This article presents a new mass transfer model which describes mass transfer rates in a spherical particle where cyclic adsorption and desorption occur. The parameters in the model equation were determined by matching the exact numerical solution to the prediction of this rate law over a range of cycle times. The maximum error was found to be 4.3%. Since the parameters are independent of cycle time, this model equation can be generally used for cyclic adsorption and desorption process regardless of the cycle time and cycle configuration.