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

Abstract

Herein, we discuss carbon capture and utilization processes using industrial wastewater. 5, 10, and 30wt% aqueous monoethanolamine (MEA) solutions were used as the absorbent solution. A pretreated brine solution, in which contained calcium ion with concentration of 21972.64ppm, was used to supply calcium cations. All of the experiments were done under ambient pressure and in a temperature range between 298.15K and 343.15K. 0.79, 0.34 and 0.19mol of CO2 was captured by 5, 10 and 30wt% of aqueous MEA solutions, respectively. When 100ml 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 0.16mol of CO2 were captured by 5, 10, and 30wt% 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.