ABSTRACT Surface complexation models have been used for thirty years to explain surface charge and adsorption properties of minerals. Macroscopic data and methods to obtain them are discussed along with their respective advantages and disadvantages. This includes titrations, electrokinetic experiments and adsorption measurements as well as combined approaches. Such data may be treated with computer codes to obtain thermodynamic data in the framework of a specified surface complexation model. Currently used surface complexation models are covered as well as some non-standard models along with their respective advantages and disadvantages. The possible options for the different components of surface complexation models (protonation/deprotonation mechanism, structure of the electrostatic double layer and treatment of heterogeneity) are introduced. The required parameters for the different model components are discussed. Methods for independent determination of the parameters and data fitting procedures are evaluated. Selected model variations, which can be synthesized from the available options for the different components are discussed in detail. Future requirements of the surface complexation models are discussed in the context of specific modelling purposes. Approaches, which allow in principle to cover a maximum of independent experimental data sources, are introduced. Various sources of experimental data, which have the potential to decrease the number of successful models, are described.
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