Do not look down on sawdust. Scientists have recruited it in the fight against the massive problem of oil spills in the Arctic.
A team of researchers have succeeded in chemically modifying sawdust to make it particularly oil-attracting and buoyant, with the aim of using it to clean up oil spills in the Arctic. The resultant material has the ability to absorb up to five times its weight in oil and can stay afloat for at least four months.
George Bonheyo, a microbiologist at the Department of Energy's Pacific Northwest National Laboratory (PNNL) explained that most of the current oil remediation materials have been designed for warm water use. However, he added that “as ice retreats in the Arctic Sea, fossil fuel developers are looking north, and we need new oil spill response methods that perform well in extreme conditions.”
“The chance of an oil spill in the Arctic is real. We hope materials like our modified sawdust can help if an accident happens,” said fellow PNNL microbiologist Robert Jeters.
Containing oil spills in the cold waters of the Arctic won't be easy. Bobbing ice chunks would push oil below the surface, making it hard to collect. And if the waters were choppy, the waves would disperse the oil.
Bonheyo and his team wanted to develop an environmentally friendly and inexpensive material that floated in rough or freezing waters, with the ability to support controlled burns. Called in-situ burning, controlled burns were important so that if weather or tides move the spilled oil to a sensitive area, the oil can be burnt to reduce the amount of oil in the water and to minimise the adverse environmental effects.
The researchers had considered other natural ingredients like rice hulls and silica so as not to create more pollution. Ultimately, they found the most ideal material: a fine dust called wood flour. A woodworking byproduct, it is often used to make wood composites.
The researchers then chemically attached components of vegetable oil onto the material's surface. These attachments made the modified material oil-grabbing and water-shunning. The final product was a light, fluffy, bleached powder.
To use it, a thin layer is sprinkled over the oil on the water surface. The powder immediately starts absorbing the oil, becoming a concentrated solid slick that stays afloat. It can then be burnt or recovered for proper disposal.
In addition, the team is also trying out adding tiny, oil-eating microbes—fungi and bacteria—to the powder's surface so that any material that has been left behind could naturally break down over time.
They are also evaluating the material in icy waters, at PNNL's Arctic simulation lab in Sequim, Washington. So far, the tests have shown that the material's water-repellent nature prevents ice from forming on it, so it can soak up the oil and remain at the surface.