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.

An ion-exchange process with thermal regeneration. V. Multistage operation

1966 ◽  
Vol 19 (5) ◽  
pp. 791 ◽  
Author(s):  
DE Weiss ◽  
BA Bolto ◽  
R McNeill ◽  
AS MacPherson ◽  
R Siudak ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Peak Concentration ◽  
Ph Value ◽  
Exchange Process ◽  
Feed Water ◽  
Resin Column ◽  
Thermal Regeneration ◽  
Water Fraction ◽  
Ion Exchange Process ◽  
Exchange Resins

Multistage column experiments have been performed using a mixed bed of finely divided weakly acidic and weakly basic ion-exchange resins with thermal regeneration of the resins at 80�. A product water fraction with a concentration of 200- 250 p.p.m. can be obtained using such a column from a feed water containing 1000 p.p.m. of sodium chloride. When the same feed water is used as the regenerant at 803 an effluent having a peak concentration of about 5000 p.p.m. can be obtained. A solution of 1000 p.p.m. magnesium sulphate can be similarly demineralized. The performance of the resin column is highly dependent on the pH value to which it has been buffered by prior treatment with acid or alkali. It is also shown that thermal regeneration is feasible when the resins are used in a softening cycle.

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

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.

An ion exchange process with thermal regeneration IX. A new type of rapidly reacting ion-exchange resin

Desalination ◽  
1973 ◽  
Vol 13 (3) ◽  
pp. 269-285 ◽  
Author(s):  
B.A. Bolto ◽  
K. Eppinger ◽  
A.S. Macpherson ◽  
R. Siudak ◽  
D.E. Weiss ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Exchange Resin ◽  
Exchange Process ◽  
Ion Exchange Resin ◽  
Thermal Regeneration ◽  
Ion Exchange Process ◽  
New Type

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.

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