Until its scientific rediscovery in 2007 at TU Graz, the “water bridge” phenomenon, discovered in the 19th century, had sank into oblivion. If extremely pure water, in other words water that has been distilled many times, is placed in two beakers and subject to a high voltage, the fluid moves up the side of each beaker and forms a floating water bridge between the two vessels.
The water in this bridge flows in both directions and is in a completely new state with its own special properties of density and structure. A research group of TU Graz and the Wetsus research centre in The Netherlands has now demonstrated that this floating water bridge produces electrically charged water and stores the charge at least for a short time.
Protonic electrical charge
The water is not electronically, but rather protonically charged. This novel kind of water is either positively or negatively charged depending on whether it contains more or fewer protons. The study shows that in anodic water — water with a positive charge — protons are formed in the context of the occurring electrolysis. These hydrogen nuclei flow through the water bridge into the cathodic water of the other beaker, which has a negative charge, and are neutralised there by hydroxyl ions. Since the protons move at a finite speed, there is always an excess of protons in one water container and a lack of protons in the other.
If the water bridge is suddenly switched off, the proton charges remain, as can be measured by means of impedance spectroscopy. The first investigations have shown that the fluid’s charge remains stable for one week.
From water battery to low-waste chemistry
The realisation that such water bridges can be used as electrochemical or biochemical reactors opens up a variety of possible industrial applications. Substances can be brought into contact with other materials in the water bridge for the purpose of chemical reactions, water can become a “water battery” as a storage of electric charge, and acids and alkalis can be produced without any opposing ions — without acid and alkaline water. This opens the way to especially eco-friendly cleaning agents, reduced waste from chemical processes, and new possibilities for medical applications.
The water bridge pictured above is formed under the influence of a high-voltage electrical field of about 15kV. It spans about 1 cm across two Teflon beakers, each filled with deionised water.
Credit: © Woisetschläger/Fuchs – TU Graz.