...AND CHEAPER...:

A UniSA-led team including Associate Professor Haolan Xu and Dr Gary Owens has developed a new remediation technique that uses a super-efficient solar evaporation surface to draw water from the soil through a sponge-like filter that traps contaminants, mimicking the process of transpiration that occurs in natural plants, but at a greatly accelerated rate.

"Plants naturally draw mineral components out of the soil when they move water from their roots into their stems, leaves and flowers, where those mineral components are trapped," Dr Owens says.

"This means plants can be used to extract contaminants from soil, but the process is very, very slow, often taking multiple growing seasons, particularly in heavily contaminated situations, where the soil toxicity means the plants struggle to grow and often die.

"We have created a system that mimics this process - a form of biomimetic plant - but one that does so at a much faster rate and without any of the problems caused by toxicity."

Worldwide, more than 10 million sites are considered soil polluted, with more than half contaminated by heavy metals such as cadmium and lead, or metalloids such as arsenic.

The new system can remove such contaminants in as little as two weeks by using a super-efficient solar evaporation surface to rapidly draw water and contaminants from the soil into the biomimetic plant body.

"The solar evaporator used in this system is a variation of technology we are developing for many purposes, including desalination and wastewater purification," Assoc Prof Xu says.

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