Nanotube 'sponge' has potential in oil spill cleanupMay 11, 2012
Carbon nanotubes, which consist of atom-thick sheets of carbon rolled into cylinders, have captured scientific attention in recent decades because of their high strength, potential high conductivity and light weight. But producing nanotubes in bulk for specialized applications was often limited by difficulties in controlling the growth process as well as dispersing and sorting the produced nanotubes.
ORNL's Bobby Sumpter was part of a multi-institutional research team that set out to grow large clumps of nanotubes by selectively substituting boron atoms into the otherwise pure carbon lattice. Sumpter and Vincent Meunier, now of Rensselaer Polytechnic Institute, conducted simulations on supercomputers, including Jaguar at ORNL's Leadership Computing Facility, to understand how the addition of boron would affect the carbon nanotube structure.
"Any time you put a different atom inside the hexagonal carbon lattice, which is a chicken wire-like network, you disrupt that network because those atoms don't necessarily want to be part of the chicken wire structure," Sumpter said. "Boron has a different number of valence electrons, which results in curvature changes that trigger a different type of growth."
Simulations and lab experiments showed that the addition of boron atoms encouraged the formation of so-called "elbow" junctions that help the nanotubes grow into a 3-D network. The team's results are published in Nature Scientific Reports.
"Instead of a forest of straight tubes, you create an interconnected, woven sponge-like material," Sumpter said. "Because it is interconnected, it becomes three-dimensionally strong, instead of only one-dimensionally strong along the tube axis."
Further experiments showed the team's material, which is visible to the human eye, is extremely efficient at absorbing oil in contaminated seawater because it attracts oil and repels water.
"It loves carbon because it is primarily carbon," Sumpter said. "Depending on the density of oil to water content and the density of the sponge network, it will absorb up to 100 times its weight in oil."
The material's mechanical flexibility, magnetic properties, and strength lend it additional appeal as a potential technology to aid in oil spill cleanup, Sumpter says.
"You can reuse the material over and over again because it's so robust," he said. "Burning it does not substantially decrease its ability to absorb oil, and squeezing it like a sponge doesn't damage it either."
The material's magnetic properties, caused by the team's use of an iron catalyst during the nanotube growth process, means it can be easily controlled or removed with a magnet in an oil cleanup scenario. This ability is an improvement over existing substances used in oil removal, which are often left behind after cleanup and can degrade the environment.
The experimental team has submitted a patent application on the technology through Rice University. The research is published as "Covalently bonded three-dimensional carbon nanotube solids via boron induced nanojunctions," and is available online here: http://www.nature.com/srep/2012/120413/srep00363/full/srep00363.html.
The research team included researchers from ORNL, Rice University; Universidade de Vigo, Spain; Rensselaer Polytechnic Institute; University of Illinois at Urbana-Champaign; Instituto de Microelectronica de Madrid, Spain; Air Force Office of Scientific Research Laboratory; Arizona State University; Universite Catholique de Louvain, Belgium; The Pennsylvania State University; and Shinshu University, Japan.
The work was supported by the National Science Foundation, the U.S. Air Force Office of Scientific Research, the U.S. Army Research Laboratory, and by the DOE Office of Science through ORNL's Center for Nanophase Materials Sciences (CNMS) and the laboratory's Leadership Computing Facility.
CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov
Oak Ridge National Laboratory
Related Carbon Nanotube Current Events and Carbon Nanotube News Articles
Carbon nanotube finding could lead to flexible electronics with longer battery life
University of Wisconsin-Madison materials engineers have made a significant leap toward creating higher-performance electronics with improved battery life -- and the ability to flex and stretch.
Nanotubes May Restore Sight to Blind Retinas
The aging process affects everything from cardiovascular function to memory to sexuality. Most worrisome for many, however, is the potential loss of eyesight due to retinal degeneration.
Better bomb-sniffing technology
University of Utah engineers have developed a new type of carbon nanotube material for handheld sensors that will be quicker and better at sniffing out explosives, deadly gases and illegal drugs.
Tiny carbon nanotube pores make big impact
A team led by the Lawrence Livermore scientists has created a new kind of ion channel based on short carbon nanotubes, which can be inserted into synthetic bilayers and live cell membranes to form tiny pores that transport water, protons, small ions and DNA.
Special UO microscope captures defects in nanotubes
University of Oregon chemists have devised a way to see the internal structures of electronic waves trapped in carbon nanotubes by external electrostatic charges.
Imaging electric charge propagating along microbial nanowires
The claim by UMass Amherst researchers that the microbe Geobacter produces tiny electrical wires has been mired in controversy for a decade, but a new collaborative study provides stronger evidence than ever to support their claims.
Beyond LEDs: Brighter, new energy-saving flat panel lights based on carbon nanotubes
Even as the 2014 Nobel Prize in Physics has enshrined light emitting diodes (LEDs) as the single most significant and disruptive energy-efficient lighting solution of today, scientists around the world continue unabated to search for the even-better-bulbs of tomorrow.
Future flexible electronics based on carbon nanotubes
Researchers from the University of Texas at Austin and Northwestern University have demonstrated a new method to improve the reliability and performance of transistors and circuits based on carbon nanotubes (CNT), a semiconductor material that has long been considered by scientists as one of the most promising successors to silicon for smaller, faster and cheaper electronic devices.
Breakthrough for Carbon Nanotube Solar Cells
Lighter, more flexible, and cheaper than conventional solar-cell materials, carbon nanotubes (CNTs) have long shown promise for photovoltaics. But research stalled when CNTs proved to be inefficient, converting far less sunlight into power than other methods.
Can our computers continue to get smaller and more powerful?
From their origins in the 1940s as sequestered, room-sized machines designed for military and scientific use, computers have made a rapid march into the mainstream, radically transforming industry, commerce, entertainment and governance while shrinking to become ubiquitous handheld portals to the world.
More Carbon Nanotube Current Events and Carbon Nanotube News Articles