The enhancement of the gas-liquid mass transfer rates in aqueous slurries containing small activated carbon particles was studied in a semi-batchwise operated stirred cell absorber with a plane interface. The maximum observed enhancement factors for absorption of propane, ethene and hydrogen in the aqueous slurries were 3.6, 3.3 and 2.0, respectively. It was shown that for our results and those reported in the literature the maximum enhancement factor, E(max), decreases with increasing liquid side gas-liquid mass transfer coefficient, k(l). From all the experimental data the following relationship is found : (E(max) - 1) = 0.0019 (k(l)/[m s(-1)])(-0.71) although different types of activated carbon particles and differences in sizes were used by the various research groups. To describe these results a simple theory is presented.