Abstract
Epoxy-based nanofiltration (NF) membranes have great potential to allow untapped applications such as the treatment of water/solvent mixtures. However, achieving reproducible membrane performance with concurrent high permeances for water/solvent mixtures and high solute rejections remains challenging. Herein, such a solvent-tolerant NF (STNF) membrane with superior performance characteristics is synthesized through optimizing the non-solvent induced phase separation (NIPS) method by simultaneously curing 2 epoxide building blocks (EPON 1009F (20 wt%) and EPON SU-8 (10 wt%)) with hyperbranched polyethylene imine (PEI) in dimethyl sulfoxide (DMSO). As a multifunctional crosslinker, the hyperbranched PEI, compared to the difunctional linear hexane diamine (HDA), increases the synthesis reproducibility, the membrane flexibility and permeability, offering a remarkable water/DMF (80/20) permeance of 5.7 L m-1 h-1 bar-1 and a rejection of rose bengal (1018 g mol−1) of 93.3%. A decreased permeance and rejection was observed when increasing the solvent content in the water/DMF or water/ethanol feed from 0 to 30 wt%, while a change in water permeance occurred before and after water/solvent filtrations. The epoxy-based membrane is also intrinsically stable in many solvents, and is easy to tune and produce, making it an ideal candidate for the purification of solvent-containing wastewaters from e.g., the pharmaceutical and chemical industries.
| Original language | English |
|---|---|
| Article number | 121862 |
| Number of pages | 11 |
| Journal | Journal of Membrane Science |
| Volume | 685 |
| DOIs | |
| Publication status | Published - 5 Nov 2023 |
Bibliographical note
Funding Information:In this study, the influence of hyperbranched PEI as curing agent on the epoxy-based membrane brittleness and performance was investigated, and compared to the previously reported HDA-cured poly(β-alkanolamine) as reference [12]. Variation of the NIPS synthesis parameters (i.e., curing time and temperature, casting thickness, and support impregnation) demonstrated the importance of the degree of control over these parameters to achieve a reproducible, flexible, and high-performance STNF membrane. Optimization of the system led to an epoxy-based STNF membrane with an excellent water/DMF permeance of ca. 6 L m-1 h-1 bar-1 and a rejection of rose bengal above 90%.Brittleness of the former HDA-cured membranes [12] could thus be significantly reduced: by using PEI as curing-agent, by reducing the curing temperature to 22 °C, by casting the membrane at a thickness of 150 μm, and by impregnating the non-woven support with DMSO via a pipet (Fig. 3c). Henceforth, these parameters were used to synthesize the PEI-cured poly(β-alkanolamine) membranes and to determine their performance under different conditions.R.V. thanks Research Foundation Flanders (FWO) for her junior postdoctoral fellowship (1216222 N). W.T. and S.E. Kindly acknowledge financial support from Research Foundation Flanders (grant G0A1219 N), KU Leuven (grant C14/18/061), and the European Union's European Fund for Regional Development, Flanders Innovation & Entrepreneurship, and the Province of West-Flanders (Accelerate3 project, Interreg Vlaanderen-Nederland program).
Funding Information:
R.V. thanks Research Foundation Flanders (FWO) for her junior postdoctoral fellowship (1216222 N). W.T. and S.E. Kindly acknowledge financial support from Research Foundation Flanders (grant G0A1219 N ), KU Leuven (grant C14/18/061 ), and the European Union's European Fund for Regional Development , Flanders Innovation & Entrepreneurship , and the Province of West-Flanders (Accelerate3 project, Interreg Vlaanderen-Nederland program).
Funding
In this study, the influence of hyperbranched PEI as curing agent on the epoxy-based membrane brittleness and performance was investigated, and compared to the previously reported HDA-cured poly(β-alkanolamine) as reference [12]. Variation of the NIPS synthesis parameters (i.e., curing time and temperature, casting thickness, and support impregnation) demonstrated the importance of the degree of control over these parameters to achieve a reproducible, flexible, and high-performance STNF membrane. Optimization of the system led to an epoxy-based STNF membrane with an excellent water/DMF permeance of ca. 6 L m-1 h-1 bar-1 and a rejection of rose bengal above 90%.Brittleness of the former HDA-cured membranes [12] could thus be significantly reduced: by using PEI as curing-agent, by reducing the curing temperature to 22 °C, by casting the membrane at a thickness of 150 μm, and by impregnating the non-woven support with DMSO via a pipet (Fig. 3c). Henceforth, these parameters were used to synthesize the PEI-cured poly(β-alkanolamine) membranes and to determine their performance under different conditions.R.V. thanks Research Foundation Flanders (FWO) for her junior postdoctoral fellowship (1216222 N). W.T. and S.E. Kindly acknowledge financial support from Research Foundation Flanders (grant G0A1219 N), KU Leuven (grant C14/18/061), and the European Union's European Fund for Regional Development, Flanders Innovation & Entrepreneurship, and the Province of West-Flanders (Accelerate3 project, Interreg Vlaanderen-Nederland program). R.V. thanks Research Foundation Flanders (FWO) for her junior postdoctoral fellowship (1216222 N). W.T. and S.E. Kindly acknowledge financial support from Research Foundation Flanders (grant G0A1219 N ), KU Leuven (grant C14/18/061 ), and the European Union's European Fund for Regional Development , Flanders Innovation & Entrepreneurship , and the Province of West-Flanders (Accelerate3 project, Interreg Vlaanderen-Nederland program).
Keywords
- Epoxy curing
- Phase inversion
- Solvent tolerant nanofiltration
- Water/solvent mixture filtration