A general rate law equation for biosorption

The pseudo first- and second-order equations have been most commonly applied to describe biosorption kinetics under various conditions. This study attempted to develop a general rate law equation for biosorption. It was shown that biosorption kinetics would be subjected to the universal rate law for a chemical process, and the pseudo first- and second-order kinetic equations are the special cases of the proposed general rate law equation for biosorption. As the reaction order cannot be theoretically calculated, it is not reasonable to preset the order of biosorption kinetics to be the first or second as commonly exercised in biosorption studies. The actual kinetic order of biosorption process should be estimated from the proposed general rate law equation without any preset constrain. (C) 2007 Elsevier B.V. All rights reserved.