Saturation states dependence of feldspar dissolution rate: Sensitivity to the timescale of geochemical processes on CO_2 geological sequestration

摘要

For the long-term assessment of CO_2 geological sequestration, the dissolution rate of feldspar was measured under various degrees of saturation 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 L- shaped 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 CO_2 geological sequestration.