CO2 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.

Integrated absorption–mineralization (IAM) involves the transformation of CO2 in a chemical-based solution with brine used as the absorbent to form insoluble carbonates and is promising for carbon capture, utilization, and storage. Various types of absorbents such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and aminomethyl propanol (AMP) were examined in multicycle integrated absorption–mineralization (multicycle IAM) involving absorption, precipitation, and regeneration steps between 20 °C and 25 °C at atmospheric pressure in order to reveal their performance in terms of CO2 absorption and conversion and absorbent degradation. We found that 5 wt.% AMP offered 89.5% CO2 absorption capacity per unit of absorbent converted into the amount of solid carbonate within 4 cycles. In addition, it was moderately degraded by 64.02% during the first cycle and then reduced from 30% to 10% in the next cycle (>2 cycles). In comparison with MEA, which was used as the initial absorbent, AMP provided a fivefold increase in the speed of multicycle IAM.

The present study aimed to investigate the feasibility of blended amine absorbents in improving the CO2 alkanolamine-based absorption of multicycle integrated absorption–mineralization (multicycle IAM) under standard operating conditions (20–25 °C and 1 atm). Multicycle IAM is a promising approach that transforms CO2 emissions into valuable products such as carbonates using amine solvents and waste brine. Previously, the use of monoethanolamine (MEA) as an absorbent had limitations in terms of CO2 conversion and absorbent degradation, which led to the exploration of blended alkanolamine absorbents, such as diethanolamine, triethanolamine, and aminomethyl propanol (AMP) combined with MEA. The blended absorbent was evaluated in terms of the absorption performance and carbonate production in continuous cycles of absorption, precipitation/regeneration, and preparation. The results showed that the fourth cycle of the blend of 15 wt.% AMP and 5 wt.% MEA achieved high CO2 absorption and conversion efficiency, with approximately 87% of the absorbed CO2 being converted into precipitated carbonates in 43 min and a slight degradation efficiency of approximately 45%. This blended absorbent can improve the efficiency of capturing and converting CO2 when compared to the use of a single MEA, which is one of the alternative options for the development of CO2 capture and utilization in the future.