Gas absorption is an operation in which a gas mixture is contacted with a liquid for the purpose of preferentially dissolving one or more components of the gas mixture and to provide a solution of them in the liquid. Generally, there are three methods in the absorption enhancement: the mechanical treatment, the chemical treatment, and nanotechnology techniques.This thesis is related to the experimental investigation on using of nanofluids in the gas absorption process in a wetted wall column. To study the proposed title, a glass wetted wall column was designed and subsequently fabricated. The inner and outer diameters of column are 28 and 32 mm, and the height of the column is 1.45m. This column equipped with liquid distributor, gas inlet system, and liquid flow meter. In this work, Fe 3 O 4 /Water, Al 2 O 3 /Water, and TiO 2 /Water nanofluids were used as solvent in the absorption process. Effect of gas and liquid flow rates and also effect of magnetic ?eld on the mass transfer rate and mass transfer coefficients at different nao-particles concentrations were investigated. Al 2 O 3 /water nanofluid with concentration of 0.01, 0.05, 0.1, 0.5, 1 v/v%, TiO 2 /water nanofluid with concentration of 0.05, 0.1 and 0.5 v/v %, and Fe 3 O 4 /water nanofluid with concentration of 0.005, 0.008 and 0.024 v/v % have been used. The gas and liquid flow rates in the experiments are 1 and 5 lit/min for gas phase, and 3.1, 4.68, 6.66 mlit/s for liquid phase. Effect of magnetic field attended on base fluid and Fe 3 O 4 /Water nanofluid. In the case of base fluid, the electric current intensity of 0, 0.5, 1, and 1.5 A have been used in direct of falling film and against direct of falling film. In the Fe 3 O 4 /Water nanofluid the intensity of electric current was 1 A in direct of falling film. Experimental results showed that the Al 2 O 3 /water nanofluid has higher mass transfer rate and mass transfer coefficient in comparison to the base fluid (water). Mass transfer coefficient and mass flux were enhanced for Al 2 O 3 /water nanofluid and the enhancement value was increased with increasing of nanoparticle concentration. The results showed that the increase in mass transfer coefficients and mass flux are 55 % and 90% for a fixed volume fraction of 1%.Mass transfer coefficients and mass flux have decreased by using TiO 2 /water nanofluid. In this nanofluid, at the concentration of 0.05%, the reduction in mass transfer coefficient and mass transfer rate was 16% and 5% respectively. Effect of magnetic field has been investigated in base fluid (water) and Fe 3 O 4 /Water nanofluid. The increase in mass transfer rate and mass transfer coefficient in water system is 22% and 59% for a fixed electric current intensity of 1A. In this system, when the direction of magnetic ?eld is same to the direction of falling ?lm, the mass transfer coefficient increases, and when thedirection of magnetic ?eld is against to the direction of falling ?lm, the mass transfer coefficients decreases. In the Fe 3 O 4 /Water nanofluid, the increase in mass transfer coefficient at intensity of 1A is 53%. In this nanofluid the mass transfer rate increased by increasing in nanoparticle volume fraction, but under all of the conditions, the mass transfer rates and mass transfer coefficients are lower than base fluid (water). Keywords: absorption, nanofluid, mass transfer coefficient, wetted wall column