| Abstract |
| This study developed a compact system to prepare high-concentration CO2 supersaturated water to address carbon emissions in the concrete industry, which accounts for approximately 8 % of global anthropogenic CO2 emissions. The system employs a pressurized pump-injector gas-liquid mixing method, overcoming the limitations of conventional nanobubble technologies, which require extended processing times and large-scale equipment. Under optimized operating conditions (100 L/min flow rate, G/L ratio 0.2), the system achieved CO2 concentrations exceeding 1,450 mg/L within 15 min, reaching a maximum of 4,200 mg/L after 120 min ―approximately three times the theoretical equilibrium concentration. The compact design (32.4 L tank volume) represents a > 90 % size reduction compared to conventional systems while maintaining > 90 % dissolution efficiency and processing capacities exceeding 100 L/min. Water quality analysis confirmed characteristic changes during operation: pH decreased from 7.2 to 4.8, alkalinity decreased by 70%, and electrical conductivity increased by 246.7%. Thermogravimetric analysis demonstrated permanent CO2 mineralization by converting free-CaO and Ca(OH)2 to CaCO3, with treated specimens exhibiting 2.8 times higher CaCO3 content than control samples. Carbon capture bricks manufactured using CO2 supersaturated water achieved 13.3 % higher compressive strength (32.5 versus 28.2 MPa, p < 0.01) than conventional bricks, attributed to nano-sized CaCO3 precipitation filling capillary pores. This system offers a practical, field-applicable solution for carbon capture and utilization technology, compatible with existing production processes with minimal modifications, contributing to achieving Korea's 2030 Nationally Determined Contribution targets through distributed carbon management systems. |
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| Key Words |
| CCU, CO₂ supersaturated water, Carbonation, Concrete, Free-CaO, Water treatment 탄소포집, CO2 과포화수, 탄산화, 콘크리트, 탄산칼슘 |
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