image: Chen Zhu view more
Credit: Indiana University
An Indiana University researcher is investigating critical geochemical processes that trap carbon dioxide in rock to better predict the potential for atmospheric carbon removal and storage at scale.
Chen Zhu, a globally recognized geologist and professor of Earth and Atmospheric Sciences within the College of Arts and Sciences at Indiana University Bloomington, has been awarded $736,000 from the National Science Foundation to solve long-standing gaps in scientists’ understanding of CO2-water-rock interactions that naturally remove carbon dioxide from the atmosphere.
According to the latest Intergovernmental Panel on Climate Change report, limiting global warming to 1.5°C or 2°C requires the storage of hundreds of gigatons of CO2 in aquifers, soils, and oceans in the next few decades. As the US and other countries accelerate efforts to decarbonize the global economy and avoid the worst impacts of climate change, strategies to remove carbon from the atmosphere are increasingly viewed as an essential part of the solution.
“It’s become clear that we must do more than just reduce global emissions,” said Zhu, an affiliate of the IU Environmental Resilience Institute. “No current technologies, however, have demonstrated the ability to capture and store CO2 at the necessary gigaton scale, though several show promise. New insight into the chemical processes that dictate CO2 mineralization could help accelerate the development of these technologies to meet society’s urgent need.”
Zhu’s team is particularly interested in investigating basalt-CO2-water interactions, which have shown potential for rapid, long-term carbon storage. Basalts, dark volcanic rocks commonly found around the world, have long piqued the interest of climate researchers. Their high concentrations of ionized calcium and magnesium act as CO2 magnets, binding with the gas to form calcite, dolomite, and magnesite. In one experiment conducted at a geothermal power plant in Iceland, 90% of carbon dioxide—dissolved in water and injected underground—transformed into minerals in just 2 years.
To better understand the ideal conditions and rate of reaction in basalt-CO2-water systems, Zhu’s team will employ the isotope tracer method, a technique in which a rare isotope is introduced to the mineral system. Researchers then monitor the isotope using mass spectrometry to gain insight into the system’s geochemical kinetics, which describe how natural materials react under a given set of conditions.
In past experiments, Zhu has successfully applied isotopes to study single mineral reactions. This time, the method will be applied to multi-mineral reactions, presenting new challenges.
“The basalt-CO2-water system is so complex, with many mineral phases and chemical components; it is difficult to define precisely which minerals are dissolving and which are precipitating into new compounds,” Zhu said. “However, this knowledge is critical. For example, clay minerals will also precipitate, competing with CO2 for available calcium and magnesium ions. Using multiple isotopic tracers, these experiments will yield unprecedented data that can be leveraged by the scientific community.”
Data gleaned from the experiments will be used to inform models that can be simulated on IU’s high performance computers to test a wide range of mineral systems relevant to carbon capture and storage. The data will also be made available to the scientific community through a public interactive data portal called a science gateway. The gateway will give other researchers the opportunity to download the data, conduct their own analysis, update existing models, or run entirely new models.
“There is a large community of climate scientists, geochemists, soil scientists, oceanographers, and others who are working on scaling up carbon capture and storage,” said Sudhakar Pamidighantam, a senior scientist with the IU Pervasive Technology Institute and a co-PI of the project. “Our science gateway will make it easier for researchers to build on this work and maximize its impact for society.”