Electrolyzed water

Electrolysed Water (sometimes known as "Electrolyzed Oxidizing Water" EOW) is produced by the electrolysis of ordinary tap water containing dissolved salt sodium chloride. In this process, hydrogen gas and hydroxide ions are produced at the cathode, leading to an alkaline solution that consists essentially of sodium hydroxide NaOH. 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 HOCl, 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 NaOCl 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.

Additional recommended knowledge

Essential Laboratory Skills Guide

How to ensure accurate weighing results every day?

Daily Sensitivity Test

Both of these species are efficient disinfecting agents; since relatively few microorganisms can tolerate acidic conditions, the acidic form of EOW is usually preferred for rinsing food-preparation surfaces, fruits and vegetables. Preparations sold for topical application to wounds are usually slightly alkaline.

Sodium hypochlorite is produced in large quantities as a byproduct of the manufacture of chlorine and its solutions are widely available as household laundry bleaches. Mixing a dilute acid such as vinegar or lemon juice with a dilute solution of laundry bleach and adjusting the pH to around 4-5 will yield a solution roughly equivalent to that produced by EOW "machines" whose capital and operating costs may not be justified if only small quantities of EOW are required.

Some promotions of EOW claim that it can act as an antioxidant food additive; however, both of the chlorine-containing components of EOW are active chemical oxidizing agents.^[1]

See also

• Disinfectant
• Electrolysis
• Electrolysis of water
• Water ionizer (produces alkaline drinking water)

References