Strong Base Anion Exchange Resin
Strong base anion resins (SBA) contain quaternary ammonium groups that exchange negatively charged ions. In hydroxide form, they exchange anions in water for hydroxide ions.
Type I and Type II refer to different functional group chemistries. Both gel and macroporous structures exist in this family, and the supplied form may differ from the form used during treatment.
Technical Specifications
| Polymer structure | Divinylbenzene-crosslinked gel polystyrene |
|---|---|
| Functional group | Type I quaternary ammonium |
| Ionic form | Cl⁻ |
| Total exchange capacity (Cl⁻) | 1.29 eq/L |
| Moisture retention (Cl⁻) | 46.2–52.7% |
| Particle size | 299–1198 µm |
| Uniformity coefficient | 1.55 |
| Specific gravity | 1.08 |
| Particle density | 1.075 g/mL |
| Shipping weight | 676–709 g/L |
Application and use
- In industrial demineralization, hydroxide-cycle operation removes anions after the cation stage; a chloride-form supply requires the specified conversion before service.
- For dissolved silica removal, regeneration and rinse conditions must support the required outlet quality throughout the service run.
- In layered anion beds or mixed-bed polishing, select grades whose particle distribution and separation behavior suit the paired resin.
Frequently asked questions
Will an anion bed remove colloidal silica as reliably as dissolved silica?
No. Colloidal silica can pass through an ion-exchange system. Confirm the silica fraction before attributing breakthrough to resin exhaustion.
Why investigate the cation bed when anion outlet quality worsens?
Sodium leakage from the upstream cation stage can raise outlet pH and accompany silica leakage. Check the upstream stage before replacing the anion resin.
Will a chloride-form delivery grade remove silica immediately?
Check the required service form. Hydroxide-cycle demineralization needs the selected grade to be properly converted and rinsed before service.
Are Type I and Type II grades interchangeable?
Do not infer interchangeability from the family name. Compare the grade’s type, temperature limits, regeneration requirements and outlet-silica target.
Can natural organics shorten the service run?
Organic contamination can foul anion resin and change rinse and working performance. Analyze the feed and a representative resin sample before deciding on cleaning or replacement.