. Researchers at Rice University and Penn State University who collaborated with peers in labs around the nation and in Spain, Belgium and Japan, have discovered that adding a dash of boron to carbon while creating nanotubes turns them into solid, spongy, reusable blocks that have an astounding ability to absorb oil spilled in water. That’s one of a range of potential innovations for the material created in a single step. The team found for the first time that boron puts kinks and elbows into the nanotubes as they grow and promotes the formation of covalent bonds, which give the sponges their robust qualities. Lead author Daniel Hashim, a graduate student in the Rice lab of materials scientist Pulickel Ajayan, said the blocks are both superhydrophobic (they hate water, so they float really well) and oleophilic (they love oil). The nanosponges, which are more than 99 percent air, also conduct electricity and can easily be manipulated with magnets. To demonstrate, Hashim dropped the sponge into a dish of water with used motor oil floating on top. The sponge soaked it up. He then put a match to the material, burned off the oil and returned the sponge to the water to absorb more. The robust sponge can be used repeatedly and stands up to abuse; he said a sample remained elastic after about 10,000 compressions in the lab. The sponge can also store the oil for later retrieval, he said. “These samples can be made pretty large and can be easily scaled up,” said Hashim, holding a half-inch square block of billions of nanotubes. “They’re super-low density, so the available volume is large. That’s why the uptake of oil can be so high.” He said the sponges described in the paper can absorb more than a hundred times their weight in oil. Ajayan said multiwalled carbon nanotubes grown on a substrate via chemical vapor deposition usually stand up straight without any real connections to their neighbors. But the boron-introduced defects induced the nanotubes to bond at the atomic level, which tangled them into a complex network. Nanotube sponges with oil-absorbing potential have been made before, but this is the first time the covalent junctions between nanotubes in such solids have been convincingly demonstrated, he said. “The interactions happen as they grow, and the material comes out of the furnace as a solid,” Ajayan said. “People have made nanotube solids via post-growth processing but without proper covalent connections. The advantage here is that the material is directly created during growth and comes out as a cross-linked porous network. The researchers have high hopes for the material’s environmental applications. “For oil spills, you would have to make large sheets of these or find a way to weld sheets together (a process Hashim continues to work on),” Ajayan said. Read More Paper
Posts Tagged ‘University’
Nanosponges Soak Up Oil
Posted in Nanotechnology 
Tags: ajayan, daniel-hashim, Japan, Material, Nanotubes, pulickel-ajayan, said-the-blocks, spain, Sponge, University 
Comments OffFaster, less expensive medical diagnostics through nanotechnology
Image courtesy of Oregon State University Artistic representation of a carbon nanotube and two protein molecules. Nanomedicine will make major contributions to health care not only by providing new and improved therapies, but by providing new diagnostic methods that will be faster and less expensive than currently available procedures. A hat tip to KurzweilAI News for reprinting this news release from Oregon State University “ Nanotube technology leading to fast, lower-cost medical diagnostics “: Researchers at Oregon State University have tapped into the extraordinary power of carbon “nanotubes” to increase the speed of biological sensors, a technology that might one day allow a doctor to routinely perform lab tests in minutes, speeding diagnosis and treatment while reducing costs. The new findings have almost tripled the speed of prototype nano-biosensors, and should find applications not only in medicine but in toxicology, environmental monitoring, new drug development and other fields. The research was just reported in Lab on a Chip [ abstract ], a professional journal. More refinements are necessary before the systems are ready for commercial production, scientists say, but they hold great potential. “With these types of sensors, it should be possible to do many medical lab tests in minutes, allowing the doctor to make a diagnosis during a single office visit,” said Ethan Minot, an OSU assistant professor of physics. “Many existing tests take days, cost quite a bit and require trained laboratory technicians. “This approach should accomplish the same thing with a hand-held sensor, and might cut the cost of an existing $50 lab test to about $1,” he said. The key to the new technology, the researchers say, is the unusual capability of carbon nanotubes. An outgrowth of nanotechnology, which deals with extraordinarily small particles near the molecular level, these nanotubes are long, hollow structures that have unique mechanical, optical and electronic properties, and are finding many applications. In this case, carbon nanotubes can be used to detect a protein on the surface of a sensor. The nanotubes change their electrical resistance when a protein lands on them, and the extent of this change can be measured to determine the presence of a particular protein – such as serum and ductal protein biomarkers that may be indicators of breast cancer. The newest advance was the creation of a way to keep proteins from sticking to other surfaces, like fluid sticking to the wall of a pipe. By finding a way to essentially “grease the pipe,” OSU researchers were able to speed the sensing process by 2.5 times. Further work is needed to improve the selective binding of proteins, the scientists said, before it is ready to develop into commercial biosensors. “Electronic detection of blood-borne biomarker proteins offers the exciting possibility of point-of-care medical diagnostics,” the researchers wrote in their study. “Ideally such electronic biosensor devices would be low-cost and would quantify multiple biomarkers within a few minutes.” The above news item indicates not only how nanotechnology is going to improve medical care, but it hints at the future economic impact of widespread nanotechnology. If a five-minute test using a handheld biosensor in the doctor’s office replaces several expensive lab tests performed by skilled technicians, what happens to the jobs of those technicians? Historically technological innovation has created more and better jobs than those that were lost, and in this case the expanding nanotechnology industry may create jobs for the displaced medical lab technicians. But it is not at all clear that this trend will persist with the more radical displacements that will occur as nanotechnology advances toward productive nanosystems and atomically precise manufacturing. As early as 1986 in Engines of Creation Eric Drexler described how advanced nanotechnology and artificial intelligence could produce a world of abundance with no need of human labor and proposed an Inheritance Day to distribute the wealth. Three years ago here on Nanodot J Storrs Hall described how artificial general intelligence could produce an “early retirement” for the human race (see “ Early retirement ” and “ Early retirement — how soon? “). Perhaps the issue of how transformative technologies will affect jobs, employment, and the distribution of wealth deserves more attention. —James Lewis, PhD
Posted in Nanotechnology Tags: distribution, extraordinary, Jobs, Nanobiotechnology, Nanotechnology, Research, speed, the-researchers, University Comments OffNanotechnology regrows blood vessels after ischemic damage
Credit: Image courtesy of University of Texas at Austin “Hindlimb ischemia was created in rats and treatments were delivered over seven days with an osmotic pump. The laser doppler imaging above shows the rat’s hind limb prior to treatment (on the left) and with increased blood flow (image on the right) just seven days after treatment.” A major advantage of nanoparticles used in nanomedicine is that they can combine and deliver together more than one therapeutic component. This capability has been brought to bear in the quest to encourage regenerative blood vessel growth after ischemic disease, which causes much cardiovascular morbidity. Delivering a growth factor in a nanoparticle containing a different biomolecule as a coreceptor achieves results where delivering the factor alone had failed. A hat tip to ScienceDaily for reprinting this University of Texas at Austin news release “ New Ability to Regrow Blood Vessels Holds Promise for Treatment of Heart Disease “: University of Texas at Austin researchers have demonstrated a new and more effective method for regrowing blood vessels in the heart and limbs — a research advancement that could have major implications for how we treat heart disease, the leading cause of death in the Western world. The treatment method developed by Cockrell School of Engineering Assistant Professor Aaron Baker could allow doctors to bypass surgery and instead repair damaged blood vessels simply by injecting a lipid-incased substance into a patient. Once inside the body, the substance stimulates cell growth and spurs the growth of new blood vessels from pre-existing ones. The method has been tested successfully on rats, and findings of the study were published recently in the Proceedings of the National Academy of Sciences [ abstract ]. “Others have tried using growth factors to stimulate vessel growth in clinical trials and have not been successful,” said Baker, a faculty member in the school’s Department of Biomedical Engineering. “We think that a major reason for this is that previous methods assumed that the diseased tissues retained the ability to respond to a growth stimulus. Our method basically delivers extra components that can restore growth factor responsiveness to the tissue of patients with long-standing clinical disease.” The ability to regrow blood vessels could prove crucial to treating chronic myocardial ischemia disease, which affects up to 27 million patients in the U.S. and leads to a reduction of blood flow in the heart and lower limbs — ultimately causing organ dysfunction and failure. … The new method introduced by Baker and his research team builds on a promising revascularization approach that, up until now, has shown limited efficacy in clinical trials for treating human disease. The method combines a growth factor — a substance capable of stimulating cellular growth, proliferation and cellular differentiation, as well as healing wounds — known as fibroblast growth factor 2 (FGF-2) with a lipid-embedded receptor to enhance its activity. A challenge for scientists and engineers, however, has been getting FGF-2 to bind with cell receptors — the very molecules often found on the surface of the cell that receive chemical signals and direct activity in the cell from outside sources. To overcome this, Baker’s method embeds the growth factors in synthetic lipid-based nanoparticles containing a coreceptor known as syndecan-4. The nanoparticles containing co-receptors that, when delivered with the growth factor, enable improved cell binding so that the growth factor can direct the targeted cell to divide, proliferate and form new cells for tissue regrowth. The incased substance was injected into rats with hindlimb ischemia and stimulated a complete recovery from the ischemia in just seven days. Mammalian cells are very complex mechanisms, and several decades of experience with biotechnology have demonstrated that newly discovered molecules expected to do great things often underperform expectations because changing a cell requires several molecules working together. Nanoparticles have the potential to be complex enough to accomplish what single molecules cannot. —James Lewis, PhD
Posted in Nanotechnology Tags: Bionanotechnology, growth, Heart, Image, Nanotechnology, regrow-blood, School, Texas, texas-at-austin, University Comments OffNanostructured adhesive can hold up to 700 pounds on glass
Photo and description courtesy of UMass Amherst “A card-sized pad of Geckskin can firmly attach very heavy objects such as this 42-inch television weighing about 40 lbs. (18 kg) to a smooth vertical surface. The key innovation by Bartlett and colleagues was to create a soft pad woven into a stiff fabric that includes a synthetic tendon. Together these features allow the stiff yet flexible pad to “drape” over a surface to maximize contact.” Another example of current nanotechnology too cool to ignore is provided by a card-sized adhesive that can support up to 700 pounds on a glass surface, be easily released, and reused many times. A hat tip to ScienceDaily for reprinting this UMass Amherst news release “ Inspired by gecko feet, UMass Amherst scientists invent super-adhesive material “: For years, biologists have been amazed by the power of gecko feet, which let these 5-ounce lizards produce an adhesive force roughly equivalent to carrying nine pounds up a wall without slipping. Now, a team of polymer scientists and a biologist at the University of Massachusetts Amherst have discovered exactly how the gecko does it, leading them to invent “Geckskin,” a device that can hold 700 pounds on a smooth wall. Doctoral candidate Michael Bartlett in Alfred Crosby’s polymer science and engineering lab at UMass Amherst is the lead author of their article describing the discovery in the current online issue of Advanced Materials [ abstract ]. The group includes biologist Duncan Irschick, a functional morphologist who has studied the gecko’s climbing and clinging abilities for over 20 years. Geckos are equally at home on vertical, slanted, even backward-tilting surfaces. “Amazingly, gecko feet can be applied and disengaged with ease, and with no sticky residue remaining on the surface,” Irschick says. These properties, high-capacity, reversibility and dry adhesion offer a tantalizing possibility for synthetic materials that can easily attach and detach heavy everyday objects such as televisions or computers to walls, as well as medical and industrial applications, among others, he and Crosby say. This combination of properties at these scales has never been achieved before, the authors point out. Crosby says, “Our Geckskin device is about 16 inches square, about the size of an index card, and can hold a maximum force of about 700 pounds while adhering to a smooth surface such as glass.” Beyond its impressive sticking ability, the device can be released with negligible effort and reused many times with no loss of effectiveness. For example, it can be used to stick a 42-inch television to a wall, released with a gentle tug and restuck to another surface as many times as needed, leaving no residue. Previous efforts to synthesize the tremendous adhesive power of gecko feet and pads were based on the qualities of microscopic hairs on their toes called setae, but efforts to translate them to larger scales were unsuccessful, in part because the complexity of the entire gecko foot was not taken into account. As Irschick explains, a gecko’s foot has several interacting elements, including tendons, bones and skin, that work together to produce easily reversible adhesion. Now he, Bartlett, Crosby and the rest of the UMass Amherst team have unlocked the simple yet elegant secret of how it’s done, to create a device that can handle excessively large weights. Geckskin and its supporting theory demonstrate that setae are not required for gecko-like performance, Crosby points out. “It’s a concept that has not been considered in other design strategies and one that may open up new research avenues in gecko-like adhesion in the future.” The key innovation by Bartlett and colleagues was to create an integrated adhesive with a soft pad woven into a stiff fabric, which allows the pad to “drape” over a surface to maximize contact. Further, as in natural gecko feet, the skin is woven into a synthetic “tendon,” yielding a design that plays a key role in maintaining stiffness and rotational freedom, the researchers explain. Importantly, the Geckskin’s adhesive pad uses simple everyday materials such as polydimethylsiloxane (PDMS), which holds promise for developing an inexpensive, strong and durable dry adhesive. An amazing example of how controlling structure at the nanometer scale can provide very substantial forces at the macroscopic scale. —James Lewis, PhD
Posted in Nanotechnology Tags: amherst, Article, Design, gecko, geckskin, Nano, Nanotechnology, Power, Research, Science, Surface, University Comments OffNanotechnology-based sensor does rapid reads of single DNA molecule
Photo and description courtesy of University of Washington “The various levels of electrical signal from the sequence of a DNA strand pulled through a nanopore reader (top) corresponds to specific DNA nucleotides, thymine, adenine, cytosine and guanine (bottom).” We recently noted the contribution of nanotechnology-based DNA sequencing methods to research and to the emerging field of personalized medicine. Another major step along this path was taken more recently by combining a mutated protein pore with a DNA polymerase molecular motor. A hat tip to ScienceDaily for reprinting this University of Washington news release written by Vince Stricherz “ Tiny reader makes fast, cheap DNA sequencing feasible “: Researchers have devised a nanoscale sensor to electronically read the sequence of a single DNA molecule, a technique that is fast and inexpensive and could make DNA sequencing widely available. The technique could lead to affordable personalized medicine, potentially revealing predispositions for afflictions such as cancer, diabetes or addiction. “There is a clear path to a workable, easily produced sequencing platform,” said Jens Gundlach, a University of Washington physics professor who leads the research team. “We augmented a protein nanopore we developed for this purpose with a molecular motor that moves a DNA strand through the pore a nucleotide at a time.” The researchers previously reported creating the nanopore by genetically engineering a protein pore from a mycobacterium. The nanopore, from Mycobacterium smegmatis porin A, has an opening 1 billionth of a meter in size, just large enough for a single DNA strand to pass through. To make it work as a reader, the nanopore was placed in a membrane surrounded by potassium-chloride solution, with a small voltage applied to create an ion current flowing through the nanopore. The electrical signature changes depending on the type of nucleotide traveling through the nanopore. Each type of DNA nucleotide – cytosine, guanine, adenine and thymine – produces a distinctive signature. The researchers attached a molecular motor, taken from an enzyme associated with replication of a virus, to pull the DNA strand through the nanopore reader. The motor was first used in a similar effort by researchers at the University of California, Santa Cruz, but they used a different pore that could not distinguish the different nucleotide types. Gundlach is the corresponding author of a paper published online March 25 by Nature Biotechnology [ abstract ] that reports a successful demonstration of the new technique using six different strands of DNA. The results corresponded to the already known DNA sequence of the strands, which had readable regions 42 to 53 nucleotides long. “The motor pulls the strand through the pore at a manageable speed of tens of milliseconds per nucleotide, which is slow enough to be able to read the current signal,” Gundlach said. Gundlach said the nanopore technique also can be used to identify how DNA is modified in a given individual. Such modifications, referred to as epigenetic DNA modifications, take place as chemical reactions within cells and are underlying causes of various conditions. “Epigenetic modifications are rather important for things like cancer,” he said. Being able to provide DNA sequencing that can identify epigenetic changes “is one of the charms of the nanopore sequencing method.” The ability to identify epigenetic modifications (mostly methylations of specific nucleotides) is indeed a plus, although we can hope that with further development the technology will be able to read DNA sequences far longer than 42 to 53 nucleotides. Because repeating sequences are prevalent in the human genome, the ability to do long reads is very important. —James Lewis, PhD
Posted in Nanotechnology Tags: dna, easily-produced, molecular-motor, nanopore, NANOTECH, pore, Research, Science, sequence, University, vince-stricherz Comments OffAtomically-precise positioning of a single atom transistor-VIDEO
A team led by Michelle Y. Simmons, who spoke on “Atomic-scale device fabrication in silicon” at the 2007 Productive Nanosystems: Launching the Technology Roadmap conference, which introduced the Technology Roadmap for Productive Nanosystems , has succeeded in the atomically precise placement of a transistor consisting of a single atom of phosphorous between source and drain electrodes and gate electrodes all made from phosphorous wires only a few atoms wide. A YouTube video illustrating this working transistor of a single atom of phosphorous placed with atomic precision on a silicon crystal includes an STM image that shows the single phosphorous atom placed several tens of rows of silicon atoms from source and drain electrodes of phosphorous that appear to be about 10 rows of atoms wide. To manufacture the phosphorous transistor and electrodes, a scanning tunneling microscope was used to remove precisely determined hydrogen atoms from the passivating layer covering a silicon crystal to form a mask that was then used to apply phosphorous atoms to the vacancies created. An overlay of silicon atoms then preserved these phosphorous nanostructures. The accomplishment is described in a NY Times article by John Markoff, which describes both the place of this work in the progression of Moore’s Law and its potential for a new generation of quantum computers: “ Physicists Create a Working Transistor From a Single Atom “: Australian and American physicists have built a working transistor from a single phosphorus atom embedded in a silicon crystal. The group of physicists, based at the University of New South Wales and Purdue University, said they had laid the groundwork for a futuristic quantum computer that might one day function in a nanoscale world and would be orders of magnitude smaller and quicker than today’s silicon-based machines. … “Their approach is extremely powerful,” said Andreas Heinrich, an I.B.M. physicist. “This is at least a 10-year effort to make very tiny electrical wires and combine them with the placement of a phosphorous atom exactly where they want them.” He said the research was a significant step toward making a functioning quantum computing system. However, whether quantum computing will ever be harnessed for useful tasks remains uncertain, and the researchers also noted that their work demonstrated the fundamental limits that today’s computers would be able to shrink to. “It shows that Moore’s Law can be scaled toward atomic scales in silicon,” said Gerhard Klimeck, professor of electrical and computer engineering at Purdue, referring to the rate at which computing gets faster and cheaper. “The technologies for classical computing can survive to the atomic scale.” The results were published in Nature Nanotechnology [ abstract ]. At least for the moment (February 19, 2012), the full text is available without charge. Also available in the same issue is a commentary by Gabriel P. Lansbergen “ Nanoelectronics: Transistors arrive at the atomic limit “, which gives additional background and details on this accomplishment. … Single-atom transistors represent the ultimate limit in solid-state device miniaturization, but they are also interesting for another reason. Deterministically positioned single-dopant atoms in silicon, electrically addressable by metallic leads, are at the heart of a number of promising proposals for quantum-information-processing devices3. The long coherence and relaxation times associated with single dopants make them very attractive candidates for quantum-device architectures. The atom-by-atom fabrication technique developed by Simmons and co-workers therefore fulfills a long-standing need for a method that is capable of atomic-scale device fabrication in silicon. And although the technique is not directly applicable on an industrial scale, it does bring the development of truly atomistic electronics — and the possibilities they offer — into the experimental realm. This latest accomplishment from Prof. Simmons and her collaborators follows swiftly on their recent demonstration published just last month in Science [ abstract ], that Ohms law holds for nanowire only four phosphorous atoms wide. From the Purdue University news service “ Down to the wire for silicon: Researchers create a wire 4 atoms wide, 1 atom tall “: The smallest wires ever developed in silicon – just one atom tall and four atoms wide – have been shown by a team of researchers from the University of New South Wales, Melbourne University and Purdue University to have the same current-carrying capability as copper wires. Experiments and atom-by-atom supercomputer models of the wires have found that the wires maintain a low capacity for resistance despite being more than 20 times thinner than conventional copper wires in microprocessors. The discovery, which was published in this week’s journal Science, has several implications, including: For engineers it could provide a roadmap to future nanoscale computational devices where atomic sizes are at the end of Moore’s law. The theory shows that a single dense row of phosphorus atoms embedded in silicon will be the ultimate limit of downscaling. For computer scientists, it places donor-atom based silicon quantum computing closer to realization. And for physicists, the results show that Ohm’s Law, which demonstrates the relationship between electrical current, resistance and voltage, continues to apply all the way down to an atomic-scale wire. … Although the path from this laboratory demonstration to a practical technology is not yet clear, as emphasized above by the researchers themselves and commentators, the progress at Zyvex Labs (and elsewhere) that we cited in Oct. 2010 in this basic technology of using an STM for atomically precise lithography holds hope that a convergence of manufacturing technology and demonstrated prototypes will not be too distant. —James Lewis
Posted in Nanotechnology Tags: collaborators, gerhard-klimeck, molecular manufacturing, NANOTECH, Nanotechnology, Possibilities, productive nanosystems, Purdue, Research, Science, south-wales, Technology, University, Work Comments OffNanodynamite Provides Power
. Researchers at the Massachusetts Institute of Technology ( MIT ) and RMIT University have made a breakthrough in energy storage and power generation. The power generated relative to the energy source size is three to four times greater than what is currently possible with the best lithium-ion batteries. While on sabbatical from RMIT in 2009 and 2010, Associate Professor Dr Kourosh Kalantar-zadeh joined MIT Associate Professor Michael Strano’s nanotechnology research group. Before he arrived, Strano’s laboratory was working on measuring the acceleration of a chemical reaction along a nanotube when they discovered that the reaction generated power. Kalantar-zadeh said that this experimental system, based on one of the materials that have come from nanotechnology – carbon nanotubes – generates power, something researchers had not seen before. “By coating a nanotube in nitrocellulose fuel and igniting one end, we set off a combustion wave along it and learned that a nanotube is an excellent conductor of heat from burning fuel. Even better, the combustion wave creates a strong electric current,” he said. Read More Read More
Posted in Nanotechnology Tags: Associate, Combustion, Energy, experimental, generates-power, massachusetts, Nanotechnology, power-generated, strong-electric, Technology, University Comments OffDNA motor navigates network of DNA tracks
The structural DNA path toward productive nanosystems has achieved another step forward with the demonstration that a DNA origami scaffolding can be used to program a DNA motor to navigate a network of tracks. A hat tip to PhysOrg.com for reprinting this news release from Kyoto University “ DNA Motor Programmed to Navigate a Network of Tracks “: Kyoto, Japan — Expanding on previous work with engines traveling on straight tracks, a team of researchers at Kyoto University and the University of Oxford have successfully used DNA building blocks to construct a motor capable of navigating a programmable network of tracks with multiple switches. The findings, published in the January 22 online edition of the journal Nature Nanotechnology [ abstract ], are expected to lead to further developments in the field of nanoengineering. The research utilizes the technology of DNA origami, where strands of DNA molecules are sequenced in a way that will cause them to self-assemble into desired 2D and even 3D structures. In this latest effort, the scientists built a network of tracks and switches atop DNA origami tiles, which made it possible for motor molecules to travel along these rail systems. “We have demonstrated that it is not only possible to build nanoscale devices that function autonomously,” explained Dr. Masayuki Endo of Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS), “but that we can cause such devices to produce predictable outputs based on different, controllable starting conditions.” The team, including lead author Dr. Shelley Wickham at Oxford, expects that the work may lead to the development of even more complex systems, such as programmable molecular assembly lines and sophisticated sensors. “We are really still at an early stage in designing DNA origami-based engineering systems,” elaborated iCeMS Prof. Hiroshi Sugiyama. “The promise is great, but at the same time there are still many technical hurdles to overcome in order to improve the quality of the output. This is just the beginning for this new and exciting field.” Courtesy Sugiyama Lab, Kyoto University iCeMS A depiction of a DNA origami tile with a built-in network of tracks. The DNA engine or motor, in red, can be programmed to navigate a series of junctions to reach one of four desired end points. Perhaps the next step is to have multiple addressable DNA motors bring different components together to be joined? —James Lewis
Posted in Nanotechnology Tags: Bionanotechnology, Development, engine-or-motor, Japan, kyoto, molecular manufacturing, Nanobiotechnology, NANOTECH, News, productive nanosystems, prof-hiroshi, roadmaps, Scientists, University, Work Comments OffNanoparticles Ubiquitous In Food Products
New research from the Arizona State University, ETH Zurich and NTNU Trondheim shows that consumers could be exposed to nanoparticles in food by a much larger degree than has been expected so far. For a modern consumer it is hard to avoid titanium dioxide (TiO2) – a widely used additive in food, personal care and other household products. Approximately 7 million tons of bulk TiO2 are produced annually and used as white pigment in order to provide whiteness and opacity to foods and other products. Many applications of titanium dioxide would benefit from smaller primary particle sizes, and we can expect the percentage of TiO2 that is produced in or near the nano range to increase. Read More Paper
Posted in Nanotechnology Tags: Arizona, arizona-state, avoid-titanium, from-smaller, household, modern-consumer, near-the-nano, percentage, Products, the-percentage, University, used-as-white, white-pigment Comments OffZeolites Open Opportunity For Carbon Capture
. Filtering carbon dioxide, a greenhouse gas, from factory smokestacks is a necessary, but expensive part of many manufacturing processes. However, a collaborative research team from the National Institute of Standards and Technology ( NIST ) and the University of Delaware has gathered new insight into the performance of a material called a zeolite that may stop carbon dioxide in its tracks far more efficiently than current scrubbers do. Zeolites are highly porous rocks—think of a sponge made of stone—and while they occur in nature, they can be manufactured as well. Their toughness, high surface area (a gram of zeolite can have hundreds of square meters of surface in its myriad internal chambers) and ability to be reused hundreds of times makes them ideal candidates for filtering gas mixtures. If an unwanted molecule in the gas mixture is found to stick to a zeolite, passing the mixture through it can scrub the gas of many impurities, so zeolites are widely used in industrial chemistry as catalysts and filters. The team explored a zeolite created decades ago in an industrial lab and known by its technical name, SSZ -13. This zeolite, which has octagonal “windows” between its interior pore spaces, is special because it seems highly capable of filtering out carbon dioxide (CO2) from a gas mixture. “That makes SSZ -13 a promising candidate for scrubbing this greenhouse gas out of such things as factory smokestacks,” says Craig Brown, a researcher at the NIST Center for Neutron Research ( NCNR ). “So we explored, on an atomic level, how it does this so well.” Using neutron diffraction, the team determined that SSZ -13’s eight-sided pore windows are particularly good at attracting the long, skinny carbon dioxide molecules and holding onto their “positively-charged” central carbon atoms, all the while allowing other molecules with different shapes and electronic properties to pass by unaffected. Like a stop sign, each pore halts one CO2 molecule—and each cubic centimeter of the zeolite has enough pores to stop 0.31 grams of CO2, a quantity that makes SSZ -13 highly competitive when compared to other adsorbent materials. Brown says a zeolite like SSZ -13 probably will become a prime candidate for carbon scrubbing because it also could prove more economical than other scrubbers currently used in industry. SSZ -13’s ability to attract only CO2 could mean its use would reduce the energy demands of scrubbing, which can require up to 25 percent of the power generated in a coal or natural gas power plant. “Many industrial zeolites attract water and carbon dioxide, which are both present in flue exhaust—meaning both molecules are, in a sense, competing for space inside the zeolite,” Brown explains. “We suspect that this novel CO2 adsorption mechanism means that water is no longer competing for the same site. A zeolite that adsorbs CO2 and little else could create significant cost savings, and that’s what this one appears to do.” Brown says his team is still collecting data to confirm this theory, and that their future efforts will concentrate on exploring whether SSZ -13 is equally good at separating CO2 from methane—the primary component of natural gas. CO2 is also released in significant quantities during gas extraction, and the team is hopeful SSZ -13 can address this problem as well. Read More
Posted in Nanotechnology Tags: carbon-dioxide, coal-or-natural, Energy, greenhouse, National, Performance, Power, problem-as-well, ssz, team, Technology, Theory, University, Zeolite Comments Off