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More than a football field of surface area in the palm of your hand. Can scientists fashion metal-organic frameworks, seen in this illustration, into carbon-absorbing sponges? Will the material work in a power plant? Berkeley Lab scientists hope to find out soon.
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Jeffrey Long’s lab will soon host a round-the-clock, robotically
choreographed hunt for carbon-hungry materials.
The Berkeley Lab chemist leads a diverse team of scientists whose goal is to
quickly discover materials that can efficiently strip carbon dioxide from a
power plant’s exhaust, before it leaves the smokestack and contributes to
climate change.
They’re betting on a recently discovered class of materials called
metal-organic frameworks that boast a record-shattering internal surface area.
A sugar cube-sized piece, if unfolded and flattened, would more than blanket a
football field. The crystalline material can also be tweaked to absorb specific
molecules.
The idea is to engineer this incredibly porous compound into a voracious
sponge that gobbles up carbon dioxide.
And they’re going for speed. The scientists hope to discover this dream
material in a breakneck three years, maybe sooner. To do this, they’ll create
an automated system that simultaneously synthesizes hundreds of metal-organic
frameworks, then screens the most promising candidates for further refinement.
“Our discovery process will be up to 100 times faster than current
techniques,” says Long. “We need to quickly find next-generation materials that
capture and release carbon without requiring a lot of energy.”
Carbon capture is the first step in carbon capture and storage, a climate
change mitigation strategy that involves pumping compressed carbon dioxide
captured from large stationary sources into underground rock formations that
can store it for geological time scales. Many scientists, including the United
Nations’ Intergovernmental Panel on Climate Change, believe that the technology
is key to curbing the amount of carbon dioxide that enters the atmosphere.
Fossil fuels such as coal and natural gas will likely remain cheap and
plentiful energy sources for decades to come—even with the continued
development of renewable energy sources.
Carbon capture and storage is being tested on a large scale in only a few
places worldwide. One of the biggest obstacles to industrial-scale
implementation is its parasitic energy cost. Today’s carbon capture materials,
such as liquid amine scrubbers, sap a whopping 30% of the power generated by a
power plant.
To overcome this, scientists are seeking alternatives that can be used again
and again with minimal energy costs. It’s a slow, finicky process. Promising
materials such as metal-organic frameworks come in millions of variations, only
a handful of which are conducive to capturing carbon. Finding just the right material
may take years.
That could change. In early May, Long’s team began negotiating a three-year,
$3.6 million grant from the Department of Energy’s Advanced Research Projects
Agency-Energy (ARPA-E) to supercharge the search.
“We want to run the discovery process very rapidly and find materials that
only consume 10% of a power plant’s energy,” says Long, who’s working with
fellow Berkeley Lab scientists Maciej Haranczyk, Eric Masanet, Jeffrey Reimer,
and Berend Smit on the project. Together, they’ll create a state-of-the-art
production line.
A robot will automatically synthesize hundreds of metal-organic frameworks
and X-ray diffraction will offer a first-pass evaluation in the search for pure
new materials. Magnetic resonance spectroscopy will then ferret out the
materials with the pore size distribution best suited for carbon capture.
Next comes the big test: can it capture carbon dioxide from a flue gas?
High-throughout gas sorption analysis conducted using new instrumentation built
by Wildcat Discovery Technologies of San Diego, California will provide the
answer.
Computer algorithms will constantly churn through the resulting data and
help refine the next round of synthesis. Promising materials will also be
assessed to determine if any ingredients are too expensive for large-scale
commercialization.
“We don’t want to discover a great material and find it’s so expensive that
no one will use it,” says Long.
As a final test, the Electric Power Research Institute will predict the
utility of the best new materials in an industrial-scale carbon capture
process.
“We need to find the optimum range of metal-organic frameworks for each
power plant,” says Long. “Ultimately, this research is intended to lead to
materials worthy of large-scale testing and commercialization.”
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