Effects of NO3– and SO42– Ions on the Coupled Reaction–Extraction–Crystallization Process of MgCl2 and CO2

Abstract

The effects of NO3– and SO42– ions on the H+ concentration in organic phase and crystal morphology of solid product nesquehonite (MgCO3·3H2O) in the coupled reaction–extraction–crystallization process were investigated. During the coupled process, the H+ concentration in organic phase increased with the increase in concentration of NO3– ions and decreased with the increase in concentration of SO42– ions, indicating that NO3– ions promoted the carbonization of MgCl2 while SO42– ions inhibited the same. The rodlike MgCO3·3H2O crystals became short and thick in the presence of both NO3– and SO42– ions. Energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and molecular dynamic simulation were used to clarify the mechanism by which impurity ions modified the structure. The results indicated that the NO3– and SO42– anions could be selectively adsorbed on the top facet (011) of MgCO3·3H2O, preventing the growth of crystal surfaces, which results in the d...