Carbon dioxide utilization using a pretreated brine solution at normal temperature and pressure

• This research deals with carbonate salts formation using pretreated brine solutions.
• Precipitated calcium carbonate salts was formed in solutions.
• XRD measurements were performed and SEM images were obtained to verify products.
• Precipitated calcium carbonate was proven to be in three different crystal structures.
• With this research, economic feasibility and wastewater treatment can be achieved at the same time.

Herein, we discuss carbon capture and utilization processes using industrial wastewater. 5, 10, and 30 wt% aqueous monoethanolamine (MEA) solutions were used as the absorbent solution. A pretreated brine solution, in which contained calcium ion with concentration of 21972.64 ppm, was used to supply calcium cations. All of the experiments were done under ambient pressure and in a temperature range between 298.15 K and 343.15 K. 0.79, 0.34 and 0.19 mol of CO2 was captured by 5, 10 and 30 wt% of aqueous MEA solutions, respectively. When 100 ml of pretreated brine solutions were added to each saturated MEA solution, 24.65%, 36.96%, and 41.65% (mol basis) of captured CO2 was converted to calcium carbonate salts by carbon fixation process. To investigate possibility of absorbent recycle after precipitation step, second absorption experiments were performed. As a result 0.55, 0.27, and 0.16 mol of CO2 were captured by 5, 10, and 30 wt% MEA solution, respectively. Through X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) analysis, it was proven that the calcium carbonate formation was possible and the majority of calcium carbonate was in the form of calcite.