On the determination of partial‐lives of dissipation and/or sorption of a solute in liquid‐solid systems

In most sorption systems, chemical equilibrium is reached before achieving complete removal of the sorbate/solute from solution. In such cases, the determination of the partial‐life values of sorbate removal using the classical approach might lead to erroneous results, since that approach assumes ultimately total dissipation of the sorbate/solute. In order to overcome this limitation, a new approach is used in this work to develop novel expressions of the partial‐life of dissipation and the partial‐life of sorption of a single sorbate (or solute) in liquid‐solid batch systems. The expressions are formulated using both first and second order rate equations, in a manner which takes into account the equilibrium concentration of the sorbate/solute. For the sake of preliminary evaluation, the expressions are tested on previously published data for various systems. It is suggested that the proposed method for the determination of partial lives is useful in improving the reliability of the analysis of kinetic data of sorption systems, in particular those which involve sorbents of high surface activity and fast kinetics, like nanomaterials.