Greg Rau, a senior scientist with the Institute of Marine Sciences at UC Santa Cruz and who also works in the Carbon Management Program at Lawrence Livermore National Laboratory, conducted a series of lab-scale experiments to find out if a seawater/mineral carbonate (limestone) gas scrubber would remove enough CO2 to be effective, and whether the resulting substance -- dissolved calcium bicarbonate -- could then be stored in the ocean where it might also benefit marine life.
In addition to global warming effects, when carbon dioxide is released into the atmosphere, a significant fraction is passively taken up by the ocean in a form that makes the ocean more acidic. This acidification has been shown to be harmful to marine life, especially corals and shellfish.
In his experiments, Rau found that the scrubber removed up to 97 percent of CO2 in a simulated flue gas stream, with a large fraction of the carbon ultimately converted to dissolved calcium bicarbonate.
At scale, the process would hydrate the carbon dioxide in power plant flue gas with water to produce a carbonic acid solution. This solution would react with limestone, neutralizing the carbon dioxide by converting it to calcium bicarbonate -- and then would be released into the ocean. While this process occurs naturally (carbonate weathering), it is much less efficient, and is too slow paced to be effective.
"The experiment in effect mimics and speeds up nature's own process," said Rau. "Given enough time, carbonate mineral (limestone) weathering will naturally consume most anthropogenic CO2. Why not speed this up where it's cost effective to do so?"
If the carbon dioxide reacted with crushed limestone and seawater, and the resulting solution was released to the ocean, this would not only sequester carbon from the atmosphere, but also would add ocean alkalinity that would help buffer and offset the effects of ongoing marine acidification. Again, this speeds up the natural CO2 consumption and buffering process offered by carbonate weathering.
Earlier research has shown that ocean acidification can cause exoskeletal components to decay, retard growth and reproduction, reduce activity and even kill marine life including coral reefs.
"This approach not only mitigates CO2, but also potentially treats the effects of ocean acidification," Rau said. "Further research at larger scales and in more realistic settings is needed to prove these dual benefits."
Rau said the process would be most applicable for CO2 mitigation at coastal, natural gas-fired power plants. Such plants frequently already use massive quantities of seawater for cooling, which could be cheaply reused for at least some of the CO2 mitigation process.
"This method allows a power plant to continue burning fossil fuel, but eliminates at least some of the carbon dioxide that is emitted, and in a way that in some locations should be less expensive and more environmentally friendly than other carbon dioxide sequestration methods," he said.
The work, funded by the Energy Innovations Small Grant Program of the California Energy Commission and LLNL, appears in the journal Environmental Science & Technology.
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
Anne Stark | EurekAlert!
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Physics and Astronomy
24.05.2017 | Physics and Astronomy
24.05.2017 | Event News