SD Enviro Engineers water purifier is a leading provider of deionization solutions. Our water deionizers are rugged, pre-engineered, pre-assembled, standardised units that minimise expensive installation and start-up prices.
We have designed our Deionization systems to maximise the potency and repeat ability of the unit throughout the service and regeneration modes.
Deionizers
The Process of Deionization or Ion-exchange
In the context of water purification, ion-exchange could be a speedy and reversible process in that impurity ions present within the water are replaced by ions released by an ion-exchange resin. The impurity ions are taken up by the resin, which should be periodically regenerated to restore it to the initial ionic type. (An ion is an atom or group of atoms with an electrical charge.
Positively-charged ions are called cations and are sometimes metals, negatively-charged ions are called anions and are usually non-metals).
The following ions are widely found in raw waters:
| Cations | Anions |
| Calcium (Ca2+) | Chloride (Cl-) |
| Magnesium (Mg2+) | Bicarbonate (HCO3-) |
| Sodium (Na+) | Nitrate (NO3-) |
| Potassium (K+) | Carbonate (CO32-) |
| Iron (Fe2+) | Sulfate (SO42-) |
Ion Exchange Resins
There are two basic varieties of resin – cation-exchange and anion-exchange resins. Cation exchange resins will release Hydrogen (H+) ions or alternative absolutely charged ions in exchange for impurity cations present in the water. Anion exchange resins will release hydroxyl (OH-) ions or different negatively charged ions in exchange for impurity anions gift in the water.
The application of ion-exchange to water treatment and purification
There are 3 ways in which in which ion-exchange technology can be employed in water treatment and purification: first, cation-exchange resins alone will be utilized to soften water by base exchange; secondly, anion-exchange resins alone can be used for organic scavenging or nitrate removal; and thirdly, mixtures of cation-exchange and anion-exchange resins can be used to remove nearly all the ionic impurities present in the feedwater, a method referred to as deionization. Water deionizers purification process leads to water of exceptionally prime quality.
Deionization
For several laboratory and industrial applications, high-purity water which is essentially free from ionic contaminants is needed. Water of this quality can be produced by deionization.
The two commonest sorts of deionization are:
- Two-bed deionization
- Mixed-bed deionization
Two-bed deionization:
The two-bed deionizer consists of two vessels – one containing a cation-exchange resin in the hydrogen (H+) type and the opposite containing an anion resin within the hydroxyl (OH-) kind. Water flows through the cation column, whereupon all the cations are exchanged for hydrogen ions.To keep the water electrically balanced, for each monovalent cation, e.g. Na+, one hydrogen ion is exchanged and for each divalent cation, e.g. Ca2+, or Mg2+, 2 hydrogen ions are exchanged. The same principle applies when considering anion-exchange. The decationised water then flows through the anion column.
This time, all the negatively charged ions are exchanged for hydroxide ions that then combine with the hydrogen ions to make water (H2O).
Mixed-bed deionization:
In mixed-bed deionizers the cation-exchange and anion-exchange resins are intimately mixed and contained in a single pressure vessel. The thorough mixture of cation-exchangers and anion-exchangers during a single column makes a mixed-bed deionizer cherish a lengthy series of two-bed plants. As a result, the water quality obtained from a mixed-bed deionizer is appreciably over that produced by a two-bed plant.
Although more efficient in purifying the incoming feedwater, mixed-bed plants are a lot of sensitive to impurities within the water supply and involve a a lot of complicated regeneration process. Mixed-bed deionizers are normally used to ‘polish’ the water to higher levels of purity when it has been initially treated by either a two-bed deionizer or a reverse osmosis unit.
Electro deionization:
EDI Electro deionization Systems take away ions from aqueous streams, typically together with reverse osmosis (RO) and alternative purification devices. Our high-quality deionization modules regularly turn out ultra pure water up to 18.2MW/cm. EDI could be run continuously or intermittently.