CO2 absorption using sodium silicate aqueous solution in a bubble column has been studied. Sodium silicate aqueous solutions are classified as non-Newtonian fluids that can affect the bubble distribution. The goal of this research is to investigate the effect of a superficial gas velocity (0.85 cm s-1, 2.55 cm s-1, and 4.25 cm s-1) and sodium silicate concentration (0.2% v, 0.6% v, and 1.0% v) on the phenomenon formation of spherical-bubbles, ellipsoidal-bubble, and rod-shape bubbles in bubble column. The experiment was carried out in one minute interval during the five minutes operation. The CO2 absorption and the gel formation is influenced by the pH of the solution where the gas holdup plays an important role in changing the pH. The characterization of the precipitated particles showed that the trona phase (C2H5Na3O8) reached 88% in the preparation of 1% aqueous sodium silicate at a superficial gas velocity of 4.25 cm s-1. The superficial velocity of the gas and the concentration of the sodium silicate solution influence the formation of bubbles. Spherical bubbles and ellipsoidal bubbles were observed in CO2 absorption experiments using a plate sparger, while rod-shaped bubbles were observed in experiments using a ball sparger.
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