The effect of water type on the absorption and desorption of carbon dioxide in bubble columns

Abstract

This study investigates the effect of alkalinity and salinity on the transfer rate of carbon dioxide, CO2, from/to several aqueous phases. The CO2 absorption and desorption experiments were performed for several water types including distilled, reverse osmosis, brackish, and brackish reject waters in addition to seawater, inside a bubble column contactor. Findings indicated that the direction of transfer (i.e. absorption or desorption) had a strong influence on the rate of mass transfer with higher values recorded for the absorption experiments. The results also showed that for the absorption and desorption experiments the volumetric mass transfer coefficient, kLa, values always decreased with increased salinity until a “threshold” value was attained, above which kLa increased again. The effect of alkalinity on kLa values was not as conclusive where the experimental results indicated that for adsorption kLa values decreases almost linearly with the increase in water alkalinity while no discernible trends were observed for the effect of alkalinity in the desorption experiments.