Enhancement of External Mass Transfer by Gaseous End Products

The conversion rate of biological particles is affected by the mass transfer rate in the particle and the surrounding liquid film. The influence of gas production on the external mass transfer rate was investigated in an inorganic model system, consisting of strong acid ion‐exchange particles converting a sodium bicarbonate solution. The enhancement by the evolution of carbon dioxide amounted to a factor of 4 compared to sodium hydroxide as a reference. The consequences of the experimental results for biological systems are discussed, and it is concluded that the conversion rate might considerably be influenced under conditions of low turbulence. However, no substantial acceleration by the investigated mechanism is to be expected for suspended biological particles, due to the relatively low gas flux at the surface of the particle.