Enzyme in white blood cells can break down carbon nanotubes
An EU-funded study of carbon nanotubes by scientists in Ireland, Sweden and the US has shown that these extraordinarily strong molecules can be broken down into carbon and water by an enzyme found in white blood cells. The discovery, published in the journal Nature Nanotechnology, offers hope that this new material may be exploited safely in medicine and industry.
The findings are an outcome of the NANOMMUNE (‘Comprehensive assessment of hazardous effects of engineered nanomaterials on the immune system’) project, financed under the NMP (‘Nanosciences, nanotechnologies, materials and new production’) theme of the EU’s Seventh Framework Programme (FP7).
Chemically driven thermopower waves
A team of scientists at MIT have discovered a previously unknown phenomenon that can cause powerful waves of energy to shoot through minuscule wires known as carbon nanotubes. The discovery could lead to a new way of producing electricity, the researchers say.
The phenomenon, described as thermopower waves, “opens up a new area of energy research, which is rare,” says Michael Strano, who was the senior author of a paper describing the new findings that appeared in Nature Materials. The lead author was Wonjoon Choi, a doctoral student in mechanical engineering.
A carbon nanotube (shown in the illustration made by Christine Daniloff) can produce a very rapid wave of power when it is coated by a layer of fuel and ignited, so that heat travels along the tube. Like a collection of flotsam propelled along the surface by waves travelling across the ocean, it turns out that a thermal wave — a moving pulse of heat — travelling along a microscopic wire can drive electrons along, creating an electrical current.
Smart capsules for water treatment with recyclable carbon nanotube cores
TEM image of the CNT core-in-hematite shell structures. (Image: Dr. Choi, KBSI)
Numerous nanomaterials are in various stages of research and development, each possessing unique functionalities that are potentially applicable to the remediation of industrial wastewater, groundwater, surface water and drinking water. The main goal for most of this research is to develop low-cost and environmentally friendly materials for removal of heavy metals from water.
Drinking or ground water could be contaminated by heavy metal ions such as lead, chromium, and arsen discarded from industrial waste water. These heavy metal ions are regarded as highly toxic pollutants which could cause a wide range of health problem in case of a long-term accumulation in the body.
NT10 international conference
Conference Scope
Carbon nanotubes have many fascinating properties, owing to their quasi one-dimensional structure. This creates a wide range of issues for fundamental research, as well as a wealth of opportunities for technological application. Progress in the field over the past few years has been remarkable, and applications for this unique material are starting to make the move from the laboratory into the mainstream. In the tradition of the NT conference series, this meeting will bring leading researchers in the area of nanotube science and technology together to evaluate the current state of the art and to identify current trends. The conference will encompass the frontiers of fundamental science as well as applied research, and will enable and encourage participants to exchange their latest ideas and results.
Topics receiving special attention include:
- Mechanical properties of nanotubes and nanotube-based composites
- Electronic properties of nanotubes and nanotube-based electronic devices
- Optical characterization and optical properties
- Progress in synthesis
- Purification and sorting of nanotubes
- Chemical processing and modification of nanotubes
- Applications for nanotubes
From June 27 to July 2, 2010 in Montreal (Canada)
Official website: NT10
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Webinar: Raman Spectroscopy as a Characterization Tool
An educational webinar from Materials Today is coming soon:
- Topic: Introduction to Raman Spectroscopy as a Characterization Tool for Graphene and Carbon Nanostructures
- When: Tuesday March 9th, 2010
- Time: 16h00 GMT, 11h00 EST
- Duration: 1 hour
Registration is free. Simply, follow this link to reserve your place.
Nanotube production
What are carbon nanotubes?
Figure 1: Geometric structure of nanotubes
The discovery of carbon nanotubes in 1991, by the japanese researcher Sumio Iijima, during the study of fullerenes (C60) synthesis reveals a new cristalline form of carbon. These cylindric structures of carbon consist of a graphitic plane rolled into a tube having a nanometric diameter (10-9 meter = 1 nanometer) and can be divided in two groups: single wall carbon nanotubes (C-SWNT) and multi-walls carbon nanotubes (C-MWNT).
Figure 2: Schematic of C-SWNT and C-MWNT
Hydrogen storage
Introduction
The automobile fleet is contributing significantly to air quality degradation in large cities. The use of hydrogen as a fuel is interesting since combustion delivers a lot of energy without polluting. However, some obstacles, like the efficient storage of this gas, remain before it can be implemented in the transportation industry.
Figure 1: Hydrogen powered car built by BMW
Hydrogen storage solutions
The United States Department of energy (DOE) has fixed two targets for hydrogen storage solutions applied to automotive transportation. The first target requires a ratio of hydrogen weight / tank weight that is superior to 0,065 (6,5% weight). This target limits the weight of the tank. The second target requires a hydrogen volumetric density higher than 62 kg/m in order to limit the volume of the tank.
Four main solutions were proposed to solve this problem:
- Compression or liquefaction of hydrogen
- Metal hydrides
- Chemical tanks
- Adsorbent materials
Hydrogen storage – literature
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Reference books
R. Saito, G. Dresselhaus and M. S. Dresselhaus, Physical Properties of carbon nanotubes, Imperial College Press, Londres, 1998
G. Gao, T. Cagin and W. A. Goddard III, Energetics, Structure, Mechanical and Vibrational Properties of Single Walled Carbon Nanotubes (SWNT), Foresight Institute, 1997 (pdf©)
D. Frenkel and B. Smit, Understanding molecular simulation: from algorithms to applications, Academic Press, San Diego, 1996
C. Ngô and H. Ngô, Physique statistique, Masson, Paris, 1995
R. A. Oriani, The physical and metallurgical aspects of hydrogen in metals, Fourth International Conference on Cold Fusion, 1993 (pdf)
Nanotube fabrication methods
S. Iijima, Helical microtubules of graphitic carbon, Nature 354 (1991), 56-58 (pdf©)
S. Iijima and T. Ichihashi, Single-shell carbon nanotubes of 1-nm diameter, Nature 363 (1993), 603-605 (pdf©)
A. Thess, R. Lee, P. Nikolaev, H. Dai, P. Petit, J. Robert, C. Xu, Y. H. Lee, S. G. Kim, A. G. Rinzler, D. T. Colbert, G. E. Scuseria, D. Tománek, J. E. Fischer and R. E. Smalley, Crystalline Ropes of Metallic Carbon Nanotubes, Science 273 (1996), 483-487 (pdf©)
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