Semiconductors water cleaners

1989/07/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Ingurumena

Scientists at Sandia National Laboratory and Solar Energy Research Institute in the US have recently developed a method to eliminate most toxic organic compounds that are emitted into water. They throw semiconductors sensitive to water light and then put them in the sun.

When ultraviolet light rays attack semiconductors, electrons are extracted and leave positive holes. Electrons and orifices react with dissolved water and oxygen by forming radical hydroxylos and peroxide ions. These two chemicals are highly oxidizing and attack and break organic products.

Because the ozone layer filters most of the Sun's ultraviolet rays, researchers must concentrate light through mirrors to generate enough radical hydroxides and peroxide ions.

In the trials carried out with this system, water contaminated with salicylic acid and titanium oxide has been used. The water had in principle 30 ppm of acid, but when extracting the semiconductor and bringing it to light, the concentration decreased to parts of the trillion in 15 seconds.

This cleaning system is still in its beginnings and it is necessary to delimit many parameters before commercial use.