Novel sponge to clear oil spills effectively

A highly effective mechanical sponge can clear oil spills using foams with interconnected open porous structures through which water can flow easily, scientists say.
The traditional method of clearing an oil spill, containing it with the use of booms and then 'sucking' the oil from the surface of the water, looks set to be replaced with polyurethane foams that can sponge the oil directly out of the water.
The new study shows that with highly interconnected open porous structures, and pore sizes below 500 micrometres, it is possible to reach absorption capacities as high as 30 grammes of oil per gramme of polyurethane.

"We wanted to understand what the key features of such foams are, and how they can affect their performance," said Javier Pinto, from the Istituto Italiano di Technologia (IIT) in Italy.
"Particularly whether it was necessary to modify the surface chemistry, or if you could reach really good performance by simply choosing foams with the right structural parameters," Pinto said.
Chemical functionalisation of the porous structure did not appear to enhance the oil absorption efficiency, but did significantly contribute to the selectivity of the process.

"It came as a surprise that there is an absence of considerations of the structure or even characterisation of the foams employed in several previous studies," said Pinto.

"Understanding this is key to evaluating proposed treatments and coatings, and their effectiveness," he said.
Pinto believes that due to the simplicity of the polyurethane foam they propose, commercialisation of the materials for oil spill remediation could happen very soon.
"Our next steps are to develop composite materials for wider water remediation," said Pinto.
"These could be low environmental impact - using materials derived from waste - and have biodegradable or biocompatible properties," he said.
"We'll explore the use of these systems not only for clearing oil spills, but also other contaminants such as heavy metals or pesticides," he said.

The study was published in the Journal of Physics D: Applied Physics.