Investigation and development of the multicycle of CO2 mineralization with wastewater under standard conditions

AbstractCO2 mineralization is promising for carbon capture and storage (CCS). The multiple reuses of monoethanolamine (MEA) as absorbents for CO2 absorption and carbonate generation with minerals in wastewater between 20 and 25°C at atmospheric pressure (standard conditions) efficiently reduce both cost and energy penalties for industrial application. In this study, the multicycle of CO2 mineralization was performed in three steps: absorption, precipitation, and regeneration. We found that 5 wt.% MEA solution has great potential in terms of 24.26 moles of CO2 absorbing capacity per mole of MEA and 0.1535 moles of carbonate conversion per mole of MEA within less than 1.8 h operation time, which the optimal repetitions was 5‐cycle before MEA complete degradation. To reduce absorption time, we studied packing bed of 2‐, 4‐, 6‐, and 8 mm diameter nonreactive spherical glass beads were operated in the columns with 5 wt.% MEA solutions. The maximum benefit was obtained from the 8‐mm‐packing diameter, which fully accorded 28.85 and 0.1687 moles of CO2 and carbonate, respectively, per mole of 5 wt.% MEA within 44 min, providing the highest conversion in a relatively short time. The efficiency of regenerated MEA absorbent was reduced from 20 to 10% due to degradation. Raman spectroscopy, X‐ray diffractometry, and scanning electron microscopy were used to analyze the composition and crystal structure of carbonates. The main product of carbonates was calcite, which was mixed with complex salts, such as aragonite, magnesite, and dolomite. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.