Tag Archives: Vikas Nandwana

Clean up oil spills with a smart sponge?

I love the part with the magnet,

All of the main points are made in the video but for those who like text, there’s a May 28, 2020 news item on phys.org describing this new smart sponge for cleaning up oil spills (Note: Links have been removed),

A Northwestern University-led [Chicago, Illinois, US] team has developed a highly porous smart sponge that selectively soaks up oil in water.

With an ability to absorb more than 30 times its weight in oil, the sponge could be used to inexpensively and efficiently clean up oil spills without harming marine life. After squeezing the oil out of the sponge, it can be reused many dozens of times without losing its effectiveness.

“Oil spills have devastating and immediate effects on the environment, human health and economy,” said Northwestern’s Vinayak Dravid, who led the research. “Although many spills are small and may not make the evening news, they are still profoundly invasive to the ecosystem and surrounding community. Our sponge can remediate these spills in a more economic, efficient and eco-friendly manner than any of the current state-of-the-art solutions.”

A May 28, 2020 Northwestern University news release (also on EurekAlert), which originated the news item, reveals (as did the video) the characteristics that make this smart sponge particularly interesting,

Oil spill clean-up is an expensive and complicated process that often harms marine life and further damages the environment. Currently used solutions include burning the oil, using chemical dispersants to breakdown oil into very small droplets, skimming oil floating on top of water and/or absorbing it with expensive, unrecyclable sorbents.

“Each approach has its own drawbacks and none are sustainable solutions,” Nandwana [Vikas Nandwana, a senior research associate in Dravid’s laboratory] said. “Burning increases carbon emissions and dispersants are terribly harmful for marine wildlife. Skimmers don’t work in rough waters or with thin layers of oil. And sorbents are not only expensive, but they generate a huge amount of physical waste — similar to the diaper landfill issue.”

The Northwestern solution bypasses these challenges by selectively absorbing oil and leaving clean water and unaffected marine life behind. The secret lies in a nanocomposite coating of magnetic nanostructures and a carbon-based substrate that is oleophilic (attracts oil), hydrophobic (resists water) and magnetic. The nanocomposite’s nanoporous 3D structure selectively interacts with and binds to the oil molecules, capturing and storing the oil until it is squeezed out. The magnetic nanostructures give the smart sponge two additional functionalities: controlled movement in the presence of an external magnetic field and desorption of adsorbed components, such as oil, in a simulated and remote manner.

The OHM (oleophilic hydrophobic magnetic) nanocomposite slurry can be used to coat any cheap, commercially available sponge. The researchers applied a thin coating of the slurry to the sponge, squeezed out the excess and let it dry. The sponge is quickly and easily converted into a smart sponge (or “OHM sponge”) with a selective affinity for oil.

Vinayak and his team tested the OHM sponge with many different types of crude oils of varying density and viscosity. The OHM sponge consistently absorbed up to 30 times its weight in oil, leaving the water behind. To mimic natural waves, researchers put the OHM sponge on a shaker submerged in water. Even after vigorous shaking, the sponge release less than 1% of its absorbed oil back into the water.

“Our sponge works effectively in diverse and extreme aquatic conditions that have different pH and salinity levels,” Dravid said. “We believe we can address a giga-ton problem with a nanoscale solution.”

“We are excited to introduce such smart sponges as an environmental remediation platform for selectively removing and recovering pollutants present in water, soil and air, such as excess nutrients, heavy metal contaminants, VOC/toxins and others,” Nandwana said. “The nanostructure coating can be tailored to selectively adsorb (and later desorb) these pollutants.”

The team also is working on another grade of OHM sponge that can selectively absorb (and later recover) excess dissolved nutrients, such as phosphates, from fertilizer runoff and agricultural pollution. Stephanie Ribet, a Ph.D. candidate in Dravid’s lab and paper coauthor is pursuing this topic. The team plans to develop and commercialize OHM technology for environmental clean-up.

Bravo to professor Vinayak Dravid and his team. I’m sure I’m not alone in wishing you and your team the best of luck as you continue to develop this remediation technology.

Here’s a link to and a citation for the paper,

OHM Sponge: A Versatile, Efficient, and Ecofriendly Environmental Remediation Platform by Vikas Nandwana, Stephanie M. Ribet, Roberto D. Reis, Yuyao Kuang, Yash More, and Vinayak P. Dravid. Ind. Eng. Chem. Res. 2020, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.iecr.0c01493 Publication Date:May 12, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Vote for favourite EnvisioNano image ’til June 17, 2016

A June 6, 2016 news item on Nanowerk announces the latest and last voting round of the semifinal judging for the 2016 EnvisioNano contest,

Members of the public are invited to vote for the best images in this round of the National Nanotechnology Initiative (NNI) EnvisioNano contest.

Now in its third round, this contest has drawn submissions from students at top labs and schools across the United States.

This round includes images such as this one (from the 3rd voting round of the EnvisioNano page),

Iron Honeycomb: Hexagonal close-packed assembly of iron oxide nanoparticles Credits: Vikas Nandwana Advisor: Vinayak Dravid Department of Materials Science and Engineering Northwestern University

Iron Honeycomb: Hexagonal close-packed assembly of iron oxide nanoparticles Credits: Vikas Nandwana Advisor: Vinayak Dravid Department of Materials Science and Engineering Northwestern University

Nandwana also provides this description of his image,

Description: The particles shown here are made of iron oxide, or rust – just like on a car. But these nanoparticles are tiny, 100,000 times thinner than a sheet of paper. At such a small size, they demonstrate some unique properties that can be used to detect and treat diseases like cancer by just applying external magnetic field without any side effects. Due to the same size and shape, the magnetic nanoparticles self-assemble (or come together) into a closely-packed honeycomb pattern.  Iron oxide nanoparticles like these are already used to help people suffering from iron deficiency (anemia). Researchers study how these magnetic nanoparticles interact with each other and tissues in the body, which can open new avenues for nontoxic, targeted tests and treatments for cancer, Alzheimer’s and cardiovascular disease.
Laboratory website: http://vpd.ms.northwestern.edu/
Technique: Transmission Electron Microscopy
Funding Source: NTU-NU Institute for NanoMedicine located at the International Institute for Nanotechnology, Northwestern University, USA and the Nanyang Technological University, Singapore.

A June 6, 2016 US National Nanotechnology Initiative news release, which originated the news item, gives more details,

In the first two rounds of the EnvisioNano contest, student images racked up over 41,000 online views and both previous winning images were featured on the back cover of the NNI Supplement to the President’s 2017 Budget! We encourage everyone to cast votes for their favorite images. All students have provided a description of their photos and research, allowing the viewer to envision where the research is headed and to learn how seeing at the nanoscale is important to reaching that vision. So, as you view the pictures, take a moment to learn about the research and how nanotechnology may improve your life.

Voting starts Monday, June 6th, and is open until June 17th [2016].
View the images and cast your vote at: www.nano.gov/EnvisioNanoVoting.

Once this voting round is completed, judges from the NNI will select the final winning image.

There are a few more details about the contest on this Envisio Nano page. It may be of interest to note that voting ends at 12 pm (noon) on June 17, 2016.

2015 winners were featured (as mentioned earlier) on the cover of the 2017 NNI budget supplement. I wrote about the supplement and embedded images of the cover in my April 4, 2016 posting.