Turns out waste cooking oil can be used to extract mercury from the environment. Who knew?
Researchers worked out a way for a canola oil polymer to trap mercury metal, mercury vapour and highly toxic organo-mercury compounds by combining it with sulphur.
“Our previous research studied a single type of inorganic mercury, so this is a significant advance,” says award-winning Flinders University scientist Dr Justin Chalker, who is a Senior Lecturer in Synthetic Chemistry.
“With the Minamata Convention on Mercury coming into force around the world this year, this discovery is an important advance in protecting the environment and human health.”
Dr Chalker says they can use this material to protect the environment by capturing toxic mercury pollution – a big problem around the world that causes brain damage in unborn children.
Adding to the awesomeness of this discovery, every single atom of the mercury-binding material can be derived from industrial byproducts. This presents a huge opportunity for recycling and re-purposing waste.
To create the material Dr Chalker and fellow researchers from around the world combined second-hand cooking oil with sulphur – a common, low-cost byproduct from petroleum production – to produce a new kind of polymer to use in remediation of soil, water and even the air.
After absorbing mercury pollution, the novel rubber-like polymer changes colour to indicate the job is done. More of the affordable polymer mixture can then be placed in the area to continue to process.
Dr Chalker says the material is being tested in field trials at mining sites and areas where mercury-based fungicides are used.
“Mercury is encountered in several industrial activities including oil and gas refining and coal combustion,” Dr Chalker says. “Alarmingly, mercury and mercury-containing materials are still used intentionally at many chloralkali plants and in artisanal gold mining. Additionally, mercury-based fungicides are still used in certain agricultural sectors.”
Dr Chalker says the largest source of mercury emissions globally is due to artisanal gold mining, where mercury metal is used to extract gold from ore. The mercury-gold amalgam that forms is then heated, often with a hand torch or on a cooking stove, to vaporise the mercury and isolate the gold.
The mercury rich tailings and exposure to mercury vapour threaten the health of the nearly 15 million people involved in this process, Dr Chalker says.
“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.”
This research was funded by The Australian Government National Environmental Science Programme Emerging Priorities Funding and The Australian Research Council.
The mercury-binding polymer is licensed for sale to Kerafast a US-based reagent company whose primary aim is to make unique laboratory-made research tools easily accessible to the global scientific community.
The Flinders University team is raising funds to develop a pilot reactor and production plant for the new polymers in South Australia.