An ion-exchange process with thermal regeneration. VI. Factors influencing the titration curve shape of weak electrolyte resins

1968 ◽  
Vol 21 (11) ◽  
pp. 2703 ◽  
Author(s):  
BA Bolto ◽  
R McNeill ◽  
AS MacPherson ◽  
R Siudak ◽  
DE Weiss ◽  
...  
Keyword(s):  
Titration Curve ◽  
Exchange Process ◽  
Ion Pairs ◽  
Curve Shape ◽  
Thermal Regeneration ◽  
Weak Electrolyte ◽  
Ion Exchange Process ◽  
Titration Curves ◽  
Counter Ions ◽  
Primary Amino

An experimental study is presented which establishes that if the titration curve of a weak electrolyte resin is to exhibit a well-defined pH plateau, it must have a structure which is homofunctional and which is not too polar. Homofunctional mono- and di-alkylamino groups in a cross-linked hydrocarbon polymeric structure exhibit such a plateau. Polymers with non-polar backbones and primary amino or carboxyl groups possess sloping titration curves. The results can be accounted for by the formation of ion pairs with monovalent counter ions in the less polar structures, or with multivalent counter ions in more polar structures.

An ion-exchange process with thermal regeneration. IV. Equilibria in a mixed bed of weak-electrolyte resins

1966 ◽  
Vol 19 (5) ◽  
pp. 765 ◽  
Author(s):  
DE Weiss ◽  
BA Bolto ◽  
R McNeill ◽  
AS MacPherson ◽  
R Siudak ◽  
...  
Keyword(s):  
Salt Solution ◽  
Titration Curve ◽  
Ph Value ◽  
Exchange Process ◽  
Effective Capacity ◽  
Thermal Regeneration ◽  
Ion Exchange Process ◽  
Titration Curves ◽  
Acid Resin ◽  
Base Resin

The titration curve data at c. 20� and 80� for weakly basic amine and carboxylic acid resins suggest that if a mixed bed of such resins is in equilibrium with a salt solution, then when the temperature of the system is raised, protons will be transferred from the base to the acid resin to an extent determined by the overlap of the titration curves of the resins. Maximum overlap would occur with two resins of appropriate acid and basic strength and which possess plateau-type titration curves, but such acid resins are not available. The theory has been confirmed by experiment. The change in salt adsorption on heating (effective capacity) depends critically on pH and may be enhanced for amine resins of homo-functional structure by increasing the ratio of acid to base resin. It is shown that to achieve the maximum effective capacity for each resin combination there is an optimum pH value and resin ratio. A screening procedure, which uses titration curve data at c. 20� and 80� and allows for the effect of pH and resin ratio, has been devised for selecting resin combinations. In a 0.030M salt solution the effective capacity of the commercial resins studied is greatest, for a poly(vinylbenzyldiethy1amine) resin in combination with a poly(acry1ic acid) resin. A-rigorous procedure has been devised for obtaining equilibrium data, which are presented for this resin combination at c. 20� and 80� in sodium chloride solutions with concentrations ranging from 0.0017 to 0.13M.

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.

An ion-exchange process with thermal regeneration. III. Properties of weakly acidic ion-exchange resins

1966 ◽  
Vol 19 (4) ◽  
pp. 589 ◽  
Author(s):  
DE Weiss ◽  
BA Bolto ◽  
R McNeill ◽  
AS MacPherson ◽  
R Siudak ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Acrylic Acid ◽  
Methacrylic Acid ◽  
Ph Value ◽  
Exchange Process ◽  
Thermal Regeneration ◽  
Ion Exchange Process ◽  
Titration Curves ◽  
Acid Resin ◽  
Poly Acrylic Acid

A series of cross-linked poly(acrylic acid) and poly(methacrylic acid) resins has been synthesized. Their titration curves, and those of similar commercial resins, show that at c. 20� the pH value at half neutralization may be varied within about one unit by using acrylic or methacrylic acid monomers, or by changing the degree of cross-linking. The titration curves of such resins do not have a pronounced plateau although the acidity is due only to carboxyl groups. Resins with flatter titration curves can be made by copolymerizing acrylic or methacrylic acids with methyl methacrylate. Copolymerization reduces the effective acid strength of carboxylic acid resins but does not always produce a resin with a flatter titration curve. The effects of salt concentration, calcium ions, and temperature on the titration curves of a poly(acry1ic acid) resin have been studied. Heating the resins in a salt solution from c. 20 to 80� decreases their effective acidity slightly. A bigger reduction in acidity with heating is observed with several polymers in which a "snake" polymer, such as a poly(ethy1ene oxide), is incorporated within a cross-linked poly(acrylic acid) resin cage.

scholarly journals Polyelectrolyte Gels: A Unique Class of Soft Materials

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 102
Author(s):  
Ferenc Horkay
Keyword(s):  
Exchange Process ◽  
Interaction Strength ◽  
Soft Materials ◽  
Industrial Applications ◽  
Future Research ◽  
Swelling Kinetics ◽  
Polyelectrolyte Gels ◽  
Ion Exchange Process ◽  
Counter Ions ◽  
Kinetics Of

The objective of this article is to introduce the readers to the field of polyelectrolyte gels. These materials are common in living systems and have great importance in many biomedical and industrial applications. In the first part of this paper, we briefly review some characteristic properties of polymer gels with an emphasis on the unique features of this type of soft material. Unsolved problems and possible future research directions are highlighted. In the second part, we focus on the typical behavior of polyelectrolyte gels. Many biological materials (e.g., tissues) are charged (mainly anionic) polyelectrolyte gels. Examples are shown to illustrate the effect of counter-ions on the osmotic swelling behavior and the kinetics of the swelling of model polyelectrolyte gels. These systems exhibit a volume transition as the concentration of higher valence counter-ions is gradually increased in the equilibrium bath. A hierarchy is established in the interaction strength between the cations and charged polymer molecules according to the chemical group to which the ions belong. The swelling kinetics of sodium polyacrylate hydrogels is investigated in NaCl solutions and in solutions containing both NaCl and CaCl2. In the presence of higher valence counter-ions, the swelling/shrinking behavior of these gels is governed by the diffusion of free ions in the swollen network, the ion exchange process and the coexistence of swollen and collapsed states.

An ion-exchange process with thermal regeneration VIII. Preliminary pilot plant results for the partial demineralisation of brackish waters

Desalination ◽  
1973 ◽  
Vol 12 (2) ◽  
pp. 217-237 ◽  
Author(s):  
H.A.J. Battaerd ◽  
N.V. Blesing ◽  
B.A. Bolto ◽  
A.F.G. Cope ◽  
G.K. Stephens ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Pilot Plant ◽  
Exchange Process ◽  
Thermal Regeneration ◽  
Brackish Waters ◽  
Ion Exchange Process

An ion-exchange process with thermal regeneration XIV thermally regenerable resin systems with high capacities

Desalination ◽  
1980 ◽  
Vol 34 (3) ◽  
pp. 171-188 ◽  
Author(s):  
B.A. Bolto ◽  
K.H. Eppinger ◽  
M.B. Jackson ◽  
R.V. Siudak
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Thermal Regeneration ◽  
Ion Exchange Process
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