Kinetic estimation of the adsorbate distribution on the surface from adsorbed amounts

Abstract

A phenomenological multilayer adsorption model for a well-dispersed, homogeneous, nonporous adsorbent and a molecular adsorbate is presented. The model provides explicit kinetic expressions associating the adsorbed amounts to the fraction of the surface occupied and reduces to the first-and second-order adsorption models for special cases. Parameters of the model are a pair of true rate constants related to the adsorbateadsorbent and adsorbate-surface adsorbate affinities. A general graphical procedure and analytical equations for special cases are provided to estimate the rate constants from kinetic adsorption data. Data from the adsorption of sodium stearate onto α-alumina from water were used to test the model. The predicted values of the rate constants suggested that the stearate was distributed homogeneously on the alumina surface and essentially adsorbed as a monolayer before starting to form the second layer.

Kinetic Modeling of the Adsorption of Basic Dyes onto Steam-Activated Bituminous Coal

“…Theses were further correlated to process parameters such as initial dye concentration, solution pH, agitation rate, adsorbent mass, and adsorbent particle size. Because modeling of adsorption kinetics is important for simulation, scaling-up, and control purposes, the rate and mechanism of dye removal have been determined from the application of several kinetic models. The pseudo-second-order kinetic model, intraparticle-diffusion model, and external mass-transfer model were used to describe the kinetic data, and the rate constants were evaluated.…”