Science
History of Photocatalysis
The field of photocatalysis can be traced back more than 80 years to early observations of the chalking of titania-based paints and to studies of the darkening of metal oxides in contact with organic compounds in sunlight. During the past 20 years, it has become an extremely well researched field due to practical interest in air and water remediation, self-cleaning surfaces, and self-sterilizing surfaces. During the same period, there has also been a strong effort to use photocatalysis for light-assisted production of hydrogen. The fundamental aspects of photocatalysis on the most studied photocatalyst, titania, are still being actively researched and have recently become quite well understood. The mechanisms by which certain types of organic compounds are decomposed completely to carbon dioxide and water, for example, have been delineated. However, certain aspects, such as the photo-induced wetting phenomenon, remain controversial, with some groups maintaining that the effect is a simple one in which organic contaminants are decomposed, while other groups maintain that there are additional effects in which the intrinsic surface properties are modified by light. During the past several years, powerful tools such as surface spectroscopic techniques and scanning probe techniques performed on single crystals in ultra-high vacuum, and ultrafast pulsed laser spectroscopic techniques have been brought to bear on these problems, and new insights have become possible. Quantum chemical calculations have also provided new insights. New materials have recently been developed based on titania, and the sensitivity to visible light has improved. The new information available is staggering, but we hope to offer an overview of some of the recent highlights, as well as to review some of the origins and indicate some possible new directions.
Production
Crude titanium dioxide is purified via converting to titanium tetrachloride in the chloride process. In this process, the crude ore (containing at least 70% TiO2) is reduced with carbon, oxidized with chlorine to give titanium tetrachloride; i.e., carbothermal chlorination. This titanium tetrachloride is distilled, and re-oxidized in a pure oxygen flame or plasma at 1500–2000 K to give pure titanium dioxide while also regenerating chlorine.[14] Aluminium chloride is often added to the process as a rutile promotor; the product is mostly anatase in its absence.
Another widely used process utilizes ilmenite as the titanium dioxide source, which is digested in sulfuric acid. The by-product iron(II) sulfate is crystallized and filtered-off to yield only the titanium salt in the digestion solution, which is processed further to give pure titanium dioxide. Another method for upgrading ilmenite is called the Becher Process. One method for the production of titanium dioxide with relevance to nanotechnology is solvothermal Synthesis of titanium dioxide.
NanoHygienix Treatments
Any surface that has been treated with NanoHygienix NCS System can achieve a high level of hygienic cleanliness using only a cloth and water to remove any residue that remains on the surface. Almost all current cleaning practices result in a surface that looks good but is not hygienically clean. In other words, a surface that is not really safe to touch and has the potential to transmit an illness or infection.
Hygienic cleanliness means that the microbes, ie. bacteria, on a surface have been reduced or removed to a level that is safe for people to touch. Sanitizing is the standard of cleanliness required for most surfaces other than those in the medical field, which require disinfection or sterilization. Germs are transmitted to people when we touch unsanitary surfaces and then touch our face around our mouth, nose, or eyes.
NanoHygienix treated surfaces maintain a high level of cleanliness longer because they do not have a layer of organic residue (biofilm) left behind on the surface as food for the next generation of microbes. In addition, any disinfectant that is used, along with cleaning, will be more effective because the disinfectant will not be used up and defeated by the organic biofilm contamination on the surface which protects the microbes at the bottom.
The results are better. A cleaner, sanitary surface is achieved with less labour, less cost and with the reduced use of toxic chemical cleaners. NanoHygienix is cleaner, safer, more effective and good for the environment.
NanoHygienix is long lasting and requires a touch up application annually only on areas subject to heavy traffic.
Feel free to request more specific research and test data.
