Tag Archives: Wade Adams

Decontamination of carbon nanotubes by microwave ovens

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The lowly microwave oven plays a starring role in this tale of carbon nanotube purification. From a Jan. 22, 2016 news item on phys.org,

Amid all the fancy equipment found in a typical nanomaterials lab, one of the most useful may turn out to be the humble microwave oven.

A standard kitchen microwave proved effective as part of a two-step process invented at Rice [US] and Swansea [UK] universities to clean carbon nanotubes.

Basic [carbon] nanotubes are good for many things, like forming into microelectronic components or electrically conductive fibers and composites; for more sensitive uses like drug delivery and solar panels, they need to be as pristine as possible.

A Jan. 22, 2016 Rice University news release (also on EurekAlert), which originated the news item, describes the problem the researchers were solving and how they did it,

[Carbon] Nanotubes form from metal catalysts in the presence of heated gas, but residues of those catalysts (usually iron) sometimes remain stuck on and inside the tubes. The catalyst remnants can be difficult to remove by physical or chemical means because the same carbon-laden gas used to make the tubes lets carbon atoms form encapsulating layers around the remaining iron, reducing the ability to remove it during purification.

In the new process, treating the tubes in open air in a microwave burns off the amorphous carbon. The nanotubes can then be treated with high-temperature chlorine to eliminate almost all of the extraneous particles.

…

The labs of chemists Robert Hauge, Andrew Barron and Charles Dunnill led the study. Barron is a professor at Rice in Houston and at Swansea University in the United Kingdom. Rice’s Hauge is a pioneer in nanotube growth techniques. Dunnill is a senior lecturer at the Energy Safety Research Institute at Swansea.

There are many ways to purify nanotubes, but at a cost, Barron said. “The chlorine method developed by Hauge has the advantage of not damaging the nanotubes, unlike other methods,” he said. “Unfortunately, many of the residual catalyst particles are surrounded by a carbon layer that stops the chlorine from reacting, and this is a problem for making high-purity carbon nanotubes.”

The researchers gathered microscope images and spectroscopy data on batches of single-walled and multiwalled nanotubes before and after microwaving them in a 1,000-watt oven, and again after bathing them in an oxidizing bath of chlorine gas under high heat and pressure. They found that once the iron particles were exposed to the microwave, it was much easier to get them to react with chlorine. The resulting volatile iron chloride was then removed.

Eliminating iron particles lodged inside large multiwalled nanotubes proved to be harder, but transmission electron microscope images showed their numbers, especially in single-walled tubes, to be greatly diminished.

“We would like to remove all the iron, but for many applications, residue within these tubes is less of an issue than if it were on the surface,” Barron said. “The presence of residual catalyst on the surface of carbon nanotubes can limit their use in biological or medical applications.”

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

Enhanced purification of carbon nanotubes by microwave and chlorine cleaning procedures by Virginia Gomez,   Silvia Irusta, Wade Adams, Robert H Hauge, Charles W Dunnill, and Andrew Ross Barron.  RSC Adv., 2016, DOI: 10.1039/C5RA24854J First published online 22 Jan 2016

I believe this paper is behind a paywall.

Alberta and Texas collaborate on nanotechnology and greenish energy; a meta analysis of public perceptions of nanotechnology risks; how scientists think

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The Premier of Alberta (Canada), Ed Stelmach, has signed a memorandum of understanding with Rice University (Texas, US) President, David Leebron, to collaborate through nanoAlberta (Alberta Advanced Education and Technology) and the Richard E. Smalley Institute for Nanoscale Science and Technology (Rice University). The two institutions will collaborate in the energy, environmental, medical,  agriculture, and forestry sectors. From the news item on Azonano,

Wade Adams, director of the Smalley Institute, said the interests of nanoAlberta and those of his team at Rice are perfectly aligned. “We want to help them figure out how to extract oil from their resources in a more environmentally friendly way, a more efficient way and one that will cause less damage to their own territory as well as provide oil for the needs of the human race, as they become a more important source of it.”

When I read the title for the item I thought they were referring to green or bio fuels but, as you can see from the quote, the intention is altogether different. From a pragmatic perspective, since we have to depend on fossil fuels for a while longer, it’s best if we can find more environmentally friendly ways to extract it while developing other renewable sources.

This reminds me of the recent invite I received from the Project on Emerging Nanotechnologies (PEN) for the Perverse Incentives: The Untold Story of Federal Subsidies for Fossil Fuels event held on Sept. 18, 2009. Unfortunately, the webcast isn’t available quite yet but I think that in light of this memorandum it could be interesting viewing and might provide a critical perspective on the initiative.

PEN is holding another somewhat related event on Tuesday, Sept. 29, 2009 at 12:30 pm EST, Nanotechnology, Synthetic Biology, and Biofuels: What does the public think? If you’re in Washington, DC, you can attend the event live but you should RSVP here, otherwise there’s a live webcast which is posted a few days later on their website.  (There’s a PEN event tomorrow, Sept. 23, 2009 at 12 pm to 2:30 pm EST, titled Transatlantic Regulatory Cooperation: Securing the Promise of Nanotechnologies. If you wish to attend the live event, you can RSVP using the link I’ve posted previously. If you’re interested in this event, in June I posted a more complete description of it here.)

One more Canadian development on the nanotechnology front, a meta analysis of 22 surveys on public perceptions of the risks and benefits of nanotechnology has been published at Nature Online as of Sept. 20, 2009. The article (lead author from the University of British Columbia, Canada)  is behind a paywall but you can read more about it in the news item on Nanowerk (from the news item),

Previous studies have found that new and unknown technologies such as biotechnology tend to be regarded as risky, but that’s not the case for nanotechnology, according to this research. People who thought nanotechnology had more benefits than risks outnumbered those who perceived greater risks by 3 to 1 in this study. The 44 percent of people who didn’t have an opinion either way surprised the researchers. “You don’t normally get that reluctance,” says Terre Satterfield of the University of British Columbia in Canada, lead author of the study and a collaborator with CNS-UCSB [Center for Nanotechnology in Society at the University of California, Santa Barbara].

In almost three years of scanning, I don’t think I’ve ever seen two announcements that both feature a Canadian nanotechnology development of sorts. This is a banner day!

Topping today off, I’m going to segue into How Scientists Think.  It’s a paper about how scientists creatively problem solve.  From the news item on Physorg.com,

Her [Dr. Nancy J. Nersessian] study of the working methods of scientists helps in understanding how class and instructional laboratory settings can be improved to foster creativity, and how new teaching methods can be developed based on this understanding. These methods will allow science students to master model-based reasoning approaches to problem solving and open the field to many more who do not think of themselves as traditional “scientists.”

I’ve been interested in how scientists think because I’ve been trying to understand why the communication with ‘non scientists’ can be so poor. To some extent I think it is cultural. After years of training in special skills and a special language, scientists are members of a unique occupational culture, which has given birth to many, many subcultures. People who are immersed in their own cultures don’t always realize that the rest of us may not understand what they’re saying very well. (Try reading art criticism if you don’t have an understanding of art history and critical theory.) That’s my short answer and, one of these days, I’m going to write a paper with my long answer.

I had every intention of writing another part of my science communication series today but I have a couple of projects to start or finish and these series postings take more time than I have to spare.