An empirical model was developed for the prediction of the absorption efficiency of nitric oxide (NO) into ammoniacal cobalt (II) solution in terms of gas flow rate, liquid flow rate, and temperature. The model parameters were determined experimentally using a spraying tower with initial absorbent solution pH of 10.0-10.2 for temperatures in the range of 281.15-323.15 K. The reactions between Co2+ complexes and NO were found to be in the fast pseudo-first-order reaction regime. The correlation between the overall mass transfer coefficient and the gas and liquid flow rates was determined for NO absorption. The liquid flow rate (0.225 to 0.730 L/min) had negligible effect on the NO absorption efficiency for the conditions with excessive Co2+ complexes in the solution due to the fast reaction rates. Temperature showed detrimental effects on the NO absorption for conditions in this study. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.