Significant research has been undertaken by Air Revolution™ to develop an air purification device that meets the myriad challenges of the modern indoor environment. By combining the most powerful non-invasive technologies available; germicidal ultraviolet light, acknowledged for almost a century as a powerful antimicrobial agent; ionisation, natures’ own polluted air revitalisation process; and nanoscaled titanium dioxide, nanotechnology at the forefront of applied physical science; we now produce devices that are unparalleled in efficiency and reliability, making them a compelling product offering for the air purification market.

Basic Photocatalysis
Of all the technologies we incorporate into our devices, photocatalysis is widely considered to be the future of effective and affordable clean air technology.

What is Photocatalysis?
Photocatalysis is defined as “acceleration by the presence of as catalyst”. A catalyst does not change in itself nor is it consumed in the photochemical reaction. This definition includes photosensitization, a process by which a photochemical alteration occurs in one molecular entity as a result of initial absorption of radiation by another molecular entity called the photosensitizer. Chlorophyll in plants is a type of photocatalyst. Photocatalysis compared to photosynthesis, in which chlorophyll captures sunlight to turn water and carbon dioxide into oxygen and glucose, photocatalysis creates a strong oxidation agent to breakdown any organic matter to carbon dioxide and water in the presence of photocatalyst, light and water.

The Mechanism of Photocatalysis
When the photocatalyst titanium dioxide (TiO2) absorbs ultraviolet (UV) radiation from sunlight or an illuminated light source (fluorescent lamps), it will produce pairs of electrons and holes. The electron of the valence band of titanium dioxide becomes excited when illuminated by light. The excess energy of this excited electron promotes the electron to the conduction band of titanium dioxide thereby creating the negative-electron (e-) and positive-hole (h+) pair. This stage is referred as the semiconductor’s ‘photo-excitation’ state. The energy difference between the valence band and the conduction band is known as the ‘Band Gap’. Wavelength of the light necessary for photo-excitation is:1240 (Planck’s constant, h) / 3.2 ev (band gap energy) = 388 nm.

Basic functions of photocatalysis
1.Sterilizing Effect
Photocatalysis not only kills bacteria cells, but also decomposes the cell itself. The titanium dioxide photocatalyst has been found to be more effective than any other antibacterial agent, because the photocatalytic reaction works even when there are cells covering the surface and while the bacteria are actively propagating. Titanium dioxide does not deteriorate and it shows a long-term anti-bacterial effect. Generally speaking, disinfections by titanium oxide is three times stronger than chlorine, and 1.5 times stronger than ozone.

2. Deodorizing Effect
On the deodorizing application, the hydroxyl radicals accelerate the breakdown of any Volatile Organic Compounds or VOCs by destroying their molecular bonds. This causes organic gases to form change their molecular form into one that is not offensive or harmful to humans thus enhancing the air cleaning efficiency. Some examples of odour molecules are: tobacco, formaldehyde, nitrogen dioxide, urine and faecal odour, gasoline, and many other hydro carbon molecules in the atmosphere. An air purifier incorporating Ti0₂ can eliminate smoke, pollen, bacteria, virus and other harmful gaseous state volatile organic compounds.

3. Air Purifying Effect
Atmospheric constituents such as chlorofluorocarbons (CFCs) and CFC substitutes, greenhouse gases and nitrogenous and sulphurous compounds, undergo photochemical reactions either directly or indirectly in the presence of sunlight. The photocatalytic capabilities of titanium oxides can also be applied in the reduction or elimination of these pollutant compounds in air, as well as cigarette smoke and other volatile organic compounds that arise from various sources in indoor environments. In polluted indoor environments, these volatile organic compounds can be controlled and in many instances removed all together.

The characteristics of Titanium Dioxide as an “ANTIMICROBIAL” agent
An ideal antimicrobial chemical agent would have characteristics that make it effective under all conditions. Currently no chemical substance possesses all the desirable characteristics listed below; however the nanoscaled Titanium Dioxide utilized in Air Revolution’s photocatalytic air purifiers comes close to being an ideal antimicrobial agent if its desirable characteristics are compared to others.

The Specifications for an ideal chemical agent are:
1) Antimicrobial activity
2) Solubility
3) Stability
4) Lack of toxicity
5) Homogeneity
6) Minimum inactivation by extraneous
7) Activity at ordinary temperatures
8) Ability to penetrate
9) Material safety
10) Deodorizing ability
11) Detergent ability
12) Availability and at low cost

By utilising highly dispersed titanium dioxide coated on the surface of an inorganic substrate inside our devices, Air Revolution has developed an extremely effective oxidative ‘antimicrobial’ mechnaism. And the characteristics of TiO₂ make it a close match to the ideal chemical agent, meeting requirements 1, 2, 3, 4, 5, 6, 8, 9, 10 and 11.

Properties associated with the use of our advanced, proprietary Tsi-Brid™ TiO2 photocatalytic emulsion in the Air Revolution range of photocatalytic air purifiers include:

1. Virucidal and Antibacterial Properties
The super oxidation (Ox hydrogen gene) of TiO2 destroys cell membranes and causes them to die as a result of the loss of cell material. It solidifies the protein of the viruses, restrains their viral activity and furthermore grasps and kills germs that are suspended in the air. The germ-killing capability is as high as 99.8% on a single pass through an Air Revolution TiO₂ based air purifier.

2. Deodorizing and Antiseptic Properties
The deodorization power of nanoscaled TiO2 is up to 150 times stronger than that of effective fabric active carbon per cm2, which is equal to 500 active carbon fridge deodorants.

3. Oxidative Properties
Nanoscaled TiO₂ is known to actively decompose airborne allergens thereby restraining the progression of various diseases and associated conditions thereby assisting in their control. Tuberculosis, croup and asthma are examples of illnesses associated with airborne pathogens.

4. Airborne Particulate Control
Because of the Air Revolution’s proprietary Tsi-Brid™ emulsion which contains both TiO₂ and photocatalytic enhancers making it both highly photoactive and photokinetic, this remarkable catalyst has greater oxidation capabilities than O3 and anion. This makes Air Revolution’s photoactive Tsi-Brid™ photocatalytic emulsion one of the most effective ways to restore and control optimum air quality in the workplace, which is immeasurable in terms of disease prevention and staff wellbeing.