Green mango peel: A slick solution for oil-contaminated soils

For the petroleum industry remediating oil sludge is a costly and an ongoing challenge, particularly when 3-7 per cent of oil processing activities are irreversibly lost as oily or sludge waste.

Lead researcher, UniSA's Dr Biruck Desalegn says without treatment oil contaminated soil presents a massive risk to ecosystems and the environment.

"Last year, global oil production reached a new record of 92.6 million barrels per day, but despite improvements in control technologies, oil refineries unavoidably continue to generate large volumes of oil sludge," Dr Desalegn says.

"Oil contamination can present cytotoxic, mutagenic and potentially carcinogenic conditions for all living things, including people."

"What's more, the toxicity and physical properties of oil change over time, which means the process of weathering can expose new, and evolved toxins."

The new nanoparticles, synthesized from green mango peel extract and iron chloride, provide a novel and effective treatment for oil contaminated soil. They work by breaking down toxins in oil sludge through chemical oxidation, leaving behind only the decontaminated materials and dissolved iron.

Dr Desalegn says the new plant-based nanoparticles can successfully decontaminate oil-polluted soil, removing more than 90 per cent of toxins.

"Plant extracts are increasingly used to create nanomaterials," Dr Desalegn says.

"In this study, we experimented with mango peel to create zerovalent iron nanoparticles which have the ability to breakdown various organic contaminants.

"With mango peel being such a rich source of bioactive compounds, it made sense that zerovalent iron made from mango peel might be more potent in the oxidation process.

"As we discovered, the mango peel iron nanoparticles worked extremely well, even outperforming a chemically synthesized counterpart by removing more of contaminants in the oil sludge."

Dr Desalegn says this discovery presents a sustainable, green solution to address the significant pollution generated by the world's oil production.

"Ever since the devastation of the 2010 Deepwater Horizon oil spill, the petroleum industry has been acutely aware of their responsibilities for safe and sustainable production processes," Dr Desalegn says.

"Our research uses the waste part of the mango -- the peel -- to present an affordable, sustainable and environmentally friendly treatment solution for oil sludge.

"And while the world continues to be economically and politically reliant on oil industries as a source of energy working to remediate the impact of oil pollution will remain a serious and persistent issue."

This research was conducted as part of Dr Desalegn's PhD with support from CRC CARE.