Regarding the important role of static hold-up in both hydrodynamic and mass transfer rate in extraction columns, average static hold-up has been studied in a Rotary Disc Contactor (RDC) as a function of rotor speed, average mother drop size and number of stages using several chemical systems. In the light of the promising potential of nanofluids in mass transfer applications, in a quite novel investigation, nanofluids were applied as dispersed phases to the RDC column. Two types of SiO2 nanoparticles with different hydrophobicities were employed in nanofluids preparation, which stabilities were appraised by sedimentation method and UV-vis spectrophotometry. Transmission Electron Microscopy was also applied to examine the size and shape of SiO2 nanoparticles