Deionized Water - The Science Behind It

Let's now talk on another filtered water - Deionized Water.

Basically, it is water that from the diagrams removes trace chemicals that are present in the water from its source, piping or the chemicals introduced from the water treatment systems. It is a chemical cleaning action and little energy is used - only the water pressure to push the water through the system and overcome pressure drops. Using crosslinked polystrene beads to remove cation ( Positive charged chemicals ) and anion ( Negative charged chemicals ). More "cleaner" as compared to distilled water but does not remove bacterial, micro-organisms or pathogens. This can be solved by installing a UV unit after the ion-resin exchanger unit to do that job.

Most of the time deionized water is used for electronics, scientific experiments, production of superconductors, nuclear industry etc where water quality is of high importance. One important process is for some places in the world where the source water is hard and change this water into soft water. ( replacing the magnesium and calcium ions found in the water with sodium ions ). Also, the filtering process is in combination with other filtering systems ( For example : pre-filter, activated carbon filter, UV filter or a series of ion-resins exchangers ) to remove effectively and get the desired filter water grade. The resins can be re-charged with a mixture of chemical cleaning but majority of the time, the resins will be thrown away.

In Conclusion :
 

Deionized water is not bad water to drink neither it is the super water that all must drink. As all chemicals have been removed from the water, other impurities such as bacteria and viruses WILL NOT be filtered out as they are more smaller in size to be trapped by the filters. Hence, an RO system would work best for the application as all things in the water will be filtered. On the other hand, one needs to re-charge or replenish the filter beads once the water quality level drops and this might be 6 months of less depending on point of use. Hence 1 or 2 pre-filters must be installed before the ion beads filter to keep overall cost low.