic, and it separates well on weak acid resins, like Amberlite XE-64 or Bio-Rex 70 or carboxymethyl cellulose and on calcium phosphate gel. Affinity chromatography of lysozyme has been carried out using dispersed chitin or carboxymethyl (CM)-chitin. The conditions required for elution from chitin columns suggest that there are two classes of adsorbent sites that are differently affected by pH and ionic strength in their interaction with the enzyme. The preparation of lysozyme from diverse animal sources is generally achieved in four main steps, which include (1) the preparation of a lysozyme-rich extract, (2) chromatography on CM-cellulose, (3) filtration on Sephadex G-25, and (4) ion exchange chromatography on Amberlite CG-50 at 20° C with a 0.2 M phosphate buffer. The chromatography is sensitive to the pH and small variation of no more than 0.1 pH unit can involve complete retention or exclusion.

Weak-acid resins soften water

Weak-acid resins soften water

Kinetics of exchange involving ion association on a weak acid resin

The first page of this article is displayed as the abstract.

クロマトグラフィーによるヒガンバナ・アルカロイドの分離定量 (第1報)

The aqueous digest solution of the corm of Lycoris radiata or its extract was treated with weakly acidic ion exchange resin (Amberlite IRC-50) to adsorb the alkaloids and separate them from non-alkaloidal substances. The alkaloids were desorbed with ammoniacal ethanol and the ethanol was evaporated from this solution of total alkaloids. The residual solution was passed through double columns of Celite, with phosphate buffer (pH 7.0) as the stationary phase. The column was eluted with chloroform to separate lycorine and determination by optical method gave a satisfactory result.

Studies on Some Physico-Chemical Properties of Ion-Exchange Resin. I. Heat of Wetting

Abstract (1) The measurement of heats of wetting of strongly acidic and weakly acidic cation exchange resins and strongly basic anion exchange resins was made by a simple method and their great dependence on the adsorbed ion species was found. (2) The series of heat of wetting with ion forms is almost parallel with the lyotropic series of ions, thus it has been shown that this penomenon has an important relation to the hydration of the ions. The acid form of the weakly acidic resin occupies a special position, and this is attributed to the undissociative nature of carboxylic radical. (3) The result on the partially wetted samples supports the view that only a few water molecules which may be called “bound water” take part in the heat of wetting or hydration of ions. (4) A theoretical interpretation based on a few assumptions was attempted and a fair agreement with the experimental results was obtained.