Researchers Discover Greenhouse Bypass for Nitrogen

Finding May Offer Farmers a Way to Reduce Harmful Emissions from Fertilized Soil

Date: January 18, 2017
Source: Virginia Institute of Marine Science
Summary: Production of a potent greenhouse gas can be bypassed as soil nitrogen breaks down into unreactive atmospheric N2, an international team of researchers has discovered.

Associate professor BK Song of the Virginia Institute of Marine Science collects water samples for analysis of nitrogen and microbes.
Credit: © D. Malmquist/VIMS.

Those concerned with water quality are familiar with nitrogen as a major pollutant whose excess runoff into coastal waters can lead to algal blooms and low-oxygen dead zones. Perhaps less familiar is the significant role that a form of nitrogen gas plays in greenhouse warming and the destruction of Earth's ozone layer.

Now, an international group of scientists including Dr. B.K. Song of William & Mary's Virginia Institute of Marine Science have discovered that production of this potent greenhouse gas -- known as N2O or nitrous oxide -- can be bypassed as complex nitrogen compounds in soil, water, and fertilizers break down into the unreactive nitrogen gas (N2) that makes up most of our atmosphere.

Their discovery, published in a recent edition of Scientific Reports, reveals an entirely new pathway in the global nitrogen cycle and could lead to new ways for farmers and others to reduce their emissions of harmful gases. The study's lead author is Rebecca Phillips of New Zealand's Landcare Research Institute, along with Landcare colleagues Andrew McMillan, Gwen Grelet, Bevan Weir, and Palmada Thilak; as well as Craig Tobias of the University of Connecticut.

Agriculture contributes more nitrous oxide to the atmosphere than any other human activity -- primarily through nitrogen fertilization. This greenhouse gas is 300 times more effective at trapping heat than carbon dioxide and 10 times more effective than methane. Nitrous oxide also moves into the stratosphere and destroys ozone.

Current wisdom holds that nitrous oxide is inevitably produced when soil nitrogen -- including fertilizer components such as ammonia, ammonium, and urea -- breaks down. It's also thought this breakdown process requires the action of microbes, and can only occur in the absence of oxygen.

The current research contradicts each of these long-held ideas.

"Our findings question the assumption that nitrous oxide is an intermediate required for formation of nitrogen gas [N2]," says Phillips. "They also throw doubt on whether microbial production of nitrous oxide must take place in the absence of oxygen."

"We now have a pathway that doesn't require microbes," adds Song. "The process of denitrification can happen abiotically, without the need for bacteria or fungi."

The team's discovery could lead to practical applications for decreasing the impacts of excess nitrogen in the environment, a topic they focused on while presenting their findings during a recent meeting in Washington D.C. sponsored by the U.S. Department of Agriculture and the National Integrated Water Quality Program.

"It might give us a way to engineer the system to reduce levels of fixed nitrogen," says Song. "By changing the types and ratios of nitrogen compounds in fertilizer, you might have a better way to reduce excess nitrogen, and to mitigate eutrophication or nutrient enrichment in nearby waters."

Phillips adds, "Further research could inform farmers of how to cultivate soil organic matter useful for nitrogen management. Organic forms of soil nitrogen, such as waste products from plants and fungi, could help convert excess inorganic nitrogen -- which would otherwise be leached into water or emitted as nitrous oxide -- into a form that isn't harmful to the environment."

However, the scientists say more research is needed to test exactly which forms of organic nitrogen are most effective. The team is now developing proposals for further funding that will allow them to investigate on-farm applications for transforming excess nitrogen from soil and water into unreactive atmospheric N2 gas without producing N2O. This may allow scientists to develop options to manage the fate of agricultural nitrogen while avoiding greenhouse-gas emissions.

Story Source:

Virginia Institute of Marine Science. "Researchers discover greenhouse bypass for nitrogen: Finding may offer farmers a way to reduce harmful emissions from fertilized soil." ScienceDaily. ScienceDaily, 18 January 2017. www.sciencedaily.com/releases/2017/01/170118163725.htm

Materials provided by Virginia Institute of Marine Science. Original written by David Malmquist.

Preventing Greenhouse Gas from Entering the Atmosphere

Date: February 5, 2015

Source: Harvard University

Summary: A novel class of materials that enable a safer, cheaper, and more energy-efficient process for removing greenhouse gas from power plant emissions has been developed by a multi-institution team of researchers. The approach could be an important advance in carbon capture and sequestration.

Microcapsule method offers new approach to carbon capture and storage at power plants. The new technique for carbon-capturing employs an abundant and environmentally benign sorbent: sodium carbonate, which is kitchen-grade baking soda. The microencapsulated carbon sorbents (MECS) achieve an order-of-magnitude increase in CO2 absorption rates compared to sorbents currently used. This illustration shows the flow-focusing microfluidic capillary device used to produce the silicone microcapsules.
Credit: John Vericella, Chris Spadaccini, and Roger Aines/LLNL; James Hardin and Jennifer Lewis/Harvard University; Nature

A team of researchers has developed a novel class of materials that enable a safer, cheaper, and more energy-efficient process for removing greenhouse gas from power-plant emissions. The approach could be an important advance in carbon capture and sequestration.

The team, led by scientists from Harvard University and Lawrence Livermore National Laboratory, employed a microfluidic assembly technique to produce microcapsules that contain liquid sorbents, or absorbing materials, encased in highly permeable polymer shells. They have significant performance advantages over the carbon-absorbing materials used in current capture and sequestration technology.

The work is described in a paper published online today in the journal Nature Communications.

"Microcapsules have been used in a variety of applications -- for example, in pharmaceuticals, food flavoring, cosmetics, and agriculture -- for controlled delivery and release, but this is one of the first demonstrations of this approach for controlled capture," said Jennifer A. Lewis, the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard School of Engineering and Applied Sciences (SEAS) and a co-lead author. Lewis is also a core faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard.

Power plants are the single largest source of carbon dioxide (CO2), a greenhouse gas that traps heat and makes the planet warmer. According to the U.S. Environmental Protection Agency, coal- and natural gas-fired plants were responsible for a third of U.S. greenhouse gas emissions in 2012.

That's why the agency has proposed rules mandating dramatically reduced carbon emissions at all new fossil fuel-fired power plants. Satisfying the new standards will require operators to equip plants with carbon-trapping technology.

Current carbon-capture technology uses caustic amine-based solvents to separate CO2 from the flue gas escaping a facility's smokestacks. But state-of-the-art processes are expensive, result in a significant reduction in a power plant's output, and yield toxic byproducts. The new technique employs an abundant and environmentally benign sorbent: sodium carbonate, which is kitchen-grade baking soda. The microencapsulated carbon sorbents (MECS) achieve an order-of-magnitude increase in CO2 absorption rates compared to sorbents currently used in carbon capture. Another advantage is that amines break down over time, while carbonates have a virtually limitless shelf life.

"MECS provide a new way to capture carbon with fewer environmental issues," said Roger D. Aines, leader of the fuel cycle innovations program at Lawrence Livermore National Laboratory and a co-lead author. "Capturing the world's carbon emissions is a huge job. We need technology that can be applied to many kinds of carbon dioxide sources, with the public's full confidence in the safety and sustainability."

Researchers at Lawrence Livermore and the U.S. Department of Energy's National Energy Technology Lab are now working on enhancements to the capture process to bring the technology to scale.

Aines says that the MECS-based approach could also be tailored to industrial processes like steel and cement production, which are significant greenhouse gas sources.

"These permeable silicone beads could be a 'sliced-bread' breakthrough for CO2 capture -- efficient, easy-to-handle, minimal waste, and cheap to make," said Stuart Haszeldine, a professor of carbon capture and storage at the University of Edinburgh, who was not involved in the research. "Durable, safe, and secure capsules containing solvents tailored to diverse applications can place CO2 capture … firmly onto the cost-reduction pathway."

MECS are produced using a double-capillary device in which the flow rates of three fluids -- a carbonate solution combined with a catalyst for enhanced CO2 absorption, a photo-curable silicone that forms the capsule shell, and an aqueous solution -- can be independently controlled.

"Encapsulation allows you to combine the advantages of solid-capture media and liquid-capture media in the same platform," said Lewis. "It is also quite flexible, in that both the core and shell chemistries can be independently modified and optimized."

"This innovative gas separation platform provides large surface areas while eliminating a number of operational issues, including corrosion, evaporative losses, and fouling," said Ah-Hyung (Alissa) Park, the chair in applied climate science and associate professor of Earth and environmental engineering at Columbia University, who was not involved in the research.

Lewis has previously conducted groundbreaking research in the 3-D printing of functional materials, including tissue constructs with embedded vasculature, lithium-ion microbatteries, and ultra-lightweight carbon-fiber epoxy materials.

Funding for the encapsulated liquid carbonates work was provided by the Innovative Materials and Processes for Advanced Carbon Capture Technology program of the U.S. Department of Energy's Advanced Research Projects Agency-Energy.

Story Source:

Harvard University. "Preventing greenhouse gas from entering the atmosphere." ScienceDaily. ScienceDaily, 5 February 2015. .

To Clean Air and Beyond: Catching Greenhouse Gases with Advanced Membranes

Source: Institute for Integrated Cell-Material Sciences, Kyoto University
Summary: An advanced membrane has been developed for the purpose of cleaning up greenhouse gases. The membranes are cheaper, long-lasting, selective and highly permeable compared to commercially available ones.

PIM-1 is a highly permeable membrane compared with commercially available ones. The orange balloon on the left illustrates this point as a higher volume of nitrogen gas is able to pass through PIM-1 into the balloon compared with the membrane on the right, connected to the pink balloon.

Greenhouse gases, originating from industrial processes and the burning of fossil fuels, blanket the Earth and are the culprits behind current global warming woes. The most abundant among them is carbon dioxide, which made up 84% of the United States' greenhouse gases in 2012, and can linger in Earth's atmosphere for up to thousands of years.

Countries all over the world are looking to reduce their carbon dioxide footprint. However, carbon dioxide is essentially a waste product with little immediate commercial value and large treatment costs. Therefore, new low-cost technologies are sorely needed to incentivize greenhouse gas capture by industry.

Easan Sivaniah -- an associate professor at Kyoto University's Institute for Integrated Cell-Material Sciences (iCeMS) -- led an international team of researchers from iCeMS and the University of Cambridge to create an advanced membrane capable of rapidly separating gases.

The membrane they worked on, referred to as PIM-1, is "typically embedded with a network of channels and cavities less than 2 nm in diameter that can trap gases of interest once they enter," said Qilei Song, who was involved in the study. "The only problem is that their intrinsic properties make them rather flimsy and their starting selectivity is weak."

To overcome PIM-1's weaknesses, Sivaniah's team heated PIM-1 at temperatures ranging from 120 to 450 °C in the presence of oxygen, a process referred to as thermal oxidation. "Oxygen, under high temperatures, chemically reacts with PIM-1 to reinforce the strength of channels while controlling the size of so-called gate openings leading into the cavities, which allows for higher selectivity," said Song.

The resulting improved PIM-1 was found to be twice as selective for carbon dioxide while allowing air to pass through it 100 times faster compared with commercially available polymers. PIM-1 can also be used for other applications such as capturing carbon dioxide from the burning of fossil fuels, enriching the oxygen content in air for efficient combustion engines, hydrogen gas production, and processes to generate plastic.

"Basically, we developed a method for making a polymer that can truly contribute to a sustainable environment," said Sivaniah. "And because it is affordable and long-lasting, our polymer could potentially cut the cost of capturing carbon dioxide by as much as 1000 times."

Story Source: The above story is based on materials provided by Institute for Integrated Cell-Material Sciences, Kyoto University.

White House Unveils Plans to Cut Methane Emissions

A worker at a hydraulic fracturing operation in Rifle, Colo. Natural gas production releases methane, which contributes to greenhouse gas pollution. Credit Brennan Linsley/Associated Press.

WASHINGTON — The Obama administration on Friday announced a strategy to start slashing emissions of methane, a powerful greenhouse gas released by landfills, cattle, and leaks from oil and natural gas production.

The methane strategy is the latest step in a series of White House actions aimed at addressing climate change without legislation from Congress. Individually, most of the steps will not be enough to drastically reduce the United States' contribution to global warming. But the Obama administration hopes that collectively they will build political support for more substantive domestic actions while signaling to other countries that the United States is serious about tackling global warming.

In a 2009 United Nations climate change accord, President Obama pledged that by 2020 the United States would lower its greenhouse gas emissions 17 percent below 2005 levels. "This methane strategy is one component, one set of actions to get there," Dan Utech, the president's special assistant for energy and climate change, said on Friday in a phone call with reporters.

Environmental advocates have long urged the Obama administration to target methane emissions. Most of the planet-warming greenhouse gas pollution in the United States comes from carbon dioxide, which is produced by burning coal, oil and natural gas. Methane accounts for just 9 percent of the nation's greenhouse gas pollution — but the gas is over 20 times more potent than carbon dioxide, so even small amounts of it can have a big impact on future global warming.

And methane emissions are projected to increase in the United States, as the nation enjoys a boom in oil and natural gas production, thanks to breakthroughs in hydraulic fracturing technology. A study published in the journal Science last month found that methane is leaking from oil and natural gas drilling sites and pipelines at rates 50 percent higher than previously thought. As he works to tackle climate change, Mr. Obama has generally supported the natural gas production boom, since natural gas, when burned for electricity, produces just half the greenhouse gas pollution of coal-fired electricity.

Environmental groups like the Sierra Club have campaigned against the boom in natural gas production, warning that it could lead to dangerous levels of methane pollution, undercutting the climate benefits of gas. The oil and gas industry has resisted pushes to regulate methane leaks from production, saying it could slow that down.

A White House official said on Friday that this spring, the Environmental Protection Agency would assess several potentially significant sources of methane and other emissions from the oil and gas sector, and that by this fall the agency "will determine how best to pursue further methane reductions from these sources." If the E.P.A. decides to develop additional regulations, it would complete them by the end of 2016 — just before Mr. Obama leaves office.

Among the steps the administration announced on Friday to address methane pollution:

• The Interior Department will propose updated standards to reduce venting and flaring of methane from oil and gas production on public lands.
• In April, the Interior Department's Bureau of Land Management will begin to gather public comment on the development of a program for the capture and sale of methane produced by coal mines on lands leased by the federal government.
• This summer, the E.P.A. will propose updated standards to reduce methane emissions from new landfills and take public comment on whether to update standards for existing landfills.
• In June, the Agriculture Department, the Energy Department and the E.P.A. will release a joint "biogas road map" aimed at accelerating adoption of methane digesters, machines that reduce methane emissions from cattle, in order to cut dairy-sector greenhouse gas emissions by 25 percent by 2020.

Advocates of climate action generally praised the plan. "Cutting methane emissions will be especially critical to climate protection as the U.S. develops its huge shale gas reserves, gaining the full greenhouse gas benefit from the switch away from coal," said Paul Bledsoe, a former White House climate change aide under President Bill Clinton, now with the German Marshall Fund.

Howard J. Feldman, director of regulatory and scientific affairs for the American Petroleum Institute, which lobbies for oil and gas companies, said he hoped the steps would not lead to new regulations on his industry. "We think regulation is not necessary at this time," he said. "People are using a lot more natural gas in the country, and that's reducing greenhouse gas."

Since cattle flatulence and manure are a significant source of methane, farmers have long been worried that a federal methane control strategy could place a burden on them. But Andrew Walmsley, director of congressional relations for the American Farm Bureau Federation, said that his group was pleased that, for now, the administration's proposals to reduce methane from cattle were voluntary.

"All indications are that it's voluntary," he said, "but we do see increased potential for scrutiny for us down the line, which would cause concern."

Source: New York Times. A version of this article appears in print on March 29, 2014, on page A12 of the New York edition with the headline: White House Unveils Plans to Cut Methane Emissions.

Meeting Climate Targets May Require Reducing Meat, Dairy Consumption

Date: March 30, 2014

Geenhouse gas emissions from food production may threaten the UN climate target of limiting global warming to 2 degrees Celsius, according to research at Chalmers University of Technology, Sweden.

On Monday 31 March the Intergovernmental Panel on Climate Change (IPCC) presents their report on the impacts of climate change.

Carbon dioxide emissions from the energy and transportation sectors currently account for the largest share of climate pollution. However, a study from Chalmers now shows that eliminating these emissions would not guarantee staying below the UN limit. Emissions from agriculture threaten to keep increasing as global meat and dairy consumption increases. If agricultural emissions are not addressed, nitrous oxide from fields and methane from livestock may double by 2070. This alone would make meeting the climate target essentially impossible.

"We have shown that reducing meat and dairy consumption is key to bringing agricultural climate pollution down to safe levels," says Fredrik Hedenus, one of the study authors. "Broad dietary change can take a long time. We should already be thinking about how we can make our food more climate friendly."

By 2070, there will be many more of us on this planet. Diets high in meat, milk, cheese, and other food associated with high emissions are expected to become more common. Because agricultural emissions are difficult and expensive to reduce via changes in production methods or technology, these growing numbers of people, eating more meat and dairy, entail increasing amounts of climate pollution from the food sector.

"These emissions can be reduced with efficiency gains in meat and dairy production, as well as with the aid of new technology," says co-author Stefan Wirsenius. "But the potential reductions from these measures are fairly limited and will probably not suffice to keep us within the climate limit, if meat and dairy consumption continue to grow."

Beef and lamb account for the largest agricultural emissions, relative to the energy they provide. By 2050, estimates indicate that beef and lamb will account for half of all agricultural greenhouse gas emissions, while only contributing 3 percent of human calorie intake. Cheese and other dairy products will account for about one quarter of total agricultural climate pollution.

Source: Chalmers University of Technology