Polymer made from waste oil cleans up mercury

A new polymer created from used cooking oil can cheaply remove toxic mercury from the environment.

Food waste has proven to be fertile ground for the creation of new products, from water filtration systems made from citrus peel to ice cream made from unsaleable produce. Now, researchers have found a way to use waste cooking oil to remove mercury from the environment.

Mercury is a neurotoxin that leaches into the water from its use in the mining and fossil fuel industries and can lead to brain damage and low IQ in humans. A new United Nations convention on controlling mercury emissions, the Minamata Convention on Mercury has recently come into force, creating a market for materials that can remove mercury from the environment. To meet this demand, a team of scientists at Flinders University in Australia, led by Dr Justin Chalker, have devised a way to create a polymer out of used cooking oil that can trap and remove mercury from the environment.

Dr Chalkers’ team originally created the polymer, called Sulfur-Limonene Polysulfide (SLP), in 2015 from orange oil. But SLP was very expensive to produce, so the team began looking for cheaper materials. They recently found that waste cooking oil not only worked well, and is more durable, but also cut the cost of the raw materials down by orders of magnitude. Says Dr Chalker, “Because our mercury-capturing material is made from waste, our goal is to provide a cost-effective and technically simple material for cleaning up mercury pollution at these gold mines.” After absorbing the mercury, the polymer changes color from brown to black, to indicate the job is done. The mercury remains permanently bound to the polymer and can be safely stored without further risk to the environment.

The polymer is currently being tested in field trials at mining sites and other areas and is licensed for sale to Kerafast, an American reagent company. Dr Chalker and his team are also working with engineering firms in Adelaide to design pilot plants and reactors that can produce the polymer on a large scale. Dr Chalker hopes that the polymer will be available commercially within a year. What other materials might be developed from food by-products that can help with environmental clean-up?