Australian scientists have developed a world-first, graphene-based filter that can remove more than 99 per cent of organic matter during treatment of drinking water.

“Our advance is to use filters based on graphene – an extremely thin form of carbon. No other filtration method has come close to removing 99 per cent of natural organic matter from water at low pressure,” said Dr Rakesh Joshi of the UNSW.

“Our results indicate that graphene-based membranes could be converted into an alternative new option that could in the future be retrofitted in conventional water treatment plants.”

Sydney Water supplies clean water to about 4.8 million people in Sydney, the Illawarra and the Blue Mountains. These natural organic matter contaminants can affect the performance of direct filtration plants, reducing their capacity after heavy rain.

“The most common methods used at present to remove organic matter from water supplies include the application of chemical coagulants,” said Sydney Water’s Dr Heriberto Bustamante.

“However, these existing treatments are only partly effective, particularly as the concentration of natural organic matter is increasing.”

Dr Joshi said: “The new treatment system is made by converting naturally occurring graphite into graphene oxide membranes that allow high water flow at atmospheric pressure, while removing virtually all of the organic matter.”

Dr Joshi has an international reputation in this area, having published many highly cited articles including one in the journal Science on graphene oxide-based filtration in 2014 while working at the University of Manchester with Nobel Laureate Sir Andre Geim.

The UNSW team is upgrading the experimental rig to construct a small pilot plant that could be tested in the field.

The results of some of the research are published in the journal Carbon.