| ION EXCHANGE | Update 16 Oct 2012 |
The values may vary according to porosity of resin (primary and secondary cross-linking). For instance, the chloride selectivity value varies from about 15 to more than 30 for different SBA type 1 resins.
| SBA resin | Type 1 | Type 2 |
|---|---|---|
| Amberlite example | IRA402 | IRA410 |
| Ion | Selectivity | |
| HSiO3– | < 1.0 | < 1.0 |
| OH– (reference) | 1.0 | 1.0 |
| F– | 1.6 | 0.3 |
| CH3COO– | 3.2 | 0.5 |
| HCOO– | 4.6 | 0.5 |
| IO3– | 5.5 | 0.5 |
| HCO3– | 6.0 | 1.2 |
| Cl– | 22 | 2.3 |
| NO2– | 24 | 3 |
| BrO3– | 27 | 3 |
| HSO3– | 27 | 3 |
| CN– | 28 | 3 |
| HSO4– | 35 | 9 |
| Br– | 50 | 6 |
| NO3– | 65 | 8 |
| ClO3– | 74 | 12 |
| SO42– | 150 | |
| I– | 175 | 17 |
| SeO42– | 280 | |
| ClO4– | > 500 | |
| CrO42– | 1700 | |
| C6H5SO3– | > 500 | 75 |
For these resins, as shown above, the order of selectivity is:
SO4= > NO3– > Cl– > HCO3– > OH– > F–
There is thus no practical way to remove only chloride from water without removing other anions as well.
| Ion | Amberlite PWA5 |
|---|---|
| Cl– | 1.0 |
| NO3– | 5.8 |
| ClO4– | 440 |
| HCO3– | 0.21 |
| SO42– | 0.019 |
With such a product, you can remove nitrate with the resin in the chloride form.
From an unknown source: selectivity scale of a SBA resin at pH 9 to 10:
V2O74– > UO2(CO3)34– > MoO42– > SO42– > CO32– > NO3– > Cl– > HCO3–
See also cation selectivity values.
© François de Dardel