A weighted average kinetic equation and its application in estimating mass transfer coefficients in liquid phase adsorption

The pseudo-first-order (PFO) and pseudo-second-order (PSO) models are widely used to describe liquid phase adsorption kinetics due to their simplicity and easy application. But these models do not take into account the diffusion or mass transfer effects that exist in adsorption. In this work a new weighted average (WA) kinetic model is presented. The model parameters are related to mass transfer coefficients, which allows for the estimation of the film mass transfer and surface diffusion coefficients from adsorption kinetic data. The WA model is applied to four adsorption systems and compared with the PFO and PSO models by using the Akaike Information Criterion (AIC). The results show that the WA model fits the experimental kinetic data much better than the PFO and PSO models.