The goal of carbon sequestration is to take carbon dioxide, either from where it is being produced or from the atmosphere, change it into a stable form and store it away from the atmosphere where it cannot contribute to climate change. Proposed schemes have involved, for example, injecting carbon underground or storing it in the deep ocean. These approaches pose both practical challenges and environmental risks.
What if, instead, we can leverage materials that we already produce in large quantities to store carbon?" said Van Roijen, who led the study as a graduate student at UC Davis.
Researchers found that while bio-based plastics could take up the largest amount of carbon by weight, by far the largest potential for carbon storage is in using carbonated aggregates (碳化骨料) to make concrete. That's because concrete is by far the world's most popular building material: Over 20 billion tons are produced every year.
"If feasible, a little bit of storage in concrete could go a long way," said Sabbie Miller, associate professor at UC Davis. The team calculated that if 10% of the world's concrete aggregate production was carbonatable, it could absorb a gigaton (十亿吨) of CO2.
"The feedstocks for these new processes for making building materials are mostly low-value waste materials such as biomass," Van Roijen said. "Performing these new processes would enhance their value, boosting economic development and promoting a circular economy."
"Some technology development is needed, particularly in cases where material performance and net-storage potential of individual manufacturing methods must be confirmed. However, many of these technologies are just waiting to be adopted," Sabbie Miller said.
