Air and water purification technology showcased
The development of efficient purification and disinfection technologies has become critical since the SARS outbreak last year. The Chinese University of Hong Kong's Department of Chemistry has recently developed a novel photocatalytic Titanium Dioxide (TiO2) coating for direct application to various substrates and for air and water purification as well.
TiO2 is a non-toxic, chemically stable semiconductor. There are three naturally occurring crystal forms of TiO2, namely, rutile, anatase and brookite. When a semiconductor TiO2 particle in the anatase form is irradiated by sunlight or placed near UV light, an electron is excited to form a superoxide anion radical as well as hydroxyl radical. These radicals are powerful oxidising agents, which can completely degrade pollutants and kill bacteria on contact.
Over the past two decades, the semiconductor TiO2 photocatalysis has been widely investigated. However, the traditional photocatalyst powders are difficult to recycle and have poor solar and near UV efficiency. Following years of investigation, the research team at the Chinese University has successfully developed new methods of coating enhanced nano-crystalline TiO2 on various substrates such as metal, tiles and glass. This coating demonstrates a strong photocatalytic activity under ultraviolet irradiation. It can, as a result, oxidise most organic and inorganic pollutants, and kill bacteria such as E. coli and Vibrio cholerae.
This technology has been commercialised and licensed as NanoPCO(tm) and is widely in use for air and high-end water purification. NanoPCO(tm) has been proved to be an easy, effective and reliable disinfectant at a lower cost.
With the support of the Department of Chemistry at Chinese University, the "Photocatalytic Technology for Air and Water Purification" exhibition has been compiled to give visitors an understanding of this important technological achievement. Two videos - "Photocatalytic Coating Technology" provided by the Department of Chemistry and "Volcano Monitoring System" provided by the National Geographic Channel - will be screened in conjunction with the exhibition.
A computer set up on site will provide exhibition-goers with a list of relevant websites.
The Science Museum is located at 2 Science Museum Road, Tsim Sha Tsui East. It opens from 1pm to 9pm from Monday to Wednesday and on Fridays, and from 10am to 9pm on Saturdays, Sundays and public holidays. It is closed on Thursdays (except public holidays). Admission is $25 with half-price concession for full-time students, people with disabilities and senior citizens aged 60 or above. Admission is free on Wednesdays.
For enquiries, call 2732 3232 or visit the Science Museum's website at http://hk.science.museum
Ends/Friday, March 12, 2004