In the present work, the influence of mixture of Al₂O₃ and Al₂O₃ - SiO₂ nanoparticles in base fluid water (nanofluid) on absorption of CO₂ in a packed column was investigated. The effects of concentration of nanoparticles and types of nanoparticles on the absorption rate were investigated. The packed column was used to study gas liquid countercurrent flow. The results indicated that the optimum value was equal to 0.05 vol% for both nanofluids, and also addition of nanoparticles increased the mass transfer rate. Besides, the maximum enhancement of mass transfer rate for nanoparticles of Al₂O₃ and mixture of Al₂O₃ - SiO₂ compared to the pure water was 14% and 10% at 0.05 vol% of the nanofluid, respectively.