Global Challenges/Chemistry Solutions

Confronting Climate Change: Smoke to soak up future oil spills

August 14, 2009

Aerogels

Aerogels, a super-lightweight solid sometimes called “frozen smoke,” may capture oil from wastewater and soak up environmental oil spills.
Credit: Wikipedia Commons
(High-resolution version)

 Summary

Experts estimate that people dump more than 200 million
gallons of used oil each year into sewers, streams and backyards,
resulting in a problem that has plagued wastewater treatment
plants for decades. But an answer might be found in a material
sometimes referred to as “frozen smoke.”

Although internationally publicized oil spills like the Exxon Valdez incident highlight the importance of ecological protection and preservation, these disasters aren’t the only environmental challenges due to oil contamination. Complex problems also occur on a smaller-scale. For example, experts estimate that people dump more than 200 million gallons of used oil each year into sewers, streams, and backyards, resulting in a problem that has plagued wastewater treatment plants for decades.

But an answer might be found in a material sometimes referred to as “frozen smoke.” Super-lightweight solids, also known aerogels, could serve as the ultimate sponge for capturing oil from wastewater and effectively soaking up environmental oil spills. From Arizona State University, here is chemical engineer Robert Pfeffer:

“Aerogels are used mainly as an insulator and for architectural structures like roofs of swimming pools to keep heat in or out. However, they have another property and that is that they are very hydrophobic, which means they love organic molecules and repel water. So that gave me the idea of maybe we could use these aerogels to remove oil and other organic contaminants from wastewater.”

Although there are many different sorbent materials for removing used oil, they are often inefficient and expensive. Hydrophobic silica aerogels are highly porous and absorbent materials and seem like excellent sponges, said Pfeffer, who discusses the dire need for such technology:

“Oh, it’s extremely important because there are a lot of industries where
the water becomes contaminated with oil, machine tool industries petroleum industry, but that isn’t the worst of it. People change the oil in their car and then without thinking they just dump the oil into the sewer and it gets into the water system. So it is really a major problem.”

To test the product’s efficiency, Pfeffer and his team packed a batch of tiny aerogel beads into a vertical column and exposed them to flowing water containing soybean oil, simulating the filtration process at a wastewater treatment plant. They showed that the aerogel beads absorbed up to seven times their weight and efficiently removed oil from the wastewater.

“It’s a lot more effective that other sorbents that were being used to remove organic contaminants from water. There are a whole bunch of them that people have tried; for example, the most common is granulated activated carbon, but people have also used vermiculite, bentonite, organoclay, all sorts of other adsorbents, and the aerogels per unit weight are much more efficient and will remove much more for example oil than any of these materials that have been previously used.”

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check our full-length podcasts on stopgap Confronting Climate Change and permanent solutions Confronting Climate Change II to this daunting problem Today’s podcast was written by Michael Woods. I’m Adam Dylewski at the American Chemical Society in Washington.

Robert Pfeffer, Ph.D.
Robert Pfeffer, Ph.D.
Image courtesy of
New Jersey Institute
of Technology.