One of the most abundant greenhouse gases, carbon dioxide is a major culprit behind today’s global warming and climate change issues. One way of tackling the problem is trapping carbon emissions right at the source. This, however, gives rise to the problem of storing and reusing the carbon sucked from the air. As part of a new research, the brilliant minds at UCLA have come up with an innovative solution: capturing atmospheric CO2 and turning it into 3D printable concrete.
Across the world, smokestacks at power plants and other factories regularly spew clouds of carbon dioxide into the atmosphere. What’s more, the production of concrete, a material that has been used pervasively in the last 200 years to construct roads, houses, bridges and buildings, actually accounts for over 5-percent of the global carbon emissions. Speaking about the research, J.R. DeShazo, a professor at UCLA, said:
What this technology does is take something that we have viewed as a nuisance — carbon dioxide that’s emitted from smokestacks — and turn it into something valuable… This technology tackles global climate change, which is one of the biggest challenges that society faces now and will face over the next century.
Termed as “upcycling”, the closed-loop process aims at capturing carbon from emissions, converting it into an entirely new and eco-friendly building material, known as CO2NCRETE, that can be fabricated with the help of 3D printers. Unlike previous attempts to trap environmentally-harmful carbon dioxide, the current research provides a viable way of reducing the atmospheric CO2, using it to produce a feasible cement substitute. Gaurav Sant, a UCLA professor of civil and environmental engineering, explained:
The approach we are trying to propose is you look at carbon dioxide as a resource — a resource you can reutilize. While cement production results in carbon dioxide, just as the production of coal or the production of natural gas does, if we can reutilize CO2 to make a building material which would be a new kind of cement, that’s an opportunity.
For the research, the scientists started by trapping carbon dioxide generated during the calcination of limestone. The process, according to them, is one of the most common ways of creating cement in factories. The captured CO2 was then used to produce a new type of concrete they are calling CO2NCRETE. The team went to determine how Ca(OH)2 (calcium hydroxide) carbonation would react upon exposure to liquid as well as supercritical carbon dioxide.
As the researchers point out, so far, the sustainable construction material has been developed only in the laboratory, with the help of 3D printers that in turn shape the new substance into tiny cone-like structures. During lab experiments, the material was tested in terms of a variety of parameters, including temperature, pressure and also time. Sant added:
We can demonstrate a process where we take lime and combine it with carbon dioxide to produce a cement-like material. The big challenge we foresee with this is we’re not just trying to develop a building material. We’re trying to develop a process solution, an integrated technology which goes right from CO2 to a finished product.
To produce the new building material, the scientists worked with 99-percent carbon dioxide. For each of the reactions, the carbon, which was stored inside a specially-designed reservoir at MPa (pascal) of pressure, was extracted with the help of siphon. DeShazo said:
We have proof of concept that we can do this. But we need to begin the process of increasing the volume of material and then think about how to pilot it commercially.
The technology, the team believes, could help reduce greenhouse gas emissions not only in the US, but also in other places, like India and China, where coal-fired power plants are a common sight. The team was reported saying:
This technology could change the economic incentives associated with these power plants in their operations and turn the smokestack flue gas into a resource countries can use, to build up their cities, extend their road systems.