Morphology control of magnesium carbonate for CO₂ utilization using Mg²⁺ ions in industrial wastewater depending on length of alkyl chain of primary alkanolamine, reaction temperature, CO₂ concentration, and Mg²⁺/Na⁺ ratio

Because global warming has been a constant issue in the environmental field, many studies on the mitigation of CO₂ have been conducted. This study for carbon dioxide utilization dealt with the characteristics of magnesium carbonate formation using Mg²⁺ ions separated from seawater-based industrial wastewater and alkanolamine absorbent depending on the alkyl chain length of the primary alkanolamine type absorbent, reaction temperature, CO₂ concentration, and Mg²⁺/Na⁺ ratio as part of the investigation. First, nesquehonite was formed with a relatively short length and amorphous MgCO₃·3H₂O was formed with a relatively long length in the alkyl chain length experiment. Second, nesquehonite at low temperature was produced, and hydromagnesite was produced as temperature increased in the reaction temperature experiment. In addition, nesquehonite was only magnesium carbonate depending on CO₂ concentration, but each product had different purities. Finally, increasing of Mg²⁺/Na⁺ ratio derived production of not nesquehonite but hydromagnesite with high purity of over 98 wt%. Through this study, the morphology and purity control of magnesium carbonate can reach commercialization levels in the particular conditions, and industrial application of carbon capture and utilization processes using wastewater and alkanolamine absorbent would be achieved.