Does Deionized Water Conduct Electricity

What is Deionized Water?

Deionization ("DI H2o" or "Demineralization") simply means the removal of ions.

Ions are electrically charged atoms or molecules found in water that have either a net negative or positive accuse. For many applications that use h2o as a rinse or ingredient, these ions are considered impurities and must be removed from the h2o.

Ions with a positive charge are called "Cations" and ions with a negative charge are called "Anions". Ion exchange resins are used to commutation non desirable cations and anions with hydrogen and hydroxyl, respectively, forming pure water (H20), which is not an ion. Below is a listing of ions normally plant in municipal water.

Cations (Removed by Cation Resins)	Anions (Removed by Anion Resins)
Calcium (Ca++)	Chlorides (Cl-)
Magnesium (Mg++)	Sulfates (SO4--)
Iron (Fe+++)	Nitrates (NO3-)
Manganese (Mn++)	Carbonates (CO3--)
Sodium (Na+)	Silica (SiO2-)
Hydrogen (H+)	Hydroxyl (OH-)

How does ion exchange work?

Ion exchange resins are used to produce deionized h2o (demineralized water or "DI Water") . These resins are small plastic beads that are composed of organic polymer chains that have charged functional groups built into the resin bead. Each functional group has either a stock-still positive or negative charge.

Cation resin has a negative functional grouping and therefore attracts positively charged ions. In that location are two types of cation resins, weak acid cation (WAC) and stiff acrid cation (SAC). Weak acid cation resin is used mainly in dealkalization and other unique applications. For this reason we will focus on explaining the office of strong acid cation resins used for producing deionized water:
- Anion resin has a positive functional group and therefore attracts negatively charged ions. At that place are ii types of anion resins, weak base anion (WBA) and strong base anion (SBA). Both types of anion resins are used to produce deionized water, withal, they have different characteristics listed beneath:
- WBA resins exercise not remove silica, C02 or have the ability to neutralize weak acids and has a lower than neutral pH when used in a dual divide bed arrangement.
- SBA resins remove all anions in the above table, including C02, and has a higher than neutral pH when used in a dual separate bed organisation due to sodium leakage.
Mixed bed resins use SAC and SBA resins combined together.

In order to produce deionized water, cation resin is regenerated with Hydrochloric Acid (HCl). The Hydrogen (H+) is positively charged and therefore attaches itself to the negatively charged cation resin bead. The anion resin is regenerated with sodium hydroxide (NaOH). Hydroxyl (OH-) is negatively charged and attaches itself to the positively charged anion resin bead.

Resin And Media

Resin chaplet

Different ions are attracted to a resin bead with different strengths. For instance, calcium is more strongly attracted to a cation resin bead than sodium is. The hydrogen on the cation resin dewdrop and the hydroxyl on the anion resin bead practice non have a strong attraction to the bead. This is what allows ion commutation to have place. As positively charged cations flow across cation resin beads, the cations are exchanged for hydrogen (H+). Likewise, as negatively charged anions flow across anion resin beads, the anions are exchanged for hydroxyl (OH-). When yous combine hydrogen (H+) and hydroxyl (OH-) y'all grade pure H20.

Eventually all of the exchange sites on the cation and anion resin beads are used up and the tank no longer produces deionized water. At this point, the resin beads require regeneration to prepare them for utilize again.

Carve up bed vs. mixed bed

Demineralization therefore requires using at to the lowest degree two types of ion exchange resins to produce deionized water. Ane resin volition remove positively charged ions and the other will remove negatively charged ions.

In a dual bed system, the cation resin is e'er beginning in line. As city h2o enters the tank filled with cation resin, all positively charged cations are attracted to the cation resin dewdrop and exchanged for hydrogen. The negatively charged anions are not attracted to the cation resin bead and pass through. For case, let's examine calcium chloride in the feed water. In solution, the calcium ion is positively charged and will adhere itself to the cation bead and will release a hydrogen ion. The chloride has a negative charge and therefore volition not attach itself to the cation resin bead. The hydrogen, which has a positive charge, will adhere itself to the chloride ion, forming muriatic acid (HCl). The resulting effluent from a SAC exchanger will have a very low pH and a much higher conductivity than the incoming feed water.

The effluent from the cation resin volition consist of strong and weak acids. This acidic water volition then enter a tank filled with anion resin. The anion resin will attract negatively charged anions such as chloride and commutation them for hydroxyl. The result is hydrogen (H+) and hydroxyl (OH-), which forms H20.

In reality, a dual bed system does not produce true H20 due to "sodium leakage". If sodium leaks past the cation exchange tank, and then it combines with hydroxyl to form sodium hydroxide which has a high conductivity. Sodium leakage occurs because sodium and hydrogen have a very similar attraction to the cation resin bead and sometimes the sodium ion does not exchange itself for a hydrogen ion.

In a mixed bed organization, the strong acrid cation and stiff base anion resin are intermixed. This effectively makes the mixed bed tank act like thousands of dual bed units in one tank. The cation/anion substitution is taking identify over and over within the resin bed. Sodium leakage is addressed because of the sheer number of repeated cation/anion exchanges taking place. By using a mixed bed you tin can produce the highest quality of deionized water possible.

How are ions measured?

Ions acquit electricity. Electric current passes through h2o using ions every bit stepping stones. Every bit a result, by measuring the electrical conductance of h2o can tell us what the ionic content of the water is. Less ions in the water will make the passage of electricity more difficult. Therefore, h2o with a lower electrical conductivity value is considered more "deionized" than water with a high electrical conductivity value.

What is a deionized water system?

A deionized h2o system is an arrangement of DI tanks and other components that are used to produce loftier purity water. The DI tanks are typically fabricated of fiberglass and come up in diverse sizes to conform different feed flow rates. A deionized water arrangement can be as simple equally a 1 tank setup or every bit complex as a multi-tank system with supporting equipment such as reverse osmosis, ultraviolet (UV) disinfection and elaborate water quality monitoring equipment. DI tanks contain ion exchange resin which selectively remove ions from water. Eventually the DI tanks need to be replaced past the service provider and replaced with a fresh tank. Many customers require standby DI tanks onsite to make certain they have an uninterrupted menstruum of deionized water. The DI tank substitution frequency depends on the incoming water quality and the amount of h2o beingness used. The higher ionic load in the incoming feed h2o will result in less gallonage produced by the DI tank.

A DI water system is a convenient and clean solution for producing deionized h2o considering Puretec handles all the equipment, off site regeneration, chancy chemical handling, maintenance, and emergency repairs for the deionized water organisation.

Frequently a DI system is used with, or in place of, a opposite osmosis system. DI tin can be used in conjunction with a reverse osmosis system to produce reliable high quality deionized water. The RO system will remove a bulk of dissolved solids (90% to 99%) before entering the DI tank which will then remove any remaining ions in the water. Placing an RO before DI tanks volition allow you to get a much longer run length from your DI tanks and reduce cost. Withal, an RO organization requires a much larger upfront investment, abiding maintenance, and the ability to discharge brine waste matter from the RO unit which must be considered when choosing a DI system.