Enhancing sustainable utilization of iron-based alkaline solid wastes for carbon mineralization: Insights into CO2 transport and adsorption dynamics

Iron-based alkaline solid wastes provide substrates for carbon mineralization, addressing global warming. However, the mechanisms of CO 2 transport and adsorption within their porous structures are not fully understood. Using advanced grand canonical Monte Carlo (GCMC) methods, this study explores CO 2 transport and adsorption in iron-based alkaline wastes under different humidity conditions. The results show that FeO and Fe 2 O 3 reduce the CO 2 adsorption capacity in calcium hydroxide (CH) nanopores, a key component of these wastes. The presence of iron-based solids causes inhomogeneous porewater distribution, diminishing CO 2 dissolution and adsorption on the gas-liquid interface. By analyzing adsorption energy and CO 2 diffusion coefficients, we found that iron-based porous systems have lower CO 2 transport efficiency and storage capacity, highlighting their limited carbonation potential. The weak CO 2 -surface interactions in these wastes are identified as the primary challenge to improving carbon mineralization. These findings provide crucial insights for enhancing the sustainable use of iron-based alkaline wastes. • CO 2 transport and adsorption mechanisms in iron-based alkaline solid wastes are uncovered. • CO 2 intake progress is effectively reproduced in iron-based alkaline solids. • Surface properties of Fe-based solids significantly influences CO 2 adsorption capacities. • Optimal water film thickness enhances CO 2 intake capacities in iron-based nanopores.