Saturation dependence of feldspar dissolution rate and its impact to CO₂ geological sequestration

Abstract

For the long-term assessment of CO2 geological sequestration, the dissolution rate of feldspar was measured under various degrees of undersaturation based on observations of the time-course change of dissolved crystal surfaces on a nanoscale. We identified that the dependence of solution saturation state on anorthite dissolution rate follows to a sigmoidal curve function, rather than to a linear function. Compared with a linear assumption, such a nonlinear form provides a much lower estimate of dissolution rate. This implies that the difference of rate formula can cause meaningful errors in the timescale evaluation of various geochemical processes. In this study, therefore, the effect of the function form of dissolution rate was also checked using the geochemical simulation code to analyze CO2 geological sequestration.