A surface complexation framework for predicting water purification through metal biosorption

Abstract

Biosorption has emerged as an alternative sustainable strategy for cleaning up water contaminated through industrial activities and/or natural processes. Since biomaterials contain discrete reactive sites to which adsorption takes place, the biosorption process is amenable to thermodynamic treatment using surface complexation theory, enabling the development of predictive models for complex natural or industrial mixtures. In this paper, we present such a surface complexation formalism as it relates to bacterial surfaces, which is verified using proton and single metal biosorption data plotted as a function of pH. The parameters extracted from these verification experiments are then used to predict biosorption in mixtures of metals, with excellent success. The model should be applicable to other biomaterials, such as algae, fungi and higher plants.