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

Abstract

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.

Effects of Alkanolamine Absorbents in Integrated Absorption–Mineralization

“…The calculation error of CO 2 absorption capacity ranged from 2.74 to 16.20%. Furthermore, these results were similar to those reported in the literature [17,24,[46][47][48]. However, the amount of CO 2 absorbed varied because of independent factors, such as human error or external factors.…”

“…The previous study [24] showed a single step of precipitation under standard conditions, whereas we performed precipitation twice (100 and 50 mL), and the results were compared, as shown in Figure 3.…”

“…Moreover, IAM processes were further developed by repeating those processes to maximize the usage of recycled absorbents and improve the formation of carbonates, despite gradual absorbent degradation during IAM cycles [22,23]. Thus, multicycle integrated CO 2 absorption-mineralization (multicycle IAM) applies to the reproducible process of absorption, precipitation, and regeneration by reusing the absorbent multiple times [24].…”

“…The brine waste is composed of exceedingly intense concentrations of metal ions such as Na + , Ca 2+ , and Mg 2+ ions, including various contaminants. Instead of treatment, these brine wastes are applied in precipitation to form carbonates [17,24]. The general separation technology and membrane spent USD 0.75-2.5 million and USD 1-1.5 million for 100 gallons per minute, respectively [25,26].…”

“…Monoethanolamine (MEA), a primary amine, is commonly used for gas scrubbing on an industrial scale because it has high CO 2 capture performance and reasonable cost [28,29]. Furthermore, aqueous MEA solution was used as in multicycle IAM, and the preliminary results suggested that the regenerated MEA could be efficiently recycled in the gas scrubber without the treatment process and that it increased CO 2 absorption and conversion [24]. Even though the MEA absorbent was suitable for CO 2 removal, its high energy consumption and erosiveness have raised environmental concerns [30].…”