S . S Madaeni - Chemical Engineering Department, Razi University Kermanshah, Iran
E Salehi - Chemical Engineering Department, Razi University Kermanshah, Iran

In a previous work published by the current authors, a mathematical model for transport and adsorption of saturated brine-anions through negatively charged nanofiltration membrane was introduced. This model was a combination of convection-diffusion equation in unsteady form with adsorption isotherms. In this study the proposed model was improved using a new adsorption- based porosity model. A novel dynamic model was derived for bulk porosity estimation on the basis of the adsorption rate and accumulation of anions on the membrane matrix during filtration process. Finally, the anion's transport partial differential equations and obtained bulk porosity relationship were combined and solved simultaneously. Introducing the variation of bulk porosity along the filtration process, results in a slight improvement in recent model predictions.

Modeling, membrane, adsorption-transport, porosity, screen phenomenon