Cleaning up oil spills and metal contaminants
in a low-impact, sustainable and inexpensive manner remains a challenge for
companies and governments globally. But a group of researchers at UW—Madison is
examining alternative materials that can be modified to absorb oil and
chemicals. If further developed, the technology may offer a cheaper and
“greener” method to absorb oil and heavy metals from water and other surfaces.
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Shaoqin “Sarah” Gong, a researcher
at the Wisconsin Institute for Discovery (WID) and associate professor of
biomedical engineering, graduate student Qifeng Zheng, and Zhiyong Cai, a
project leader at the USDA Forest Products Laboratory in Madison, have recently
created and patented the new aerogel technology.
Aerogels, which are highly porous
materials and the lightest solids in existence, are already used in a variety
of applications, ranging from insulation and aerospace materials to thickening
agents in paints. The aerogel prepared in Gong’s lab is made of cellulose
nanofibrils (sustainable wood-based materials) and an environmentally friendly
polymer. Furthermore, these cellulose-based aerogels are made using an
environmentally friendly freeze-drying process without the use of organic solvents.
It’s the combination of this
“greener” material and its high performance that got Gong’s attention.
“For this material, one unique
property is that it has superior absorbing ability for organic solvents — up to
nearly 100 times its own weight,” she says. “It also has strong absorbing
ability for metal ions.”
Treating the cellulose-based
aerogel with specific types of silane after it is made through 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,” she says. “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 reused for a couple of
cycles.”
In addition, this cellulose-based
aerogel exhibits excellent flexibility as demonstrated by compression
mechanical testing.
Though much work needs to be done
before 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,” she says. “We are passionate to develop technology to make a
positive societal impact.”
Gong and her colleagues have
featured their findings in the Journal of Materials Chemistry A.
Read more at the University of Wisconsin-Madison.
Aerogel image via UWM.