On the application of surface complexation models to ionic adsorption

Surface complexation models (SCMs) have been used extensively to describe t he acid-base properties and adsorption behaviors of inorganic and organic c ations and anions on many single-phase adsorbents. The success of SCMs resu lts from the conformation of adsorption to mass-action and material-balance laws and the flexibility in adjustable parameters. However, the assumption s made in the derivation of the SCMs are really not justified and the SCMs are not so thoroughly grounded in fundamental chemistry. The SCMs are reall y the data-fitting model, rather than the chemical model. The premises of a pplication of SCMs are the accurate identification of surface species and t he low surface coverage. Though the application of the SCMs comes into vogu e, the SCMs should be applied with caution. (C) 2000 Academic Press.