Fixed bed sorption processes such as adsorption and ion exchange do not operate at

steady state. The design equations are differential that usually require numerical methods

to solve. Thomas gives a general analytical solution for these equations. It is based on

second-order reaction kinetics and the assumption of Langmuir isotherm. Computer

program for the solution of Thomas model was designed using MATLAB 7.0. Four sets

of experimental data are tested to show the capability of Thomas model to predict the

breakthrough curves for adsorption and ion exchange processes. These data represent the

sorption of o-cresol from water by activated carbon, acetic acid from air by activated

carbon, phenol from water by natural zeolite, and trichloroethylene from air by zeolite-

5A.The results show that there are a good agreement between the experimental data and

the model.