An Experimental Technique for Measuring Spatiotemporal pH and Carbon Concentration During Density-Driven Convection of CO2 in Water

Density-driven convection of CO2 in water will trigger the spatiotemporal evolution of pH and carbon concentration, impacting the understanding of CO2 dissolution and implementations of geological carbon sequestration. Building upon the conventional methodology which applies a single pH indicator and Schlieren imaging analysis, the enhanced experimental technique, offering a holistic view of CO2 convection within water, resulted in an accurate and visual representation of the CO2 plume propagation and a wider range of pH alteration and carbon concentration during CO2-water interactions. In response to the broad pH variations with continuous CO2 dissolution, this study utilized three pH indicators combined with the novel image analysis method to correlate the solutions’ colors to their pH. Afterwards, the carbon concentration is derived from the pH values by employing the pseudo-equilibrium theories. Leveraging an experimental technique and analytical tools to measure the spatiotemporal pH and carbon concentration, the research aims to deepen the understanding of CO2 convection behaviors, paving the way for enhanced insights into carbon sequestration and related environmental processes.