The transition to a sustainable economy requires a more effective and less energy-intensive industry. Membrane technology could augment or partially substitute classical molecular separation processes such as distillation to reduce energy, carbon, and water intensity. Organic solvent nanofiltration and reverse osmosis (OSN and OSRO) can positively impact the petrochemical, pharmaceutical, food, and fine chemical industries, among others, if broadly implemented. While hybrid and inorganic materials have the potential for game-changing performance, polymeric membranes provide key advantages in scalability and processability. Improved materials able to operate in challenging conditions, including combinations of organic solvents, high temperatures, extreme pHs, and oxidative environments are crucial. This is a comprehensive review of the state-of-the-art of polymeric membranes for use in OSN and OSRO, including a critical analysis of current academic approaches and potential polymer systems capable of enabling high-temperature liquid phase membrane separations. The challenges and prospects of OSN and OSRO membranes are discussed in the final section.
Bibliographical noteFunding Information:
This work has been sponsored by King Abdullah University of Science and Technology ( KAUST ). RPL was supported by the National Science Foundation ( CBET-1653153 ).
The most commercially fabricated membranes for OSN have been polydimethylsiloxane (PDMS) or polyimide-based. In the mid-1990s, PDMS membranes started to be commercialized for application in organic solvents by membrane manufacturers, such as Koch Membrane Systems, which produced the flat-sheet membranes MPF-50 and MPF-60 (no longer being sold). They consisted of PDMS coated on a crosslinked polyacrylonitrile (PAN) support, for applications in triglycerides isolation from alkanes, catalyst and organometallic complexes recovery from toluene, tetrahydrofuran (THF), and dichloromethane (DCM), and solvent exchange in pharmaceutical manufacturing . MPF-50 was used to purify a rhodium catalyst during a hydroformylation process in butyraldehyde. However, it was reported in the following years that the membrane was not stable in organic solvents in continuous operation beyond 10 days .PAN support was recently used by Radmanesh et al.  to develop a solvent resistant TFC nanofiltration membrane, by creating a non-standard polyphosphazene cyclomatrix using hexachlorocyclotriphosphazene as the monomer. The MWCO of polystyrene markers was found to be 500 g mol−1 in acetone when the interfacial polymerization was done on top of alumina support, whereas for the PAN support the permeance was higher with lower rejection due to the presence of pinholes in the selective layer. The authors suggested that an optimization of the selective layer could be done through infrared-heat-treated PAN supports stable on DMSO.Kim et al.  reported a TFC membrane based on an ultrathin polyamide separating layer with a new highly porous, thermally and chemically robust polybenzoxazole-co-imide support from a thermally rearranged polymer. The TR-TFC membranes obtained had an MWCO of 600 g mol−1 in DMF with a permeance of 7.7 L m−2 h−1 bar−1 after 50 h of compaction at 30 bar and was stable under DMF filtration at 90 °C with a permeance of 12 L m−2 h−1 bar−1 with no significant change in the rejection (Fig. 9).This work has been sponsored by King Abdullah University of Science and Technology (KAUST). RPL was supported by the National Science Foundation (CBET-1653153).
© 2023 Elsevier B.V.
- High performance polymer
- Membrane separation
- Organic solvent nanofiltration (OSN)
- Organic solvent reverse osmosis (OSRO)
- Polymeric membranes
- Porous materials
- Solvent-resistant membranes
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry
- Filtration and Separation