Models of surface complexation

With a chapter on particle-particle interaction (coagulation) the characteristics of particles and colloids as chemical reactants are discussed. Since charge, and in turn the surface potential of the colloids is important in coagulation, it is illustrated how in simple cases the modelling of surface complex formation permits the calculation of surface charge and potential. The role of particle-particle interaction in natural water and soil systems and in water technology (coagulation, filtration, flotation) is exemplified. 

The specifics of surface complexation is associated with the participation of the surface and minerals electrostatic field whose potential depends on the structure of the dual electric layer. Due to this, there are several different models of surface complexation. Most commonly used are the constant capacitance model, dual diffuse-layer model and triple layer model. 

Figure 2.18 Used models of surface complexation. A - model of constant capacitance B model of dual or diffusion layer B - model of triple layer.

The dissolution of most minerals due to hydrolysis is a very complex, multistep and not always completely studied process. Currently it became obvious that it is associated with surface complexing. And in recent times ever more attention is devoted to what is going on on the surface of the mineral and within the inner layer Helmholtz layer. In 1970-2000 were simultaneously proposed several models of surface complexation participation in dissolution, which try to tie in properties of minerals with chemical reactions on their surface taking into account mass action law, balance of the substance and of the charge. Without discussing details of this mechanism we will only review its balance. 

CHEMICAL MODELS OF SURFACE COMPLEXATION sufficient here only to note that their ratio is... 

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