Biozone air purifiers remove contaminants from
air and surfaces by utilizing the principles of
photochemistry, cold fusion plasma, and
photoionization through the photoelectric effect.
While all of these methods for air purification have
been well studied and documented by the scientific
community, it is the unique synergy of their
combined interaction that produces a truly
superlative air purification method.
Photochemistry is the chemical reaction or change
in materials caused by
exposure to light energy.
The process typically requires the use of photons in
the ultraviolet spectral range. Ultraviolet
radiation serves to excite or cleave chemical bonds
and leads to the desired photoinduced reaction.
Energetic ultraviolet radiation is useful for
disinfection purposes. For this application, the
fundamental physical requirements for the
ultraviolet lgiht source is sufficiently high photon
energy (wavelength) at the required intensity. When
sufficient photon energy is present, ultraviolet
light becomes particularly useful in the destruction
of contaminating organic compounds. Almost all
indoor contaminates are organic. Organic compounds
are carbon-based. Many common organic compounds are
based on the carbon and hydrogen combination, or
hydrocarbons. Hydrocarbons can be toxic, volatile
organic compounds such formaldehyde and benzene.
Airborne, indoor dust particles like dander, hair,
dust mites, feces, etc., are based upon organic
compounds generally associated with the lipid group.
Biological contaminates like bacteria, viruses, and
fungi, are carbon based. Photochemistry can break
down these harmful organic molecules. Ultraviolet
light with enough energy, such as in the 100-280
nanometer (nm) wavelength range, can break down the
electron bonds of an organic molecule.
The shorter the ultraviolet wavelength, the more
energy created to break molecular bonds. All organic
material is photodegradable at certain wavelengths.
Ultraviolet wavelengths in the 100-280 nm
bandwidth not only break down electron bonding of an
organic molecule, but also initiate the formation of
a cold gas plasma. A plasma is an excitation
of gas by radio frequency energy. In our case, we
excite gases by the energy from ultraviolet waves,
creating a highly energized gaseous state.
The plasma, or highly energized gaseous state, is
aggressive and highly reactive and contains excited
atoms and molecules, ionized gases, radicals, and
free electrons. It can destroy nearly all organic
contaminants. The destruction mechanism primarily
involves the photo disassociation of molecular
oxygen leading to the formation of highly oxidizing
species, such as atomic oxygen, molecular singlet
oxygen, and ozone. These agents interact with
contaminants, converting most to volatilized carbon
dioxide and water. The UV radiation also creates
electron ejection of organic molecules that produces
additional free radical creation. The radicals react
with oxygen, producing hydroperoxide ions. The
hydroperoxide process activates a chain reaction
with organic compounds, triggering further
oxidation. When additional hydrogen is added, as in
the form of water or water vapor (humidity), the
highly oxidative species hydroxyl radicals
is
created. These radical ions are a stable but a very
potent one-electron oxidant. They are very
destructive to organic contaminants because they
steal hydrogen atoms from the organic materials,
leaving decaying carbon ions. The theft of hydrogen
from organic molecules forms even stronger hydroxyl
radical bonds with even higher oxidative potential.
This entire process turns into a chain reaction -
the breakdown and formation of new hydroxyl radicals
results in the continual decay of organic material.
While the photoelectric effect created by
high-energy ultraviolet light is ejecting electrons
from a molecule, it is further enhanced by
irradiating what is called a "photoelectron
emitting member" with ultraviolet light. A
photoelectron emitting member may be made of any
material that emits photoelectrons upon exposure to
ultraviolet radiation. Such a photoelectron emitting
member is contained in Biozone Air Purifiers. The
photoelectrons ejected from the photoelectron
emitting members are used to charge fine particles
in a gas which are then removed from the airstream
as they attach to oppositely-charged surfaces. This
electrical charging of dust and other particulates
can remove particles as small as .001 microns. It
should be noted that each of the electron ejections
can cause multiple ionization events. For example,
in the photoelectric effect, the photon undergoes
only one interaction, yet thousands of ionizations
can be caused by the resultant electron and its
products.
The combination of ultraviolet light and plasma
has been reported to be an extremely potent method
of removing contaminants from surfaces. As an
example and for comparative purposes, it has been
estimated that removing biological contaminants from
surfaces by corona
discharge created ozone may take 10 hours. UV
light, in the highly bactericidal range of 253.7 nm,
would take 1 hour for the same result. Corona
discharge ozone and ultraviolet light combined would
achieve the same result in 1.5 minutes. However,
the use of a broader and more energetic UV bandwidth
combined with the resulting plasma would clean the
same surface in 20 seconds.
