The Enhancement of CO2 Sequestration of Limestone By Modified with Attapulgite

Limestone can be used for Carbon dioxide (CO₂) capture and sequestration (CCS) in flue gas effectively. However, its CCS capability will dramatically decline after several cycles due to the surface “sintering”. In order to improve the efficiency of recirculated CaO, here we modified the limestone with attapulgite, a natural mineral with nano-fibrous structure. Attapulgite can reduce the sintering phenomenon between the limestone particles, thus can improve the carbonation rate of Limestone during the CCS process. The experimental results shown that, the limestone modified with both natural attapulgite and purified attapulgite can improve the carbonation rate, and purified attapulgite showed better result. The morphology change of limestone with the modification of attapulgite was studied by SEM. We found that after the modification with attapulgite, the absorbent’s porous surface will be kept and the surface sintering was postponed. As a consequence, the carbonation rate was increased by 13.11% with the adding of 5wt% attapulgite.