Navin D. Shah

Date of Award


Document Type


Degree Name

Master of Science (MS)


Chemical Engineering


The separation of a mixture of benzene and n-hexane was studied using a liquid membrane technique. Sparkleen^ detergent was used as the surfactant and heavy mineral oil was used as the solvent to receive the permeate.

The effects of the following variables on the separation factor were investigated:

1. The relative proportion of benzene and n-hexane in the original mixture.

2 . Surfactant concentration.

3 . Quantity of surfactant solution.

4. Amount of solvent.

5 . Contact time with solvent.

The effect of each variable was studied by varying the values of that variable while holding other variables constant.

It was found that both the separation factor and the permeate composition vary with the feed composition. Under the experimental conditions employed in the present study, the average value of the separation factor for 0.1 to 0.9 mole fraction of benzene in the feed was found to be approximately 6.

Under the experimental conditions employed in the present study, the separation factor was found to be low for the volumes of solvent less than 180 c.c. The separation factor was found to be about constant for the volumes of solvent between 180 and 250 c.c. Beyond 250 c.c. , the separation factor was again found to be low.

For low values of concentration of surfactant and contact times with solvent, the separation factor was found to be low. As the values of these variables were increased the separation factor increased and reached a maximum and for large values of these variables, the separation factor again decreased.

From the study of the variation of separation factor with the quantity of surfactant solution, it was found that the separation factor was independent of the quantity of surfactant solution beyond a certain volume of surfactant solution. For volumes less than this minimum, the separation factor was lower, but increased as the volume increased.

A rough estimate of the theoretical and experimental error involved in the present study has been made. The relative advantages and disadvantages of the separation by liquid membrane were also discussed.