Super-absorbent aerogel developed for oil spills

Aerogels could offer a sustainable and inexpensive way to clean up oil spills and heavy metal contaminants from water and other surfaces, researchers from the University of Wisconsin-Madison say. The materials could be modified to absorb oil and chemicals without absorbing water.

Aerogels are highly porous materials and are the lightest solids in existence. They are used in a range of applications, from insulation and aerospace materials to thickening agents in paints.

Researchers from the Wisconsin Institute for Discovery (WID) have developed an aerogel made of cellulose nanofibrils (sustainable wood-based materials) and an environmentally friendly polymer. The aerogel is made using an environmentally friendly freeze-drying process without the use of organic solvents.

“For this material, one unique property is that it has superior absorbing quality for organic solvents - up to nearly 100 times its own weight,” said Shaoqin Gong, a researcher at WID and associate professor of biomedical engineering. “It also has a strong absorbing ability for metal ions.”

Treating the cellulose-based aerogel with specific types of silane after it is made using the freeze-drying process is a key step that gives the aerogel its water-repelling and oil-absorbing properties.

“So if you had an oil spill, for example, the idea is you could throw this aerogel sheet in the water and it would start to absorb the oil very quickly and efficiently. Once it’s fully saturated, you can take it out and squeeze out all the oil. Although its absorbing capacity reduces after each use, it can be re-used for a couple of cycles,” said Gong.

In addition, the aerogel exhibits excellent flexibility as demonstrated by compression mechanical testing.

Although Gong’s team still has a long way to go until the aerogel can be mass produced, Gong says she’s eager to share the technology’s potential benefits beyond the scientific community.

“We are living in a time where pollution is a serious problem - especially for human health and for animals in the ocean. We are passionate about developing technology to make a positive societal impact,” Gong said.