Nano-solution to clean drinking water

Prof Peter Majewski and PhD student Chiu Ping Chan from UniSA’s School of Advanced Manufacturing and Mechanical Engineering have developed a new technique which can remove bacteria, chemicals, viruses and other contaminants from water much more effectively than conventional water purification methods.

“Its major benefits include an easy-to-use chemical and physical treatment process that cleans water without requiring additional energy, and uses recyclable non-toxic base materials like the waste product silica and water, which bring costs down,” Prof Majewski said.

“These features make it a very attractive alternative to desalination, which incurs high energy costs."

Prof Majewski says current water purification techniques are often complicated and use sophisticated equipment, which is expensive to operate and maintain, and includes a final, costly disinfection stage.

“Our technology is simple. We coat tiny silica particles with a nanometre-thin layer of an active material based on a hydrocarbon with a silicon-containing anchor. The coating is made by a chemical self-assembly process, which involves simply mixing the ingredients to make what is called active ‘surface engineered particles’,” Prof Majewski said.

"We put the prepared particles in the contaminated water and stir it, or flush the contaminated water through a filter containing the active particles, which is much easier to handle. As the water runs through the filter, the toxins attach themselves to the coated particles through an electrostatic attraction between the contaminants and the particles and remain in the filter, leaving good quality water of drinking standard."

Testing of the active particles demonstrates that they can remove pathogens such as the Polio virus, bacteria such as Escherichia coli, and the waterborne parasite Cryptosporidium parvum.

Prof Majewski says that all water can be treated and his researchers are looking into processed water treated for re-use in industry, which requires fewer regulations than drinking water.