A comparison of kinetic models describing the sorption of pollutants has been reviewed. The rate models evaluated include the Elovich equation, the pseudo-first order equation and the pseudo-second order equation. Results show that chemisorption processes could be rate limiting in the sorption step. The pseudo-second order equation may be applied for chemisorption processes with a high degree of correlation in several Literature cases where a pseudo-first order rate mechanism has been arbitrarily assumed.