The mass transfer process of growing bubbles has important effect on the design and optimization of gas-liquid contacting devices. By investigating a single carbon dioxide bubble growing in a sodium carboxymethyl cellulose (CMC) solution

the effects of gas velocity

concentration of CMC solution

and diameter of the needle on gas-liquid mass transfer were examined. The shape

surface area and volume of growing bubble were captured by a dynamic contact angle analysis instrument with a micro-CCD camera and the liquid mass transfer coefficient kl was calculated. The results show that the mass transfer coefficient increased with the solution viscosity as CMC concentration increased from 0.2% to 0.8%

with the diameter of the needle changing from 2.5 mm to 4 mm

and with the gas injection rate increased from 1 ml·min-1 to 9 ml·min-1.