Kinetic modeling of adsorption of di-2-pyridylketone salicyloylhydrazone on silica gel

Abstract

The kinetics of DPKSH (di-2-pyridylketone salicyloylhydrazone) adsorption onto silica gel has been investigated at (25 ± 1) ° C and pH 1 and 4.7. The kinetics of adsorption of DPKSH is discussed using three kinetic models, the first-order Lagergren model, the pseudo-second-order model, and the intraparticle diffusion model. The adsorption of DPKSH, at pH 1 and 4.7, onto silica gel proceeds according to the pseudo-second-order model and the correlation coefficients were very close to 1. The intraparticle diffusion of DPKSH molecules within the silica gel particles was identified as the rate-limiting step. The parameters of the pseudo-second-order model are qmax, calc = 1.02 × 10-4 and 1.5 × 10-4 g DPKSH/g silica; k2 = 3.01 × 104 and 9.67 × 104 h-1 g silica/g DPKSH, respectively, for pH 1 and 4.7. © 2006 Elsevier Inc. All rights reserved.