In this article, the impacts of liquid properties, loading of solid phase and operating conditions on the hydrodynamic and mass transfer coefficient in a split-cylindrical airlift reactor sparged by air were investigated. The various oil-in-water micro-emulsion systems containing light naphtha, heavy naphtha, kerosene and diesel were used as the liquid phase with oil concentrations of 5% and the solid phase with the loading of 0, 0.25 and 0.5 wt.%. The experimental results showed that a micro-emulsion with the lowest density, viscosity and surface tension had maximum mass transfer and gas hold-up and minimum liquid circulation velocity. The gas hold-up and mass transfer decreased and liquid circulation velocity increased by solid particles addition. Further, solid loading enhancement had a dramatic effect on the mentioned parameters. Moreover, a proper correlation based on dimensionless numbers was used to predict mass transfer in this process. A very good agreement was observed between the correlated data and the experimental ones. (C) 2012 Elsevier Ltd. All rights reserved.