A new catalytic process from Purdue is able to convert the biomass waste lignin into lucrative chemical products that can be used to create high-octane fuel for racecars and jets or even in fragrances or flavorings. The Purdue team of researchers has developed a process that uses a chemical catalyst and heat to spur reactions that convert lignin into valuable chemical commodities.

Lignin is the notoriously tough and highly complex molecule that gives the plant cell wall its rigid structure. Plant biomass is made up primarily of lignin and cellulose, a long chain of sugar molecules that is the bulk material of plant cell walls. In standard production of ethanol, enzymes are used to break down the biomass and release sugars. Yeast then feast on the sugars and create ethanol. So far the lignin has defied economic use and clogged up the works.

Purdue University’s Center for Direct Catalytic Conversion of Biomass to Biofuels, or C3Bio professor Mahdi Abu-Omar, the R.B. Wetherill Professor of Chemistry and Professor of Chemical Engineering and associate director of C3Bio, led the team.

Mahdi Abu-Omar Purdue's R.B. Wetherill Professor of Chemistry in His Lab.   Professor Abu-Omar holds a small vial containing results of a new catalytic process that can convert the lignin in wood into high-value chemical products for use in fragrances and flavoring.  Image Credit: Purdue University photo by Mark Simons.  Click image for the largest view.

Mahdi Abu-Omar Purdue’s R.B. Wetherill Professor of Chemistry in His Lab. Professor Abu-Omar holds a small vial containing results of a new catalytic process that can convert the lignin in wood into high-value chemical products for use in fragrances and flavoring. Image Credit: Purdue University photo by Mark Simons. Click image for the largest view.

The processes and resulting products are detailed in a paper published online in the Royal Society of Chemistry journal Green Chemistry.

Professor Abu-Omar explained, “We are able to take lignin – which most biorefineries consider waste to be burned for its heat – and turn it into high-value molecules that have applications in fragrance, flavoring and high-octane jet fuels. We can do this while simultaneously producing from the biomass lignin-free cellulose, which is the basis of ethanol and other liquid fuels. We do all of this in a one-step process.”

Lignin acts as a physical barrier that makes it difficult to extract sugars from biomass and acts as a chemical barrier that poisons the enzymes. Many refining processes include harsh pretreatment steps to break down and remove lignin, he said.

“Lignin is far more than just a tough barrier preventing us from getting the good stuff out of biomass, and we need to look at the problem differently. While lignin accounts for approximately 25 percent of the biomass by weight, it accounts for approximately 37 percent of the carbon in biomass. As a carbon source lignin can be very valuable, we just need a way to tap into it without jeopardizing the sugars we need for biofuels,” professor Abu-Omar explained.

The Purdue team developed a process that starts with untreated chipped and milled wood from sustainable poplar, eucalyptus or birch trees. Abu-Omar described the process where a catalyst, a bimetallic Zn/Pd/C, is added to initiate and speed the desired chemical reactions, but is not consumed in the reactions and can be recycled and used again. A solvent is added to the mix to help dissolve and loosen up the materials. The mixture is contained in a pressurized reactor and heated for several hours. The process breaks up the lignin molecules and results in lignin-free cellulose and a liquid stream that contains two additional chemical products.

The liquid stream contains the solvent, which is easily evaporated and recycled, and two phenols, a class of aromatic hydrocarbon compounds used in perfumes and flavorings. A commonly used artificial vanilla flavoring is currently produced using a phenol that comes from petroleum.

The team also developed an additional process that uses another catalyst to convert the two phenol products into high-octane hydrocarbon fuel suitable for use as drop-in gasoline. The fuel produced has a research octane rating greater than 100, whereas the average gas we put into our cars has an octane rating in the eighties.

Professor Abu-Omar noted the catalyst is expensive, and the team plans to further study efficient ways to recycle it, along with ways to scale up the entire process.

Looking into the future the professor sees, “A biorefinery that focuses not only on ethanol, but on other products that can be made from the biomass (that) is more efficient and profitable overall. It is possible that lignin could turn out to be more valuable than cellulose and could subsidize the production of ethanol from sustainable biomass.”

The concept is already launching, the Purdue Research Foundation has filed patent applications and launched a startup company, Spero Energy, which was founded by Abu-Omar.

This work obviously has market legs. The abstract notes that the leftover carbohydrate residue when hydrolyzed by cellulases produces glucose at a 95% yield, which is comparable to a lignin-free cellulose. That seems like a miracle. The catalyst might well be expensive, but its likely worth it and will come down in cost as a market volume grows.  It will be a kind of revolution to see lignin become a worthwhile commodity instead of a huge processing problem.

While professor Abu-Omar is the leader there is an impressive list of collaborators. Co-authors include Trenton Parsell, a visiting scholar in the Department of Chemistry; chemical engineering graduate students Sara Yohe, John Degenstein, Emre Gencer, and Harshavardhan Choudhari; chemistry graduate students Ian Klein, Tiffany Jarrell, and Matt Hurt; agricultural and biological engineering graduate student Barron Hewetson; Jeong Im Kim, associate research scientist in biochemistry; Basudeb Saha, associate research scientist in chemistry; Richard Meilan, professor of forestry and natural reserouces; Nathan Mosier, associate professor of agricultural and biological engineering; Fabio Ribeiro, the R. Norris and Eleanor Shreve Professor of Chemical Engineering; W. Nicholas Delgass, the Maxine S. Nichols Emeritus Professor of Chemical Engineering; Clint Chapple, the head and distinguished professor of biochemistry; Hilkka I. Kenttamaa, professor of chemistry; and Rakesh Agrawal, the Winthrop E. Stone Distinguished Professor of Chemical Engineering.

A University of New South Wales (UNSW) research team is converting over 40 percent of the sunlight hitting a solar system into electricity. The solar cell system has been independently confirmed by the National Renewable Energy Laboratory (NREL) at their outdoor test facility in the United States.

40 percent is a very big number, the highest solar cell efficiency ever reported.

It isn’t a lab unit working under lights. The new world class efficiency record was achieved in outdoor tests in Sydney.

A very proud UNSW Scientia Professor and Director of the Australian Centre for Advanced Photovoltaics (ACAP) Professor Martin Green said, “This is the highest efficiency ever reported for sunlight conversion into electricity.”

Dr Mark Keevers, the UNSW solar scientist who managed the project explains, “We used commercial solar cells, but in a new way, so these efficiency improvements are readily accessible to the solar industry.”

“The new results are based on the use of focused sunlight, and are particularly relevant to photovoltaic ‘power towers’ being developed in Australia,” Professor Green said.

The team allows that a key part of the prototype’s design is the use of a custom optical bandpass filter to capture sunlight that is normally wasted by commercial solar cells on towers and convert it to electricity at a higher efficiency than the solar cells themselves ever could. These types of filters reflect particular wavelengths of light while transmitting others.

RayGen's CSPV Power Station. Image Credit: RayGen Resources, Pty Ltd. Click image for the largest view.

RayGen’s CSPV Power Station. Image Credit: RayGen Resources, Pty Ltd. Click image for the largest view.

Power towers are being developed by the Australian company, RayGen Resources, which provided design and technical support for the high efficiency prototype. Another partner in the research was Spectrolab, a U.S.based company that provided some of the cells used in the project.

The 40 percent efficiency milestone is the latest in a long line of achievements by UNSW solar researchers spanning four decades. These include the first photovoltaic system to convert sunlight to electricity with over 20% efficiency in 1989, with the new result doubling this performance.

Funded by the Australian Renewable Energy Agency (ARENA) and supported by the Australia–US Institute for Advanced Photovoltaics (AUSIAPV), ARENA CEO Ivor Frischknecht said the achievement is another world first for Australian research and development and further demonstrates the value of investing in Australia’s renewable energy ingenuity.

“We hope to see this home grown innovation take the next steps from prototyping to pilot scale demonstrations. Ultimately, more efficient commercial solar plants will make renewable energy cheaper, increasing its competitiveness.”

The UNSW team’s achievement for a new efficiency record is expected to be published by the Progress in Photovoltaics journal. It also was to be presented at the Australian PV Institute’s Asia-Pacific Solar Research Conference that began at UNSW last week.

Professor Green is not someone to be taken lightly. In some circles he is regarded as the ‘Father of photovoltaics’ as the author of six books on solar cells and numerous papers in the area of semiconductors, microelectronics, optoelectronics and, of course, solar cells.

He has experience as a Director of CSG Solar, a company formed specifically to commercialize the University’s thin-film, polycrystalline-silicon-on-glass solar cell. He leads a group well known for contributions to photovoltaics including the development of the world’s highest efficiency silicon solar cells and the successes of several spin-off companies.

Green’s awards include the 1999 Australia Prize, the 2002 Right Livelihood Award (also known as the Alternative Nobel Prize), the 2004 World Technology Award for Energy and the 2007 SolarWorld Einstein Award. He was elected into the prestigious Fellowship of the Royal Society in 2013.

The Aussie’s live in one of the best solar locations on the planet, a huge one, and they know it. We’ll be watching out for the ‘power tower’ idea. It’s a good bet that at 40 percent efficiency the idea will likely get to a pilot demonstrator and will likely amaze us all.

University of Minnesota (UM) researchers found that vehicles using electricity from renewable energy could reduce the deaths due to air pollution by 70 percent. The study isn’t exactly simple. The findings come from a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts.

From another view the study also shows that switching to vehicles powered by electricity made using natural gas also yields large health benefits.

The UM team did a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts. The results have been published in the Proceedings of the National Academy of Sciences, without a paywall.

There are many renewable and natural gas points to celebrate. On the other side of the study are some disappointments.

Vehicles running on corn ethanol or vehicles powered by coal-based or “grid average” electricity are worse for health. The study alleges switching from gasoline to those fuels would increase the number of resulting deaths due to air pollution by 80 percent or more.

The team would have been less subject to incredulous criticism had they split out the source fuels for study. It very hard to imagine that there is a 150 percent difference from renewables to ethanol. Ethanol is after all a time tested renewable. Something isn’t ringing quite right here.

Chris Tessum, co-author on the study and a researcher in the Department of Civil, Environmental, and Geo-Engineering in the University of Minnesota’s College of Science and Engineering said, “These findings demonstrate the importance of clean electricity, such as from natural gas or renewables, in substantially reducing the negative health impacts of transportation.”

The University of Minnesota team estimated how concentrations of two important pollutants – particulate matter and ground-level ozone – change as a result of using various options for powering vehicles. Air pollution is the largest environmental health hazard in the U.S., in total killing more than 100,000 people per year. Air pollution increases rates of heart attack, stroke, and respiratory disease.

The team looked at liquid biofuels, diesel, compressed natural gas, and electricity from a range of conventional and renewable sources. Their analysis included not only the pollution from vehicles, but also emissions generated during production of the fuels or electricity that power them. With ethanol, for example, air pollution is released from tractors on farms, from soils after fertilizers are applied, and to supply the energy for fermenting and distilling corn into ethanol.

Of course the team didn’t note that those ethanol pollution factors would still be there if the corn, sugarcane or other crop was used in a different way. Its a sure thing that same thread of uses applies to the full range of energy sources in the study.

Bioproducts and Biosystems Engineering Assistant Professor Jason Hill, co-author of the study said, “Our work highlights the importance of looking at the full life cycle of energy production and use, not just at what comes out of tailpipes. We greatly underestimate transportation’s impacts on air quality if we ignore the upstream emissions from producing fuels or electricity.”

The UM researchers also point out that whereas recent studies on life cycle environmental impacts of transportation have focused mainly on greenhouse gas emissions, it is also important to consider air pollution and health. The study provides a unique look at where life cycle emissions occur, how they move in the environment, and where people breathe that pollution. Their results provide unprecedented detail on the air quality-related health impacts of transportation fuel production and use.

Civil, Environmental and Geo- Engineering Associate Professor Julian Marshall, co-author on this study said, “Air pollution has enormous health impacts, including increasing death rates across the U.S. This study provides valuable new information on how some transportation options would improve or worsen those health impacts.”

The UM professors have asked an important question, what energy sources for transportation offers the lowest pollution impact on people’s health. Its a question of more importance than the greenhouse gas thing. That’s about as far as the professors get before the bias shows up. Models, assumptions, simulations, and so forth might make for interesting reading and dramatic results and conclusions, but there is very little hard evidence in the less than 5 pages of reporting.

Moreover the study still rolls in the climate change aspect as a reason for the effort.

It looks like authors poured in a lot of effort on a worthy question and came away with a narrative that generally misses the point. An energy rich standard of living and life style does not come without costs. One is the damage done through air pollution. Other than clobbering corn ethanol and coal there isn’t much here. That seems to be the point.

Its fairly obvious that energy stores and sources that rely on processes without chemical combustion are going to be advantageous. Its also plain that combustion isn’t particularly efficient as there is always heat to be used or lost.

Its a great question to be raised, but the route to useful information in planning a better more energy rich and healthier future has simply been missed.

A research team at Helmholtz Institute Ulm (HIU) established by Karlsruhe Institute of Technology has now developed an electrolyte that may be used for the construction of magnesium-sulfur battery cells.

The element magnesium is a another light metal offering very high theoretical battery capacity. Moreover magnesium is abundant in nature, it is non-toxic, and does not degrade in the atmosphere.

Magnesium Sulfur Battery Cathode Electron Microscopy Composite.  Image Credit: HIU, Karlsruhe Institute of Technology.  Click image for the largest view.

Magnesium Sulfur Battery Cathode Electron Microscopy Composite. Image Credit: HIU, Karlsruhe Institute of Technology. Click image for the largest view.

In many electrical devices, lithium-ion and metal-hydride batteries are used for energy storage. While lithium is a very good metallic base for batteries alternatives are under study because lithium batteries as good as they are not a perfect solution.

Scientists are also studying alternatives to these established battery systems in order to enhance the safety, cost efficiency, sustainability, and performance of future devices. It is their objective to replace lithium by other elements. For this purpose, all battery components have to be newly developed and the understanding of the operating electrochemical processes is required.

Magnesium-based battery cells can be considered an attractive option to replace lithium in batteries. In principle, magnesium allows higher storage densities to be reached than lithium. Other advantages of magnesium are its relative abundance in nature, its also non-toxic in most forms, and it has low degradation in air in contrast to lithium. So far, progress achieved in this area has been limited. For the design of magnesium batteries of high storage capacity and power density, suitable electrolytes are needed that can be easy to produced, that are stable, and can be used in high concentrations in different solvents.

A research team at HIU headed by Maximilian Fichtner and Zhirong Zhao-Karger has presented a new promising electrolyte in the journal Advanced Energy Materials that might allow for the development of an entirely new generation of batteries.

The new electrolyte is characterized by a number of promising properties. It possesses an unprecedented electrochemical stability window and a very high efficiency. In addition, the electrolyte can be used in various solvents and at high concentrations. Moreover, the electrolyte is chemically compatible with a sulfur cathode, which can be discharged at a voltage close to the theoretical value.

Fichtner explained that another advantage is the very simple production of the electrolyte. “Two commercially available standard chemicals, a magnesium amide and aluminium chloride, are applied. They are added to the solvent desired and subjected to stirring. This simple mixture can then be used directly as an electrolyte in the battery,” he said.

Building the magnesium sulfur battery electrolyte solution using a two-step reaction in one-pot is for now a laboratory process. There is a very long way to go with questions adding up fast for which its too soon for many good answers.

But for now, a magnesium sulfur battery electrolyte is working and getting tested with more interest and innovation sure to be on its way.

Tufts University School of Engineering researchers and collaborators from other university and national laboratories have designed and investigated a catalyst with a unique structure of single gold atoms.

The family of catalysts are composed of a unique structure of single gold atoms bound by oxygen to sodium or potassium atoms supported on non-reactive silica materials. They demonstrate comparable activity and stability with catalysts comprised of precious metal nanoparticles like platinum on rare earth and other reducible oxide supports when used in producing highly purified hydrogen.

Au-Na/[Si]MCM41 Showing a Few Gold ~1 nm Clusters and an Abundance of Atomically Dispersed Gold Species.  Image Credit: Tufts University.  Click image for the largest view.

Au-Na/[Si]MCM41 Showing a Few Gold ~1 nm Clusters and an Abundance of Atomically Dispersed Gold Species. Image Credit: Tufts University. Click image for the largest view.

The new catalysts have the potential to greatly reduce processing costs in future fuels like hydrogen.

The research paper appeared in the journal Science Express and points to new avenues for producing single-site supported gold catalysts that could produce high-grade hydrogen for cleaner energy use in fuel-cell powered devices, including vehicles.

Senior author Maria Flytzani-Stephanopoulos, the Robert and Marcy Haber Endowed Professor in Energy Sustainability and professor in the Department of Chemical and Biological Engineering at Tufts said, “In the face of precious metals scarcity and exorbitant fuel-processing costs, these systems are promising in the search for sustainable global energy solutions.”

While gold isn’t low cost, it also isn’t scarce. There is plenty around.

Flytzani-Stephanopoulos’s research group has been busy designing catalysts requiring a lower amount of precious metals to generate high-grade hydrogen for use in fuel cells. The water-gas shift reaction, in which carbon monoxide is removed from the fuel gas stream by reacting with water to produce carbon dioxide and hydrogen, is a key step in the process. Catalysts, such as metal oxide supported precious metals like platinum and gold, are used to lower the reaction temperature and increase the production of hydrogen.

The Tufts group was the first to demonstrate that atomically dispersed gold or platinum on supports, such as cerium oxide, are the active sites for the water-gas shift reaction. Metal nanoparticles are “spectator species” for this reaction.

Flytzani-Stephanopoulos explained the new research suggests single precious metal atoms stabilized with alkali ions may be the only important catalyst sites for other catalytic reactions. “If the other particles are truly ‘spectator species’, they are therefore unnecessary. Future catalyst production should then focus on avoiding particle formation altogether and instead be prepared solely with atomic dispersion on various supports,” she said.

The just published research describes how single gold atoms dispersed on non-reactive supports based on silica materials can be stabilized with alkali ions. As long as the gold atoms, or cations, are stabilized in a single-site form configuration, irrespective of the type of support, the precious metal will be stable and operate for many hours at a range of practical temperatures.

Professor Flytzani-Stephanopoulos, who also directs the Tufts Nano Catalysis and Energy Laboratory noted the results, “This novel atomic-scale catalyst configuration achieves the maximum efficiency and utilization of the gold. Our work showed that these single-site gold cations were active for the low-temperature water-gas shift reaction and stable in operation at temperatures as high as 200° C.”

“Armed with this new understanding, practitioners will be able to design catalysts using just the necessary amount of the precious metals like gold and platinum, dramatically cutting down the catalyst cost in fuels and chemicals production processes,” she concluded.

Research in the field is intensifying as the platinum cost and availability block is a major problem. The problem looks to be getting worse with the Russian sources are sure to dry up as that government tries to exert more influence and gain more cash income. All the catalyst efforts that steer around platinum are very welcome indeed.


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