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Internal concentration polarization (ICP) in a dense support layer is one of the main reasons holding back forward osmosis (FO) process. In this regard, a highly porous microstructured support (HPμS) featuring a quasi-sponge-free sublayer pore structure can be considered a suitable alternative to develop high-performance FO membranes. However, it has not been tested for its effects on FO. This study demonstrates that a TFC membrane prepared using the HPμS works out for FO by inducing 3.35 times higher water flux without compromising a reverse salt flux (J s) compared to a control TFC membrane prepared without support adjustment. The performance improvement could be achieved by HPμS's almost no sponge-like region and lateral walls, which were desirable to minimize ICP. Furthermore, we verified that it is possible to leverage co-solvent assisted interfacial polymerization (CAIP) to further improve FO membrane performances by creating a more permeable active layer. The in-house TFC membrane optimized by the HPμS and CAIP displayed 5.3 times higher FO water flux than the control membrane, while keeping comparable J s. We expect that this research could contribute to kicking the FO membrane performance up a notch by providing a practical example of simultaneous optimization of both support and active layers. [Display omitted] • A highly porous microstructured support (HPμS) successfully reduced ICP in FO. • Almost no sponge-like region and lateral walls of the HPμS were key in reducing ICP. • A sublayer structure of a support layer was examined by a non-destructive inspection. • Co-solvent assisted interfacial polymerization further improved FO performances. • The simultaneous optimizations of support and active layers maximized FO performances. [ABSTRACT FROM AUTHOR]

A scaled-up hollow fibre thin-film composite (TFC) module was successfully developed for organic solvent forward osmosis (OSFO) application in the pharmaceutical industry. The membrane consists of cross-linked P84 polyimide substrate with a polyamide selective layer, formed via interfacial polymerisation. The performance of the lab-scale module was compared to the scaled-up module in reverse osmosis and forward osmosis modes. The results from both tests revealed that the solvent permeability of the scaled-up module decreased while its selectivity increased slightly. This might be caused by the uneven distribution of liquids during interfacial polymerisation, leading to varied membrane performance. The scaled-up module was further tested for OSFO performance using a range of PEG-400 concentrations (0.5–2 M) in acetone and isopropanol as draw solutions. At 2 M PEG-400 concentration, the module demonstrated high isopropanol and acetone permeability of 0.63 LMH and 13.9 LMH, respectively. Moreover, the reverse solute flux of PEG-400 in acetone and isopropanol were relatively low at 0.188 g/l and 0.153 g/l, respectively. The module was further tested for OSFO application in the pharmaceutical industry by concentrating levofloxacin in acetone, using 2 M PEG-400 as draw solution. The process was able to concentrate levofloxacin from 1000 ppm to 16,000 ppm with very low reverse solute flux of 0.178 g/l. Therefore, this work presents a scalable TFC membrane for OSFO application in the pharmaceutical industry. [Display omitted] • Scaled-up module (0.4 m2) of TFC hollow fibre membrane for organic solvent forward osmosis process was successfully fabricated. • High porosity (79%) and low structural parameter (217 μm) for membrane substrate was achieved. • Membrane exhibited excellent acetone and IPA solvent flux of 13.9 LMH and 0.63 LMH, respectively, using a 2 M PEG-400 draw solution. • A pharmaceutical stream was concentrated to a factor of 16 with low specific reverse solute flux [ABSTRACT FROM AUTHOR]

A scaled-up hollow fibre thin-film composite (TFC) module was successfully developed for organic solvent forward osmosis (OSFO) application in the pharmaceutical industry. The membrane consists of cross-linked P84 polyimide substrate with a polyamide selective layer, formed via interfacial polymerisation. The performance of the lab-scale module was compared to the scaled-up module in reverse osmosis and forward osmosis modes. The results from both tests revealed that the solvent permeability of the scaled-up module decreased while its selectivity increased slightly. This might be caused by the uneven distribution of liquids during interfacial polymerisation, leading to varied membrane performance. The scaled-up module was further tested for OSFO performance using a range of PEG-400 concentrations (0.5–2 M) in acetone and isopropanol as draw solutions. At 2 M PEG-400 concentration, the module demonstrated high isopropanol and acetone permeability of 0.63 LMH and 13.9 LMH, respectively. Moreover, the reverse solute flux of PEG-400 in acetone and isopropanol were relatively low at 0.188 g/l and 0.153 g/l, respectively. The module was further tested for OSFO application in the pharmaceutical industry by concentrating levofloxacin in acetone, using 2 M PEG-400 as draw solution. The process was able to concentrate levofloxacin from 1000 ppm to 16,000 ppm with very low reverse solute flux of 0.178 g/l. Therefore, this work presents a scalable TFC membrane for OSFO application in the pharmaceutical industry. [Display omitted] • Scaled-up module (0.4 m2) of TFC hollow fibre membrane for organic solvent forward osmosis process was successfully fabricated. • High porosity (79%) and low structural parameter (217 μm) for membrane substrate was achieved. • Membrane exhibited excellent acetone and IPA solvent flux of 13.9 LMH and 0.63 LMH, respectively, using a 2 M PEG-400 draw solution. • A pharmaceutical stream was concentrated to a factor of 16 with low specific reverse solute flux [ABSTRACT FROM AUTHOR]