Effect of sodium dodecyl sulfate (SDS) on bubble characteristics and ozone transfer in a bubble column

The rising of ozone-containing bubbles in a bubble column was examined by a high-speed micro video camera. The shape of the bubbles shifted from spherical to ellipsoidal during their rise along the column. The experimental observation indicated that the average diameter at the X-axis of the bubbles was markedly increased after the bubbles left the diffuser because the gas pressure inside the bubbles was not balanced with the surrounding water pressure. However, the shape of bubbles was kept spherical along the column during an experiment conducted in the presence of sodium dodecyl sulfate (SDS), a commonly used surfactant. In pure water, the intrinsic interfacial areas for the bubble column were determined to be in the range of 2.958 to 8.607 m(-1) for experiments conducted with the gas flow rate from 3.25 x 10(-6) to 1.16 x 10(-5) m(3)/s, and the intrinsic mass transfer coefficient of ozone, k(L), was found to be 0.0004 m/s at 25 degrees C and 1 atm. The determined overall and the specific gas-liquid contact area were notably increased from 0.0059 m(2) and 2.958 m(-1) to 0.0197 m(2) and 8.964 m(-1), respectively, with the presence of 0.0346 mM of SDS in the aqueous solution.