Nano breakthrough to revolutionise waste water management

PUBLISHED : Thursday, 22 January, 2009, 12:00am
UPDATED : Thursday, 22 January, 2009, 12:00am



Dunwell Enviro-Tech

Nanotechnology, developed jointly by a local enterprise and a local university, is set to revolutionise waste water management.

Grand winner of the Technological Achievement category, Dunwell Enviro-Tech, a Hong Kong-based technology firm, has developed a nanoparticle that is recyclable.

This makes its use in environmental applications affordable.

Nanoparticles are less than 100 nanometres (a nanometre is 1 millionth of a millimetre) in size. Because of their unusually high surface-to-volume ratio, they attract metal ions and organic molecules by ionic charges or specific bonding. These particles act as tiny vehicles that transport other substances, and are widely used in medicine, transporting medicines to the desired parts of the body. Because they can be used once, and due to the high cost of production, they are suitable for only a limited number of high-end applications.

Now it is possible for Dunwell to recycle nanoparticles. According to Daniel M Cheng, managing director of Dunwell Enviro-Tech, nanoparticles are 'like microscopic bowling balls with a charge on the surface. The idea of reducing something to nanosize is that you create a very small mass with a huge surface area that has charges on it'.

'The special breakthrough in our case is that we have engineered the nano so that it can release the contaminant and then be used again,' Mr Cheng said. 'Once you have that, you can create treatment systems that are very cost effective.'

The technology can be used to create other applications besides the treatment of wastewater. It could be used to recover precious metals such as gold, platinum and silver. In plating and mining operations, a lot of water is used. When this water is released, it pollutes the environment.

'With this technology, they can treat the water and recover precious metals at the same time,' Mr Cheng said. 'The function of this type of nano is to act as a sort of transport vehicle that grabs the precious metals, releases them and goes back to work. They are almost like microscopic trucks.'

Dunwell worked with the Hong Kong Polytechnic University on the development of the technology. It took four years to get from the conceptual stage to the commercial market. It was introduced to the market last year.

'Hopefully with this and the other awards we have won, we will gain more recognition and can go worldwide,' Mr Cheng said.

'For a small and medium-sized enterprise like us, investing in research and development is a very painful process. That is why there are so few breakthroughs like this in Hong Kong. 'The potential for this technology is huge. Once we develop one type of nano for one type of application, we can develop other types for other applications. This is just the beginning.'