Chemical Engineering Communications, Vol.206, No.11, 1474-1484, 2019
Analysis of intraparticle diffusion on adsorption of crystal violet on bentonite
In the present work, kinetics of crystal violet (CV) adsorption on bentonite was studied by pore volume and surface diffusion model (PVSDM), surface diffusion model (SDM), and pore volume diffusion model (PVDM). The adsorption decay curves were obtained in batch system using different adsorbent dosages. The PVDM model did not interpreted the kinetic adsorption since the calculated value of D-p equal to 5.64 x 10(-7) cm(2) s(-1) predicted a slower adsorption than that obtained by the experimental data. The PVSDM results indicates that the intraparticle diffusion is predominantly due to surface diffusion (93%) and the pore volume diffusion can be negligible. Once the surface diffusion was the limiting step, the estimation with one (D-s) and two (D-sq and alpha) parameters were tested in the SDM model. The statistical analysis revealed that the one-parameter SDM model was most appropriate to predict the CV adsorption on bentonite. The optimal values of Ds ranged from 6.19 x 10(-10) to 6.49 x 10(-10) cm(2) s(-1), and decrease with the adsorbent dosage.