Characteristics of CO₂ fixation by chemical conversion to carbonate salts
2013
Park, Sangwon | Min, Jaehong | Lee, Min-Gu | Jo, Hoyong | Park, Jinwon
We propose a new method of CO₂ removal by combining carbon dioxide capture and storage (CCS) and CO₂ fixation processes. In this study, amine solutions were used to make carbonates and calcium ions were used for CO₂ fixation. Primary (MEA), secondary (DEA), and tertiary (MDEA) amines were selected for use in a 10 or 30wt% amine solution with H₂O and Ca²⁺ in a CO₂ saturated solution. CO₂ fixation was verified and the carbonate was formed under normal temperature and pressure conditions. As a result, most of the CO₂ was converted to a precipitate (more than 84% by weight). The molar yield of MDEA was higher than that of the other amines (MEA and DEA). We believe that this is due to the fact that tertiary amines (MDEA) do not have H⁺ in their structure. Therefore, MDEA does not produce carbamate when CO₂ is absorbed in solution. Further, we measured the residual CO₂ in each solution through a desorption process. These results also demonstrate less residual CO₂ in the MDEA than in the other amines. Product carbonates were analyzed by X-ray diffractometry (XRD) and were found to consist of calcite, aragonite, and vaterite with various compositions depending on the particular amine solution used for the CO₂ conversion. Therefore, we conclude that CO₂ fixation is possible using amine solutions and metal ions. We believe that this process can be applied to CO₂ emission capture techniques where no external energy is required.
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