Abstract: Amine-based carbon dioxide (CO₂) capture is still limited by high desorption energy consumption. Fixing CO₂ into carbonate is a safer and more permanent method. In this work, calcium oxide (CaO) is introduced to perform chemical desorption instead of thermal desorption on 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) aqueous solution after CO₂ absorption. The X-ray diffraction (XRD) patterns of solid products show the formation of calcite calcium carbonate (CaCO₃), which prove the feasibility of this method. The effects of reaction temperature, reaction time and Ca²⁺/CO₃^2- molar ratios on the related reactions in CO₂ absorption-mineralization process and CaCO₃ precipitation are discussed, and purer CaCO₃ is obtained by ultrasonic treatment. The CaCO₃ content can be increased to 95.8% and the CO₂ desorption ratio can achieve 80% by 30 min ultrasonic dispersion treatment under the conditions (40 ℃, 180 min, Ca²⁺/CO₃^2- molar ratio = 1.0). After five cycles, DBU aqueous solution shows stable CO₂ absorption and mineralization ability. Fourier transform infrared spectroscopy (FT-IR) spectra of the reaction process also indicate the regeneration of the solvent. Compared with thermal desorption, this process is exothermic, almost without no additional heat.

Key words: CO₂ mineralization, CaCO3, 1,8-Diazabicyclo [5.4.0] undec-7-ene aqueous, Reaction process

摘要： Amine-based carbon dioxide (CO₂) capture is still limited by high desorption energy consumption. Fixing CO₂ into carbonate is a safer and more permanent method. In this work, calcium oxide (CaO) is introduced to perform chemical desorption instead of thermal desorption on 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) aqueous solution after CO₂ absorption. The X-ray diffraction (XRD) patterns of solid products show the formation of calcite calcium carbonate (CaCO₃), which prove the feasibility of this method. The effects of reaction temperature, reaction time and Ca²⁺/CO₃^2- molar ratios on the related reactions in CO₂ absorption-mineralization process and CaCO₃ precipitation are discussed, and purer CaCO₃ is obtained by ultrasonic treatment. The CaCO₃ content can be increased to 95.8% and the CO₂ desorption ratio can achieve 80% by 30 min ultrasonic dispersion treatment under the conditions (40 ℃, 180 min, Ca²⁺/CO₃^2- molar ratio = 1.0). After five cycles, DBU aqueous solution shows stable CO₂ absorption and mineralization ability. Fourier transform infrared spectroscopy (FT-IR) spectra of the reaction process also indicate the regeneration of the solvent. Compared with thermal desorption, this process is exothermic, almost without no additional heat.

关键词: CO₂ mineralization, CaCO3, 1,8-Diazabicyclo [5.4.0] undec-7-ene aqueous, Reaction process