A group of scientists from South Korea have converted used-cigarette butts into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles and wind turbines to store energy. Presenting their findings today, 5 August 2014, in IOP Publishing’s journal Nanotechnology, the researchers have demonstrated the material’s superior performance compared to commercially available carbon, graphene and carbon nanotubes. It is hoped the material can be used to coat the electrodes of supercapacitors—electrochemical components that can store extremely large amounts of electrical energy—whilst also offering a solution to the growing environmental problem caused by used-cigarette filters. It is estimated that as many as 5.6 trillion used-cigarettes, or 766,571 metric tons, are deposited into the environment worldwide every year. Co-author of the study Professor Jongheop Yi, from Seoul National University, said: “Our study has shown that used-cigarette filters can be transformed into a high-performing carbon-based material using a simple one step process, which simultaneously offers a green solution to meeting the energy demands of society. “Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used-cigarette filters that are disposed of into the environment each year—our method is just one way of achieving this.” Carbon is the
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Earlier this month, Dr. Kent Brantly and Nancy Writebol were close to death. The two American aid workers infected with the deadly Ebola virus were flown from Liberia to Atlanta, Georgia, where they were promptly sent to the Emory University Hospital. At the moment, there is no officially approved treatment or vaccine for the Ebola virus, which has a 50 to 90 percent mortality rate. But Brantly and Writebol were each given doses of an experimental anti-Ebola serum that had never been tested in humans. Soon after, according to Emory University doctors, both patients were improving.
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Colourful LEDs made from a material known as perovskite could lead to LED displays which are both cheaper and easier to manufacture in future. This technology could provide a lot of value to the ever growing flat-panel display industry Zhi-Kuang Tan A hybrid form of perovskite – the same type of material which has recently been found to make highly efficient solar cells that could one day replace silicon – has been used to make low-cost, easily manufactured LEDs, potentially opening up a wide range of commercial applications in future, such as flexible colour displays. This particular class of semiconducting perovskites have generated excitement in the solar cell field over the past several years, after Professor Henry Snaith’s group at Oxford University found them to be remarkably efficient at converting light to electricity. In just two short years, perovskite-based solar cells have reached efficiencies of nearly 20%, a level which took conventional silicon-based solar cells 20 years to reach. Now, researchers from the University of Cambridge, University of Oxford and the Ludwig-Maximilians-Universität in Munich have demonstrated a new application for perovskite materials, using them to make high-brightness LEDs. The results are published in the journal Nature Nanotechnology. Perovskite is a general term used
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The billion-euro Graphene Flagship project of the European Commission doubled in size this June. The expansion brought Spain to the second place by the number of Flagship partners, just below Germany and Italy which share the first place as countries with most project participants. Among the freshly accepted projects is GRAPHESALT, “Graphene based capacitive deionization for an energy efficient desalination system”. GRAPHESALT was proposed by the Spanish research organization Tecnalia and the French membrane maker SME Polymem.
GRAPHESALT is one of 21 projects selected from a total of 218 proposals submitted. It focuses on the development of a water desalination system based on a technique called capacitive deionization (CDI).
Image: Sketch of capacitive deionization (CDI). Courtesy of Azonano.
During CDI salt is separated from water by passing seawater between two electrically charged electrodes (anode and cathode), so that the salts are adsorbed on the surface of the electrodes, thereby obtaining drinking water. By reversing the electric charge of the electrodes, the salt is washed out, recovering part of the electric energy used in the process. Although the technology is not new, its performance can be increased dramatically by using metal oxide-graphene electrodes, achieving higher efficiency than that of reverse osmosis desalination. Reverse osmosis is the predominant method in desalination plants today, although it consumes much energy. Metal oxide in contact with graphene is also, not incidentally, the main ingredient of our recently reported efficient organic light emitting diodes (OLEDs). In GRAPHESALT, the graphene will form part of the porous material component of the filter.
Graphene water desalination and filtering is a hot research topic. Back in February, MIT researchers demonstrated a graphene film drilled with closely packed nanopores. The nanoporous graphene is a membrane material that has earlier shown, in calculation, to be ideally suited for water desalination, as salt molecules are too large to pass through the sieve. Following up on that, research that came out of the Oak Ridge National Lab demonstrated a real graphene desalination filter, with performance 100 times better than currently used technology. In that case, the approach was based on graphene oxide, or more precisely graphene oxide frameworks (GOFs). Graphene desalination filters warranted a technology review in a popular desalination online magazine.
GRAPHESALT will play on the excellent performance of metal oxide-graphene electrodes to enhance the performance of the available CDI technology. The method is expected to compete with nanoporous graphene and GOFs on the way to the desalination marketplace.
