Turning greenhouse gases into something useful at U of T

lanthierj — Tue, 11 Apr 2017 17:48:23 +0000

lanthierj Tue, 04/11/2017 - 13:48

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Alexander Ip and his U of T research team, led by Professor Ted Sargent, will receive nearly $1 million from the Ontario government for the semi-final round of the Carbon XPRIZE competition (photo by Kevin Soobrian)

Chris Sorensen

Author legacy

Chris Sorensen

Topic

Breaking Research

Innovation

Entrepreneurship

Greenhouse Gas

Oil Sands

Carbon

Subheadline

Ontario supports U of T researchers competing for Carbon XPRIZE

�ؿ�ζSM researchers are set to receive nearly $1 million from the Ontario government as they compete in the semi-final round of a $20 million global contest that looks for ways to turn harmful greenhouse gases into useful products like fuels and fertilizers.

The province recently said the team of over 15 multidisciplinary researchers, known as Carbon Electrocatalytic Recycling Toronto or CERT, will receive $833,000 to support the development and demonstration of its concept during the NRG COSIA Carbon XPRIZE competition, which boasts $20 million worth of prizes.

The U of T team’s technology transforms carbon dioxide (CO₂) into formic acid, a colourless liquid commonly used to tan leather or as a preservative for livestock feed.

“We’re excited to see the province supporting U of T’s Carbon Electrocatalytic Recycling Toronto as it competes in the prestigious XPRIZE competition,” said Vivek Goel, U of T’s vice-president of research and innovation. “This funding will help CERT in this clean-tech research that will have meaningful impact on environmental sustainability.”

U of T research could help sponge up oil sands wastewater

ullahnor — Tue, 28 Feb 2017 21:23:44 +0000

U of T research could help sponge up oil sands wastewater

ullahnor Tue, 02/28/2017 - 16:23

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U of T PhD candidate Pavani Cherukupally uses ordinary sponges to remove droplets of oil or other contaminants dispersed in water. Her technology could help remediate oil sands wastewater (photo by Kevin Soobrian)

Tyler Irving

Author legacy

Tyler Irving

Topic

Breaking Research

Environment

Oil Sands

Faculty of Applied Science & Engineering

In theory, oil and water don’t mix. In reality, the two liquids can be almost impossible to separate, especially from complex chemical cocktails such as the wastewater produced by Alberta’s oil sands mining operations.

Contaminated by small amounts of bitumen and other oily substances, this wastewater can’t be discharged to the environment and is held in vast ponds awaiting treatment. A new potential solution developed by researchers at U of T's Faculty of Applied Science & Engineering starts with a surprisingly simple device: a sponge.

U of T PhD student Pavani Cherukupally leads the project under the supervision of Professor Chul Park and Assistant Professor Amy Bilton. Previous work in Park’s lab focused on designing sponges that could be deployed to soak up oil in the event of a spill – these were made of superhydrophobic materials, which repel water but attract neutrally charged substances like oil.

Cherukupally is modifying the process to treat oil sands wastewater. Her idea is to pump the contaminated water through the sponges: due to attractive forces, the oily contaminants should stick to the surface of the sponge, while the clean water should flow straight through.

Using an ordinary polyurethane sponge, Pavani Cherukupally has been able to reduce the amount of oil contamination in water from 8,000 parts per million down to 54 (photo by Kevin Soobrian)

But when Cherukupally tried this with the superhydrophobic sponges, it didn’t work at all.

“The water stayed just as dirty as it was,” she says.

Drawing on her background in physical chemistry, Cherukupally realized that the problem was that oil in wastewater behaves very differently than in an oil spill. Oil in wastewater is dispersed into tiny droplets rather than forming a cohesive slick. Each of these droplets is surrounded by a layer of charged particles, which means that they will be attracted to charged surfaces, not neutral ones.

Cherukupally ditched her neutral, superhydrophobic foams for ordinary polyurethane foam, similar to the type found in couch cushions. When she did, her sponge system removed more than 99 per cent of the suspended oil.

“The slight positive charge on the polyurethane attracts the slight negative charge on the suspended oil droplets,” says Cherukupally. “As well, the pore size is small enough to provide a large surface area, but not so small that the sponge gets clogged with debris.”

“We’ve been both surprised and impressed by the results that Pavani has achieved so far,” says Park. “Her expertise in surface chemistry and physics led us in a new direction that we wouldn’t otherwise have tried.”

Now, Cherukupally is experimenting with ways of coating the sponge to modify its surface chemistry and adjust its performance to a wider range of situations. In collaboration with U of T researchers Wei Sun and Annabelle Wong, who are supervised by Professor Geoffrey Ozin, Cherukupally has created foams that have both charged and neutral areas on their surface.

When tested with oil sands wastewater, these “hybrid” sponges had an overall removal efficiency of 98 per cent, slightly less than regular polyurethane. However, their removal rate – the speed at which they suck up the pollutant particles – was six times faster.

“A faster uptake of contaminants will directly impact the operational energy costs as well as the overall cost-effectiveness of the final system,” says Bilton. “To get things ready for scale-up, we’ll need to perform some systematic experiments to evaluate how this new foam works as part of the treatment process.”

Cherukupally was inspired to work in water treatment by witnessing the slow, gradual pollution of the Musi river in her home city of Hyderabad, India.

“Nobody knew how to clean the water, and a lot of my classmates got sick,” she says. “When this project was proposed to me, I thought: ‘This is what I should be doing.’”

Oil Sands

Turning greenhouse gases into something useful at U of T

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U of T research could help sponge up oil sands wastewater