AUSTRALIAN scientists have developed a new material made from inexpensive industrial by-products to remove mercury from soil and water.
Mercury can leach into the environment from a variety of sources, including mining and burning fossil fuels. It has toxic effects on bird and fish reproduction, and can retard brain development in children.
Developed by a team of chemists, led by Dr Justin Chalker at Flinders University in South Australia, the new polymer, Sulfur-Limonene Polysulfide (SLP), appears to show promise for the removal of mercury from soil and water.
“SLP is a polymer that looks like red rubber, and is made quite cheaply from industrial by-products,” said Chalker. “We can make it into any shape we want.”
SLP is manufactured from sulfur – available as a by-product of the crude oil industry – and limonene, which is found in orange peel and an unused waste material from the citrus industry. Both components are readily and cheaply available, making SLP a highly sustainable product.
“To make the SLP polymer, we melt the sulfur, and add limonene to it and then can coat devices or make it into any shape we like,” said Chalker.
By lining storage containers with SLP, Chalker and his colleagues have successfully removed mercury from river and pond water, and soil.
The material can transform water from toxic to nearly drinkable, with concentrations of mercury reduced a thousand fold, from several parts per million down to several parts per billion.
SLP turns from red to yellow when it binds mercury. After contact with SLP, mercury remains permanently bound and can be stored safely without further environmental risk.
“The mercury forms nano- and micro-particles that are embedded in the polymer, and don’t get washed off even with flowing water,” he said.
The paper describing the discovery of SLP has been published in the journal Angewandte Chemie International Edition, and Chalker’s team has also filed an international patent application describing SLP and its use in removing toxic mercury from the environment.
They are currently seeking industry partners to develop the material further.
