ANALYTICAL SOLUTION OF THE BREAKTHROUGH CURVE FOR RECTANGULAR ISOTHERM SYSTEMS

A general solution including both film and intraparticle diffusion resistances is derived for the breakthrough curve for an adsorption or ion exchange system with irreversible equilibrium. Both fluid and solid resistances are represented by linearized rate expressions but the solution is obtained without recourse to the constant pattern assumption. A numerical solution has also been obtained for intraparticle diffusion with external fluid film resistance. The deviation between the predictions of the two models increases with the magnitude of the intraparticle resistance. Numerical solutions were also obtained for Langmuir and Freundlich isotherms in order to establish the range where the simple rectangular models can be considered as an acceptable approximation.