Exploring and Exploiting the Effect of Solvent Treatment in Membrane Separations

Abstract

It is well-known that solvent treatment and preconditioning play an important role in rejection and flux performance of membranes due to solvent -induced swelling and solvent adsorption. Investigations into the effect of solvent treatment are scarce and application specific, and were limited 2 to a few solvents only. This study reveals the trend in solvent treatment based "on solvent polarity in a systematic A. investigation with the aim to harness such effect for 0 intensification of membrane processes. Nine solvents with polarity indices ranging from 0.1 to 5.8 (hexane to acetonitrile) were used as treatment and process solvents on commercial Borsig GMT-oNF-2, Evonik Duramem 300, and emerging tailor-made polybenzimidazole membranes. TGA-GCMS, HS-GCFID, and 4\TM.R. techniques were employed to better understand the effect of solvent treatment on the polymer matrix of membranes. In this work) apart from the solvent treatment's direct effect "on the membrane performance, a subsequent indirect effect on the ultimate separation process was observed. Consequently, a pharmaceutical case study employing chlorhexicline disinfectant and antiseptic was used to demonstrate the effect of solvent treatment on the nanofiltration-based purification. It is shown that treatment of polybenzimidazole membranes with acetone resulted in a 25% increase in product recovery at 99% impurity removal. The cost of the process intensification is negligible in terms of solvent consumption, mass intensity, and processing time.