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| Photocatalyst absorbs light and causes various chemical
reactions. Metal oxide and sulfide are known for photocatalyst,
and especially TiO2 is being widely commercialized due
to high photocatalytic efficiency, chemical stability
and wide range of application.
Under the condition of light energy which is bigger
than band-gap energy(under 380nm) of the TiO2, it occurs
photo-oxidation, photo-reduction and hydrophilic reaction.
This reactivity can be used for a variety of uses. For
example, the dissolution of hazardous VOCs, the removal
of endocrine disruptors, the recovery of heavy metal,
the reduction of NOx and SOx, antibiotics, sterilization,
deodorization, anti-fogging, decontamination and self-cleaning.
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The decomposition of organic contaminants:
A photocatalytic TiO2 can decompose completely harmful
organic contaminants which are hard to be decomposed using
purification methods of chlorine or ozone. Therefore,
it is very effective in decomposing and removing endocrine
disruptors which are detrimental to environment and organic
contaminants, despite existing small amounts.
Organic chloride: Trichloroethylene
Endocrine
disruptors : Dioxin, Bisphenol, Nonylphenol, Estradiol
Harmful VOCs: Acetaldehyde, Formaldeyhde, Toluene
Odored gas: H2S, Thiol, Amine
Other odor:
Cigarette smell
The decomposition of air contaminants:
NOx, SOx, Dioxine from exhaust gas of cars, incinerators
and power plants.
Self-Cleaning: The dirt is
removed naturally. Hydrophilicity makes dirt to be washed
away by raindrop or water. The organic compounds on surface
are decomposed by an oxidation reaction. These reactions
unable dirt or organic compound to be accumlated on the
TiO2 film.
<Applications: building materials(interior
& exterior), roads, tunnel lightening, signboards
etc>
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| Anitbiosis & Sterilization: When
UV light hits a photocatalytic TiO2, hydroxy radical(ㆍOH)
occurs on surface and it kills bacteria. It means thatㆍOH
even decompose the remains of bacteria and poisonous substances
and other antibiotics although Ag and Cu do not show such
a strong effect. |
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