South African Journal of Chemistry
On-line version ISSN 1996-840X
SHIKUKU, Victor O. et al. A comparison of adsorption equilibrium, kinetics and thermodynamics of aqueous phase clomazone between faujasite X and a natural zeolite from Kenya. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp. 245-252. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a33.
In this study, a well-studied synthetic faujasite X (FAU-X) zeolite and a recently discovered natural zeolite material from Kenya (NZ-K) were compared for their efficiency in removal of clomazone, a herbicide and water contaminant, from aqueous solution. The adsorption kinetics, isotherms and thermodynamics parameters were investigated. Equilibrium sorption data were describable by both the Langmuir and Freundlich models. The adsorption kinetics obeyed the pseudo-second-order kinetic law while pore diffusion was not the sole operating rate determining step. The derived thermodynamic parameters, namely AG and AH, indicated the adsorption process was feasible, spontaneous and exothermic for the natural zeolite and non-spontaneous for the synthetic zeolite via a physical and chemical process, respectively. The natural zeolite proved to be a suitable low-cost adsorbent for clomazone removal with removal efficiency above 70 %, five-fold more efficient than faujasite X.
Keywords : Adsorption; natural zeolite; faujasite X; clomazone.