Preparation of red mud derived eggshell coupling adsorbent and study on carbon dioxide capture performance based on experiment and density functional theory simulation

Abstract

Preparing advanced CO2 capture materials is crucial for mitigating carbon emissions and alleviating global warming. Calcium-based adsorbents have attracted much attention due to their excellent environmental performance and high theoretical CO2 adsorption capacity. However, its poor cycling stability limits its widespread application. In this study, a red mud derived eggshell coupled CO2 adsorbent (RM/CaO) was prepared using solid waste RM and eggshell. The structure, CO2 capture performance, and micro-mechanism of the adsorbent were evaluated through macro micro-experiments combined with quantum mechanics simulations, to improve the adsorption performance of calcium-based adsorbents and achieve waste resource utilisation—an active, open area of research. The 1-1RM/CaO adsorbent had a specific surface area of 10.62 m2/g and a spatial structure with fused cross-linking layers. Its CO2 saturation adsorption capacity was 0.481 g/g; 171.43 % that of pure CaO. High level cycling stability can still be maintained after 15 cycles of CO2 adsorption desorption. Quantum mechanics simulations revealed that the CO2 adsorption energy on the RM/CaO (200) crystal plane can be enhanced to −8.25 eV. This indicates that the interaction between RM/CaO atoms is stronger, which is enhances the CO2 adsorption. This study optimized environmental and economic benefits by utilizing waste resources, deepened understanding of the interaction mechanism between CO2 adsorbents, and provided theoretical guidance for designing as well as optimizing future adsorbents.