Absorption of carbon dioxide into aqueous colloidal silica solution with diisopropanolamine

Carbon dioxide was absorbed into the aqueous nanometer-sized colloidal silica solution of 0–31 wt% and diisopropanolamine of 0–2 kmol/m³ in a flat-stirred vessel with the impeller of various sizes and speeds at 25 °C and 0.101 MPa to measure the absorption rate of CO₂. The volumetric liquid-side mass transfer coefficient (k_La) of CO₂ was used to obtain the empirical correlation formula containing the rheological behavior of the aqueous colloidal silica solution. Reduction of the measured k_La was explained by the viscoelastic properties of the aqueous colloidal silica solution. The theoretical value of the absorption rate of CO₂ was estimated from the model based on the film theory accompanied by chemical reaction and compared with the measured value.