ExjobbsforslagPhotocatalyt5.doc
Solyta
- large scale functional coatings of photocatalysts
Solar energy impinging on a surface on earth can be utilised in many ways. The radiation energy can be
converted to electrical power as in solar cells and other photovoltaic devices, it can be transformed to thermal
energy as in solar panels and solar heaters or the energy can be used to initialize chemical reactions;
photodissociation, photolysis, or photodecomposition. The acceleration of a photoreaction in the presence of a
catalyst is called photocatalysis which is presently extensively studied because of its potential use in sterilization,
sanitation, self-cleaning, surface treatment and remediation applications. Of special importance are its water
purification properties1.
Foremost of photocatalysts are nanoparticles of titanium dioxide (titania) TiO2. TiO2 is active under UV light.
Hydrolysis of water in oxygen and hydrogen then takes place 2. The resulting free-radicals (hydroxyl radicals:
OH-) are very efficient oxidizers of organic matter. They are highly reactive and take part in so called secondary
reactions. Thus organic pollutants are oxidized into nontoxic materials, such as CO 2 and water and can disinfect
certain micro-organisms such as fecal coli form bacteria by attacking the cell membranes.
Today a broad spectrum of TiO2 products appears on the market for purification use.
At the Swedish School of Textiles a research project called Soltråd has been performed where one part has been
photocatalysis. Different binders have been tested. This final thesis work is a continuation of these efforts.
The goal is to develop an up- scaled application method for titanium oxide on textiles using sol gel technology
Focus i8n the work will be on coating and dyeing aspects.
The applicant must
- be self-going
- have experience with textile coating processes
- be interested in the physical process behind
- be cooperative
- have familiarity with chemical laboratory work
The work contains:
-
study of the literature
mimicking earlier work
test three different formulas for coating
up scaled test on stenter or similar
characterizing using surface energy analysis and FTIR
write an report
For questions and interest, please contact Soltråd project coordinator, PhD Nils-Krister Persson, Högskolan i
Borås, Swedish School of Textile, e-post: nils-krister.persson@hb.se PhD Kenneth Tingsvik, Swedish School of
Textile
1
Solar Photocatalytic Detoxification and Disinfection of Water: Recent Overview J. Sol. Energy Eng. February
2007 Volume 129, Issue 1, 4
2
Fujishima A., Honda K. (1972), Electrochemical Photolysis of water at a semiconductor electrode, Nature,
238, 37-38.