Absorption and desorption of carbon dioxide in several water types

Abstract

The effect of water type on the rate of CO2 transfer from/to an aqueous phase with varying degree of water salinity was investigated. The absorption and desorption experiments were performed on reverse osmosis product, brackish well, and brackish water reverse osmosis reject waters as well as seawater in a mechanically agitated tank. Results showed that the direction of mass transfer has a great impact on the value of the volumetric mass transfer coefficient, kLa, with the absorption experiments always rendering higher values. Additionally, kLa values always decreased with salinity in both absorption and desorption experiments until a certain critical salinity value was reached, beyond which mass transfer increased again. However, kLa values decreased continuously with an increase in the water alkalinity in absorption experiments, while no clear conclusion could be drawn for the alkalinity effect in the case of desorption experiments.