Abstract In this study, a novel strategy for controlling the mass transfer rate in a gas-liquid system was reported and used for the industrially important system of CO2 absorption. The strategy used Fe3O4 nanoparticles in the liquid phase and also exerting an external electric field. To demonstrate this approach, a unique experimental set up was applied to form a falling liquid film, which was water, to be in contact with the gas phase, which was pure carbon dioxide. Nanofluid with concentrations less than 0.03% by volume and field intensities of 133, 200, 266 kV/m were used in this study. Experimental results showed that the external electric field was able to remarkably enhance the gas absorption rate in dilute nanofluids, while it deteriorated mass transfer in concentrated nanofluids. In order to explain the results, the viscosity of the nanofluid was also experimentally measured in the presence of the electric field.