The formation and growth of carbon dioxide gas bubbles from supersaturated aqueous solutions

Abstract

A simple stopped-flow apparatus has been devised to follow the growth of gas bubbles formed after the rapid establishment of a supersaturated aqueous carbon dioxide solution by the reaction of hydrogen ions with bicarbonate ions. Turbidimetric measurements taken over a period of c.200 ms, supplemented by analysis of photographic and videotape recordings at later times have shown that bubble growth is a diffusion-limited process. Experimental results obtained with a hydrophobised cell led to the conclusion that at supersaturations typical of carbonated beverages the mechanism of bubble formation probably involves pre-existing gas cells trapped on the surface. Adsorption of sodium dodecyl sulphate, β-casein or β-lactoglobulin onto the hydrophobic surface reduced the number of bubbles, but solutions of sodium dodecyl sulphate above the critical micelle concentration produced additional bubbles.