(545h) Carbon Capture and Utilization Using Metal Cation in Seawater-Based Wastewater

Many nations in the world are concerning the climate change caused by greenhouse gases emission. There are some types of greenhouse gases and the level of contribution for each gas is all different. However, for carbon dioxide, the global warming potential (GWP) is the lowest but it contribute to the climate change quite seriously due to the amount of its emission. Also, carbon dioxide is produced in the fossil fuel combustions and the amount of fossil fuel usage is gradually increasing. Many industrial processes and the powerplants are operated based on the fossil fuel and the carbon dioxide should be captured before they are emitted to the atmosphere. In order to prevent carbon dioxide emission, the CCS (Carbon Capture and Storage) technology was introduced. The main concept of the technology is to separate the carbon dioxide contained in the flue gas and store the carbon dioxide in the safe palce such as deep ocean or the underground. However, the places which was thought to be safe can be changed to the most unstable place due to crust activities and the ocean ecosystems may affected when carbon dioxide is injected in the ocean. With this drawbacks of CCS technology, the new and novel technology that is called CCU (Carbon Capture and Utilization) have got much attention. In ths CCU technology, the carbon dioxide can be converted into useful materials that is organic or inorganic. In this research, inorganic carbon dioxide utilization was dealt with. Carbon dioxide was captured using liquid absorbent comprised of alkanolamine type absorbents. After its separation or capture, industrial seawater containing high concentrations of metal ions was added to the saturated absorbents. When carbon dioxide is dissolved at the amine type absorbents, they are converted to ionic state such as carbonate, bicarbonate or carbamate. Since the reactivity of ionic substances are extremely higher than any other substances, metal carbonate salt which can be used for various purposes can be produced. The merits of this indirect aqueous carbon fixation is that they consume less energy compared to the direct carbonation reaction. The carbonation reaction was taken place under ambient pressure and room temperature. But for direct carbonation, the carbonation reaction can be occurred under high pressure and temperature. As a result of carbon fixation, calcium carbonate salt was produced. In order to investigate the physical properties of the product, XRD (X-ray diffractogram) and SEM (Scanning Electron Microscopy) were used. The final products can be used for construction materials, additives or fillers, and pharmaceutical purpoes and so on.