Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

Abstract

In this present work, the kinetic reaction constants including the forward (kf, Cs adsorption onto granite) and backward (kb, Cs desorption from granite) rate constants of Cs on granite were determined by fitting the experimental data from both adsorption and desorption experiments with a pseudo first-order reaction model. In the case of Cs adsorption, both forward and backward rate constants are consistent with one another as Cs loading less than 0.1 mM. In contrast, both forward and backward reaction constants from desorption experiment dramatically increase as the Cs loading increases. Rearrangement of these desorption data by linearization technique, a notable instantaneous desorption process appears, which profoundly influences the determination of the rate constants. Based on our fitting results, the rate constants including both forward and backward reactions determined from Cs adsorption onto granite are much suitable to represent the adsorption behavior, in which the recommended values are of 0.42 and 0.03 h−1, respectively.