This New Sulphur-Based Polymer Is the Key to a Cleaner World
From a distance, they look like mammoth masses of bright yellow sand, a mystical, majestic sight, until you notice the industrial cranes and scaffolding surrounding it. Sulphur, synonymous with the archaic brimstone, is one of the most common and versatile elements in nature. While pure sulphur is odourless, sulphur compounds emit a miasma of putrescence akin to rotten eggs. From its bright yellow solid form, it burns to create blue, menacing flames and melts into a dark crimson liquid-like goo. This distinctive material is produced in the process of refining natural gas and fossil fuels like petroleum. And right now, there’s too much of it sitting idle on earth.
More than a waste of space, these stockpiles are also costly to maintain. “Some of the sulphur is used, but the rest of the surplus is just accumulating in large amounts around the world,” says Louisa Esdaile, an Australia-based solution specialist who works with the Chalker Laboratory at Flinders University. With lab director Justin Chalker, they have developed ground-breaking solutions that have the potential to put this excess sulphur to good use.
The team’s interest in this area started with reading a publication describing the large sulphur stockpiles. Louisa recalls, “They reported a polymerisation using a large amount of sulphur to create a material with interesting physical properties. They proposed that this type of material could use a lot of sulphur. The other material they polymerised with it is not available on a scale that is near that of sulphur. So we investigated other materials that are available on that scale, and focused on looking at waste products and materials that can be regenerated and grown again from crops.”
She continues, “We started by looking at limonene, a waste product derived from orange peels, which is currently used in cleaning products. Then, we considered other types of materials that were available in even larger quantities. We were trying to find something that could match the scale of the mountains of sulphur just sitting around the world.”
Eventually, the team at Flinders landed on canola oil (even used cooking oil), which when added to sulphur and heated together, forms a new material with a host of properties. The team has spent more than five years of research in this area, developing the product, and investigating its suitability for a number of applications. So far it’s been found to immobilise mercury into its safest form, cinnabar, enabling its use in mercury remediation; it can also be used to create a slow-release fertiliser. Louisa adds, “The material is also quite hydrophobic. It doesn’t like water, but likes fats, and we have found it’s effective at taking oil out of water, so we could use this to treat oil spills.” She continues, “We are also investigating recycling and repurposing these sulphur-based polymers as well as their biodegradability. We feel that they have the potential to be an alternative to non-biodegradable plastic materials.”
“It’s basically a powder, which can be put into all sorts of casings. We can cut it into different shapes as well. It’s a spongy material that can be ground up,” she explains. Kevin Fell, the group CEO of Clean Earth Technologies—a Singapore-incorporated company building solutions to create a more sustainable planet, which has been collaborating with Flinders for the past year—chimes in, “You could sprinkle it into a bag-type format, or use it as a filter, and we can dispose of it quite easily.” It doesn’t take long for the material to work its magic either.
This revolutionary innovation will help with Clean Earth Technologies’ development of greener gold mining practices, especially in the artisanal industry which produces about “15% to 25% of the world’s gold,” says Louisa. “This sector is also responsible for over a third of the world’s mercury emissions.” One commonly used procedure sees the burning of mercury to release the gold, despite the detrimental effects of this toxic practice. With this new sulphur-based polymer, we should be able to safely extract and remove the mercury without harming the environment or the people and communities at risk of being infected by toxic mercury fumes.
“There are quite a number of areas that we can look into for environmental clean-up and remediation purposes, but we’re focusing on getting a few things out first, before we expand from there,” says Louisa. For now, Clean Earth Technologies is concentrating on oil spills, mercury remediation and artisanal gold for the first half of 2020. Kevin elaborates, “By the second quarter of 2020, we’ll probably be collaborating with industry bodies around oil spill remediation through the necessary environmental or government agencies, and we’ll be in the Indaba Conference in February in South Africa, the world’s biggest congregation of gold miners.”