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

1971 ◽  
Vol 24 (12) ◽  
pp. 2439 ◽  
Author(s):  
SD Hamann
Keyword(s):  
Ion Exchange ◽  
Functional Groups ◽  
Ionization Constant ◽  
Ion Pairs ◽  
Ion Exchange Resins ◽  
Thermal Regeneration ◽  
Degree Of Ionization ◽  
Titration Curves ◽  
Two Factors ◽  
Exchange Resins

The model described in Part I1 has been extended to allow for two factors which may explain the abnormally flat titration curves of some amine ion-exchange resins. They are (a) the possible formation of ion pairs within a resin and (b) a possible increase in the ionization constant of the functional groups in a resin as its degree of ionization increases. It is suggested that the change (b) may occur if the di- electric constant of a resin is increased sufficiently by the absorption of ions and water as titration proceeds. ��� Calculations have been made of the influence of both effects on thermal regeneration equilibria.

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

1971 ◽  
Vol 24 (10) ◽  
pp. 1979 ◽  
Author(s):  
SD Hamann
Keyword(s):  
Ion Exchange ◽  
Weak Acid ◽  
Ion Exchange Resins ◽  
Equilibrium Conditions ◽  
Thermal Regeneration ◽  
Equilibrium Relationship ◽  
Acid And Base ◽  
Temperature And Pressure ◽  
Exchange Resins ◽  
Ionization Of Water

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.

CO2 Absorption over Ion Exchange Resins: The Effect of Amine Functional Groups and Microporous Structures

2020 ◽  
Vol 59 (38) ◽  
pp. 16507-16515
Author(s):  
Xueru Wang ◽  
Juzheng Song ◽  
Yan Chen ◽  
Hang Xiao ◽  
Xiaoyang Shi ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Functional Groups ◽  
Ion Exchange Resins ◽  
Co2 Absorption ◽  
Exchange Resins

An ion-exchange process with thermal regeneration. II. Properties of weakly basic resins

1966 ◽  
Vol 19 (4) ◽  
pp. 561 ◽  
Author(s):  
DE Weiss ◽  
BA Bolto ◽  
R McNeill ◽  
AS MacPherson ◽  
R Siudak ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Secondary Amines ◽  
Maximum Effect ◽  
Cross Linking ◽  
Thermal Regeneration ◽  
Ion Exchange Process ◽  
Titration Curves ◽  
Exchange Resins ◽  
Basic Amine

Weakly basic ion-exchange resins have been synthesized by treating cross-linked chloromethylated polystyrene beads with primary and secondary amines and with polyamines. Titration curve data show that such resins may be either homo-functional and possess flat titration curves, or heterofunctional and possess sloping titration curves, depending on whether the basic sites within the resin have the same or different basicities. A comparison of the titration curves determined at c. 20� or 80� reveals that all amine resins become weaker bases when heated, but the maximum effect is shown by the resins with homo-functional structures; e.g. the plateau-shaped curves at c. 20� and 80� of a polyvinylbenzyldiethylamine resin differ by about 1.2 of a pH unit at half neutralization. The effect is fully reversible. The influence of amino group substituents, cross-linking, salt concentration, sulphate ions, and temperature on the titration curves of weakly basic amine resins has been studied. Titration curves of a variety of commercial amine resins have been determined at c. 20� and 80� and show that at least two resins with homo-functional structures are commercially available.

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