ALDEX Weak Acid Cation Series

WAC Weak Acid Cation Resin

Aldex WAC is premium grade, weak acid gel-type, cation resin supplied in the hydrogen form as moist, tough, uniform spherical beads. Ion exchange activity in based on its carboxylic functional group. Aldex WAC is intended for use in dealkalization, deionization, and chemical processing applications.

Download Aldex WAC Technical Bulletin (PDF)

Physical Chemical Properties

Polymer Structure: Acrylic / divinylbenzene copolymer
Functional GroupR-(COOH)-
Ionic Form as Shipped:Hydrogen
Physical Form: Tough, spherical beads
Screen Size Distribution:

+16 mesh
-40 mesh
16 to 40 mesh

Less than 5%
Less than 2%
pH Range:0 to 14
Moisture Content:53 to 58%
Shipping Weight:47 lbs per cubic foot
Swelling H+ to Na+:90% maximum
Total Capacity:4.2 meq/ml minimum

Recommended Operating Conditions

Maximum Temperature:165ºF (75ºC)
Bed Depth:30” minimum
Service Flow Rate:2 to 5 US GPM per cubic foot
Backwash Flow Rate:50 to 75% bed expansion
Regenerant Strength*:
Hydrochloric Acid
Sulfuric Acid

3 to 6%
0.5 to 0.8%
Regenerant Flow Rate:0.3 to 0.75 US GPM per cubic foot
Regenerant Contact Time:30 minutes minimum
Regenerant Dosage Level: Depends on alkalinity
Displacement Rinse0.3 to 0.75 US GPM per cubic foot
Displacement Rinse Volume:10 to 15 gallons per cubic foot
Fast Rinse Rate:2 to 5 US GPM per cubic foot
Fast Rinse Volume:35 to 60 gallons per cubic foot

*Caution: Do not mix ion exchange resins with strong oxidizing agents. Nitric acid and other strong oxidizing agents can cause explosive reactions when mixed with organic materials, such as ion exchange resins.

WAC Features

Carboxylic Functional Groups

Give extremely high regeneration efficiencies and high operating capacities.

Uniform Particle Size

95% of all beads are in the minus 16 to plus 40 mesh range; giving a lower pressure drop while maintaining the superior kinetics of standard mesh size products.

Superior Physical Stability

90% plus sphericity and high crush strengths together with a very uniform particle size provide greater resistance to bead breakages and maintaining low pressure drops.

Low Swelling

Less than 90% on complete exhaustion to the sodium form.

Safety Information

A material safety data sheet is available for Aldex WAC. Copies can be obtained from Aldex Chemical Co., LTD. Aldex WAC is not a hazardous product and is not WHMIS controlled.

Caution: Acidic and basic regenerant solutions are corrosive and should be handled in a manner that will prevent eye and skin contact. Before using strong oxidizing agents in contact with ion exchange resin, consult sources knowledgeable in the handling of these materials.

Pressure Drop

The graph below (Fig 1.) shows the expected pressure loss per foot of bed depth as a function of flow rate, at various water temperatures.

Fig. 1 Pressure Drop vs Flow Rate at various degrees Fahrenheit (F°)

Backwash Characteristics

After each cycle the resin bed should be backwashed at a rate that expands the bed 50 to 75 percent. This will remove any foreign matter and reclassify the bed. (Fig 2.)

Fig. 2 Expansion vs Flow Rate at various degrees Fahrenheit (F°)



Aldex WAC can be used to remove cations associated with alkalinity in multiple bed demineralizers.


In certain applications, Aldex WAC can be operated as softener in sodium cycle. This requires a two stage regeneration using a strong acid first stage to remove multivalent ions from the bed followed by a neutralization rinse with an alkali.


Bicarbonate alkalinity can be effectively removed using Aldex WAC in the hydrogen form.

Operating Capacity

These suggestions and data are based on information we believe to be reliable. They are offered in good faith. However, we do not make any guarantee or warranty. We caution against using these products in an unsafe manner or in violation of any patents. Further, we assume no liability for the consequences of such actions.