Cement (of certain types) relies on direct carbon capture from the atmosphere to complete curing (although conventional cement only carbonizes through a finite

Cement (of certain types) relies on direct carbon capture from the atmosphere to complete curing (although conventional cement only carbonizes through a finite depth during its expected lifetime), so it's definitely possible. It just takes a lot of energy. About 2 MWh (thermal, or ~7GJ) per tonne of CO2 captured (not counting storing that CO2) to regenerate the chemical CO2 capturing agent. Here's a review: https://www.sciencedirect.com/science/article/pii/S0959652619307772 https://www.sciencedirect.com/science/article/pii/S095965261... (As an aside, a gallon of gasoline emits about 10kg of CO2, so to capture that CO2 from a gallon of gasoline would require about 20kWh worth of electricity.... Typically, a gallon of gasoline gives you about as much range as 10 kWh in an electric car, so you can go 2 times as far in an electric car just using the energy it'd take to capture the CO2 from a gasoline car. And that doesn't count the electricity required to refine/crack the gasoline from crude.) And also, on board the International Space Station, CO2 is captured from the atmosphere regeneratively. Capturing CO2 in this way takes less energy at the higher concentrations on board ISS, but is still possible. As an aside: Much of the ISS's CO2 is converted into a hydrocarbon (methane) using hydrogen (from water and solar electricity) and, amusingly, vented to space as a waste product. The point is to recover the oxygen (again, in the form of water) from the CO2.