The proposed mathematical model covered in this paper includes the most important parameters associated with the rates of adsorption and desorption. Also, partial pressure is included since it is an important factor that affects rates of adsorption and desorption. The study focuses on the effects of the constant rates on adsorption of pollutant concentrations for benzene, nickel, cadmium, and copper using modified active carbon. When the rate constant of adsorption decreases, the pollutant concentration will also decrease, yielding high acceptable evidence of the logic of the proposed mathematical model. Also, the proposed model is compared with experimental data and other models to give good outcomes with high accuracy.