UVa Engineers Propose Using Wastewater to Make Algae-Based Biofuel to Overcome Significant Environmental Impacts

With many companies investing heavily in algae-based biofuels, researchers from the University of Virginia's Department of Civil and Environmental Engineering have found there are significant environmental hurdles to overcome before fuel production ramps up. They propose using wastewater as a solution to some of these challenges.

These findings come after ExxonMobil invested $600 million last summer and the U.S. Department of Energy announced last week that it is awarding $78 million in stimulus money for research and development of the biofuel.

The U.Va. research, just published in the journal Environmental Science & Technology, demonstrates that algae production consumes more energy, has higher greenhouse gas emissions and uses more water than other biofuel sources, such as switchgrass, canola and corn.

"Given what we know about algae production pilot projects over the past 10 to 15 years, we've found that algae's environmental footprint is larger than other terrestrial crops," said Andres Clarens, an assistant professor in U.Va.'s Civil and Environmental Department and lead author on the paper. Clarens collaborated on the paper with Lisa M. Colosi, also an assistant professor in the Civil and Environmental Engineering Department; Eleazar P. Resurreccion, a graduate student in the department; and Mark A. White, a professor in U.Va.'s McIntire School of Commerce.

As an environmentally sustainable alternative to current algae production methods, the researchers propose situating algae production ponds behind wastewater treatment facilities to capture phosphorous and nitrogen – essential nutrients for growing algae that would otherwise need to be produced from petroleum. Those same nutrients are discharged to local waterways, damaging the Chesapeake Bay and other water bodies, and current technology to remove them is prohibitively expensive.

While the researchers found algae production to have a greater environmental impact than other sources, it remains an attractive source for energy. Algae, which are grown in water, don't compete with food crops grown on land and also tend to have higher energy yields than sources such as corn or switchgrass. Additionally, algae's high lipid content makes for efficient refinement to liquid fuels that could be used to power vehicles, according to the research.

"Before we make major investments in algae production, we should really know the environmental impact of this technology," Clarens said. "If we do decide to move forward with algae as a fuel source, it's important we understand the ways we can produce it with the least impact, and that's where combining production with wastewater treatment operations comes in."

As an example of the importance of completing the environmental life cycle study, Clarens

points to the 2008 ethanol boom which created a spike in corn prices worldwide and raised complex ethical issues that could have been avoided by producing separate crops for food and fuel.

"People were investing in ethanol refineries, but then we realized that it takes a lot of petroleum to grow corn and convert it to ethanol," Clarens said. "By the time you get done, you've used almost as much petroleum to make ethanol that you would have if you just put the oil straight into your car."

The research group's plans include conducting demonstration projects for the wastewater production methods. They are also pursuing complementary research on the economic lifecycle of algae compared to other bionenergy feedstocks.

The research paper is available online at http://pubs.acs.org/doi/abs/10.1021/es902838n.

Contact: Zak Richards
zr8n@virginia.edu
434-924-1383
University of Virginia

Korean Researchers Set Precedent with Manufacturing Method for Metal/Carbon Nanotube Nano-Composites Using Electroplating

 Image Source: KAIST Patent Application 20070199826, Figure 4.

Korea Advanced Institute of Science and Technology (KAIST) (Daejeon, KR) inventors Yoon-Chul Son, Jung-Joon Yoo and Jin Yu disclose a precedent setting method for manufacturing metal/carbon nanotube nano-composites using electroplating in U.S. Patent Application 20070199826.  The metal/carbon nanotube nano-composite can replace all metal thin film materials capable of being electroplated including semiconductor interconnection material like aluminum, copper, and others.

The KAIST method for manufacturing metal/carbon nanotube nano-composite includes: adding carbon nanotubes and cationic surfactants in metal plating solution including metal or metal salt and performing electroplating in the cathode.  The method for manufacturing metal/carbon nanotube nano-composite using electroplating further comprises: immersing carbon nanotubes in acid solution and filtering the solution and carrying out heat treatment; adding the heat treated carbon nanotubes and cationic surfactants in metal plating solution including metal or metal salt and dispersing the carbon nanotubes.  Then a cathode and an anode are provided in the metal plating solution including the carbon nanotubes and the cationic surfactant, to which current is applied and electroplating is carried out in order to obtain metal/carbon nanotube nano-composite (complex material).

The carbon nanotube has excellent electrical conductivity, thermal conductivity and strength, thus is expected to show more excellent physical properties when combined with specific qualities of specific metals. Therefore, there have been a lot of developments of composites including carbon nanotubes.

Especially, when it comes to forming nano-composite of metal and carbon nanotubes, researches are directed to improving mechanical properties and the nano-composite is mainly made in the form of bulk. The nano-composite in the above form is mainly manufactured via a powder method or a sintering process.

Pure carbon nanotubes are formed at high temperature of 600.about.1000.degree. C. via chemical vapor deposition method deposition method and surface treatment prior to the deposition are important to control the growing direction and speed of the pure carbon nanotube. The carbon nanotube does not constitute densely packed structure to leave empty spaces between carbon nanotubes when it grows, leading to a big problem in replacing the existing metal thin film material. There have been attempts to fill the empty spaces between the carbon nanotubes with SiO₂ etc. to use as semiconductor interconnections. When these interconnections are connected to form some layers, there is no alternative as to a process for the next layer.

There are no precedents of forming metal/carbon nanotube nano-composite in the type of thin film using electroplating until now due to the characteristics of the bar shape structure and no charges of the carbon nanotube. If metal and carbon nanotubes are simultaneously deposited at the same time by electroplating, densely packed structure unlike the growth of pure carbon nanotubes can be obtained and depositions at desired portions in a type of thin film are possible, also. Thus, all the metal thin films including the existing semiconductor metal interconnection can be replaced, improving their electrical, mechanical and thermal physical properties. Moreover, the KIST manufacturing method can be applied without changing the existing semiconductor interconnection process or the surface finishing process of electronic products, thus the present invention has good marketability and practicality.

The manufacturing method for metal/carbon nanotube nano-composite distributes carbon nanotubes at a molecule level, by a system that includes: adding carbon nanotubes and cationic surfactants which is adsorbed on the surface of the carbon nanotube in metal plating solution including metal or metal salt to constitute the plating solution; and completely separating and dispersing individual carbon nanotubes each other and carrying out electroplating.

The cationic surfactant is at least one selected from the group consisting of poly(diallyldimethylammonium chloride, PDMA), cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium chloride (DTAC), Decylamine, Dodecylamine, Hexadecylamine, Triethylamine, Octylsulfate, sodium salt, Hexylamine and Octadecylamine.

The KAIST method overcomes many prior limitations in manufacturing a metal/carbon nanotube complex material. . The metal/carbon nanotube nano-composite manufactured according KIST’s method can produce metal/carbon nanotube nano-composite in a type of thin film using electroplating, and can replace all metal thin film materials capable of being electroplated including semiconductor interconnection material like aluminum and copper, etc.

The KAIST metal/carbon nanotube nano-composite contrary to the growth of pure carbon nanotubes, grows to thin film with a densely packed structure and can be used without changing the existing process method.  As the metal/carbon nanotube nano-composite has carbon nanotubes uniformly dispersed into a metal matrix, the existing metal thin film is expected to improve the electric, mechanic and thermal physical characteristics.

Taiwanese Scientists Create More Powerful & Durable Fuel Cell Nanocatalyst Using 3D Network of Silicon Dioxide-Platinum Nanospheres

Institute Of Nuclear Energy Research (Long Tang, Taoyuan, TW) scientists Chun Ching Chien, King Tsai Jeng, Shean Du Chiou and Su Hsine Lin reveal preparations of noble metal catalysts, i.e., platinum and platinum alloys, on suitable supports with nanonetwork structures and high catalytic efficiencies in U.S. Patent Application 20090312180.  The prepared catalysts have characteristics of a three-dimensional (3-D) nano network with rigid structure, uniform hole-size and high surface area.  In addition, the platinum and platinum alloys catalysts prepared by the Chien et al’s methods will significantly improve the performances of  direct methanol fuel cells (DMFCs) and proton exchange membrane fuel cells (PEMFCs) due to robust structure, resistance to recombination, and high catalytic surfaces.

A compact structure of a monolayer or a few layers is formed by self-assembly of organic polymer, e.g., polystyrene (PS), nanospheres or inorganic, i.e., silicon dioxide (SiO₂), nanospheres on a support surface. In the void spaces of such a compact arrangement, catalyst is formed by filling with catalyst metal ion-containing aqueous solution and reduced by chemical reduction, or formed by vacuum sputtering.

When using organic polymer nanospheres as the starting or structure-directing material, the polymer particles are removed by burning at a high temperature and the catalyst having a nanonetwork structure is obtained. In the case of using silicon dioxide nanospheres as the starting material, silicon dioxide particles are dissolved with hydrofluoric acid solution and evaporated away leading to formation of a similar nanonetwork structure made of catalyst.

The catalysts prepared by these methods possess characteristics of robust in structure, uniform in hole size and high in catalytic surface area. Their main applications include uses as catalysts in direct methanol and proton exchange membrane fuel cells, as well as in chemical reactors, fuel reformers, catalytic converters, etc.

Polystyrene nanospheres or silicon dioxide nanospheres are used as the starting or structure-directing material to form a perfectly arranged, layered structure through a self-assembly process on a support. The catalyst is then formed and filled in the void spaces of the layered structure by chemical reduction or vacuum sputtering. Removing the starting material by means of burning or chemical dissolution, a catalyst with nanonetwork structure is obtained.

Due to the advancement of nanotechnologies, nanostructures can be readily fabricated. Briefly, inorganic nanoparticles are used as a precursor and mixed with organic polymer to form a homogeneous thermoplastics compound. The organic polymer is then removed by sintering at a high temperature and a nanostructure is formed. However, in general these nanostructures are suitable for used as catalyst supports only rather than as catalysts. It would be very beneficial if a catalyst itself can be fabricated into a nanostructure with excellent resistances to recombination, recrystallization and sintering while providing high surface area and high catalytic efficiency.

In conventional preparation of  platinum catalysts for DMFC and PEMFC applications, high surface area carbon supports, such as Cabot Vulcan XC-72 and Chevron Shawinigan, are commonly used. In general, catalyst metal in ions or colloidal sols are adsorbed to carbon support surfaces and reduced by chemical reactions. High temperature reduction using hydrogen gas is also commonly used. However, such prepared nanocatalysts suffer from drawbacks of re-construction, re-crystallization and sintering when in use to form larger particles and substantially lose their catalytic surfaces. These give rise to significantly lower catalytic efficiencies and shorter service lives. Novel approaches are needed to prepare and stabilize catalysts under all application conditions, which researchers from the Institute Of Nuclear Energy Research believe they have succeeded in developing.

In fact, using some Institute Of Nuclear Energy Research nanomaterials, e.g., polystyrene nanospheres and silicon dioxide nanospheres, as structure-directing agents, do provide a new approach to achieve this goal. These nanospheres readily form closely packed, layered structures of one to several layers on a smooth support surface when applied at diluted conditions. With these unique characteristics of such nanomaterials, the researchers are able to prepare novel catalysts with nanonetwork structures on suitable supports that are totally different from those of the conventional nano catalysts. The advantages are to overcome the drawbacks encountered by conventional nanocatalysts and provide more durable and efficient fuel cell catalysts.

Catalysts play key roles in most of the important chemical reactions, including syntheses of organic compounds, reforming production of hydrogen from methanol, natural gas and gasoline, catalytic conversion of carbon monoxide, nitrogen oxides and unburned fuels, etc. In particular, platinum and platinum alloys are indispensable catalysts for direct methanol and proton exchange membrane fuel cells with respect to electro-reduction of oxygen and electro-oxidation of fuel.  

The world fuel cell market is estimated at $8.8 billion for 2009 and is expected to achieve a value of more than $14 billion by 2014 showing a compound average growth rate of about 9.6% according to iRAP report Fuel Cells, Hydrogen Energy and Related Nanotechnology—A Global Industry and Market Analysis.  The still infant fuel cell and hydrogen energy industry is highly fragmented. Worldwide about 3870 organizations are involved in research or the supply chain for fuel cells, hydrogen energy and related nanotechnology. Those organizations spent an estimated $8.4 billion in 2008. More than 2180 organizations are involved in nanotechnology research and development related to fuel cells and hydrogen energy and are estimated to have spent a total of $4.7 billion for fuel cells and hydrogen energy incorporating nanotechnology in 2008. Of that $4.7 billion, about $2 billion represents the value of nanotechnology for fuel cells and hydrogen energy separate from all other expenditures. The $2 billion includes both nanomaterials incorporated into fuel cells and the cost of nanotechnology research directed at the fuel cell industry.

Siemens Says $44 Billion 2009 Global Wind Power Market Will Reach $294 Billion by 2030

 Siemens has confirmed its objective to become one of the world’s top providers of wind turbines. Siemens entered the wind power market five years ago with its acquisition of Denmark’s Bonus Energy. Since then, wind power operations at Siemens have undergone rapid development. The workforce has grown sevenfold, while revenue has actually increased tenfold. "This is a success story whose narrative we wish to continue," says Andreas Nauen, CEO of the Wind Power Business Unit. "The overall global wind power market is growing at 12 percent annually. We intend to significantly outpace the market growth to become one of the top three providers by 2012." Siemens’ strategy will be to strengthen its position as a global market leader in offshore wind farms while expanding its international production network in key markets and ensuring technology leadership, for example gearless and floating wind turbines, with innovative products.

"Wind power has excellent perspectives," says Nauen. "The global wind power market will grow from about $44 billion (EUR30 billion) annually today to more than $294 billion (EUR200 billion) by 2030. We anticipate especially robust growth in the Asia-Pacific region. The market growth in North America and Europe, however, will also be significant.”

Offshore wind farms are playing an increasingly important role. The potential for offshore wind power in Europe is estimated at around 70 gigawatts, about half of the power plant capacity currently installed in Germany. At present, only 1.5 percent of that is being utilized. In the past fiscal year, Siemens secured the largest offshore wind power contract ever granted: to provide Dong Energy with 500 turbines of the 3.6-megawatt class. Some of these turbines will be used in London Array, which will be the world’s largest offshore wind farm when it is complete. To date, Siemens has realized ten offshore wind farms with a capacity of 850 megawatts. Contracts from Germany include the offshore wind farm Baltic 1. Siemens is also successful in the onshore wind power market: In the past fiscal year, for example, Siemens secured contracts for six wind farms in North America and for Europe’s largest onshore wind farm in Scotland. Recent orders have come from Mexico and New Zealand.

Siemens Wind Power has pursued a consistent strategy of further expanding its international production network in key markets. After establishing a rotor blade production plant in Fort Madison, Iowa, Siemens recently began construction on a new nacelle production facility in Hutchinson, Kansas. And in 2010, a plant outside of Shanghai will commence production of rotor blades and nacelles. Production is also planned in India.

Siemens relies on innovative products to ensure its future success. In early December 2009, Siemens completed the prototype of its newly developed gearless wind turbine, which promises even higher availability than standard wind turbines with about half the number of parts. Siemens is also working with StatoilHydro to promote the innovative Hywind project. Hywind is a floating wind turbine that can be positioned in waters from 120 to 700 meters in depth. This opens up new opportunities for offshore wind power.

Siemens Wind Power currently has a record order backlog of $8.8 billion (EUR6 billion.) Over 8,000 wind turbines are in operation worldwide with a capacity of more than 9,600 megawatts. Together, they make an important contribution to protecting our climate by saving over 20 million metric tons of CO2 emissions annually. The Business Unit Wind Power is part of the Renewable Energy Division of Siemens which also includes photovoltaics and solar thermal power plants.

Wind energy is part of Siemens’ Environmental Portfolio. In fiscal 2009, revenue from the Portfolio totaled about $33.8 billion (EUR23 billion), making Siemens the world’s largest supplier of ecofriendly technologies. In the same period, its products and solutions enabled customers to reduce their CO2 emissions by 210 million tons.   Nanotechnology is used to manufacture larger and stronger wind turbine rotor blades.

Titanium Dioxide Nanocoating Market in Japan Pegged at $1.1 Billion

Two-thirds of Tokyo’s buildings, as well as other high -profile constructions around the world, now incorporate ‘self-cleaning’ window glass coated with a 10 -20 nm layer of titanium dioxide (TiO2), noted Akira Fijishime (Kanagawa Academy of Science and Technology, Japan) at “Nanotechnology for Sustainable Economy European and International Forum on Nanotechnology” (Prague, Czech Republic, June 2-5, 2009). TiO2 promotes the decomposition of pollutants such as NOx, and acts as a wetting agent to facilitate the washing action of rainfall. Other applications of this versatile material are in fog -resistant mirrors and self –disinfecting coatings on tiles used in hospitals, as well as in air - and water-purification. In Japan alone, the market size is estimated at around $1.1 billion (€750 million), according to conference proceedings.

The market in Europe for TiO2 coatings remains slow due to delays in the introduction of relevant international standards, according to a conference report. Self-cleaning glass coatings are available from a number of manufacturers in the U.S. Titanium dioxide is a safe substance, which is harmless to humans. It has been approved by the food-testing laboratory of the United States Food and Drug Administration (FDA).

Photocatalytic materials have massive commercial potential, e.g. in the construction and environmental sectors. Studies over many years have focused mainly on titanium dioxide (TiO2) because of its stability, commercial availability and ecological safety. When the photo-catalyst, TiO2, captures ultraviolet light it forms activated oxygen from water or oxygen in the air. Because of its catalytic nature photo-catalyst properties are not consumed during this chemical reaction. The treated surface regenerates its photo-catalytic effect by reacting with oxygen in the air. TiO2 actively decompose bacteria, biological and chemical pollutants, toxins, bad odors, mold and other fungi.

Deserts and Nanotechnology Can Provide Clean Power and Water for 10 Billion

The global annual fossil energy consumption corresponds to the energy received by 5.7 hours sunshine in deserts. This is about 0.15 % of annually incoming radiation.  Solar power from deserts could supply electricity to 10 billion people in 2050.    

The technology exists to convert 15% of solar radiation into the useful energy form of electricity.  This means, that 1% of the area of global deserts would be sufficient  to produce the entire annual primary energy consumption of humankind as electric power. In other words: any conceivable global demand of energy, today or in future, could be produced from solar energy in deserts.

The DESERTEC Concept is an inter-continental project to supply sustainable electricity to Europe (EU), the Middle East (ME) and North Africa (NA) up to the year 2050. It shows that a transition to competitive, secure and compatible supply is possible using renewable energy sources and efficiency gains, and fossil fuels as backup for balancing power.   The project will harness the sun’s power, supplying the energy needs of that region as well as transporting power from Africa to Europe along energy superhighways (high-efficiency high voltage direct current lines). Spain is already using solar thermal plants, and they have also been in use in the U.S. for more than 20 years.

To this end red squares in the figure represent the accumulated areas for collectors typically needed to generate 17,000 TWh/y (terawatt hours per year) which is approximately the current world consumption, 3200 TWh/y (approx. EU-25 consumption), and 600 TWh/y (approx. Middle East/North Africa (MENA) consumption).

The square labeled “TRANS-CSP Mix 2050” indicates the space needed for solar collectors to supply the needs for seawater desalination and about two-thirds of the electricity consumption in MENA in the year 2050 and about one-fifth of the European electricity consumption by Concentrating Solar Thermal Power Plants (2,940 TWh/y in total)

The figure below shows Concentrating Solar Thermal Power Plants in the Mojave Desert.

Until 2020, the market for solar thermal power plants will show annual double-digit growth rates and attain annual sales of over $28 billion (EUR20 billion). In the future, the primary focal growth regions will be the U.S., South Africa, Australia, Spain, India, North Africa and the Middle East.  The developing and in particular the developed world depend crucially on the continuous supply of energy. The fossil fuel consumption in 2005 was 107,000 TWh/y.

If desalination of sea water is powered by solar energy instead by fossil fuels, its environmental impacts are significantly reduced. However, seawater desalination itself is always a considerable burden to the environment, due to the resulting salty brine and the necessary chemical water treatment. Nano-filtration of intake water can mitigate those impacts, but more energy is required in that case. Therefore, activating the existing potential for enhanced efficiency of water use, water management and infrastructure is also a very high priority, in order to minimize the need for desalination. The European AQUA-CSP study analyzes the environmental impact of a broad application of solar-powered seawater desalination to cover the expected freshwater deficits.

Siemens AG is acquiring the solar thermal power company Solel Solar Systems Ltd. to bolster its position in renewable power.  Solel has a workforce of over 500 and is one of the world´s two leading suppliers of solar receivers, which are key components of so-called parabolic trough power plants. The high-growth company, which posted revenue totaling almost $90 million in the first six months of its current fiscal year (January 1 to June 30, 2009), is also a leader in the planning and construction of solar fields. The purchase price is about $418 million.  Since 2006, Solel has also been present on the Spanish market, supplying key components for 15 solar thermal power plants with a combined capacity of 750 megawatts. In addition, the company is also active in the U.S. market. The transaction which much receive regulatory approval is expected to close before 2010.

Tsinghua University Carbon Nanotube Magnesium Composite Suitable for Aerospace and Auto Use

Nowadays, various alloys have been developed for special applications. Among these alloys, magnesium alloys have relatively superior mechanical properties, such as low density, good wear resistance, and high elastic modulus. However, the toughness and the strength of the magnesium alloys are not able to meet the increasing needs of the automotive and aerospace industry for tougher and stronger alloys. Tsinghua University scientists created a magnesium-based carbon nanotube composite material that is strong, tough, has a high density, and can be widely used in a variety of fields including the automotive and aerospace industries.

In the magnesium-based composite material, nanoscale reinforcements (e.g. carbon nanotubes and carbon nanofibers) are mixed with the magnesium metal or alloy. The most common methods for making the magnesium-based composite material have been thixomolding and die-casting. However, in die-casting, the magnesium or magnesium alloy is easily oxidized. In thixomolding, the nanoscale reinforcements are added to melted metal or alloy but are prone to aggregate. As such, the nanoscale reinforcements can't be well dispersed.

Tsinghua researchers Kam-Shau Chan, Cheng-Shi Chen, Guang-Liang Sheu, Qing-Chun Du And Wen-Zhen Li developed an apparatus for fabricating a magnesium-based carbon nanotube composite material, in which the problems of aggregation and settling are eliminated or at least alleviated. Tsinghua University’s method includes the steps of: (a) providing a magnesium-based melt and carbon nanotubes, mixing the carbon nanotubes with the magnesium-based melt to achieve a mixture; (b) injecting the mixture into at least one mold to achieve a preform; and (c) extruding the preform to achieve the magnesium-based carbon nanotube composite material.

The mixing device includes a container with a protective gas therein, a stirrer disposed in a center of the container, and a heater (e.g. hot wires) disposed on a outer wall of the container. Quite suitably, the protective gas can, beneficially, be made up of at least one of nitrogen, ammonia, and a noble gas. The heater heats the container to a predetermined temperature in the approximate range from 550 degree C. to 750 degree C. Carbon nanotubes are in the approximate range from 1% to 5% by weight in the alloy. The materials is extruded into performs where it cools quickly enough to prevent settling and aggregation of the carbon nanotubes.

In the extrusion step, the preforms experience a deformation process when extruded from the exit. In the deformation process, different parts of the preforms will be mixed together. The carbon nanotubes are redistributed in the preforms which enhances dispersion uniformity of the carbon nanotubes in the magnesium-based carbon nanotube composite material. The mixing apparatus is detailed in U.S. Patent Application 20090127743. It is one of 47 applications concerning carbon nanotubes filed by Tsinghua University which is among China's leaders in nanotechnology research and development. The University already hold 20 U.S. Patents related to nanotechnology.