Prediction of Pervaporative Performance for Benzene /normal Hexane Mixtures through Polyurethane Membranes

The separation behavior of benzene- normal hexane mixture by membrane based process of pervaporation using polyurethane membrane was studied over the entire concentration range 0-100% benzene at 25 C ο . Separation of this mixture by membrane based pervaportion process is analyzed by the solution-diffusion model which assumes that a permeating component is first dissolved in the membrane and then diffuses through the membrane due to its driving force. Therefore the separate evaluation of sorption equiliria is necessary in order to determine the controlling step in overall mass transport in the membrane. In this study, the sorption of aromatic/aliphatic hydrocarbon mixtures was modeled using classical Flory-Huggins thermodynamic model. The binary interaction parameters were calculated using pure component uptake data. Using these parameters, the multi-components sorption performance was then predicted by the extended Flory-Huggins model. Diffusion step was modeled by Maxwell- Stefan model. Diffusion coefficients concentration dependency was described by an empirical exponential correlation. The results indicate a close agreement between the experimental data and the predicted sorption and diffusion values. The results also revealed that the aromatic compounds are preferentially adsorbed into polyurethane over the entire rage of composition.

کلیدواژه ها:

Pervaportion ، solution-diffusion ، Flory-Huggins ، Benzene ، normal hexane ، Maxwell- Stefan