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ADVANCED AIR TECHNOLOGIES
IMPROVING INDOOR ENVIRONMENT


Back to start About air quality Electron 180A Risk Assessment Evidence with References We would be pleased to answer your questions


 
NANO PHOTO-CATALYTIC FILTER

What is Nano Photo-Catalytic Filter?

The action of this filter is based on photo-catalytic oxidation (PCO) technique. Airborne pollutants are treated by semiconductor photo-catalysis, in which the key material is TiO2.
TiO2 particles are used as photo-catalyst because it is non-toxic, chemically stable, and possesses relatively high photo-catalytic activity. Laboratory studies have demonstrated TiO2 as the most efficient photo-catalyst for organic oxidative degradation due to its unique features:

  • Deep and thorough action under low temperature
    At room temperature, TiO2 is active enough to completely oxidize organic contaminants in water, air and soil into harmless carbon dioxide, water, and simple mineral acids. This is different from the traditional catalyzed oxidation, which requires a temperature of at least hundreds of degrees Celsius.

  • Effective for a wide spectrum of organic contaminants
    TiO2 has been proved to be effective for all kinds of organic compounds varying from hydrocarbon to carboxylic acid. All of the 114 kinds of pollutants published by the US Environmental Protection Agency can be treated by TiO2. Atomic organic compounds, such as dyes, nitrides and organic pesticides are also within the capability of TiO2.

  • Strong oxidation ability
    Even organic compounds which are hardly oxidized by ozone, such as trifluoro methane, carbon tetrachloride and hexachlorobenzene can also be dealt with by PCO. This is possible, because the oxidation ability of TiO2 is far stronger than that of ozone, hypochlorous acid, potassium permanganate. This feature is especially useful for the degradation of obstinate organics.

  • Permanent function
    TiO2 is not consumed in PCO reactions since it can deoxidize itself under UV irradiation and resumes its high oxidation efficiency. It can be used permanently without need of refilling. UVA and UVC are usually required as activating light source for TiO2.

Mechanism of TiO2 photo-catalytic degradation process

Under UV illumination, the TiO2 photo-catalyst absorbs photons with energy equal or higher than its band gap energy (<385nm, usually UVA and UVC are applied). This will delocalizes a valence electron and excites it to the conduction band of the semiconductor. These photo excited charge carriers can initiate the degradation of the adsorbed chemical species by one or more forms of electron transfer reactions.
Our Air Purifier Electron 180A applies this technology to treat different type of contaminants such as Volatile Organic Compounds (VOCs), germs, bacteria, microbes and viruses, and other pathogenic microorganisms latent in home. Further more, what we adopt is the nano-sized TiO2 technique, which allows enlarging the surface area available for adsorption and decomposition of the organic pollutants and thus enhancing the purification efficiency of the filter.

How does the UV irradiation work?

Ultraviolet Germicidal Irradiation, specifically in the UVC wavelength, has been proven safe and effective for almost 100 years in applications of killing harmful microorganisms through a process called photochemistry, which is the chemical reaction or change in material caused by exposure to light energy. In the photochemistry, photons in the ultraviolet spectral range are used to excite or cleave chemical bonds of the irradiated microorganisms and lead to the desired photo induced reaction and thus achieve sterilization and disinfection. Many common organic compounds based on the carbon and hydrogen combination, or hydrocarbons, toxic compounds generally formed by hydrocarbons associated with the lipid group as well as carbon based biological contaminants like bacteria, viruses and fungi all can be destructed by ultraviolet germicidal irradiation. Almost all indoor contaminants are this type of organic compounds.

UV light becomes particularly useful in the destruction of contaminating organic compounds, but only when sufficient photon energy is present. The fundamental physical requirement for the UV light source is sufficiently high photon energy (proper wavelength) at the required intensity. Wavelength of 254nm is the recognized standard for optimum UV germicidal killing power. The radiation emitted by this wavelength of UV light is very high and any microorganism that comes in contact with it will be destroyed almost instantaneously. The radiation emitted by the UV lamps of Electron 180A is approximately of this wavelength.

 

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