Two-step mineral carbonation using seawater-based industrial wastewater: an eco-friendly carbon capture, utilization, and storage process

Carbon dioxide is contained in the flue gas of many industrial plants, including those producing cement and power, and makes a significant contribution to climate change. Thus, methods to reduce carbon dioxide emissions are under intensive investigation. Carbon capture, utilization, and storage (CCUS) is a technology for converting captured carbon into useful chemical compounds while reducing CO₂ emissions. Thus, CCUS technology is a promising method for combating global warming. In this study, we focused on a mineral carbonation CCUS process using seawater-based industrial wastewater (SBIW). A two-step CCUS process using NaOH as an absorbent for CO₂ capture was used to produce two types of metal carbonate. Inductively coupled plasma optical emission spectroscopy, X-ray diffractometry, thermogravimetric analysis, and field-emission scanning electron microscopy techniques were used for analysis. Using our new technique, we obtained high-purity NaHCO₃ (92.2%) and MgCO₃ ·3H₂O (93%). We also found that it is possible to improve the utilization of the cations present in seawater.