Direct Carbon Capture Repeatability of Magnesium Oxide (MgO) Nanoparticles Synthesized by Aerosol Methods at Room Temperature

KYUNGIL CHO, Yeryeong Kang, Jihye Park, Sukbyung Chae, Changhyuk Kim, Pusan National University

     Abstract Number: 794
     Working Group: Nanoparticles and Materials Synthesis

Abstract
Climate change has caused more frequent extreme weather events than ever. For mitigating climate change, carbon dioxide (CO₂) should be removed and reduced from the flue gas and the atmosphere. Mineral Carbonation is one of promising direct carbon capture technologies using the alkaline earth metal oxides such as magnesium oxides (MgO). Cho et al. reported that aerosol processed MgO NPs showed direct carbonation with less hydration during the wet based carbonation processes, different with the commercial ones. In this study, the effects of the direct carbonation characteristics of the MgO NPs on the durability of direct carbon capture performance were investigated through repeated carbonation and decarbonation processes.

The MgO NPs were synthesized by two aerosol methods and mixed with D.I. water in flasks for continuous direct carbon capture of pure CO₂ (99.99%). While the carbonation, magnetic stirring was applied for uniform carbonation with constant RPM. pH of the MgO slurries were monitored during the carbonation processes to check the end of the processes. Carbonates were dried in the oven and decarbonated at 800℃ in a furnace. The carbonation and decarbonation processes were repeated up to 15 cycles. The changes of morphology and chemical composition of the MgO NPs and carbonates were analyzed with the carbon capture amounts per unit mass of the adsorbents.

The MgO NP based CO₂ adsorbents showed less hydration and direct carbonation during the repeated carbonation experiments. After the carbonation, the MgO NPs were transformed into pillar shaped carbonates. Interestingly, the carbonates did not return to their original shapes of MgO NPs, even though the chemical compositions were MgO. The decarbonated particles had porous surface pillar shapes, where CO₂ gas molecules were adsorbed during the carbonation processes. The change of CO₂ adsorption capacity for each MgO NP will also be discussed as a function of repeating cycles.