Monday, November 11, 2019

Latest Innovations in Field of Chemistry Essay

One of the latest inventions developed by researchers from Stellenbosch University in South Africa is a one of a kind â€Å"tea bag† that makes use of nanotechnology to clean drinking water, making it free from contaminants and bacteria. It would be interesting to note that the â€Å"tea bag† is made of the same material that is used to make the actual tea bags. The only difference is that in the Stellenbosch researchers’ invention the ingredients are nanoscale fibers and grains of carbon, reports io9. Both fibers and grains of carbon filter water from all hazardous contaminants. In order to purify the water, the user needs to place the tea bag in the neck of a water bottle. The tea bag filters the water when the person drinks from the bottle. One bag can be used to filter up to 1 liter of water and it costs less than a half of an American cent. Loopwing Korea Unveils Solar-Powered Streetlights, Wind Power Generators Having the goal of reducing the demand for grid electricity, a South Korean company decided to create a new type of streetlights and renewable energy generators. Looping Korea presented its latest inventions at the Renewable Energy World 2010. Its loopwing-type wind power generators boast a one-of-a-kind loop-shaped wing structure that allows generating electricity from winds that have speed as low as 2m/s. In addition, the design also makes it possible for the device to produce power without much noise. One of the models of loopwing type wind power generator is called the TRONC. It features a hybrid solar and wind energy generator and it doesn’t need extra source of energy. Besides, the streetlight can be even connected to such external devices as LED display systems, informs Aving. TRONC represents a complex that includes a small windmill and sunlight panel mounted on top. It also features a loop wing style blade of that is 1. 5 meters in diameter. Latest Invention: LED Light Bulbs that Makes Use of Salmon DNA Researchers from the University of Connecticut recently unveiled their latest invention, which is a long-lasting LED light bulb that makes use of salmon DNA. Scientists added two different fluorescent colors to the DNA molecules, the dyes being spaced from each other at a distance ranging from 2 to 10 nanometers. After the colors were added, the DNA molecules are spun into nanofibers. The UV light that produces LED is then covered with DNA nanofibers. David Walt, a chemistry professor at Tufts University, explained: â€Å"When UV light is shined on the material, one dye absorbs the energy and produces blue light. If the other dye molecule is at the right distance, it will absorb part of that blue-light energy and emit orange light. † By changing the ratios of dyes, one can adjust the quality of light, for example turning cool white into warm white. But just like all latest inventions, this one still requires more studying. Besides there is currently no information regarding how many lumens per watt the salmon DNA LEDs generate, which is why it is too early to say anything about longer life or improved light quality. New research shows that exposing polymer molecular sieve membranes to ultraviolet (UV) irradiation in the presence of oxygen produces highly permeable and selective membranes for more efficient molecular-level separation, an essential process in everything from water purification to controlling gas emissions. Published in the journal Nature Communications, the study finds that short-wavelength UV exposure of the sponge-like polymer membranes in the presence of oxygen allows the formation of ozone within the polymer matrix. The ozone induces oxidation of the polymer and chops longer polymer chains into much shorter segments, increasing the density of its surface. By controlling this ‘densification’, resulting in smaller cavities on the membrane surface, scientists have found they are able to create a greatly enhanced ‘sieve’ for molecular-level separation – as these ‘micro-cavities’ improve the ability of the membrane to selectively separate, to a significant degree, molecules with various sizes , remaining highly permeable for small molecules while effectively blocking larger ones. The research from the University of Cambridge’s Cavendish Laboratory partly mirrors nature, as our planet’s ozone layer is created from oxygen hit by ultraviolet light irradiated from the sun. Researchers have now demonstrated that the ‘selectivity’ of these newly modified membranes could be enhanced to a remarkable level for practical applications, with the permeability potentially increasing between anywhere from a hundred to a thousand times greater than the current commercially-used polymer membranes. Scientists believe such research is an important step towards more energy efficient and environmentally friendly gas-separation applications in major global energy processes – ranging from purification of natural gases and hydrogen for sustainable energy production, the production of enriched oxygen from air for cleaner combustion of fossil fuels and more-efficient power generation, and the capture of carbon dioxide and other harmful greenhouse gases. Chemists at Indiana University Bloomington have created a symmetrical, five-sided macrocycle that is easy to synthesize and has characteristics that may help expand the molecular tool box available to researchers in biology, chemistry and materials sciences. The molecule, which the researchers call cyanostar, was developed in the lab of Amar Flood, associate professor in the Department of Chemistry in the College of Arts and Sciences. It is described in an article in the journal Nature Chemistry, scheduled for publication in August and available online. Doctoral student Semin Lee is the lead author of the article, â€Å"A pentagonal cyanostar macrocycle with cyanostilbene CH donors binds anions and forms dialkylphosphate (3)rotaxanes. † Flood and Chun-Hsing Chen, research crystallographer in the IU Molecular Structure Center, are co-authors. â€Å"Macrocycles have been at the heart of molecular recognition experiments in recent years,† Flood said. â€Å"But they’re a dime a dozen. To make a contribution, you have to raise the bar. Cyanostar raises the bar not only because it is easy to make, but for its unprecedented ability to bind with large, negatively charged ions, suggesting potential applications ranging from environmental remediation of perchlorate and molecular sensing of biological phosphates, to processes related to the life cycle of lithium ion batteries. The creation follows from earlier work in Flood’s lab showing that organic molecules could be designed to remove negatively charged ions fro m solutions. While the molecules have a neutral charge overall, their structure causes them to exhibit electro-positive properties and bind with weakly coordinating anions that were once thought to be incapable of being captured by molecular receptors. breakthrough in fuel cell technology. Scientists from Julich and Berlin have developed a material for converting hydrogen and oxygen to water using a tenth of the typical amount of platinum that was previously required. With the aid of state-of-the-art electron microscopy, the researchers discovered that the function of the nanometre-scale catalyst particles is decisively determined by their geometric shape and atomic structure. This discovery opens up new paths for further improving catalysts for energy conversion and storage. The results have been published in the current issue of the respected journal Nature Materials (DOI: 10. 1038/nmat3668). Hydrogen-powered fuel cells are regarded as a clean alternative to conventional combustion engines, as, aside from electric energy, the only substance produced during operation is water. At present, the implementation of hydrogen fuel cells is being hindered by the high material costs of platinum. Large quantities of the expensive noble metal are still required for the electrodes in the fuel cells at which the chemical conversion processes take place. Without the catalytic effect of the platinum, it is not currently possible to achieve the necessary conversion rates. As catalysis takes place at the surface of the platinum only, material can be saved and, simultaneously, the efficiency of the electrodes improved by using platinum nanoparticles, thus increasing the ratio of platinum surface to material required. Although the tiny particles are around ten thousand times smaller than the diameter of a human hair, the surface area of a kilogram of such particles is equivalent to that of several football fields. Still more platinum can be saved by mixing it with other, less valuable metals, such as nickel or copper. Scientists from Forschungszentrum Julich and Technische Universitat Berlin have succeeded in developing efficient metallic catalyst particles for converting hydrogen and oxygen to water using only a tenth of the typical amount of platinum that was previously required. Researchers from Ulsan National Institute of Science and Technology (UNIST), S. Korea, developed a novel, simple method to synthesize hierarchically nanoporous frameworks of nanocrystalline metal oxides such as magnesia and ceria by the thermal conversion of well-designed metal-organic frameworks (MOFs). The novel material developed by the UNIST research team has exceptionally high CO2 adsorption capacity which could pave the way to save the Earth from CO2 pollution. Nanoporous materials consist of organic or inorganic frameworks with a regular, porous structure. Because of their uniform pore sizes they have the property of letting only certain substances pass through, while blocking others. Nanoporous metal oxide materials are ubiquitous in materials science because of their numerous potential applications in various areas, including adsorption, catalysis, energy conversion and storage, optoelectronics, and drug delivery. While synthetic strategies for the preparation of siliceous nanoporous materials are well-established, non-siliceous metal oxide-based nanoporous materials still present challenges. A description of the new research was published (Web) on May 7 in the Journal of the American Chemical Society. (Title: Nanoporous Metal Oxides with Tunable and Nanocrystalline Frameworks via Conversion of Metal-Organic Frameworks) This article will be also highlighted in the Editor’s Choice of the journal Science. Ionic liquid formulation improves herbicide Scientists in Poland and the US have reformulated the herbicide dicamba to reduce its environmental impact. The use of chemicals in agriculture is widespread, however, there are increasing concerns about their other environmental effects. Dicamba, used to control broadleaf weeds in grain fields and grasslands, is known to enter the environment via water runoff and evaporation following its application. In an attempt to reduce its volatility, a team led by Robin Rogers, from the University of Alabama, and Juliusz Pernak, from Poznan University of Technology, has formulated dicamba as an ionic liquid. Ionic liquids are liquid salts, consisting of a cation and an anion. Deprotonated dicamba assumed the role of anion and the team tested different cations to see which combination was most effective. The team formulated 28 new dicamba ionic liquids using hydrophobic cations that had surfactant or antimicrobial activities. ‘We have always thought of ionic liquids as dual-acting; that is, one can combine an active ingredient in both ions into a single salt,’ exaplins Rogers. By forming a hydrophobic ionic liquid, the water solubility of the herbicide was reduced. The new ionic liquids showed lower volatility, increased thermal stability and improved efficacy in field tests over the parent dicamba. Not only are the ionic liquid forms desirable because of the potential for lower environmental impact, they actually work better, leading to lower application rates of the chemicals,’ Rogers adds. Bill Johnson from Purdue University, Indiana, US, an expert in the development of weed management systems, comments that ‘if a less volatile form of the herbicide can still provide the same level of weed control, the concerns about off-site movement will be greatly reduced. ’ He also says that this approach could be taken with other weak acid herbicides, such as 2,4-D (2,4-dichlorophenoxyacetic acid). The next step for Rogers and co-workers is to investigate other cations with the dicamba anion to create a herbicide with other useful properties. Sustainable iron catalyst for clean hydrogenation 27 June 2013Emma Eley An international team of chemists has reported a clean and green way to perform one of the most important industrial reactions for pharmaceutical and petrochemical synthesis. Platinum group metals are currently the catalysts of choice for hydrogenations due to their high activity. However, they are also expensive, toxic and very rare. Now, in a joint project between McGill University, Canada, and the RIKEN Institute, Japan, a polymer supported iron catalyst has demonstrated excellent performance as a hydrogenation catalyst in the most environmentally-friendly of reaction mediums – water. Iron is abundant and far less toxic than the precious metal catalysts currently used, but its use in industry is limited by it rusting in the presence of oxygen and water. ‘When rusted, iron nanoparticles stop acting as hydrogenation catalysts,’ explains project leader Audrey Moores from McGill University. The system we report solves this limitation and makes iron active in water. ’ Amphiphilic polymers, developed by Yasuhiro Uozumi at the RIKEN Institute, are used to protect the iron catalyst from being deactivated by water while still allowing reactants to reach the catalyst’s active site. After overcoming some synthetic difficulties involving the use of toxic iron pentacarbonyl, the team showed that their robust catalyst was tolerant to water and could be viewed as a realistic competitor to the platinum series metals. The authors demonstrate that the catalyst can be used in a flow system with little leaching, allowing for continuous hydrogenation at the multi-gram scale,’ says Jianliang Xiao, a catalysis expert at the University of Liverpool, UK. ‘As it stands now, the catalytic activity is still low; that said, the study presents an excellent example of green chemistry in practice – total atom-economic reduction in flow with an inexpensive and safe iron catalyst. ’Future work from the team will focus on developing and understanding the protective power of the polymer. We are also interested in developing this catalyst for other industrially relevant reactions,’ says Moores. Titanium takes on Haber–Bosch process The synthesis of ammonia under milder condition, using less energy and fewer resources, has moved a step closer. Scientists in Japan have created a trinuclear titanium polyhydride complex that can cleave the dinitrogen bond and form nitrogen–hydrogen bonds at ambient temperature and pressure without additional reducing agents or proton sources. 1 Nitrogen is the most abundant gas in our atmosphere, essential to life, yet largely inert. Some microbes generate bioavailable nitrogen by reducing nitrogen to ammonia. Industrially, ammonia is produced via the Haber–Bosch process, which is so energy intensive that it consumes 1% of the energy generated globally. The process combines nitrogen and hydrogen over activated iron surfaces to generate ammonia for use as a fertiliser or as a chemical feedstock. This titanium complex could be part of the answer to producing cheaper fertiliser  © Science/AAAS The intrinsic inertness of nitrogen has made it challenging to discover metal complexes that can both bind and activate it. By experimental and computational studies, we determined that the dinitrogen reduction by a trinuclear titanium hydride complex proceeds sequentially through scission of a nitrogen molecule bonded to three titanium atoms in an end-on-side-on fashion, followed by N–H bond formation,’ says study author Zhaomin Hou, of the RIKEN Center for Sustainable Resource Science, Japan. ‘The hydride ligands serve as the source of both electron and proton. ’ Cleaving the N–N bond and forming N–H bonds directly from a hydride complex has been seen only rarely, with some f the most influential work coming from Michael Fryzuk at the University of British Columbia, Canada, who has championed the ‘hydride route’ to dinitrogen complexes. 2 ‘The active sites of both major N2 reduction catalysts – nitrogenases and the Haber–Bosch process – have hydride species as their resting states, but in neither case is the detailed mechan ism of hydrogen loss and nitrogen cleavage known,’ says Patrick Holland of the University of Rochester, US. The authors, he adds, ‘conclusively determined the structures of many of the intermediates along the pathway, giving insight into possible structures and pathways of intermediates on the catalysts’. Fryzuk, who wrote an accompanying perspective,3 says the paper adds important fundamental knowledge about potential elementary reactions such as cleaving N–N triple bonds and forming N–H bonds, which are relevant to the Haber–Bosch process. He predicts it ‘will change the way people think about N2 activation so that in the future perhaps a soluble, suitably designed multi-metallic hydride complex will be able to both activate and functionalise molecular nitrogen productively to form ammonia or some other higher-value nitrogen containing material’. However, there still challenges to overcome to make this process practically useful, Hou says. But if successful the low temperature, low pressure synthesis of ammonia in smaller reactors is on the cards. Latest Invention: World’s First Battery Powered by Paper Sony has recently announced it managed to come up with a battery powered by paper. However, the whole process is more complex than simply using a standard paper. The batteries developed by the Japanese tech giant make use of enzymes in order to break down the glucose found in the cellulose of the paper (which by the way is made of wood pulp fibers). It would be interesting to note that Sony was able to demonstrate its bio-battery. The demo took place at the Eco-Products exhibition in Tokyo. During the presentation the paper was placed into a mix of water and enzymes. After a couple of minutes the liquid started generating enough power to activate a small fan. After enzymes broke down the paper, they were left with sugar that was produced from cellulose. Then they were able to process the sugar to produce hydrogen ions and electrons. The latter then went through an outer circuit to produce power. Mixed with oxygen in the air, the hydrogen ions were then able to create H2O. â€Å"This is the same mechanism with which termites eat wood to get energy. Bio batteries are environmentally friendly and have great potential as they use no metals or harmful chemicals,† explained Chisato Kitsukawa, a PR manager at Sony. Scientists use electron ‘ink’ to write on graphene ‘paper’ Nanoscale writing offers a reliable way to record information at extremely high densities, making it a promising tool for patterning nanostructures for a variety of electronic applications. In a recent study, scientists have demonstrated a simple yet effective way to write and draw on the nanoscale by using an electron beam to selectively break the carbon atoms in single-layer graphene. The researchers, Wei Zhang and Luise Theil Kuhn at the Technical University of Denmark in Roskilde, Denmark; and Qiang Zhang and Meng-Qiang Zhao at Tsinghua University in Beijing, China, have published their study on using electron ink to write on graphene paper in a recent issue of Nanotechnology. â€Å"The ability to record information has been directly correlated with the process of human civilization since ancient times,† Wei Zhang told Phys. org. â€Å"Paper and ink are the two essential factors to record history. Currently, information communication has proceeded onto an unprecedented scale. † Nanoscale writing, which is essentially the manipulation of matter on the nanoscale, has already been widely explored. The current methods can be classified into two groups: lithography (top down), which imprints a pre-made pattern on a substrate, but has restricted resolution; and self-assembly (bottom up), which manipulates atoms or molecules individually, but faces challenges with controllability. Herein, the researchers proposed a combination method based on both types of methods to overcome the difficulties of each, which they demonstrated on â€Å"the thinnest paper in the world†: graphene. â€Å"The rise of graphene calls for broad attention,† Qiang Zhang said. â€Å"One distinct characteristic is its flatness, which provides the perfect opportunity to be regarded as the thinnest paper. In order to directly write on this ultimate thin paper, the suitable ink must be found. At the small scale, typically nanoscale, the ink candidate ust meet the qualification as both high-resolution writing and visualization function. Therefore, high-energy electrons in a transmission electron microscope (TEM) are the best choice. The electron beam can be manipulated as ink for direct writing, but is by itself invisible. † When an electron beam (green) writes on graphene paper, some of the carbon atoms in the graphene are kicked off, and external carbon atoms are deposit ed onto the dangling bonds to form an irregular structure that appears as â€Å"ink. † Credit: Wei Zhang, et al.  ©2013 IOP Publishing Ltd. As the researchers explain, the carbon atoms in graphene are sensitive to a variety of irradiation effects. Here, a 300 keV electron beam was used to break local carbon-carbon bonds in single-layer graphene. When the bonds break, carbon atoms are kicked off, resulting in dangling bonds that are free to attract new carbon species from the vacuum and on the graphene surface. These new amorphous carbon species become absorbed onto the dangling bonds to stabilize the edge, forming only along the scanning direction of the electron beam.

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