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UV radiation at 185 nm is used to generate ozone. The UV lamps for water treatment consist of specialized low-pressure mercury-vapor lamps that produce ultraviolet radiation at 254 nm, or medium-pressure UV lamps that produce a polychromatic output from 200 nm to visible and infrared energy. The UV lamp never contacts the water; it is either ...
A germicidal lamp (also known as disinfection lamp or sterilizer lamp) is an electric light that produces ultraviolet C (UVC) light. This short-wave ultraviolet light disrupts DNA base pairing , causing formation of pyrimidine dimers , and leads to the inactivation of bacteria , viruses , and protozoans .
These ozone molecules absorb UVB light, following which ozone splits into a molecule of O 2 and an oxygen atom. The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process that terminates when an oxygen atom recombines with an ozone molecule to make two O 2 molecules. It is worth noting that ozone is ...
UV ozone generators use ambient air for ozone production, no air prep systems are used (air dryer or oxygen concentrator), therefore these generators tend to be less expensive. However, UV ozone generators usually produce ozone with a concentration of about 0.5% or lower which limits the potential ozone production rate.
The formation of the ozone layer is also caused by photodissociation. Ozone in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O 2), splitting them into individual oxygen atoms (atomic oxygen). The atomic oxygen then combines with unbroken O 2 to create ozone, O 3. [17]
Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
A white light source—emitting light of multiple wavelengths—is focused on a sample (the pairs of complementary colors are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) are absorbed , exciting the molecules.
Because ozone absorbs light in the UV spectrum, the most common way to measure ozone is to measure how much of this light spectrum is absorbed in the atmosphere. [ 14 ] [ 15 ] Because the stratosphere has higher ozone concentration than the troposphere, it is important for remote sensing instruments to be able to determine altitude along with ...