The research team used systematic computer simulations to study the effectiveness of liquid solvents and nanoporous zeolites, porous materials commonly used as commercial absorbents, to capture methane. The work at LLNL was funded by the US Department of Energy’s Advanced Research Projects Agency-Energy.
The research, which appears in the journal Nature Communications, found the liquid solvents were not effective for methane capture. Of the 87,000 zeolites screened, a handful had sufficient methane absorption to be technologically promising, the researchers said.
Unlike carbon dioxide, which can be captured both physically and chemically in a variety of solvents and porous solids, methane is non-polar and interacts weakly with most materials.
Zeolites can be used for different types of gas separations and storage applications because of their diverse topology from various networks of the framework atoms (see photo). The blue on the photo above represents absorption sites, which are optimal for methane uptake, researchers said.
Methane, the second highest concentration greenhouse gas emitted into the atmosphere, contributes 30 percent of current net climate climate warming, according to LLNL.
Concern over methane gas and its effects on climate have increased with the rapid expansion of unconventional oil and gas extraction and as ice cover in the Arctic continues to melt, threatening to release large amounts of the greenhouse gas trapped in decayed material.
It’s far more potent as a greenhouse gas than CO2. Researchers say that as little as 1 percent of methane from the Arctic alone could have the same warming effect as all of the CO2 pumped into the atmosphere since the Industrial Revolution.
Total greenhouse gas emissions in the US fell 1.6 percent to 6,702,000 million metric tons of CO2 equivalent in 2011, according to an annual EPA report released in April. The EPA attributes the drop to multiple factors including reduced emissions from electricity generation, improvements in fuel efficiency in vehicles with reductions in miles traveled and year-to-year changes in the prevailing weather.