Electrolysed water ("'electrolyzed water'", EOW, ECA, electrolyzed oxidizing water, electro-activated water or electro-chemically activated water solution) is produced by the electrolysis of ordinary tap water containing dissolved sodium chloride. Typically, tap water has sufficient dissolved salts for the electrolysis of water. The electrolysis of such salt solutions produces a solution of sodium hypochlorite, which is the most common ingredient in store-bought household bleach. The resulting water is a known cleanser and disinfectant / sanitizer but is not a surfactant (soap).
The electrolysis occurs in a specially designed reactor which allows the separation of the cathodic and anodic solutions. In this process, hydrogen gas and hydroxide ions are produced at the cathode, leading to an alkaline solution that consists essentially of sodium hydroxide. At the anode, chloride ions are oxidized to elemental chlorine. If some of this chlorine is allowed to combine with some of the hydroxide ions produced at the cathode, it disproportionates into hypochlorous acid, 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 sodium hypochlorite (NaClO) which is the major component of ordinary household laundry bleach. 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 acid.
Both sodium hydroxide and hypochlorous acid are efficient disinfecting agents; since the effectiveness of EOW seems to increase at low pH, the acidic form of EOW is usually preferred for rinsing food-preparation surfaces, fruits and vegetables.
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 bleach generators. These avoid the need to ship and store chlorine gas, as well as the weight penalty of shipping prepared bleach solutions.
Although the field of electro-chemical activation (“ECA”) technology has existed for more than 40 years, companies producing anolyte solutions have only recently approached the U.S. Environmental Protection Agency (EPA) seeking registration. This is due to the lack of advances in equipment that can reliably deliver the solutions in the consistent, repeatable manner needed to meet and pass the battery of various EPA product registration tests.
Electrolyzed water loses its potency fairly quickly, so it cannot be stored for long. Electrolysis machines are expensive. The electrolysis process needs to be monitored frequently for the correct potency.
- Dickerson, Marla (2009-02-23). "Simple elixir called a 'miracle liquid'". Los Angeles Times.
- Huang, Yu-Ru; Yen-Con Hung; Shun-Yao Hsu; Yao-Wen Huang; Deng-Fwu Hwang (April 2008). "Application of electrolyzed water in the food industry". Food Control 19 (4): 329–345. doi:10.1016/j.foodcont.2007.08.012. ISSN 0956-7135.
- Electrolyzed water effective as chemical cleaner, study finds, by Ahmed ElAmin, 2006
- "Inherently Safer Water Purification": Chemical & Engineering News 2007 87(06) pp 22–23