Organic solvent mixture separation using fluorine-incorporated thin film composite reverse osmosis membrane

Abstract

Organic solvent reverse osmosis (OSRO) is currently considered as an energy-efficient membrane technology for separation of organic liquid mixtures. The conventional hydrophilic polyamide thin film (TFC) membrane was previously reported to be chemically stable and capable of separation of organic liquids with varying polarity. In order to augment the performance and applicability of the TFC membrane for a wider array of organic liquids, we report the preparation of a hydrophobic fluorine-incorporated TFC membrane for OSRO. 5-Trifluoro-1,3-phenylenediamine (TFMPD) and trimesoyl chloride (TMC) were used as the respective fluorine-containing hydrophobic diamine monomer in aqueous phase and acid chloride in organic phase. The hydrophobic membrane was able to allow the permeation of nonpolar solvents, such as aliphatic and aromatic hydrocarbons, which could not permeate through the conventional hydrophilic polyamide membranes using m-phenylenediamine (MPD) as a diamine monomer. In addition, the OSRO test showed high performance in toluene mixed solvent systems with selective permeation of toluene and 93.9% rejection of 1,3,5-triisopropylbenzene (TIPB). The successful preparation of a hydrophobic fluorine-incorporated polyamide TFC membrane suitable for OSRO for separation of nonpolar organic liquid mixtures has proven to be simple, cost-efficient, and highly-scalable.