Cation resins
Cation resins are negatively charged and attract positively charged ions.
01 Specialized Treatment
Ion Exchange Systems
Ion exchange water treatment is a specialized technology used in water and wastewater treatment to remove dissolved ions and contaminants.
02 Principle
Resins act like powerful magnets
All natural waters contain dissolved salts that dissociate into charged ions — positively charged cations and negatively charged anions.
Ion exchange resins act much like powerful magnets, attracting and holding contaminating mineral ions from the source water through electromagnetic attraction.
Anion resins
Anion resins are positively charged and attract negatively charged ions.
03 Resins
Cation and anion resins
Each type naturally draws a distinct set of minerals.
The polymeric resin beads are engineered with thousands of tiny cracks to maximize surface area. As source water passes through the resin beads, mineral-bearing molecules cling to their many surfaces.
IX resins vary in shape, size, and structure — most systems use a bed of tiny, porous microbeads, typically 0.25 to 1.25 millimeters in radius, though some applications, such as electrodialysis, use a sheet-like mesh resin instead.
0.25 – 1.25 mm
Typical microbead radius
8 – 12%
Brine concentration for hardness regeneration
Fully automated
Normal mode of regeneration
04 Regeneration
A reversible exchange
This exchange process is reversible: once fully loaded, the resin can be regenerated using a concentrated salt, acid, or caustic solution that flushes out the accumulated minerals and restores the resin to like-new condition.
Operating note
Regeneration for ion exchange systems is more complex than for typical filtration operations, and is normally fully automated.
05 Applications
Hardness and radionuclide removal
WETS has designed and installed ion exchange systems for water hardness removal and for radionuclide removal, including radium treatment.
Hardness removal
For hardness removal, ion exchange replaces calcium and magnesium ions with sodium ions on a strong acid cation resin. Regeneration uses a concentrated sodium chloride brine solution (typically 8 to 12 percent) to displace accumulated hardness ions from the resin.
Radionuclide removal
Radionuclides present larger ions than typical ion exchange applications, and specialized resins have been developed to perform better in these services — standard resins tend to foul more easily with these larger ions, affecting performance over time and complicating end-of-life landfill disposal.
Specialty resins
Specialty resins feature an activated outer shell and inert core, improving regeneration capability and overall performance while reducing fouling and improving disposal suitability.
06 Design
Tailored to the application
While widely used for softening, ion exchange systems serve numerous other applications, including metals removal and dealkalization.
- Treatment stream composition
- Targeted contaminants and removal goals
- Operating and maintenance cost
A well-designed system must be tailored to each application’s treatment stream composition, targeted contaminants and removal goals, and operating and maintenance cost considerations.
Our team of professional engineers brings decades of experience developing customized ion exchange designs for our clients.
- Pilot study customization
- Conceptual design
- Detailed design
- Equipment manufacture
- Installation
07 Get Started
WETS stands ready to develop the optimal solution
From pilot study customization through conceptual and detailed design, equipment manufacture, and installation, WETS stands ready to develop the optimal solution to your water treatment challenge.
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