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Industrial by-products clean up mercury pollution Flinders University researcher Dr Justin Chalker has led the

limonene. This makes the polymer affordable for use in large-scale

development of a new, cheap, non-toxic polymer that literally sucks

environmental clean-ups.

mercury out of water and soil. The polymer is expected to have a

“More than 70 million tonnes of sulfur is produced each year by

big impact on both environmental and human health, as mercury

the petroleum industry, so there are literally mountains of it lying

exposure can damage the central nervous system and is particularly

unused around the globe, while more than 70,000 tonne of limonene

dangerous to pregnant women and children.

is produced each year by the citrus industry,” he said.

Sulfur-limonene polysulfide (SLP) is manufactured from sulfur

“So not only is this new polymer good for solving the problem

— a by-product of the crude oil industry — and limonene, which

of mercury pollution, but it also has the added environmental bonus

is found in orange peel and is an unused waste material from the

of putting this waste material to good use while converting it into

citrus industry. Dr Chalker explained, “We melt the sulfur and add

a form that is much easier to store so that once the material is

limonene to it, and then can coat devices or make it into any shape

‘full’, it can easily be removed and replaced.”

we like.” Both components are readily and cheaply available, Dr

By lining storage containers with SLP, Dr Chalker and his

Chalker added, due to the global abundance of waste sulfur and

colleagues have successfully removed mercury from rivers, ponds and soil. The material can transform water from toxic to nearly drinkable, with concentrations of mercury reduced 1000-fold — from several parts per million down to several parts per billion. The dark red material, which looks like rubber, turns bright yellow when it absorbs mercury. Not only does this indicate that the SLP is saturated and “needs to be changed”, said Dr Chalker, but it also means it can be used as a mercury detector in areas where pollution is suspected. After contact with SLP, the mercury remains permanently bound and can be stored safely without further environmental risk. Dr Chalker explained, “The mercury forms nano- and micro-particles that are embedded in the polymer and don’t get washed off even with flowing water.” Dr Chalker’s research, which included contributions by Flinders University colleagues as well as The University of Tulsa, the Institute

Top right: A block of the sulfur-limonene polysulfide: a polymer synthesised entirely from industrial by-products. Image credit: Flinders University. L-R: Max Worthington and Dr Justin Chalker. Image credit: Flinders University.

of Molecular Medicine at the University of Lisbon and the University of Cambridge, has been published in the journal Angewandte Chemie International Edition.

Nanosheet material absorbs oil like a sponge Materials scientists from Deakin University

work has been published in the journal Nature

have manufactured a material, called a boron

Communications.

Professor Chen’s co-lead author, IFM scientist Dr Weiwei Lei, said turning the powder

nitride nanosheet, that can absorb up to 33

According to Alfred Deakin Professor Ying

into a sponge was a big challenge. The team

times its weight in oils and organic solvents.

(Ian) Chen, the lead author on the paper, the

started with boron nitride powder known as

The material, which literally absorbs the

material is the most exciting advancement

‘white graphite’ and broke it into atomically

oil like a sponge, is the result of support

in oil spill clean-up technology in decades.

thin sheets that were used to make a sponge.

from the Australian Research Council and

“Current methods of cleaning up oil spills are

“The groundbreaking material is called a

is now ready to be tested by industry

inefficient and unsophisticated, taking too long,

boron nitride nanosheet, which is made up of

after two years of refinement at Deakin’s

causing ongoing and expensive damage, which

flakes which are just several nanometres in

Institute for Frontier Materials (IFM). The

is why the development of our technology

thickness with tiny holes which can increase

was supported by the Australian Research

its surface area per gram to effectively the

Council,” he said.

size of 5.5 tennis courts,” Dr Lei said.

SEM image of boron nitride aerogel with a density of 20 mg cm-3.

14 Sustainability Matters - Feb/Mar 2016

Professor Chen explained that in 2013, when

“The pores in the nanosheet provide the

the first stage of the material was developed,

surface area to absorb oils and organic solvents

it was in a powder form. “This powder had

up to 33 times its own weight.”

absorption capabilities, but you cannot simply

The Australians cooperated with US

throw powder onto oil — you need to be able

researchers from Drexel University and Missouri

to bind that powder into a sponge so that we

University of Science and Technology in the

can soak the oil up, and also separate it from

development of the nanosheets.

water,” he noted.

Source: www.deakin.edu.au

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Sustainability Matters Feb/Mar 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...

Sustainability Matters Feb/Mar 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...