OSRO TRADE-OFF CURVE

Organic Solvent Reverse Osmosis (OSRO) is a rapidly growing area of membrane science. One observation is that the use of upper bound plots in gas separations drove the development of exceptional materials for eventual use as membranes. While these plots are only one piece of the puzzle when it comes to membrane system design, they are nonetheless useful in creating a consistent test that can be utilized to easily compare membrane materials.

We have created a trade-off curve for the separation of toluene and tri-isopropylbenzene (TIPB). While there are many organic solvent separations of interest, we believe toluene/TIPB is a simple and useful OSRO test case. Critically, toluene and TIPB have no internal conformations (unlike something like hexane or hexanol), similar polarities, and viscosities. Additionally, from a practical, lab testing perspective, toluene and TIPB are both liquids at room temperature and can be easily differentiated in a GC, which makes this a straightforward experiment to conduct.

We present this "trade-off curve" as an exemplar - we hope and expect that many others will emerge in the future for additional separations. This site will be updated periodically as new toluene/TIPB data emerges.

Data Compiled by Yi Ren and Woo Jin Jang

Figure: Cross flow permeation, 10 - 60 bar applied pressure to the membrane, 293 K, 1-10 mol% TIPB. Closed points are all-polymer materials; the open points are composites or non-polymeric materials. (Latest Update: Oct 19, 2025)

*Linear, high glass transition temperature polymers

 

Download data in the trade-off curve figure by clicking here.

 

References:

  1. Rivera, M. P.; Bruno, N. C.; Finn, M.G.; Lively, R. P. Organic solvent reverse osmosis using CuAAC-crosslinked molecularly-mixed composite membranes. J. Membr. Sci., 2021. https://doi.org/10.1016/j.memsci.2021.119700

  2. Jang, Hye-Youn.; Johnson, J. R.; Ma, Y.; Mathias, R.; Bhandari, D. A.; Lively, R. P. Torlon® hollow fiber membranes for organic solvent reverse osmosis separation of complex aromatic hydrocarbon mixtures, AIChE J., 2019. https://doi.org/10.1002/aic.16757

  3. Thompson, K. A.; Mathias, R.; Kim, D.; Kim, J.; Rangnekar, N.; Johnson, J. R.; Hoy, S. J.; Bechis, I.; Tarzia, A.; Jelfs, K. E.; McCool, B. A.; Livingston, A. G.; Lively, R. P.; Finn, M. G. N-Aryl–linked spirocyclic polymers for membrane separations of complex hydrocarbon mixtures. Science, 2020. 10.1126/science.aba9806

  4. McGuinness, E. K.; Zhang, F.; Ma, Y.; Lively, R. P.; Losego, M. D. Vapor Phase Infiltration of Metal Oxides into Nanoporous Polymers for Organic Solvent Separation Membranes. Chem. Mater., 2019. https://doi.org/10.1021/acs.chemmater.9b01141

  5. Kushida, W.; Gonzales, R. R.; Shintani, T.; Matsuoka, A.; Nakagawa, K.; Yoshioka, T.; Matsuyama, H. J. Mater. Chem. A., 2022. https://doi.org/10.1039/D1TA09192A

  6. Bruno, N.; Mathias, R.; Zhu, G.; Ahn, Y.; Rangnekar, N.; Johnson, J.R.; Hoy, S.; Bechis, I.; Tarzia, A.; Jelfs, K.; McCool, B.; Lively, R.; Finn, MG. Solution Processable Polytriazoles from Spirocyclic Monomers for Membrane-based Hydocarbon Separations. ChemRxiv, 2022. https://doi.org/10.26434/chemrxiv-2022-0g577

  7. Thompson, K. A.; Mathias, R.; Lively, R. P.; Finn, M.G. Structure-Function Relationships in Membrane-Based Hydrocarbon Separations Using N-Aryl-Linked Spirocyclic Polymers. Chem. Mater. 2023, https://doi.org/10.1021/acs.chemmater.2c02646

  8. Y. Feliachi, A. Roy, Y. Ren, M. G. Finn, R. P. Lively, Solid-state crosslinking of thin film composite membranes for organic solvent reverse osmosis separations. J. Membr. Sci. 695, 122462 (2024). https://doi.org/10.1016/j.memsci.2024.122462

  9. T. H. Lee, M. Balcik, W.-N. Wu, I. Pinnau, Z. P. Smith, Dual-phase microporous polymer nanofilms by interfacial polymerization for ultrafast molecular separation. Sci. Adv. 10, eadp6666 (2024). https://doi.org/10.1126/sciadv.adp6666

  10. P. Ramesh, M. M. Sta Cruz, S. Karla, J. Ahn, S. Lee, P. T. Underhill, G. Belfort, A new class of “structure-by-design” polymer membranes for organic solvent nanofiltration with controllable selectivity. J. Membr. Sci. 692, 122296 (2024). https://doi.org/10.1016/j.memsci.2023.122296

  11. Y. Ren, H. Ma, J. Kim, M. Al Otmi, P. Lin, C. Dai, Y. J. Lee, Z. Zhai, W. J. Jang, S. Yang, A. Sarswat, Y. Feliachi, J. Sampath, M. J. Realff, R. P. Lively, S. Guo, Fluorine-rich poly(arylene amine) membranes for the separation of liquid aliphatic compounds. Science 387, 208–214 (2025). https://doi.org/10.1126/science.adp2619

  12. T. H. Lee, M. Balcik, Z. Ali, T. Joo, M. P. Rivera, I. Pinnau, Z. P. Smith, Microporous polyimine membranes for efficient separation of liquid hydrocarbon mixtures. Science 388, 839–844 (2025). https://doi.org/10.1126/science.adv6886

 
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