An oily solution

Researchers at Adelaide’s Flinders University have discovered a new product to quickly remediate oil spills – made entirely from waste products.

On 20 April, 2010, the oil drilling rig Deepwater Horizon, working in the Macondo Prospect in the Gulf of Mexico, exploded and sank, causing the largest oil spill in the history of marine oil drilling operations.

Four million barrels of oil emerged from the damaged Macondo over an 87-day period before the damage was reined in. Oil spills such as in the Macondo are all too common and can have devastating impacts on the environment and marine life. According to the International Tanker Owners Pollution Federal, around 7000 tonnes of crude oil spilled from tankers into oceans in 2017.

Spills can take anywhere from weeks to years to clean up and depend on a range of factors, including the type of oil spilled, the temperature of the water and the types of shorelines involved.

It’s why a team of researchers at Flinders University have looked at a more cost effective and sustainable way of doing things. Dr Justin Chalker, Senior Lecturer in Synthetic Chemistry at Flinders University in Adelaide, led an international research team which recently discovered a new way to soak up crude oil with an absorbent polymer – made entirely from waste products from the petroleum and refining industries.

The project was funded by a range of sources, including Flinders University, the federal government’s National Environmental Science Program emerging priorities funding, the Foundation for Science and Technology Portugal, the Royal Society University Research Fellowship, the Engineering and Physical Sciences Research Council and the European Research Council starting grant.

The absorbent polymer, made from waste cooking oil and sulphur, was found to be able to clean up crude oil and diesel spills. It acts similar to a sponge to absorb the waste materials from sea water and can be squeezed to recover the oil for reuse. The polymer is buoyant, so it will not sink to the bottom of the ocean. It aggregates so that when the water comes into contact with the polymer, the polymer forms a gel that can be easily scooped out. It can be added directly to a spill or packed through a filter to pass the oil water mixtures through and discharge the remaining water into the supply. The discovery was made six months ago and requires field trials before it can be commercialised, but could be available by the end of this year.

Justin tells Waste Management Review that there are a range of commercial sorbents on the market, from polypropylene fibres to polyurethane foams, effective at removing oil from water, but these come with added operational costs, including deploying sea vessels to take them to the site.

“In contrast to those sorbents, our materials are comparable in the   amount of oil they can take up. Our polymer is elastic like a sponge and the oil can be recovered more readily than you can with many of the other skimming technologies,” Justin says.

He says an influx of petroleum feedstock with no end destination makes the concept a valuable business proposition. While the clean-up depends on economies of scale, Justin says the raw materials are virtually free. He says it should be easy for industries to source used cooking oil as it is primarily used in the production of biodiesel.

“Sulphur is stockpiled across the globe because the petroleum industry rightfully de-sulphurises crude oil when they refine it so we don’t make acid rain. The problem is, you have millions of tonnes of aboveground deposits of sulphur and not much to do with it.

“In contrast, the other commercial sorbents are mostly prepared from non-sustainable petroleum feedstocks. Sulphur is a petroleum feedstock but there aren’t a lot of uses for it currently, so this study is also important for managing chemical lifecycles.”

He says it could be deployed in nations that lack the remediation resources, including in the Niger Delta in Nigeria and Amazon basin in Ecuador, suffering from active spills that have remained unclean for years.

“Our polymer is also non-toxic. We’ve done toxicity studies, which is important if you’re going to use the polymer in open water or even in ports on some small scale manual clean ups, so you want to make sure you’re not putting anything in the water that is going to cause harm.”

Justin adds that surfactants, another cleaning agent, may conversely have toxic ecological effects as the oil breaks up into tiny droplets and is degraded biologically.

“The fact that our polymer works on contact is very promising for mitigating damage quickly,” he says.

“The next steps are to test this in the field and in parallel to that, we’ll be working on establishing a pilot plant in South Australia so we can make the quantities required to be a serious competitor in oil spill remediation.”