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.

Keywords: Carbon sequestration, CO₂ convection, density-driven, pH, carbon concentration