Green CO₂ Capture using Waste Concrete and Natural Seawater

Global warming associated with rising CO₂ concentrations in the atmosphere has become one of the most critical issues. Carbone capture and storage (CCS) is promising technology to mitigate the global warming. In this research, a new method of CO₂ mineralization is proposed. In the microfluidic device, CO₂ is captured in the seawater at ambient pressure. Further, the solution is exposed to minerals extracted from waste concrete, which can react with carbonate ions and precipitate carbonate minerals. Minute analysis of CO₂ dissolution and the chemical reaction of minerals and carbonate ions in seawater is viable in a microfluidic device with a controlled environment. The use of seawater in our method lessens the heavy demands of freshwater in the conventional method. Additionally, utilizing waste concrete makes the CO₂ capture process economical. Preliminary results show that the CO₂ dissolution capacity of seawater is similar to freshwater with a negligible difference. Around 3% of CaO and other minerals are found in the few samples of waste concrete in the XRD analysis. These minerals are precipitated as carbonated minerals by reacting with CO₂, which can be helpful in the growth of marine life like coral reefs and seashells.