Pseudo second order kinetic model for the sorption of U (VI) onto soil: A comparison of linear and non-linear methods

Abstract

Batch kinetic experiments were carried out for the sorption of U(VI) onto three types of soil. The experimental kinetics were fitted to the pseudo second-order kinetics by linear and a nonlinear method. The four different types of Ho pseudo second-order expression have been discussed. A comparison of linear least-squares method and a trial and error non-linear method of estimating the pseudo second-order rate kinetic parameters were examined. The sorption process was found to follow pseudo second-order kinetic model. Present investigation showed that it is appropriate to use a linear model-1 pseudo second-order expressions as proposed by Ho for predicting the kinetic rate constants and the initial sorption rate for the studied system. And the transformation of nonlinear form to linear model-1 changed the conditions in a positive way leads to minimization of error structure and that caused that the linear model-1 give very similar or better fits than other models. Different linear models predicts different reaction rate, hence to avoid this ambiguity it is better to use nonlinear model if the process designer is unable to study the experimental data using all the models.