Isothermal growth of hydrogen bubbles during electrolysis

✍ Scribed by D. E. Westerheide; J. W. Westwater

• Publisher: American Institute of Chemical Engineers
• Year: 1961
• Tongue: English
• Weight: 906 KB
• Volume: 7
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690070303

✦ Synopsis

Abstract

The investigation was concerned with measuring growth rates of bubbles in an isothermal medium where growth is controlled by mass diffusion. The conditions were met by generating hydrogen bubbles at a platinum cathode during the electrolysis of water. Growth data were obtained by motion picture photography at 800 to 2,400 frames/sec. taken through a microscope to produce an enlargement of 30X on the film.

Growth took place in 0.1 normal and 1.0 normal sulfuric acid in water at 77°F. Current densities between 0.1 and 0.2 amp./sq. cm. were used. The observed diameters were all less than 0.006 in., and the growth times were less than 2 sec. Beside growth phenomena interesting features recorded included the coalescence of bubbles, the jumping of bubbles off the solid and then back again, and the slip of the bubble contact at the solid surface.

Some bubbles grew with their radii proportional to the square root of time as predicted theoretically by Scriven. For these bubbles the calculated supersaturation of hydrogen in the solution was found to be from eight to twenty‐four times the concentration at saturation.