The gasliquid volumetric mass transfer coefficient was determined by the dynamic oxygen absorption technique using a polarographic dissolved oxygen probe and the gasliquid interfacial area was measured using dual-tip conductivity probes in a bubble column slurry reactor at ambient temperature and normal pressure. The solid particles used were ultrafine hollow glass microspheres with a mean diameter of 8.624 mu m. The effects of various axial locations (heightdiameter ratio=112), superficial gas velocity (uG=0.0110.085m/s) and solid concentration (epsilon S=030wt.%) on the gasliquid volumetric mass transfer coefficient kLaL and liquid-side mass transfer coefficient kL were discussed in detail in the range of operating variables investigated. Empirical correlations by dimensional analysis were obtained and feed-forward back propagation neural network models were employed to predict the gasliquid volumetric mass transfer coefficient and liquid-side mass transfer coefficient for an airwaterhollow glass microspheres system in a commercial-scale bubble column slurry reactor. (c) 2012 Canadian Society for Chemical Engineering