Water purification with a graphene oxide membrane

Monash University engineers have created technology that can purify contaminated water, making it fit for consumption faster and more energy efficiently than ever before.

Using membranes made from graphene oxide, an atomically thin sheet where every atom is present on the surface and chemically inert so it doesn’t react with other chemicals, the researchers have developed water treatment technology that can be manufactured using gravure printing — a widely available industrial printing process. The technology will directly benefit Australian and international companies seeking energy savings and other cost advantages in water and wastewater filtration and industrial processes associated with pulp and paper, food and beverage, inks, pigments and dyes, pharmaceuticals and metals.

“This Australian-made, world-first technology can be easily adapted by industries in everything from drinking water purification, to mining waste treatment, to food and beverage industry applications,” said lead researcher Professor Mainak Majumder, from Monash’s Nanoscale Science and Engineering Laboratory. He said the graphene oxide membrane technology offers an enormous cost advantage to industry due to its ability to reduce energy consumption during water filtration.

“Since the membrane can be produced using standard industrial printing processes, the technology is also highly versatile and cost-efficient,” he said. “The graphene oxide sheets are layered into a structure that looks a little like puff pastry when viewed under a powerful microscope. Water and small molecules can flow around individual sheets or through pin-hole defects in the sheets and pass through the layered structure.”

Dr Sam Martin, who leads Prof Majumder’s membrane development team, said: “The gaps between the sheets are very small, around a one billionth of a metre, and permit only the smallest of molecules to pass, sieving out and rejecting the larger ones.

“Industry can use the new membranes where nanofiltration and reverse osmosis are currently used. The energy-efficient nature of the membrane makes it more cost-efficient than conventional membranes used in industrial processes.”

Supported by funding from the Australian Government’s Cooperative Research Centre (CRC) program of approximately $1.2 million, and with investment from industry partners Clean TeQ Holdings and Ionic Industries, the technology is now entering the commercialisation phase after undergoing seven years of research and development. Simon Savage, Managing Director of Ionic Industries, said people across the world will benefit from the technology.

“In wastewater treatment, the ability to remove pesticides and hormones is becoming more important, especially when water re-use is considered,” he said. “In countries such as China, India and Africa, where access to fresh water for drinking, agriculture and industry is critical, the new membranes may be used to filter surface and ground water into drinking water.”

Peter Voigt, founder and CTO of Clean Teq, added, “We aim to be manufacturing these membranes by the second half of 2019. We expect that the improved flux and the better robustness of the membrane will make the whole-of-life costs significantly lower than those currently in operation.”

Image credit: ©stock.adobe.com/au/Chepko Danil

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