Effect of alcohol on the crystallization process of MgCO₃·3H₂O: an experimental and molecular dynamics simulation study

ABSTRACT

The effect of alcohols (methanol, ethanol, n-propanol, and isopropanol) on the crystallization process of nesquehonite was investigated by combining experiments and molecular dynamics simulation. With the presence of alcohol, the transformation rate from Mg(HCO₃)₂ to MgCO₃ · 3H₂O can be accelerated apparently and the solubility of MgCO₃ · 3H₂O can be reduced significantly. X-ray diffraction (XRD) analysis indicates that Mg(HCO₃)₂ is unstable and can be transformed to pure MgCO₃ · 3H₂O easily. Based on the molecular dynamics simulation, we find that alcohol enhances the desolvation of Mg²⁺ through reducing the water molecules in the first solvation circle of Mg²⁺. Hence, the solvation energy could be reduced, which is beneficial for the precipitation of Mg²⁺. The results in this study provide theoretical foundations for the coupled reaction-extraction-alcohol precipitation process to fix CO₂ and produce MgCO₃ · 3H₂O.

KEYWORDS:

• Alcohol precipitation
• CO₂ mineralization
• nesquehonite
• desolvation
• molecular dynamics simulation

Acknowledgments

The authors are grateful for the financial support from the National Key R&D Program of China (No. 2018YFB0605703), Program of Shanghai Academic/Technology Research Leader（No. 18XD1424600）and National Natural Science Foundation of China (No. U1607112).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [U1607112];National Key R&D Program of China [2018YFB0605703];Program of Shanghai Academic/Technology Research Leader [18XD1424600].

Notes on contributors

Xingfu Song

Xingfu Song is from National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai China.

Chaoyan Dai

Chaoyan Dai is from National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai China.

Guilan Chen

Guilan Chen is from National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai China.

Chunhua Dong

Chunhua Dong is from National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai China.

Jianguo Yu

Jianguo Yu is from National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai China.