Researchers find new materials to capture methane
English.news.cn 2013-04-17 13:57:05
WASHINGTON, April 16 (Xinhua) — U.S. researchers have discovered new materials that can capture and concentrate methane, the second highest concentration greenhouse gas emitted into the atmosphere.
Unlike carbon dioxide, the largest emitted greenhouse gas, which can be captured both physically and chemically in a variety of solvents and porous solids, methane is completely non-polar and interacts very weakly with most materials.
Researchers at the Lawrence Livermore National Laboratory and University of California, Berkeley, performed systematic computer simulation studies on the effectiveness of methane capture using two different materials: liquid solvents and nanoporous zeolites, porous materials commonly used as commercial adsorbents.
While the liquid solvents were not effective for methane capture, a handful of zeolites had sufficient methane sorption to be technologically promising.
The researchers tested some 100,000 zeolites during this study, which appears in the journal Nature Communications on Tuesday.
Zeolites are unique structures that can be used for many different types of gas separations and storage applications because of their diverse topology from various networks of the framework atoms.
In the team’s simulations, one specific zeolite, dubbed SBN, captured enough medium source methane to turn it to high purity methane, which in turn could be used to generate efficient electricity.
“We used free-energy profiling and geometric analysis in these candidate zeolites to understand how the distribution and connectivity of pore structures and binding sites can lead to enhanced sorption of methane while being competitive with carbon dioxide sorption at the same time,” said Amitesh Maiti, who works in the U.S. Lawrence Livermore National Laboratory and is one of the authors of the paper.
Other zeolites, named ZON and FER, were able to concentrate dilute methane streams into moderate concentrations that could be used to treat coal-mine ventilation air.