Membrane processing of an aqueous waste stream from a catalyst manufacturing plant

Abstract

Separation of rhenium from a dilute aqueous waste stream of a catalyst manufacturing plant by a thin film composite polyamide membrane using the principle of reverse osmosis is studied. In the present study, permeate flux increases linearly with applied pressure, with slight increase in percent rejection of rhenium from the wastewater. Over 96% retention of rhenium by the membrane is observed. Increase in concentration of rhenium decreases permeate flux, relatively rapid in the beginning and then gradually, whereas, percent rejection increases marginally with increase in concentration and reaches a value of over 98. An attempt has been made to analyze the separation data by a graphical method of combined film theory–Solution–Diffusion model.

Keywords:

• Reverse osmosis
• Rhenium
• Aqueous waste stream
• Polyamide membrane

Acknowledgments

Authors are thankful to the Management of Indian Petrochemicals Corporation Limited for their permission to publish this manuscript, to Mr P. T. Naik, and Mrs A. A. Purohit for their help in analysis, and to M/s Permionics, Baroda, Gujarat, India for providing the TFC polyamide membrane.