Tiny particles of pure silica coated with an active material could be used to remove toxic chemicals, bacteria, viruses, and other hazardous materials from water much more effectively and at lower cost than conventional water purification methods.
Recent research that was conducted by Peter Majewski and Chiu Ping Chan of the Ian Wark Research Institute, at the University of South Australia, looked at how tiny particles of pure silica that are coated with an active material could be used to remove toxic chemicals, bacteria, viruses, and other hazardous materials from water much more effectively and at lower cost than conventional water purification methods.
Their work is published in the current issue of the International Journal of Nanotechnology.
The two researchers, according to a press release, explain the availability of drinking quality water is fast becoming a major socio-economic issue across the globe, especially in the developing world.
Water purification technology is often complicated and requires sophisticated equipment. It is also expensive to run and maintain. As well, it usually requires a final costly disinfection stage. The researchers suggest that nanotechnology could provide a simple answer to the problem.
The team has investigated how silica particles can be coated easily with a nanometre-thin layer of active material based on a hydrocarbon with a silicon-containing anchor. The coating is formed through a chemical self-assembly process so involves nothing more than stirring the ingredients to make the active particles.
The next step was to test these active particles, so called Surface Engineered Silica (SES), in order to demonstrate that they could remove biological molecules, pathogens such as viruses like the Polio virus, bacteria like Escherichia coli, and Cryptosporidium parvum, which is a waterborne parasite.
"The results clearly show that organic species can efficiently be removed at pH ranges of drinking water by stirring the coated particles in the contaminated water for up to one hour and filtering the powder," the researchers say. They point out that the filtration process occurs through an electrostatic attraction between the pathogens and the surface engineered particles.
The recent report entitled 'Water for People - Water for Life' of the World Water Assessment Program of the UNESCO says that more than 6000 people die every day due to water-related diseases, including diarrhoea, worm infections, and infectious diseases.
Organic pollutants from industrial waste water from pulp and paper mills, textiles and leather factories, steel foundries, and petrochemicals refineries, are a major cause of illness in parts of the world where regulations do not necessarily protect people from such industrial outflows.
The nanotech approach to water purification could help prevent disease and poisoning for potentially millions of people.