ABSTRACT
To examine the controlling mechanism of adsorption processes such as mass transfer and chemical reaction, pseudo-first-order and pseudo-second-order kinetic equations were used to test the experimental data. The pseudo-first-order kinetic model was suggested by Lagergren for the adsorption of solid/liquid systems, and its linear form can be formulated as follows (Chen & Wang, 2009):
log( ) log 2.303
1q q q k t
e t e− = − (1)
where qt is the adsorption capacity at time t (mg/g) and k1 (min-1) is the rate constant of the pseudo-first-order adsorption applied to the present study of Cr6+ adsorption.
