Mostrando entradas con la etiqueta Potabilización. Mostrar todas las entradas
Mostrando entradas con la etiqueta Potabilización. Mostrar todas las entradas

miércoles, 24 de abril de 2013

High-Concentration Photovoltaic Thermal System From IBM Promises 80% Efficiency, Potable Water, And Air Conditioning

ORIGINAL: SolarLove
How does a cost-competitive photovoltaic system that is able to concentrate sunlight 2000 times and then capture 80% of the concentrated energy sound? Pretty good, right? Such a system is currently being developed by researchers at IBM Research, Airlight Energy, ETH Zurich, and Interstate University of Applied Sciences Buchs NTB, after winning a three-year $2.4 million grant from the Swiss Commission for Technology and Innovation.
Image Credit: © IBM
And in addition to generating electricity, the system can its<div style="font-size: medium; line-height: 1.5em; text-align: justify;">elf desalinate water and provide air-conditioning, useful features for the sunny and remote regions that the system is designed for.

An economical High Concentration Photovoltaic Thermal (HCPVT) system, that in addition to supplying electricity can desalinate water and provide air conditioning, is the complete package as far as many regions of the world are concerned.

The prototype system makes use of a large parabolic dish, composed of a number of mirror facets, which are coordinated to a sun tracking system. The system automatically repositions itself to the optimum angle for power generation. The sunlight that hits the mirrors is reflected off of them onto a number of microchannel-liquid cooled receivers with triple junction photovoltaic chips. Every one of these 1×1 centimeter chips “can convert 200-250 watts, on average, over a typical eight hour day in a sunny region.” And there are hundreds of these chips in the design, providing a total of about 25 kilowatts of electrical power.


The press release notes:

The photovoltaic chips are mounted on micro-structured layers that pipe liquid coolants within a few tens of micrometers off the chip to absorb the heat and draw it away 10 times more effective than with passive air cooling. The coolant maintains the chips almost at the same temperature for a solar concentration of 2,000 times and can keep them at safe temperatures up to a solar concentration of 5,000 times.

The direct cooling solution with very small pumping power is inspired by the hierarchical branched blood supply system of the human body and has been already tested by IBM scientists in high performance computers, including Aquasar. An initial demonstrator of the multi-chip receiver was developed in a previous collaboration between IBM and the Egypt Nanotechnology Research Center.

“We plan to use triple-junction photovoltaic cells on a micro-channel cooled module which can directly convert more than 30 percent of collected solar radiation into electrical energy and allow for the efficient recovery of an additional 50 percent waste heat,” said Bruno Michel , manager, advanced thermal packaging at IBM Research. “We believe that we can achieve this with a very practical design that is made of lightweight and high strength concrete, which is used in bridges, and primary optics composed of inexpensive pneumatic mirrors — it’s frugal innovation, but builds on decades of experience in microtechnology.

By utilizing such a high concentration of sunlight, and the rather low cost of the design, the researchers think that they can realize a cost per aperture area under $250 per square meter — that is roughly 3 times lower than in similar systems. According to them, “the levelized cost of energy will be less than 10 cents per kilowatt hour (KWh). For comparison, feed in tariffs for electrical energy in Germany are currently still larger than 25 cents per KWh and production cost at coal power stations are around 5-10 cents per KWh.”

One of the innovations of the new system is its collection and repurposing of the “waste heat” generated by solar thermal. By utilizing the heat instead of simply allowing it to dissipate, it becomes possible to cheaply desalinate water and provide cooling via a thermal-driven adsorption chiller, while also solving the overheating problems of solar chips.

In order to efficiently capture the waste heat, the researchers made use of an advanced technology that was already developed and in use, the water-cooling systems for very high-performance computers such as Aquasar and SuperMUC. While that heat is simply reused to provide space heating for the facilities, the captured heat in this instance will be used to heat salty water that is then distiller via vaporization. The researchers say that the system could provide up to “30-40 liters of drinkable water per square meter of receiver area per day, while still generating electricity with a more than 25 percent yield or two kilowatt hours per day.” So with a large array of these systems it would be very possible to provide enough water for a small city/town.

The system also possesses the ability to provide air conditioning, via a thermal driven adsorption chiller. “An adsorption chiller is a device that converts heat into cooling via a thermal cycle applied to an absorber made from silica gel, for example. Adsorption chillers, with water as working fluid, can replace compression chillers, which stress electrical grids in hot climates and contain working fluids that are harmful to the ozone layer.”

Researchers are currently testing a prototype of the HCPVT system at IBM Research — Zurich.

domingo, 3 de marzo de 2013

The top 10 emerging technologies for 2013

(according The World Economic Forum)

Image: A wrist band created by means of 3D printing in Berlin REUTERS/Thomas Peter

New challenges need new technologies to tackle them. Here, the World Economic Forum’s Global Agenda Council on Emerging Technologies identifies the top 10 most promising technology trends that can help to deliver sustainable growth in decades to come as global population and material demands on the environment continue to grow rapidly. These are technologies that the Council considers have made development breakthroughs and are nearing large-scale deployment.
OnLine Electric Vehicles (OLEV)
Wireless technology can now deliver electric power to moving vehicles. In next-generation electric cars, pick-up coil sets under the vehicle floor receive power remotely via an electromagnetic field broadcast from cables installed under the road. The current also charges an onboard battery used to power the vehicle when it is out of range. As electricity is supplied externally, these vehicles need only a fifth of the battery capacity of a standard electric car, and can achieve transmission efficiencies of over 80%. Online electric vehicles are currently undergoing road tests in Seoul, South Korea.

3-D printing and remote manufacturing
Three-dimensional printing allows the creation of solid structures from a digital computer file, potentially revolutionizing the economics of manufacturing if objects can be printed remotely in the home or office. The process involves layers of material being deposited on top of each other in to create free-standing structures from the bottom up. Blueprints from computer-aided design are sliced into cross-section for print templates, allowing virtually created objects to be used as models for “hard copies” made from plastics, metal alloys or other materials.

Self-healing materials
One of the defining characteristics of living organisms is their inherent ability to repair physical damage. A growing trend in biomimicry is the creation of non-living structural materials that also have the capacity to heal themselves when cut, torn or cracked. Self-healing materials which can repair damage without external human intervention could give manufactured goods longer lifetimes and reduce the demand for raw materials, as well as improving the inherent safety of materials used in construction or to form the bodies of aircraft.

Energy-efficient water purification
Water scarcity is a worsening ecological problem in many parts of the world due to competing demands from agriculture, cities and other human uses. Where freshwater systems are over-used or exhausted, desalination from the sea offers near-unlimited water but a considerable use of energy – mostly from fossil fuels – to drive evaporation or reverse-osmosis systems. Emerging technologies offer the potential for significantly higher energy efficiency in desalination or purification of wastewater, potentially reducing energy consumption by 50% or more. Techniques such as forward-osmosis can additionally improve efficiency by utilizing low-grade heat from thermal power production or renewable heat produced by solar-thermal geothermal installations.

Carbon dioxide (CO2) conversion and use
Long-promised technologies for the capture and underground sequestration of carbon dioxide have yet to be proven commercially viable, even at the scale of a single large power station. New technologies that convert the unwanted CO2 into saleable goods can potentially address both the economic and energetic shortcomings of conventional CCS strategies. One of the most promising approaches uses biologically engineered photosynthetic bacteria to turn waste CO2 into liquid fuels or chemicals, in low-cost, modular solar converter systems. Individual systems are expected to reach hundreds of acres within two years. Being 10 to 100 times as productive per unit of land area, these systems address one of the main environmental constraints on biofuels from agricultural or algal feedstock, and could supply lower carbon fuels for automobiles, aviation or other big liquid-fuel users.

Enhanced nutrition to drive health at the molecular level
Even in developed countries millions of people suffer from malnutrition due to nutrient deficiencies in their diets. Now modern genomic techniques can determine at the gene sequence level the vast number of naturally consumed proteins which are important in the human diet. The proteins identified may have advantages over standard protein supplements in that they can supply a greater percentage of essential amino acids, and have improved solubility, taste, texture and nutritional characteristics. The large-scale production of pure human dietary proteins based on the application of biotechnology to molecular nutrition can deliver health benefits such as muscle development, managing diabetes or reducing obesity.

Remote sensing
The increasingly widespread use of sensors that allow often passive responses to external stimulae will continue to change the way we respond to the environment, particularly in the area of health. Examples include sensors that continually monitor bodily function – such as heart rate, blood oxygen and blood sugar levels – and, if necessary, trigger a medical response such as insulin provision. Advances rely on wireless communication between devices, low power-sensing technologies and, sometimes, active energy harvesting. Other examples include vehicle-to-vehicle sensing for improved safety on the road.

Precise drug delivery through nanoscale engineering
Pharmaceuticals that can be precisely delivered at the molecular level within or around a diseased cell offer unprecedented opportunities for more effective treatments while reducing unwanted side effects. Targeted nanoparticles that adhere to diseased tissue allow for the micro-scale delivery of potent therapeutic compounds while minimizing their impact on healthy tissue, and are now advancing in medical trials. After almost a decade of research, these new approaches are finally showing signs of clinical utility.

Organic electronics and photovoltaics
Organic electronics – a type of printed electronics – is the use of organic materials such as polymers to create electronic circuits and devices. In contrast to traditional (silicon-based) semiconductors that are fabricated with expensive photolithographic techniques, organic electronics can be printed using low-cost, scalable processes such as ink jet printing, making them extremely cheap compared with traditional electronics devices, both in terms of the cost per device and the capital equipment required to produce them. While organic electronics are currently unlikely to compete with silicon in terms of speed and density, they have the potential to provide a significant edge in cost and versatility. The cost implications of printed mass-produced solar photovoltaic collectors, for example, could accelerate the transition to renewable energy.

Fourth-generation reactors and nuclear-waste recycling
Current once-through nuclear power reactors use only 1% of the potential energy available in uranium, leaving the rest radioactively contaminated as nuclear “waste”. While the technical challenge of geological disposal is manageable, the political challenge of nuclear waste seriously limits the appeal of this zero-carbon and highly scalable energy technology. Spent-fuel recycling and breeding uranium-238 into new fissile material – known as Nuclear 2.0 – would extend already-mined uranium resources for centuries while dramatically reducing the volume and long-term toxicity of wastes, whose radioactivity will drop below the level of the original uranium ore on a timescale of centuries rather millennia. This makes geological disposal much less of a challenge (and arguably even unnecessary) and nuclear waste a minor environmental issue compared to hazardous wastes produced by other industries. Fourth-generation technologies, including liquid metal-cooled fast reactors, are now being deployed in several countries and are offered by established nuclear engineering companies.

This list has been compiled by the World Economic Forum’s Global Agenda Council on Emerging Technologies, of which David King is currently chair. For a full list of the Council’s members see here

Noubar Afeyan. Founder and Chairman Joule Unlimited
PhD in Biochemical Engineering, MIT. Since 2000, Co-Founder, Managing Partner and Chief Executive Officer, Flagship Ventures; concurrently, Senior Lecturer, MIT and Visiting Scholar, Wyss Institute for Biologically Inspired Engineering, Harvard University. Author, numerous scientific publications. Holder of several patents.






Sir David King. Professor and Director Cambridge Kaspakas
Formerly: Head, Department of Chemistry, University of Cambridge; Master, Downing College, Cambridge; 2000-07, Chief Scientific Adviser, UK Government, widely considered responsible for persuading the UK Government to take a world leading position on climate change; 2008-12, Founding Director, Smith School of Enterprise and the Environment, University of Oxford. Currently: Senior Science Adviser, UBS; Director, Cambridge Kaspakas; Chancellor, University of Liverpool, UK; Member, President's Advisory Council, Government of Rwanda. Published around 500 papers on physical chemistry and science policy issues. Recipient of awards and honours including: knighted for contributions to science and science policy; Officier of the Legion of Honour, awarded by the French President.


Michael Grätzel. Professor,
Laboratory of Photonics and Interfaces
Ecole Polytechnique Fédérale de Lausanne (EPFL)
Doctorate in Natural Science, Technical University, Berlin. Professor, Ecole Polytechnique de Lausanne, directs Laboratory of Photonics and Interface; pioneered research on energy and electron transfer reactions in mesoscopic-materials and application in solar energy conversion systems, optoelectronic devices and lithium ion batteries; discovered new type of solar cell based on dye sensitized nanocrystalline semiconductor oxide particles. Author of over 800 peer-reviewed publications, two books and holder of more than 50 patents. Recipient of awards including: Balzan Prize; Galvani Medal; Faraday Medal; Harvey Prize; Gerischer Award; Dutch Havinga Award and Medal; International Prize, Japanese Society of Coordination Chemistry.


Nayef Al-Rodhan. Senior Member
St Antony's College, University of Oxford
Studies, Yale University, Mayo Clinic and Harvard University. Philosopher, neuroscientist and geostrategist (www.sustainable-history.com). Senior Member, St Antony's College, University of Oxford, UK; Director, Geopolitics of Globalisation and Transnational Security Programme, Geneva Centre for Security Policy, Geneva. Author of 21 books. Recipient of awards.





Hu Zhijian. Secretary-General of the CPC,
Chinese Academy of Science and Technology for Development
Ministry of Science and Technology of the People's Republic of China

Degree in Electronic Engineering, Shanghai Jiao Tong Univ.; postgraduate degree in Science and Mgmt, Fudan Univ.; Doctorate in Technological Innovation and Mgmt, Chinese Academy of Sciences. 1987-93, Teaching Assistant and Lecturer, Chinese Academy of Sciences; 1993-96, Assistant Consultant, State Commission of Science Technology of China; 1996-98, Assistant Consultant, State Leading Group for Science and Tech. With the Ministry of Science and Technology: 1998-2001, Divisional Director, and 2001-08, Deputy Director-General, Department of Policy, Regulations and Reform; 2008-09, Counsel of the General Office; since 2009, current position. Since 2010, Deputy Director, research and drafting group of the 12th National Five-Year Plan for Science and Technology Development.


Clare Grey. Fellow of the Royal Society and
Professor of Chemistry.
University of Cambridge
BA and 1991, DPhil in Chemistry, Oxford University. 1992-93, Visiting Scientist, DuPont CR&D, Wilmington, Delaware; 1994, Assistant, 1997, Associate and 2001, Full Professor, Stony Brook University (SBU). Geoffrey Moorhouse-Gibson Professor of Chemistry, Cambridge University. Since moving to Cambridge in 2009, maintains a part-time position at SBU as Associate Director, Northeastern Chemical Energy Storage Center, a US DOE Energy Frontier Research Center. Research interests: development of structure-function correlations for materials for use in energy storage and conversion.



James Wilsdon. Professor of Science and Democracy 
University of Sussex
2001-08, Head of Science and Innovation, Demos (UK think tank) and Director, Atlas of Ideas project, which explored changing global geography of science and innovation; 2008-11, Director, Science Policy, Royal Society, the UK's national academy of science. Currently, Professor of Science and Democracy, Science Policy Research Unit (SPRU), University of Sussex, UK. Author on science policy, innovation and emerging technologies.





Andrew D. Maynard.
Director, Risk Science Center 
University of Michigan
BSc, Birmingham University, UK; PhD, Cambridge University. Formerly, Co-Chairman, Nanotechnology Health and Environment Implications working group, US National Nanotechnology Initiative. Interim Chair, Environmental Health Sciences Dept. Member of the Advisory Board: Centre for Environmental Impacts of Nanotechnology; NISE Net; C&E News; nanotech advisory group to President's Council of Advisors on Science and Technology. Member of the Advisory Panel: National Academies of Science; Council of Canadian Academies; US EPA. Director, Risk Science Center, University of Michigan. Author. International speaker and commentator on emerging technologies.



Mark Lynas. Freelance Writer on Climate Change 
2009, Adviser on Climate Change to the President of the Maldives; was in the Maldives' effort to be the first carbon neutral country on Earth by 2020, and its role in the international climate change process. Visiting Research Associate, School of Geography and the Environment, Oxford University. Author of: High Tide: News from a warming world (2004); Six Degrees: Our future on a hotter planet (2007; translated into 22 languages; also a TV series by National Geographic); The God Species: How the Planet Can Survive the Age of Humans (2011; also available in Swedish, Dutch and other languages). Frequent speaker on climate change science and policy, focusing in particular on how carbon neutral targets can break the international logjam on climate mitigation, and how emissions reduction should be seen as an opportunity not a sacrifice.

Tim Harper. Chief Executive Officer and President Cientifica
Technology entrepreneur. Founder, Cientifica. Co-Founder, Nanosight, a nanoparticle visualization and sizing company. Adviser to universities, European Commission, large companies and national governments, including Austria and Singapore. Founder and former Executive Director, European NanoBusiness Association. Frequent public speaker and media commentator on nanotechnologies. Author of articles published in: Nanotechnology; Nature; Microscopy and Analysis. Co-Author, Nanotechnology Opportunity Report. Expertise: nanotechnologies, entrepreneurship, venture capital, technology transfer, government policy, regulation of technologies.

Jeffrey Carbeck. Chief Technology Officer MC10
1990, BSE, University of Michigan; 1996-98, postdoctoral research, Harvard; 1996, PhD, MIT. 1998-2006, Faculty, Dept of Chemical Engineering, Princeton; concurrently, Director, Program in Engineering Biology and Member, Princeton Institute for the Science and Technology of Materials (PRISM). 2006: Chief Scientist, Nano-Terra and Co-Founder and CTO, Arsenal Medical (spun-off into 480 Biomedical). 2009: Clean Energy Fellow, New England Clean Energy Council and founding CTO, MC10. Currently, Subject Matter Expert, Deloitte Consulting, expertise in advanced materials and process technologies. Member: Advisory Board, Department of Materials Science and Engineering and National Advisory Board for Technology Transfer, University of Michigan. Author of over 30 articles; co-inventor on over 25 patents and patent applications. Recipient of numerous awards and honours, including: named one of 40 outstanding professionals under the age of 40, Boston Business Journal.


Kiyoshi Matsuda. Chief Innovation Officer, Corporate Strategy Office 
Mitsubishi Chemical Holdings Corporation
BSc, University of Tokyo; MSc, MIT. Since 1977, with Mitsubishi Chemical including: 10 years' engineering experience in fine chemicals operation; Research Engineer; Director, Central Research Centre; currently, engaged in new business development and strategic planning of sustainable development. Chair, Capacity Building Task Force, ICCA CP&H.








Javier Garcia-Martinez. Founder and Director 
Rive Technology
Professor of Chemistry and Director, Nanotechnology Molecular Laboratory, University of Alicante, Spain. Co-Founder, Rive Technology, a clean energy company, commercializing advanced catalyst technology. Holder of 15 patents. Author on nanomaterials, catalysis and energy, including: Nanotechnology for the Energy Challenge (2010); The Chemical Element: Chemistry's Contribution to our Global Future (2011). Recipient, the Europa Medal and the TR 35 Award, MIT's Technology Review magazine.




Angela Belcher. Professor of Materials Science and
Engineering and Biological Engineering 
Massachusetts Institute of Technology (MIT)
1991, BA in Creative Studies and 1997, PhD in Chemistry, University of California, Santa Barbara. Materials Chemist, with experience in the fields of biomaterials, biomolecular materials, organic-inorganic interfaces and solid state chemistry. Expertise: understanding and using the process by which nature makes materials in order to design novel hybrid organic-inorganic electronic and magnetic materials on new length scales. Recipient of awards: Du Pont Young Investigators Award (1999); Presidential Early Career Award in Science and Engineering (2000).







Julia R. Greer. Assistant Professor of Materials Science and Mechanics 
California Institute of Technology (Caltech)
1997, SB in Chemical Engineering with minor in Advanced Music Performance, Massachusetts Institute of Technology; 2005, PhD in Materials Science, Stanford University. 2000-03, Integration Engineer, mask micro-fabrication facility, Intel Corporation. 2005-07, Post-Doctoral Fellow, Palo Alto Research Center, studied flexible electronics. 2007, joined Division of Engineering and Applied Sciences, California Institute of Technology. Key focus of research on development of innovative experimental approaches to assess mechanical properties and deformation mechanisms in nano structures. Recipient of numerous awards.

jueves, 31 de enero de 2013

Nano-Sponge Cleans Up Water Runoff

January 24, 2013


We’ve all seen the oily rainbow sheen in parking lot puddles after a storm. But it’s easy to forget what happens next: That oil finds its way to a storm drainage system, where it’s likely to be flushed untreated into local waterways, and could carry with it pesticides, household chemicals, PCBs, and nutrients that cause algae blooms. 

"Stormwater runoff is one of the biggest problems in America in terms of water pollution," says Paul Edmiston, a chemist with ABSMaterials who won a 2011 PopMech Breakthrough Award for Osorb, a nanoparticle product that soaks up non-polar molecules and can remove 90 to 100 percent of water pollutants. (You can watch the video of Edmiston emptying a bottle of motor oil into a glass of water, shaking in the white powder, and then drinking it up.) Edmiston and ABSMaterials have announced they are now using Osorb to clean up storm water runoff at the College of Wooster in Ohio. 


Wooster contracted the ABSMaterials team to set up bioswales, drainage ditches that use plants to slow the movement of water, across the campus’ agricultural fields and parking lots. These bioswales will also contain a small percentage of Osorb mixed in with the soil and plants. The Osorb grabs the pollutants in the runoff, then releases them slowly so that the soil microbes and plants can biodegrade the chemicals without being poisoned. 

Edmiston estimates that one 20-foot by 5-foot Osorb bioswale plot can reduce the runoff from a 30,000 square foot parking lot by 516,000 gallons of water per year, and could treat up to 1 million gallons per month. The output is clean water that seeps into the ground, and Edmiston says the plants seem to like growing in the Osorb-soil. 

His team has already been testing a plot at the College of Wooster, and is now working to expanding to treat runoff from the campus’ 20 acres of parking lots and other areas where drainage is a problem. Ohio State and Purdue universities are also considering installing Osorb-enhanced bioswales. 

"We can’t build a pipe to every parking lot and agricultural field, but if we can take a small amount of space and turn it into green infrastructure, we can treat the water on-site and percolate it into groundwater cleanly," Edmiston says. 

viernes, 18 de enero de 2013

Descontaminan agua con llantas recicladas

10 de Enero de 2013

Add caption

Con menos químicos y energía se puede producir carbón activado, material indispensable para purificar el agua potable. Esto es posible al aprovechar neumáticos usados que no tienen buen manejo ambiental.

En Colombia se usaron 4.493.092 llantas en el año 2008, según estimaciones del Ministerio de Ambiente y Desarrollo Sostenible (MADS). La cifra preocupa, por cuanto, luego de su uso, son almacenadas en depósitos clandestinos o desechadas en espacios públicos, lo que ocasiona graves problemas ambientales.

“Los neumáticos usados se convierten en el hábitat ideal para vectores como ratas y mosquitos, que transmiten enfermedades como el dengue, la fiebre amarilla y la encefalitis equina. Cuando cumplen su ciclo, son arrojados en botaderos a cielo abierto, contaminan el suelo, los recursos naturales renovables y afectan el paisaje. Adicionalmente, dificultan la operación de los rellenos sanitarios”, indica la Resolución 1457 del MADS, que regula la disposición de estos residuos.

El principal problema es que el caucho del que están hechas es difícil de degradar y no hay una manera de hacerlo sin contaminar. Por eso, investigadores de la Universidad Nacional de Colombia en Bogotá desarrollaron una técnica que consume bajas cantidades de químicos y menos energía, para obtener carbón activado, material indispensable para descontaminar el agua.

Este material se puede obtener de productos con alto contenido de carbono; por ejemplo, de residuos de frutas, madera, breas de petróleo o de carbón mineral. En la literatura científica se le conoce como el adsorbente universal, porque con él se pueden descontaminar sistemas gaseosos, líquidos, solventes, aceites y azúcar, entre otras sustancias.

Melina Cantillo Castrillón, estudiante de la Maestría en Ciencias Químicas, consiguió carbones activados que adsorben en un 85%, aproximadamente, el fenol y el cobre del agua.

Los fenoles son compuestos químicos que quedan como residuos de procesos industriales, por lo cual aparecen con mucha frecuencia en las fuentes hídricas y están catalogados entre los principales contaminantes del agua. Son muy utilizados en la industria química, farmacéutica y clínica como fungicidas, bactericidas, antisépticos y desinfectantes. Para ser considerada potable, el agua debe contener máximo unos 10 microgramos por litro.

Además, el cobre es un metal pesado que se encuentra con frecuencia en aguas de la región cundiboyacense.

De neumático a carbón
El primer paso del novedoso proceso consiste en retirar los hilos de metal que refuerzan la estructura de la llanta. Luego, el caucho se muele con cuchillas especiales para triturarlo lo máximo posible y se impregna con soluciones de ácido sulfúrico, ácido fosfórico y cloruro de zinc (compuestos químicos que producen estructuras porosas sobre el material carbonoso).

“Estos agentes actúan como si un taladro se introdujera en el interior de la partícula, pues abren huecos”, precisa la profesora Liliana Giraldo Gutiérrez, directora de la tesis de maestría de Cantillo. Después se retiran los químicos y se somete el material a un proceso térmico.

“Según la literatura, el tratamiento se hace a 1.000 o 1.200 grados centígrados, pero nosotros disminuimos la temperatura a 700 grados. Esta reducción es sumamente beneficiosa en lo económico, porque así moderamos el consumo energético y los costos de producción del carbón activado”, explica.

Una vez producido, el siguiente paso es caracterizarlo; es decir, determinar qué capacidad tiene para retener diferentes contaminantes.

“Obtuvimos un carbón activado comparable con los comerciales. Es muy satisfactorio porque, teniendo un material difícil de tratar, en unas condiciones de temperatura más bajas y con concentraciones menores de los agentes químicos activantes, obtuvimos otro con buenas características de adsorción”, asevera la experta.

Aclara que el nuevo material solo tiene diferencias de composición de la química superficial con respecto a los que se consiguen en el mercado.

Este desarrollo es una buena alternativa para solucionar el problema de contaminación que provocan las llantas. Según la resolución del MADS, sus productores deben hacer un manejo ambiental adecuado de los desechos. De hecho, están en la obligación de formular, presentar e implementar sistemas de recolección selectiva y de gestión ambiental, algo que en muchos casos no se cumple.

martes, 1 de mayo de 2012

Clean Drinking Water for Everyone

ORIGINAL: MTU
April 30, 2012
By Marcia Goodrich
Leaving bottles of water in the sun kills pathogens--but only if the water is transparent. Michigan Tech's Joshua Pearce has devised a simple way to clarify water, so even muddy water could be made safe for drinking. SODIS Eawag photo

Nearly 80 percent of disease in developing countries is linked to bad water and sanitation. Now a scientist at Michigan Technological University has developed a simple, cheap way to make water safe to drink, even if it’s muddy.

It’s easy enough to purify clear water. The solar water disinfection method, or SODIS, calls for leaving a transparent plastic bottle of clear water out in the sun for six hours. That allows heat and ultraviolet radiation to wipe out most pathogens that cause diarrhea, a malady that kills 4,000 children a day in Africa.

It’s a different story if the water is murky, as it often is where people must fetch water from rivers, streams and boreholes. “In the developing world, many people don’t have access to clear water, and it’s very hard to get rid of the suspended clay particles,” says Joshua Pearce, an associate professor of materials science and engineering. “But if you don’t, SODIS doesn’t work. The microorganisms hide under the clay and avoid the UV.”

Thus, to purify your water, you first have to get the clay to settle out, a process called flocculation. Working with student Brittney Dawney of Queen’s University in Ontario, Pearce discovered that one of the most abundant minerals on Earth does this job very well: sodium chloride, or simple table salt.

Salt is inexpensive and available almost everywhere. And it doesn’t take very much to make muddy water clear again.

“The water has a lower sodium concentration than Gatorade,” Pearce says. This would still be too much salt to pass muster as American tap water, but American tap water is not the alternative.

“I’ve drunk this water myself. If I were somewhere with no clean water and had kids with diarrhea, and this could save their lives, I’d use this, no question,” he says.

Salt works best when the suspended particles are a type of clay called bentonite. The technique doesn’t work as well with other kinds of clay. However, by adding a little bentonite with the salt to water containing these different clays, most of the particles glom together and settle out, creating water clear enough for SODIS treatment.

Pearce and Dawney are running more tests on water containing various types of clays, and they are also investigating different soil types across Africa to see where their methods might work the best.

Their paper “Optimizing the Solar Water Disinfection (SODIS) Method by Decreasing Turbidity with NaCl” has been accepted for publication in the Journal of Water, Sanitation, and Hygiene for Development and will appear in June. A preprint of the paper is available here.

Michigan Technological University (www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.