Electrolysed water (electrolyzed water, EOW, ECA, electrolyzed oxidizing water, electro-activated water or electro-chemically activated water solution) is produced by the

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from n ...

of ordinary

tap water Tap water (also known as faucet water, running water, or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, ...

containing dissolved

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35. ...

. The electrolysis of such salt solutions produces a solution of

hypochlorous acid Hypochlorous acid (HClO, HOCl, or ClHO) is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite, ClO−. HClO and ClO− are oxidizers, and the primary disinfection agents of chlorine sol ...

and

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and al ...

. The resulting water can be used as a disinfectant.

Creation

The electrolysis occurs in a specially designed reactor which allows the separation of the cathodic and anodic solutions. In this process,

hydrogen gas Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, a ...

and

hydroxide ion Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It ...

s can be produced at the cathode, leading to an alkaline solution that consists essentially of

. At the anode, chloride ions can be oxidized to elemental chlorine, which is present in acidic solution and can be corrosive to metals. If the solution near the anode is acidic then it will contain elemental chlorine, if it is alkaline then it will comprise sodium hydroxide. The key to delivering a powerful sanitising agent is to form hypochlorous acid without elemental chlorine - this occurs at around neutral pH. Hypochlorous is a weak acid and an oxidizing agent. This "acidic electrolyzed water" can be raised in pH by mixing in the desired amount of hydroxide ion solution from the cathode compartment, yielding a solution of

Hypochlorous acid Hypochlorous acid (HClO, HOCl, or ClHO) is a weak acid that forms when chlorine dissolves in water, and itself partially dissociates, forming hypochlorite, ClO−. HClO and ClO− are oxidizers, and the primary disinfection agents of chlorine sol ...

(HOCl) and sodium hydroxide (NaOH). A solution whose pH is 7.3 will contain equal concentrations of hypochlorous acid and hypochlorite ion; reducing the pH will shift the balance toward the hypochlorous acid. At a pH between 5.5 and 6.0 approximately 90% of the ions are in the form of hypochlorous acid. In that pH range, the disinfectant capability of the solution is more effective than regular sodium hypochlorite (household bleach).

Efficient disinfectant

Both sodium hydroxide and hypochlorous acid are efficient

disinfecting A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...

agents;Electrolyzed water effective as chemical cleaner, study finds
by Ahmed ElAmin, 2006 as mentioned above, the key to effective sanitation is to have a high proportion of hypochlorous acid present, this happens between acidic and neutral pH conditions. EOW will kill spores and many viruses and bacteria. Electrolysis units sold for industrial and institutional disinfectant use and for municipal water-treatment are known as chlorine ''generators''. These avoid the need to ship and store chlorine, as well as the weight penalty of shipping prepared chlorine solutions. In March, 2016 inexpensive units have become available for home or small business users.

EPA registration

Although the field of electro-chemical activation (ECA) technology has existed for more than 40 years, companies producing such solutions have only recently approached the

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...

(EPA) seeking registration. Recently, a number of companies that manufacture electrolytic devices have sought and received EPA registration as a disinfectant.

Drawbacks

Electrolyzed alkaline ionized water loses its potency fairly quickly, so it cannot be stored for long. But, acidic ionized water (a byproduct of electrolysis) will store indefinitely (until used or evaporated). Electrolysis machines can be but are not necessarily expensive. In some but not all instances the electrolysis process needs to be monitored frequently for the correct potency.

References

{{DEFAULTSORT:Electrolysed Water Water Electrolysis Disinfectants Chemistry

Creation

Efficient disinfectant

EPA registration

Drawbacks

See also

References