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Bionic Leaf Makes Liquid Fuel From Sunlight

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Harvard professor Daniel Nocera (Photo by Kris Krüg) Creative Commons license via Flickr

by Sunny Lewis

CAMBRIDGE, Massachusetts, September 8, 2016 (Maximpact.com News) – Scientists at Harvard have developed a technology that mimics the way leaves produce energy from sunlight, water and air.

A device about the size of a credit card, the “bionic leaf” includes a solar panel. When placed in water, it uses energy from sunlight to split the water into hydrogen and oxygen, just like a real plant does during photosynthesis.

The device uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels. It’s a kind of living battery, which the scientists call a bionic leaf for its melding of biology and technology.

The system can convert solar energy to biomass with 10 percent efficiency, far above the one percent seen in the fastest-growing plants.

Chemist Daniel Nocera, a professor of energy at Harvard University, and Pamela Silver, a professor of biochemistry and systems biology at Harvard Medical School, have co-created the new system.

This is a true artificial photosynthesis system,” Nocera said. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.

While the study shows the system can be used to generate usable fuels, its potential does not end there, said Silver.

The beauty of biology is it’s the world’s greatest chemist – biology can do chemistry we can’t do easily,” she said. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”

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Pamela Silver, a professor of biochemistry and systems biology at Harvard Medical School (Photo by Rose Lincoln, Harvard)

Nicknamed the “Bionic Leaf 2.0,” the new system builds on earlier work by Nocera, Silver, and others. Though capable of using solar energy to make isopropanol, that work was imperfect.

First, Nocera said, the catalyst used to produce hydrogen – a nickel-molybdenum-zinc alloy – also created reactive oxygen species, molecules that attacked and destroyed the bacteria’s DNA.

To avoid that, researchers were forced to run the system at abnormally high voltages, reducing its efficiency.

 “For this paper, we designed a new cobalt-phosphorous alloy catalyst, which we showed does not make reactive oxygen species,” Nocera said. “That allowed us to lower the voltage, and that led to a dramatic increase in efficiency.

I don’t know why yet,” said Nocera. “That will be fun to figure out.

With this new catalyst in the bionic leaf, the team boosted version 2.0’s efficiency at producing alcohol fuels like isopropanol and isobutanol to roughly 10 percent.

For every kilowatt-hour of electricity used the microbes could scrub 130 grams of carbon dioxide out of 230,000 liters of air to make 60 grams of isopropanol fuel. That is better than the efficiency of natural photosynthesis at converting water, sunlight and air into stored energy.

This is the genius of Dan,” Silver said. “These catalysts are totally biologically compatible.”

 Researchers also used the system to create PHB, a bio-plastic precursor, a process first demonstrated by Professor Anthony Sinskey of MIT.

There may yet be room for additional increases in efficiency, but Nocera said the system is already effective enough to consider potential commercial uses for the new technology.

It’s an important discovery – it says we can do better than photosynthesis,” Nocera said. “But I also want to bring this technology to the developing world as well.”

Working in conjunction with the First 100 Watts program at Harvard, which helped fund the research, Nocera hopes to continue developing the technology and its applications in nations like India, with the help of their scientists.

In many ways, Nocera said, the new system marks the fulfillment of the promise of his earlier “artificial leaf,” which used solar power to split water and make hydrogen fuel.

If you think about it, photosynthesis is amazing,” he said. “It takes sunlight, water, and air – and then look at a tree. That’s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.

This research was supported by the Office of Naval Research, Air Force Office of Scientific Research, and the Wyss Institute for Biologically Inspired Engineering. The Harvard University Climate Change Solutions Fund  is supporting ongoing research into the bionic leaf platform.


Featured Image: The tiny bionic leaf can turn sunlight, water and air into liquid fuel. (Screengrab from video by Harvard University)

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Dirtiest Air in World’s Poorest Cities

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By Sunny Lewis                                                                                           Follow us at: @Maximpactdotcom

GENEVA, Switzerland, May 12, 2016 (Maximpact.com News) – The poorest cities on Earth have the worst air pollution, data revealed today by the World Health Organization shows.

More than 80 percent of the people living in cities that monitor pollutants in their air are exposed to levels up to 10 times higher than limits set by the World Health Organization (WHO), that UN-affiliated global health agency said today, releasing the latest figures.

The highest urban air pollution levels were found in low-and middle-income countries in WHO’s Eastern Mediterranean and South-East Asia regions, where annual mean levels often measured as much as 10 times WHO limits.

While all regions of the world are affected, residents of low-income cities are the most impacted.

WHO’s latest urban air quality data shows that 98 percent of cities in low-income and middle income countries with more than 100,000 inhabitants do not meet WHO air quality guidelines.

In high-income countries, that percentage decreases to 56 percent.

“Air pollution is a major cause of disease and death. It is good news that more cities are stepping up to monitor air quality, so when they take actions to improve it they have a benchmark,” said Dr. Flavia Bustreo, WHO assistant-director general, Family, Women and Children’s Health.

“When dirty air blankets our cities the most vulnerable urban populations – the youngest, oldest and poorest – are the most impacted,” Dr. Bustreo said.

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At sunset, hazy air lingers over Dakar, Senegal, one the world’s 10 poorest cities. (Photo by Jeff Attaway) Creative Commons licence via Flickr

WHO researchers compared a total of 795 cities in 67 countries for levels of small and fine particulate matter (PM10 and PM2.5) during the five-year period, 2008-2013.

PM10 and PM2.5 include pollutants such as sulfate, nitrates and black carbon. They penetrate deep into the lungs and cardiovascular system, posing the greatest risks to human health.

In the past two years, the database – now covering 3,000 cities in 103 countries – has nearly doubled, with more cities measuring air pollution levels and recognizing the associated health impacts.

As urban air quality declines, the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma, increases for the people who live in them.

Ambient air pollution, made of high concentrations of small and fine particulate matter, is the greatest environmental risk to health, say WHO executives. It causes more than three million premature deaths worldwide each year.

“Urban air pollution continues to  rise at an alarming rate, wreaking havoc on human health,” says Dr. Maria Neira, WHO director, Department of Public Health, Environmental and Social Determinants of Health. “At the same time, awareness is rising and more cities are monitoring their air quality. When air quality improves, global respiratory and cardiovascular-related illnesses decrease.”

 Most sources of urban outdoor air pollution are beyond the control of individuals and demand action by cities, as well as national and international policymakers to promote cleaner transport, more efficient energy production and waste management.

Yet it is possible for cities to clear the air. More than half of the monitored cities in high-income countries and more than one-third in low  and middle income countries reduced their air pollution levels by more than five percent in five years.

The successful cities reduced industrial smokestack emissions, increased their use of renewables, like solar and wind, and prioritized rapid transit, walking and cycling networks.

“It is crucial for city and national governments to make urban air quality a health and development priority,” says WHO’s Dr. Carlos Dora. “When air quality improves, health costs from air pollution-related diseases shrink, worker productivity expands and life expectancy grows. Reducing air pollution also brings an added climate bonus, which can become a part of countries’ commitments to the climate treaty.”

Analysis of the data reveals that during the 2008-2013 period:

  • Global urban air pollution levels increased by eight percent, although there were improvements in some regions.
  • Urban air pollution levels were lowest in high-income countries, with lower levels most prevalent in Europe, the Americas, and the Western Pacific Region.
  •  In the Eastern Mediterranean and South-East Asia Regions and low-income countries in the Western Pacific Region, levels of urban air pollution has increased by more than 5 percent in more than two-thirds of the cities.
  • In the African Region urban air pollution data remains very sparse, however available data revealed particulate matter (PM) levels above the median.

The world’s 10 poorest cities, by UN ranking, are the capitals of sub-Saharan African nations. They are lacking in the most rudimentary of supplies, and clean water, public transportation and overcrowding are major issues. While the UN categorizes these cities as being among the poorest in the world, they are still expanding rapidly.

During the World Health Assembly, May 24-30, Member States will try to map out a better global response to the health effects of air pollution.


 Main Image: An aerial view of Liberia’s capital city, Monrovia, one the world’s 10 poorest cities. (Photo by Christopher Herwig / United Nations) Creative Commons licence via Flickr

Featured Image: 123rf stock photos