Use of hydrated cement pastes (HCP) as a CO₂ sponge

In this study, the feasibility of using hydrated cement paste (HCP) as a CO₂ sponge was investigated. The grounded HCP were carbonated, calcined and re-carbonated to investigate the potential of CO₂ transportation through the use of HCP. Facilitated by the microstructural analysis, the capacity of CO₂ sequestration and release via HCP, as well as the carbonation phases formed within the carbonated/calcined/recarbonated cement paste, were investigated. The initial results indicate that HCP could sequestrate CO₂ to become carbonated cement paste (HCP_carbonated) with a high CO₂ capture ratio, where a number of carbonates formed. After the calcination of HCP_carbonated, the calcined carbonated cement paste (HCP_calcined) was produced and some new phases formed with a large release amount of CO₂. In terms of the re-carbonation process, moisture within the HCP_calcined played an important role concerning its re-carbonation efficiency. Finally, by means ofHCP, this research innovatively proposed a new concept to effectively transport CO₂, that is, a CO₂ sponge, as well as a technology roadmap, to achieve this goal.