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News Article | February 23, 2017
Site: www.eurekalert.org

PULLMAN, Wash. - A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods. The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy. "The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.


News Article | February 24, 2017
Site: www.rdmag.com

A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods. The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy. "The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.


News Article | February 24, 2017
Site: www.rdmag.com

A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods. The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy. "The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.


News Article | February 23, 2017
Site: phys.org

The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated. Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks. The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system. The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard. Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy."The logistics are very challenging," he said. The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory. The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. The researchers also hope the work will contribute to the study of other poorly understood chemical compounds. More information: Jamie Weaver et al, Chemical Trends in Solid Alkali Pertechnetates, Inorganic Chemistry (2017). DOI: 10.1021/acs.inorgchem.6b02694


News Article | February 25, 2017
Site: www.techtimes.com

Washington State University conducted tests to study the effects of the chemical substance known as technetium-99. The study was led by John McCloy, an associate professor in the School of Mechanical and Materials Engineering along with Jamie Weaver, a chemistry graduate student. They worked in collaboration with researchers from the Office of River Protection and Lawrence Berkeley National Laboratory and Pacific Northwest National Laboratory. Technetium-99 is the chemical by-product derived as a result of plutonium weapon production. It is being considered a major problem as scientists are trying to find new methods of disposing the nuclear waste. In fact, there exists about 2000 pounds of technetium-99 which is stored in 177 storage tanks at the Hanford nuclear site in Washington. The element is readily soluble in water and so poses an intense risk. Due to its volatility, it can easily contaminate water streams which would cause major health issues. Nuclear wastes are generated from nuclear power plants in significant amounts and thus, it needs to be managed and disposed of properly. The most important issue concerning the nuclear waste is the management of its toxic nature, so that it poses no risk to the workers or the general public. The Washington State University conducted the study of technetium-99 in PNNL's highly specialized Radiochemical Processing Laboratory. Researchers carried out various tests with the compound. Their aim was to precisely observe technetium-99 and determine how it may be stored. They found that the sodium reacts differently in the compound than in any other alkalis, which may go a long way in defining why technetium-99 is so reactive with water. This may also reveal the reason behind its volatility. "The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy. Currently, U.S. Department of Energy at Hanford is in the act of constructing a waste treatment plant. They aim to store threatening nuclear waste in a glass. However, researchers have to find an alternative as the entire technetium-99 cannot be incorporated in a glass. The volatilized gas would also be needed to be recycled back into the system. These innovative ideas may pave the way for a safer future. However, for now the threat of nuclear contamination due to the high volume of nuclear waste being produced seems to be looming. It has become essential to come up with a reliable way to dispose these wastes of. The study has been published in the journal Inorganic Chemistry. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | October 27, 2016
Site: www.rdmag.com

The process of creating hydrogen from water for renewable energy production just got a little bit easier thanks to researchers at Washington State University. Professors Yuehe Lin and Scott Beckman at Washington State’s School of Mechanical and Materials Engineering, have developed a catalyst from low-cost materials that outperformed catalysts made from precious metals that are commonly used for hydrogen creation. The research team added nanoparticles of relatively inexpensive copper to a cobalt-based framework to create a cheaper and more efficient catalyst. “The research team has provided a new perspective in designing and improving non-precious metal-based catalyst for hydrogen production," said Lin. "This catalyst will pave the way for the development of high-performance, electrolysis-based hydrogen production applications." Energy conversation is a key component to the clean energy economy because solar and wind sources only produce power intermittently and there is a critical need for ways to store and save the electricity they create. The research team was able to store renewable energy using the excess electricity generated from renewables to split water into oxygen and hydrogen, in which the hydrogen can be then fed into fuel-cell vehicles. “Hydrogen production by electrolysis of water is the greenest way to convert electricity to chemical fuel,” Junhua Song, a WSU Ph.D. student, who synthesized the catalyst and performed most of the experimental work, said in a statement. To create the catalyst the researchers used both theoretical modeling and experimental assessments to demonstrate and fine tune the catalyst’s effectiveness. Currently, industries have not widely used the water splitting process because of the cost of precious metal catalysts—usually platinum or ruthenium—that are required. Another issue is many of the methods to split water also require too much energy or the required materials breakdown too quickly. However, if the Washington State team is able to secure additional funding they hope to scale up their work to improve the new catalyst’s stability and efficiency. The work is published in the journal Advanced Energy Materials.


News Article | August 23, 2016
Site: www.nanotech-now.com

Abstract: Washington State University researchers have developed a novel nanomaterial that could improve the performance and lower the costs of fuel cells by using fewer precious metals like platinum or palladium. Led by Yuehe Lin, professor in the School of Mechanical and Materials Engineering, the researchers used inexpensive metal to make a super low density material, called an aerogel, to reduce the amount of precious metals required for fuel cell reactions. They also sped up the time to make the aerogels, which makes them more viable for large-scale production. Their work is published in Advanced Materials. Hydrogen fuel cells are a promising green energy solution, producing electricity much more efficiently and cleanly than combustion engines. But they need expensive precious metals to fuel their chemical reactions. This need has limited their acceptance in the marketplace. Aerogels, which are sometimes also called liquid smoke, are solid materials that are about 92 percent air. Effective insulators, they are used in wet suits, firefighting gear, windows, paints and in fuel cell catalysts. Because metal-based aerogels have large surface areas and are highly porous, they work well for catalyzing in fuel cells. The WSU team created a series of bimetallic aerogels, incorporating inexpensive copper and using less precious metal than other metal aerogels. Researchers introduced the copper in the bimetallic system through their new, one-step reduction method to create hydrogel. The hydrogel is the liquid-filled form of aerogel. The liquid component is carefully and completely dried out of the hydrogel to create aerogel. Their method has reduced the manufacturing time of hydrogel from three days to six hours. "This will be a great advantage for large scale production," said Chengzhou Zhu, a WSU assistant research professor who created the aerogel. The research is in keeping with WSU's Grand Challenges, a suite of research initiatives aimed at large societal issues. It is particularly relevant to the challenge of sustainable resources and its theme of energy. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Abstract: Researchers have reached a critical milestone in solar cell fabrication, helping pave the way for solar energy to directly compete with electricity generated by conventional energy sources. Led by the U.S. Department of Energy's National Renewable Energy Laboratory and in collaboration with Washington State University and the University of Tennessee, the researchers improved the maximum voltage available from a cadmium telluride (CdTe) solar cell, overcoming a practical limit that has been pursued for six decades and is key to improving its efficiency. The work is published in the Feb. 29 issue of Nature Energy. Silicon solar cells currently represent 90% of the solar cell market, but it will be difficult to significantly reduce their manufacturing costs. CdTe solar cells offer a low-cost alternative. They have the lowest carbon footprint of any other solar technology and perform better than silicon in real world conditions, including in hot, humid weather and under low light. However, until recently, CdTe cells haven't been as efficient as silicon-based cells. One key area where CdTe has underperformed was in the maximum voltage available from the solar cell, called open-circuit voltage. Limited by the quality of CdTe materials, researchers for the past 60 years were not able to get more than 900 millivolts out of the material, which was considered its practical limit. The research team improved cell voltage by shifting away from a standard processing step using cadmium chloride. Instead, they placed a small number of phosphorus atoms on tellurium lattice sites and then carefully formed ideal interfaces between materials with different atomic spacing to complete the solar cell. This approach improved the CdTe conductivity and carrier lifetime each by orders of magnitude, thereby enabling the fabrication of CdTe solar cells with an open-circuit voltage breaking the 1-volt barrier for the first time. The innovation establishes new research paths for solar cells to become more efficient and provide electricity at lower cost than fossil fuels. "It's a significant milestone. It's been below 900 millivolts for decades," said Kelvin Lynn, Regents professor in WSU's School of Mechanical and Materials Engineering and Department of Physics, who led WSU's effort. The NREL researchers treated the crystals, built and characterized the solar cells, while WSU researchers, including Santosh Swain and Tursun Ablekim, developed -the crystal material used in the cells. The WSU researchers grow their crystals in a technique called melt growth, which allows precise control over purity and composition. Purity is extremely critical to the process, so the researchers mix, prepare and vacuum-seal the materials in an industry-standard clean room. They then synthesize the crystal in a furnace above 1100 degree °C and then cool it from the bottom up at a rate of about one millimeter per hour. The researchers then cut the crystal into polished wafers to make the solar cells. "Others have tried dopants, but they didn't have the control and purity that we have. And, the purity matters,'' said Lynn. "WSU is known for growing really high quality and purity crystals. You have to control every step." While researchers have improved silicon-based cells almost to their theoretical limit, there is significant room for efficiency improvements for cadmium telluride, which could be bettered by an additional 30 percent, said Lynn. ### The research was funded by the Energy Department's SunShot Initiative, which aims to make solar cost-competitive with traditional energy sources. It was also supported in part by Oak Ridge National Laboratory's Center for Nanophase Materials Sciences. The research is in keeping with Washington State University's Grand Challenges initiative stimulating research to address some of society's most complex issues. It is particularly relevant to the challenge of "Sustainable Resources for Society" and its theme of meeting energy needs while protecting the environment. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | October 25, 2016
Site: phys.org

The researchers, led by professors Yuehe Lin and Scott Beckman in the School of Mechanical and Materials Engineering, have developed a catalyst from low cost materials. It performs as well as or better than catalysts made from precious metals that are used for the process. The work is published in the journal Advanced Energy Materials. Energy conversion is a key to the clean energy economy. Because solar and wind sources produce power only intermittently, there is a critical need for ways to store and save the electricity they create. One of the most promising ideas for storing renewable energy is to use the excess electricity generated from renewables to split water into oxygen and hydrogen; the hydrogen can then be fed into fuel-cell vehicles. "Hydrogen production by electrolysis of water is the greenest way to convert electricity to chemical fuel," said Junhua Song, a WSU Ph.D. student who synthesized the catalyst and performed most of the experimental work. Industries have not widely used the water splitting process, however, because of the prohibitive cost of the precious metal catalysts that are required - usually platinum or ruthenium. Many of the methods to split water also require too much energy, or the required materials break down too quickly. Instead, industries generally use a fossil-fuel based process to produce hydrogen for fuel cells, which generates harmful greenhouse gas emissions. For their catalyst, the WSU research team added nanoparticles of relatively inexpensive copper to a cobalt-based framework. The new catalyst was able to conduct electricity better than the commonly used precious metal catalysts. It produced oxygen better than existing commercial catalysts and produced hydrogen at a comparable rate. The researchers used both theoretical modeling and experimental assessments to demonstrate and fine tune their catalyst's effectiveness. "The modeling helped the researchers gain understanding at the atomic level of how the copper atoms improve the catalyst, which helped in precisely choosing and tuning the elements to enhance performance," said Beckman. "The research team has provided a new perspective in designing and improving non-precious metal-based catalysts for hydrogen production," said Lin. "This catalyst will pave the way for the development of high-performance, electrolysis-based hydrogen production applications." The researchers are looking for external funding to scale up their work. They hope to improve the catalyst's stability and efficiency. The work is in keeping with WSU's Grand Challenges, a suite of research initiatives aimed at large societal issues. It is particularly relevant to the challenge of sustainable resources and its theme of meeting energy needs while protecting the environment. More information: Junhua Song et al, Bimetallic Cobalt-Based Phosphide Zeolitic Imidazolate Framework: CoPPhase-Dependent Electrical Conductivity and Hydrogen Atom Adsorption Energy for Efficient Overall Water Splitting, Advanced Energy Materials (2016). DOI: 10.1002/aenm.201601555


News Article
Site: www.asminternational.org

How do you boil water? Eschewing the traditional kettle and flame, engineers at the Massachusetts Institute of Technology, Cambridge, invented a bubble-wrapped, sponge-like device that soaks up natural sunlight and heats water to boiling temperatures, generating steam through its pores. The design, which the researchers call a "solar vapor generator," requires no expensive mirrors or lenses to concentrate the sunlight, but instead relies on a combination of relatively low-tech materials to capture ambient sunlight and concentrate it as heat. The heat is then directed toward the pores of the sponge, which draw water up and release it as steam. From their experiments—including one in which they simply placed the solar sponge on the roof of MIT's Building 3—researchers found the structure heated water to its boiling temperature of 100°C (212°F), even on relatively cool, overcast days. The sponge also converted 20% of the incoming sunlight to steam. The low-tech design may provide inexpensive alternatives for applications ranging from desalination and residential water heating, to wastewater treatment and medical tool sterilization. The research was led by George Ni, an MIT graduate student; and Gang Chen, the Carl Richard Soderberg Professor in Power Engineering and the head of the Department of Mechanical Engineering; in collaboration with TieJun Zhang and his group members Hongxia Li and Weilin Yang from the Department of Mechanical and Materials Engineering at the Masdar Institute of Science and Technology, in the United Arab Emirates. The current design builds on a solar-absorbing structure they developed in 2014—a similar floating, sponge-like material made of graphite and carbon foam, that was able to boil water to 100°C and convert 85% of the incoming sunlight to steam. To generate steam at such efficient levels, researchers had to expose the structure to simulated sunlight that was 10 times the intensity of sunlight in normal, ambient conditions. "It was relatively low optical concentration," Chen says. "But I kept asking myself, ‘Can we basically boil water on a rooftop, in normal conditions, without optically concentrating the sunlight?' That was the basic premise." In ambient sunlight, while the black graphite structure absorbed sunlight well, it also tended to radiate heat back out into the environment. To minimize the amount of heat lost, the team looked for materials that would better trap solar energy. In their new design, researchers settled on a spectrally-selective absorber—a thin, blue, metallic-like film that is commonly used in solar water heaters and possesses unique absorptive properties. The material absorbs radiation in the visible range of the electromagnetic spectrum, but it does not radiate in the infrared range, meaning that it both absorbs sunlight and traps heat, minimizing heat loss. Researchers obtained a thin sheet of copper, chosen for its heat-conducting abilities and coated with the spectrally-selective absorber. They then mounted the structure on a thermally-insulating piece of floating foam. However, even though the structure did not radiate much heat back out to the environment, heat was still escaping through convection, in which moving air molecules such as wind would naturally cool the surface. A solution to this problem came from an unlikely source: Chen's 16-year-old daughter, who at the time was working on a science fair project in which she constructed a makeshift greenhouse from simple materials, including bubble wrap. "She was able to heat it to 160°F, in winter!" Chen says. "It was very effective." Chen proposed the packing material to Ni, as a cost-effective way to prevent heat loss by convection. This approach would let sunlight in through the material's transparent wrapping, while trapping air in its insulating bubbles. "I was very skeptical of the idea at first," Ni recalls. "I did not think it was a high-performance material. But we tried the clearer bubble wrap with bigger bubbles for more air trapping effect, and it turns out, it works. Now because of this bubble wrap, we don't need mirrors to concentrate the sun." The bubble wrap, combined with the selective absorber, keeps heat from escaping the surface of the sponge. Once heat is trapped, the copper layer conducts heat toward a single hole, or channel, that researchers drilled through the structure. When the sponge was placed in water, water creeps up the channel, where it is heated to 100°C, then turns to steam. Chen and Ni say that solar absorbers based on this general design could be used as large sheets to desalinate small bodies of water, or to treat wastewater. Ni says other solar-based technologies that rely on optical-concentrating technologies typically are designed to last 10 to 20 years, though they require expensive parts and maintenance. This new, low-tech design, he says, could operate for one to two years before needing to be replaced. "Even so, the cost is pretty competitive," Ni says. "It's kind of a different approach, where before, people were doing high-tech and long-term [solar absorbers]. We're doing low-tech and short-term." "What fascinates us is the innovative idea behind this inexpensive device, where we have creatively designed this device based on basic understanding of capillarity and solar thermal radiation," says Zhang. "Meanwhile, we are excited to continue probing the complicated physics of solar vapor generation and to discover new knowledge for the scientific community." This research was funded, in part, by a cooperative agreement between the Masdar Institute of Science and Technology and MIT; and by the Solid-State Solar Thermal Energy Conversion Center, an Energy Frontier Research Center funded by U.S. Department of Energy. Image caption — Bubble wrap, combined with a selective absorber, keeps heat from escaping the surface of the sponge. Courtesy of George Ni.

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