Navigation Links
Graphene oxide gets green
Date:7/22/2010

"We can make you and we can break you." If Rice University scientists wrote country songs, their ode to graphene oxide would start something like that. But this song wouldn't break anybody's heart.

A new paper from the lab of Rice chemist James Tour demonstrates an environmentally friendly way to make bulk quantities of graphene oxide (GO), an insulating version of single-atom-thick graphene expected to find use in all kinds of material and electronic applications.

A second paper from Tour and Andreas Lttge, a Rice professor of Earth science and chemistry, shows how GO is broken down by common bacteria that leave behind only harmless, natural graphite.

The one-two punch appears online this week in the journal ACS Nano.

"These are the pillars that make graphene oxide production practical," said Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. The GO manufacturing process was developed as part of a research project with M-I SWACO, a Houston-based producer of drilling fluids for the petrochemical industry that hopes to use graphene to improve the productivity of wells. (Read about that here.)

Scientists have been making GO since the 19th century, but the new process eliminates a significant stumbling block to bulk production, Tour said. "People were using potassium chlorate or sodium nitrates that release toxic gases one of which, chlorine dioxide, is explosive," he said. "Manufacturers are always reluctant to go to a large scale with any process that generates explosive intermediates."

Tour and his colleagues used a process similar to the one they employed to unzip multiwalled nanotubes into graphene nanoribbons, as described in a Nature paper last year. They process flakes of graphite pencil lead with potassium permanganate, sulfuric acid and phosphoric acid, all common, inexpensive chemicals.

"Many companies have started to make graphene and graphene oxide, and I think they're going to be very hard pressed to come up with a cheaper procedure that's this efficient and as safe and environmentally friendly," Tour said.

The researchers suggested the water-soluble product could find use in polymers, ceramics and metals, as thin films for electronics, as drug-delivery devices and for hydrogen storage, as well as for oil and gas recovery.

Though GO is a natural insulator, it could be chemically reduced to a conductor or semiconductor, though not without defects, Tour said.

With so many potential paths into the environment, the fate of GO nanomaterials concerned Tour, who sought the advice of Rice colleague Lttge.

Lttge and Everett Salas, a postdoctoral researcher in his lab and primary author of the second paper, had already been studying the effects of bacteria on carbon, so it was simple to shift their attention to GO. They found bacteria from the genus Shewanella easily convert GO to harmless graphene. The graphene then stacks itself into graphite.

"That's a big plus for green nano, because these ubiquitous bacteria are quickly converting GO into an environmentally benign mineral," Tour said.

Essentially, Salas said, Shewanella have figured out how to "breathe" solid metal oxides. "These bacteria have turned themselves inside out. When we breathe oxygen, the reactions happen inside our cells. These microbes have taken those components and put them on the outside of their cells."

It is this capability that allows them to reduce GO to graphene. "It's a mechanism we don't understand completely because we didn't know it was possible until a few months ago," he said of the process as it relates to GO.

The best news of all, Lttge said, is that these metal-reducing bacteria "are found pretty much everywhere, so there will be no need to 'inoculate' the environment with them," he said. "These bacteria have been isolated from every imaginable environment lakes, the sea floor, river mud, the open ocean, oil brines and even uranium mines."

He said the microbes also turn iron, chromium, uranium and arsenic compounds into "mostly benign" minerals. "Because of this, they're playing a major role in efforts to develop bacteria-based bioremediation technologies."

Lttge expects the discovery will lead to other practical technologies. His lab is investigating the interaction between bacteria and graphite electrodes to develop microbe-powered fuel cells, in collaboration with the Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative (MURI).


'/>"/>

Contact: David Ruth
druth@rice.edu
713-348-6327
Rice University
Source:Eurekalert

Related biology news :

1. Rice researchers make graphene hybrid
2. 24-carat gold snowflakes improve graphenes electrical properties
3. Engineers develop method to disperse chemically modified graphene in organic solvents
4. Warmer climate entails increased release of carbon dioxide by inland lakes
5. Global model confirms: Cool roofs can offset carbon dioxide emissions and mitigate global warming
6. Solid oxide fuel cells getting closer to the market
7. In elevated carbon dioxide, soybeans stumble but cheatgrass keeps on truckin
8. Storing carbon dioxide deep underground in rock form
9. Study: Carbon monoxide exposure can be reduced during routine anesthesia in kids
10. Grape news: New treatment combination safe alternative to sulfur dioxide
11. E20 fuel reduces carbon monoxide and hydrocarbon emissions in automobiles
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/7/2016)... -- Syngrafii Inc. and San Antonio Credit Union (SACU) ... Syngrafii,s patented LongPen™ eSignature "Wet" solution into SACU,s ... in greater convenience for SACU members and operational ... document workflow and compliance requirements. Logo ... Highlights: ...
(Date:6/1/2016)... Favorable Government Initiatives Coupled With ... Identification to Boost Global Biometrics System Market Through 2021  ... report, " Global Biometrics Market By Type, By ... 2011 - 2021", the global biometrics market is projected ... of growing security concerns across various end use sectors ...
(Date:5/9/2016)... UAE, May 9, 2016 Elevay ... comes to expanding freedom for high net worth professionals ... in today,s globally connected world, there is still no ... could ever duplicate sealing your deal with a firm ... passports by taking advantage of citizenship via investment programs ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... N.C. (PRWEB) , ... June 27, 2016 , ... ... commercial operations for Amgen, will join the faculty of the University of ... as adjunct professor of strategy and entrepreneurship at UNC Kenan-Flagler, with a focus ...
(Date:6/24/2016)... DIEGO , June 24, 2016 ... more sensitively detects cancers susceptible to PARP inhibitors ... circulating tumor cells (CTCs). The new test has ... HRD-targeted therapeutics in multiple cancer types. ... targeting DNA damage response pathways, including PARP, ATM, ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS ... the launch of their brand, UP4™ Probiotics, into Target stores nationwide. The company, ... proud to add Target to its list of well-respected retailers. This list includes ...
(Date:6/23/2016)... , June 23, 2016 Houston Methodist ... the Cy-Fair Sports Association to serve as their ... agreement, Houston Methodist Willowbrook will provide sponsorship support, ... connectivity with association coaches, volunteers, athletes and families. ... the Cy-Fair Sports Association and to bring Houston ...
Breaking Biology Technology: