文献类型：期刊文献

英文题名：Insights into conversion of Mg(HCO3)2 to MgCO3·3H2O in solvent-mediated CO2 mineralization from bischofite waste

作者：Wang, Jingxin[1,2]; Chen, Guilan[3]; Liu, Chenglin[1,2]; Yu, Jianguo[1,2]

机构：[1] National Engineering Research Center for Integrated Utilization of Salt Lake Resources, East China University of Science and Technology, Shanghai, 200237, China; [2] Engineering Research Center of Salt Lake Resources Process Engineering, Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China; [3] Central Laboratory, Laboratory Management Center, Qingdao Agriculture University, Qingdao, 266109, China

年份：2026

外文期刊名：Green Chemical Engineering

收录：EI(收录号：20260620019427)

语种：英文

外文关键词：Carbon dioxide - Crystals - Growth kinetics - Magnesium - Magnesium compounds - Mineralogy - Molecular dynamics - Morphology - Potassium chloride - Solvents

摘要：The excessive accumulation of bischofite waste following potassium extraction poses a significant threat to the ecological environment of chloride-type salt lakes, while CO2 mineralization of Mg-rich minerals shows great potential for achieving carbon neutrality. Previous studies have identified Mg(HCO3)2 as an inevitable intermediate in the synthesis of the high-value MgCO3·3H2O product from bischofite waste, yet the atomic-level mechanism of Mg(HCO3)2 converting to MgCO3·3H2O remains unclear. In this study, the decomposition-crystallization process and solvent effects were systematically investigated by integrating molecular dynamics (MD) simulations, density functional theory (DFT) calculations, in-situ, and ex-situ characterization methods. In-situ analysis using attenuated total reflectance fourier-transform infrared spectroscopy (ATR-FTIR), pH, and conductivity measurements indicated that the ionization of Mg(HCO3)2 is the primary kinetic obstacle, followed by zero-order kinetics. EtOH accelerated the ionization rate of Mg(HCO3)2 and reduced the average aspect ratio of MgCO3·3H2O crystals from 21.6 to 7.5. MD simulations quantitatively proved that EtOH could replace H2O molecules in the first solvation shell of Mg(HCO3)2 and disrupt the bulk H2O-H2O H-bond network. DFT calculations revealed that the OC adsorption mode of the growth unit on the (0 1 1) surface was predominant, causing the (0 1 1) surface to evolve into the axial faces of acicular MgCO3·3H2O crystallite. EtOH inhibited the axial growth by altering the relative growth rates of crystal surfaces, rather than by adsorbing onto the (0 1 1) surface to impede growth. These findings offer mechanistic understanding of MgCO3·3H2O morphology control, enhancing the CO2 mineralization efficiency and Mg-rich resources sustainability. ? 2026