Technical Detail

---

This section explains the foundation of the photoplasma air purification technology and the most important physical and chemical process that take place inside Biozone air purifiers.

There are five different mechanisms that Biozone's air purifiers use for this purification. The relative intensities of these can be individually controlled and varied in order to create customised devices for particular applications.

Photo Catalytic Oxidation, PCO

Photocatalytic chemistry (PCO) has been extensively studied over the last 25 years for removal of organic and inorganic compounds from contaminated air and water. PCO utilizes ultraviolet light in conjunction with a semiconductor photocatalyst and breaks down contaminants into non-toxic compounds such as CO2, H2O and simple mineral acids.

In the PCO process the destruction of chemical compounds, mainly VOC's, is done catalytically on the surface of the target material using the energy of UV photons. Aluminium and aluminium oxide have small photoelectric work functions and therefore upon their illumination by ultraviolet light emit photoelectrons producing a photocatalyst. Biozone also ofiers PCO units that utilise Titanium Dioxide (TiO2) as the photocatalyst which is a preferred material and produces enhanced purifying results.

The photons energy must be larger than the band-gap of the the catalyst material (aluminium, aluminium oxide or titanium oxide), because the energy is used to excite an electron from the non conducting energy state into the conductor belt in which the electron can move freely into the semiconductor material. The excited electron leaves a positively charged hole behind it, and together the electron and the gap form an electron-hole system which has electric potential energy which must be consumed before the pair are re-united. The catalyst itself is unchanged and no residue frm the reaction remains. These attributes provide an effective process for removing and destroying pollutants such as VOCs, bacteria, viruses and fungi in indoor air.

This potential energy is used for oxidisation that occurs when a molecule arrives on the surface of the semiconductor material. The oxidisation process breaks the harmful molecule apart forming non-harmful chemicals. When this process is kept going long enough the end product is carbon dioxide, water vapour and mineral salts.

Photocatalytic oxidation technology has been studied and endorsed by the EPA, Sandia National Labs, US Department of Defense, US Department of Energy, the National Energy Labs, American Lung Association, Industry Canada - Environmential Affairs Branch, and numerous universities around the world.

Photoplasma

Photoplasma is gas that is fully ionized by UVlight (wavelength less than 280 nm) containing ions and free electrons. UV-light and plasma destroy oxygen and water molecules (02 and H20), producing ozone (03), hydroxyl radicals (OH), free oxygen atoms (0.) superoxide ions (02-) etc. These species are highly reactive, and they react with impurities in the air oxidizing toxins into less harmful chemical compounds, such as carbon dioxide and water. UV-light that creates the plasma or electrically charged particles of the plasma (namely electrons) can also directly destroy many other types of molecules.

Photoplasma is highly reactive and will break bonds of organic compounds in some cases 180 times faster than UV light alone and 2000
times faster than Ozone alone. This occurs because of a combination of chemical reactions where photoplasma acts as a catalyst in an intermediate state of the reactions which in itself speeds up the reaction.

Germicidal Light

Ultraviolet light with a wavelength of 254nm and 185nm can be used to sterilize (kill) micro-organisms.

BioZone's lamps use a specially formulated glass that passes through the deep UV-light wavelength of 185nm. This generates a very efficient germicidal light for sterilisation purposes. The UV-light causes thymine molecules on DNA to dimerize. If the light intensity and exposure time is sufficient the defects on thymine is enough to cause its replication to be inhibited, thereby rendering it harmelss.

If the exposure is longer it kills the micro-organism. The light itself can never kill all micro-organisms because, when air is passed through the purifiers, there is always some shaded places where the micro-organisms can survive. However Biozone's use of multiple technologies in its units ensures that those micro-organisms that survive the germicidal light are then dealt with by ozone, photoplasma and PCO.

It should be noted that many commercially available sterilisation lamps are often made of Quarz glass, which does not pass through the effective 185nm light and thus are less effective than Biozone's lamps.

Negative Ions

Ions are electrically charged atomic particles, consisting of atoms and molecules which have gained or lost electrons. Negatively charged ions (negative ions) have excess amounts of electrons giving them a negative electric charge. Negative ions are being created inside Biozone's air purification devices and they float in the air interacting with chemical compounds and micro-organisms.

Ions may cause harmful chemical compounds to react by decreasing the total concentration of the chemicals in the air, however the main effects of the negative ions are the biological effects.

The nature of the interaction between the negative ions and micro-organisms is not fully understood, nevertheless there are number of articles proving the effectiveness of negative ions in air purification and their positive health effects. Thus the negative ions created in BioZone's devices can be expected to increase the quality of the air surrounding the device.

Ozone

Ozone (03) is a very reactive gaseous compound that is normally found in the atmosphere and is produced by the natural oxygen and UV-light reaction cycles.

Ozone generators have been used for over a hundred years for purification and sanitation purposes in a wide variety of industrial and medical applications. It's properties as a bactericide, viricide, fungicide, and deodorizer are well accepted by the scientific community.

While ozone is a very reactive oxidizing agent in low to moderate concentrations it can efficiently be used for killing harmful micro-organisms and destroying harmful substances such as VOC's. The main thing to keep in mind is that Biozone's air purifiers emit ozone levels that will saturate to less than 0.05ppm in the room size they are designed for. Ozone production rates are found to be well below the internationally recognized Indoor Air Quality limits.

Ozone starts to become dangerous at around 1000-5000ppm, which is 20,000-100,000 times more than the device normally emits. It is not even theoretically possible for Biozone's devices to generate these amounts of ozone as the energy of the lamps is not sufficient to create even fractions of these amounts.

The complete lack of ozone in indoor air should be considered a bigger health hazard than indoor air that has low amounts of ozone.