The modern world seems to be throwing up banana skins for we poor humans to slip up on. The more we try to clean up, the more inventive nature becomes in resisting our attempts or the more modern man wants to pollute it with the need for his toys and tools.
Super-bugs in hospitals, emissions from cars and factories, complex gasses from process plant are countered by chemical cleaners, chemical converters, filters or vapours are simply blown as high into the atmosphere as possible. Chemical germicides are now found to cause more problems than they solve, (germicidal paint additives used in fridges and on pre-coated building claddings utilises Troclosan, the most common biocide, which is now banned) and the other remedies simply send the problem further down the line to licensed disposal companies.
There must be an alternative out there. A simple, safe way of attacking the things that we would all throw into Room 101.
· Germs. (MRSA)
· Car exhaust fumes.
· Cigarette smells and smoke.
· The slippery black mildew on paving.
· New building smells and toxic gasses.
· Polluted water in ponds and lakes. (Chrome VI problems)
· Paint smells outside factories.
We can of course attack the problem with heat. A naked flame would burn them up but you would need a large energy input and it would damage the surrounding area as well.
Burning things in air breaks the substance apart and adds oxygen to the broken bits. In the main we are left with an oxide of Hydrogen, (water) and Carbon Dioxide.
Is there a way of attacking the things in the above list with the oxygen around us, but doing it without heat? The fact is that eventually all these things are broken down by oxygen, they decay, but it takes a very long time. To speed it up we need a catalyst. This is a material which increases the rate of oxidation but does not get used up in doing so. It may need some energy to get it going and the most convenient source of energy is sunlight or artificial light.
Employing a “˜light-catalyst’ or photocatalyst, will kick start oxidation so any germs, oils, fumes, smells, or even little algae spores which land on a surface near the photocatalyst will be burned off in a few minutes. Any surface we wish to keep clean needs to receive a little light and be coated with a minute amount of a photocatalyst. So little in fact that you would not know it was there.
To make this commercially sensible we need a simple material to act as a photocatalyst and we need it to be very active. The material of choice is Titanium Dioxide, (the white stuff in toothpaste and the pigment used to mark the lines at Wimbledon). When it is made as tiny, (nano) particles it makes oxygen as lively as if it were next to a blow torch. Each reactive particle is so small that if sheet of glass is viewed through a very powerful microscope the surface looks like the Himalayas and our nano-size Titanium Dioxide is a cottage on its slopes. (Very difficult to rub off)
Does it work? This photocatalyst route is being used to coat hospital wards in Japan, to combat SARS and MRSA. It is used to coat ceramic tiles and light bulbs to prevent smells in public toilets. In Korea it is very popular to have your new appartment coated as there is a big scare about toxic chemicals given off in new buildings. It is being sprayed onto pavements outside nursery schools to cut the toxic gasses in the vicinity. The knock on effect has been to keep all these surfaces clean and free of mildew and general organic debris. Pilkington, the glass maker uses it as the active agent in their stay clean glass sheets, (ACTIVA.) You can even buy a room fan which draws air, including the germs and smells, through a photocatalyst coated foam. This cleans a room in minutes. Ideal for use in areas where people are susceptible to infection.
The coating, for that’s what we are talking about, may now be spray applied to just about any surface from stainless to cement, from plastic to ceramic. It renders the surface self cleaning on the macro scale, by removing general grime, and the microscopic scale of virus and germ free. This coating is now being used under license by several British companies who have entered into a joint commercial venture with us. We would welcome any contact with companies who have a use for this material and would like further information. www.photocatalyst.co.uk
So there is a simple safe way of dealing with some of our little difficulties. Coming soon to a theatre near you. The theatre which is germ free and doesn’t smell!
Chris Gummer www.photocatalyst.co.uk