Harvesting CaCO3 Polymorphs from In Situ CO2 Capture Process

详细信息    查看全文

• 作者：Mari Vinoba ; Margandan Bhagiyalakshmi ; Song Yi Choi ; Ki Tae Park ; Hak Joo Kim ; Soon Kwan Jeong
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 7, 2014
• 年：2014
• 卷：118
• 期：31
• 页码：17556-17566
• 全文大小：487K
• ISSN：1932-7455

文摘

The in situ sequestration of CO₂ using alkanolamine and organometallic calcium (OMC) offers an ecofriendly method for synthesizing a diverse range of calcite, vaterite, and aragonite polymorphs of CaCO₃. Aqueous N-methyldiethanolamine (MDEA) has high CO₂ loading capacity with low regeneration energy, but rate of CO₂ absorption was found to be slow. The driving force for the binding between CO₂ and MDEA could be enhanced by the presence of bovine carbonic anhydrase (bCA). The absorbed CO₂ was converted to stable carbonates through the addition of an OMC. The bCA enzyme both accelerated the CO₂ absorption and mineralization in the amine鈥揅O₂鈥揙MC system and improved the catalytic efficiency to 1.07 脳 10⁴ M^鈥? s^鈥?. The enthalpy of in situ mineralization, the mechanism underlying the CO₂ absorption process, and the formation of an aggregated composition of CaCO₃ were examined using calorimetric, NMR, and X-ray diffraction techniques, respectively. The crystal formation depended crucially on the mineralization process involving the anions of the OMC precursors. The CaO-based sorbents derived from the CaCO₃ polymorphs shows good CO₂ capture capacity on combustion process, and the consecutive re-formation鈥搑egeneration cycles of the CaO sorbents followed the trend aragonite > vaterite > calcite. Hence, the MDEA鈥揙MC鈥揵CA system offers a promising method for transitioning between CaCO₃ polymorphs.