Abstract
The current CO2 sequestration efficiency (CO2 SE) of steel slag waste (SSW) remains relatively low, and the underlying mechanisms of the carbonation reaction are not fully understood, limiting its potential for resource utilisation. In this study, N-methyl diethanolamine (MDEA) was introduced into an aqueous carbonation system to enhance the CO2 SE of SSW, and the associated reaction mechanisms and microstructural evolutions were systematically investigated. The results indicate that the addition of 5 wt.% MDEA increased the CO2 sequestration rate (CO2 SR) to 14.44%, representing a 68.5% improvement over the control group. MDEA enhanced CO2 dissolution and diffusion in the aqueous phase, facilitated the sustained release of Ca2+ and Mg2+ from SSW, and promoted the formation of stable, cauliflower-like calcite structures. These findings provide new insights into improving the CO2 SE of SSW, thereby supporting its potential application in CO2 capture and sustainable material recycling.
Keywords
steel slag, CO2 sequestration, MDEA, phase evolution, microstructure.
DOI
10.5703/1288284318145
Recommended Citation
Liu, Yanming; Shi, Tao; and Zhou, Xiangming, "MDEA-enhanced CO2 Sequestration via Steel Slag Waste: Mechanisms and Microstructural Evolution during Aqueous Carbonation" (2025). International Conference on Durability of Concrete Structures. 10.
https://docs.lib.purdue.edu/icdcs/2025/ddm/10
MDEA-enhanced CO2 Sequestration via Steel Slag Waste: Mechanisms and Microstructural Evolution during Aqueous Carbonation
The current CO2 sequestration efficiency (CO2 SE) of steel slag waste (SSW) remains relatively low, and the underlying mechanisms of the carbonation reaction are not fully understood, limiting its potential for resource utilisation. In this study, N-methyl diethanolamine (MDEA) was introduced into an aqueous carbonation system to enhance the CO2 SE of SSW, and the associated reaction mechanisms and microstructural evolutions were systematically investigated. The results indicate that the addition of 5 wt.% MDEA increased the CO2 sequestration rate (CO2 SR) to 14.44%, representing a 68.5% improvement over the control group. MDEA enhanced CO2 dissolution and diffusion in the aqueous phase, facilitated the sustained release of Ca2+ and Mg2+ from SSW, and promoted the formation of stable, cauliflower-like calcite structures. These findings provide new insights into improving the CO2 SE of SSW, thereby supporting its potential application in CO2 capture and sustainable material recycling.
