Lawrence Livermore scientists, along with colleagues from Harvard University and the University of Illinois at Urbana-Champaign, have developed a new type of carbon capture media composed of core-shell microcapsules. Each capsule consists of a highly permeable polymer shell and a fluid (sodium carbonate solution) that reacts with and absorbs carbon dioxide (CO2). The capsules keep the liquid contained inside the core and allow the CO2 gas to pass back and forth through the capsule shell. The team’s work was published online in the February 5, 2015, edition of Nature Communications.
The aim of carbon capture is to prevent the release of large quantities of CO2—a greenhouse gas that traps heat and makes the planet warmer—into the atmosphere from fossil fuel use in power generation and other industries. However, currently used carbon capture methods can be harmful to the environment. “Our method is a huge improvement in terms of environmental impacts because we are able to use simple baking soda, present in every kitchen, as the active chemical for capturing CO2,” says Roger Aines, one of the Lawrence Livermore team members.
The ability to move away from caustic fluids, such as monoethanolamine, to more environmentally benign ones, such as carbonates, is a key attribute of the team’s research. Unlike the more caustic sorbents, the microcapsules react only with the gas of interest (in this case CO2). The new process can be designed to work with coal or natural gas-fired power plants as well as in industrial processes such as steel and cement production. “The microcapsule technology provides a a more efficient method for carbon capture with fewer environmental issues,” says Aines.
Contact: Roger Aines (925) 423-7184 (aines1@llnl.gov).
Research published in the January 7, 2015, online edition of Geology reports that humans’ use of land has eroded soil 100 times faster than natural processes. Scientists discovered that the rate of hillslope erosion before European settlement was about 2.5 centimeters every 2,500 years, but spiked to about 2.5 centimeters every 25 years because of increased logging and agriculture use in the late 1800s and early 1900s. “The Earth doesn’t create that precious soil for crops fast enough to replenish what the humans took off,” says former Laboratory scientist Dylan Rood, who conducted the research while at Livermore. “This pattern is unsustainable if continued.”
The team, which also includes Lucas Reusser and Paul Bierman of the Rubenstein School of Environment and Natural Resources at the University of Vermont, collected 24 sediment samples from the Roanoke, Savannah, and Chattahoochee rivers along with seven other river basins, where clay soils were built up over many millennia. From these samples, the team extracted a rare isotope of beryllium, Be-10, which is formed by cosmic rays and builds up in about the top meter of soil. The slower the rate of erosion, the longer the soil is exposed at Earth’s surface, and the more Be-10 the soil accumulates. Using Livermore’s Center for Accelerator Mass Spectrometry, Rood measured how much Be-10 was in the samples, and found, for the first time, a precise quantification of this background rate of erosion. The background rates were then compared to postsettlement rates of both upland erosion and downriver sediment yield. Says Rood, “We can use the Be-10 erosion rates as a target for successful resource conservation strategies to develop smart environmental policies and regulations that will protect threatened soil and water resources for generations to come.”
Contact: Anne M. Stark (925) 422-9799 (stark8@llnl.gov).
In a Nature Physics paper published on January 19, 2015, Lawrence Livermore researchers report, for the first time, well-developed, oriented magnetic filaments generated by the Weibel mechanism in counter-streaming, collisionless flows from high-power lasers. The team’s findings demonstrate the power of the Weibel filamentation instability—a plasma instability present in homogeneous or nearly homogeneous electromagnetic plasmas—to produce small-scale seed magnetic fields throughout the cosmos. These fields can be further amplified to larger scales to create the ubiquitous magnetic fields that exist in astrophysical systems.
Experiments were conducted at the Omega Laser Facility at the University of Rochester’s Laboratory for Laser Energetics. The researchers used protons produced by the implosion of a deuterium and helium capsule. The resulting data revealed the elusive Weibel filamentation instability. “A range of magnetic field scales exist in the cosmos, but the origin of these fields has been elusive,” says lead author Channing Huntington, a Livermore physicist. “Weibel instability has long been theorized as a mechanism to generate these fields, but this work offers the most compelling experimental evidence to date that it is indeed possible.”
The team envisions a broad range of follow-up experiments on Omega to test the magnetic field generation under conditions that are relevant to astrophysical systems. The researchers also have begun experiments at the Laboratory’s National Ignition Facility, where larger, faster plasma flows could produce even higher fields and the Weibel-mediated shock formation would be fully mature. These experiments will reach conditions not previously achieved in a laboratory setting.
Contact: Channing Huntington (925) 424-2258 (huntington4@llnl.gov).