Sorption processes of styryl dyes dications with N -ammonioalkyl substituent of varying length on the surface of polystyrene submicroparticles

We have investigated the multilayer adsorption isotherms of styryl dyes (SDs) of pyridine series (dications) with active centers (COOH) of the surface of polystyrene colloidal particles in an aqueous solution, depending on the length of N -substituent and the particle diameter. A proposed model of sorption takes into account both the ion-exchange sorption mechanism (exchange of H+ ions to SD dications) and a phase equilibrium shift of SD solution to multilayer ionic condensate in the ionic diffusive layer near the electric charged surface of the particles if the concentration of the SD solution is high enough. Modeled sorption isotherms are in agreement with the experimental data.