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\n\n \n \n \n \n \n \n Overcoming water Co-transport in PIM-1/PVDF composite membranes for sustainable ammonia recovery from wastewater.\n \n \n \n \n\n\n \n Park, J.; Park, J.; Hwang, Y.; and Koh, D.\n\n\n \n\n\n\n
Separation and Purification Technology,136673. December 2025.\n
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\n\n \n \n ![\"Overcoming](\"//bibbase.org/img/filetypes/link.svg\"\n\t "\\"Paper\\"\n\t")
Paper\n \n \n\n \n \n doi\n \n \n\n \n link\n \n \n\n bibtex\n \n\n \n \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{park_overcoming_2025,\n\ttitle = {Overcoming water {Co}-transport in {PIM}-1/{PVDF} composite membranes for sustainable ammonia recovery from wastewater},\n\tissn = {1383-5866},\n\turl = {https://www.sciencedirect.com/science/article/pii/S1383586625052700},\n\tdoi = {10.1016/j.seppur.2025.136673},\n\tabstract = {Ammonia contamination in industrial wastewater poses significant environmental challenges due to its toxicity and strict regulatory constraints. Although membrane contactors using nonselective membranes are widely used for ammonia recovery via liquid-liquid extraction, where an acidic extractant flows on the opposite side of the membrane, unintended water cotransport imposes a burden on overall treatment efficiency. To overcome this limitation, we propose a novel approach using PIM-1/PVDF thin film composite hollow fiber membranes that enable selective ammonia permeation while effectively rejecting water. A dense PIM-1 layer coated on the PVDF support shifts the transport mechanism from pore-flow model to solution–diffusion model, effectively suppressing water vapor transport due to its hydrophobic nature. Membrane performance was evaluated under both liquid-vacuum and liquid-liquid (with aqueous phosphoric acid as extractant) operational modes using simulated ammonia wastewater at varying temperatures and concentrations. Both modes exhibited similar trends in water and ammonia permeate fluxes, however, the liquid-liquid mode consistently demonstrated higher ammonia flux and lower water flux across all studied process conditions. Long-term operational stability was further validated by reaching a concentration-based ammonia removal efficiency of 95.4 \\% with dramatically reduced water loss of less than 17 \\%. The thin film composite hollow fiber membranes demonstrated a 4.2-fold higher separation factor compared to porous membranes, offering a material-driven solution to water cotransport issues in conventional membrane contactors for more sustainable wastewater treatment.},\n\turldate = {2025-12-30},\n\tjournal = {Separation and Purification Technology},\n\tauthor = {Park, Jimin and Park, Joon-Hyun and Hwang, Young-Eun and Koh, Dong-Yeun},\n\tmonth = dec,\n\tyear = {2025},\n\tkeywords = {Ammonia, Hollow Fiber membrane, PIM-1, PVDF, Thin film composite membrane},\n\tpages = {136673},\n}\n\n\n\n\n\n\n\n\n\n\n\n\n
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\n Ammonia contamination in industrial wastewater poses significant environmental challenges due to its toxicity and strict regulatory constraints. Although membrane contactors using nonselective membranes are widely used for ammonia recovery via liquid-liquid extraction, where an acidic extractant flows on the opposite side of the membrane, unintended water cotransport imposes a burden on overall treatment efficiency. To overcome this limitation, we propose a novel approach using PIM-1/PVDF thin film composite hollow fiber membranes that enable selective ammonia permeation while effectively rejecting water. A dense PIM-1 layer coated on the PVDF support shifts the transport mechanism from pore-flow model to solution–diffusion model, effectively suppressing water vapor transport due to its hydrophobic nature. Membrane performance was evaluated under both liquid-vacuum and liquid-liquid (with aqueous phosphoric acid as extractant) operational modes using simulated ammonia wastewater at varying temperatures and concentrations. Both modes exhibited similar trends in water and ammonia permeate fluxes, however, the liquid-liquid mode consistently demonstrated higher ammonia flux and lower water flux across all studied process conditions. Long-term operational stability was further validated by reaching a concentration-based ammonia removal efficiency of 95.4 % with dramatically reduced water loss of less than 17 %. The thin film composite hollow fiber membranes demonstrated a 4.2-fold higher separation factor compared to porous membranes, offering a material-driven solution to water cotransport issues in conventional membrane contactors for more sustainable wastewater treatment.\n
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\n\n \n \n \n \n \n \n Tailoring MnO2 nanodomains in organic-inorganic hybrid interfaces toward tunable hydrocarbon separation.\n \n \n \n \n\n\n \n Choi, J.; Shin, W.; Seo, H.; Heo, H.; Jang, M.; and Koh, D.\n\n\n \n\n\n\n
Journal of Membrane Science, 736: 124615. December 2025.\n
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\n\n \n \n Paper\n \n \n\n \n \n doi\n \n \n\n \n link\n \n \n\n bibtex\n \n\n \n \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{choi_tailoring_2025,\n\ttitle = {Tailoring {MnO2} nanodomains in organic-inorganic hybrid interfaces toward tunable hydrocarbon separation},\n\tvolume = {736},\n\tissn = {0376-7388},\n\turl = {https://www.sciencedirect.com/science/article/pii/S0376738825009287},\n\tdoi = {10.1016/j.memsci.2025.124615},\n\tabstract = {Organic solvent nanofiltration offers an energy-saving alternative to distillation for hydrocarbon fractionation. Here, we introduce a simple and scalable method for fabricating novel organic-inorganic hybrid membranes from polybenzimidazole (PBI) and manganese oxide (MnO2), designed for the separation of complex hydrocarbons. Homogeneously integrated MnO2 domains, formed via oxidative interaction with imidazole moieties within the PBI matrix, create a rigid hybrid structure with enhanced molecular selectivity. By systematically tuning PBI concentration, KMnO4 dosage, and reaction time, we achieved membranes with low molecular weight cut-off (MWCO) as low as 266 g mol−1. Notably, these membranes surpassed the reported upper bound for toluene/1,3,5-triisopropylbenzene separation and demonstrated effective fractionation of complex hydrocarbon mixtures, such as naphtha, enriching the lighter fractions. This study clarifies the role of KMnO4 in PBI modification: rather than inducing direct N–N crosslinking as previously suggested, it facilitates the in situ generation of crystalline MnO2 domains that bolster membrane rigidity and molecular selectivity. These findings underscore the potential of hybrid PBI membranes as a practical platform for membrane-assisted crude oil fractionation and offer prospects for advanced energy-efficient separation strategies.},\n\turldate = {2025-12-26},\n\tjournal = {Journal of Membrane Science},\n\tauthor = {Choi, Jihoon and Shin, Woong-Chul and Seo, Hyeokjun and Heo, Huiryung and Jang, Min-Jun and Koh, Dong-Yeun},\n\tmonth = dec,\n\tyear = {2025},\n\tkeywords = {In situ oxidation, Manganese oxide, Molecular weight cut-off, Organic solvent nanofiltration, Organic-inorganic hybrid membrane},\n\tpages = {124615},\n}\n\n\n\n\n\n\n\n\n
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\n Organic solvent nanofiltration offers an energy-saving alternative to distillation for hydrocarbon fractionation. Here, we introduce a simple and scalable method for fabricating novel organic-inorganic hybrid membranes from polybenzimidazole (PBI) and manganese oxide (MnO2), designed for the separation of complex hydrocarbons. Homogeneously integrated MnO2 domains, formed via oxidative interaction with imidazole moieties within the PBI matrix, create a rigid hybrid structure with enhanced molecular selectivity. By systematically tuning PBI concentration, KMnO4 dosage, and reaction time, we achieved membranes with low molecular weight cut-off (MWCO) as low as 266 g mol−1. Notably, these membranes surpassed the reported upper bound for toluene/1,3,5-triisopropylbenzene separation and demonstrated effective fractionation of complex hydrocarbon mixtures, such as naphtha, enriching the lighter fractions. This study clarifies the role of KMnO4 in PBI modification: rather than inducing direct N–N crosslinking as previously suggested, it facilitates the in situ generation of crystalline MnO2 domains that bolster membrane rigidity and molecular selectivity. These findings underscore the potential of hybrid PBI membranes as a practical platform for membrane-assisted crude oil fractionation and offer prospects for advanced energy-efficient separation strategies.\n
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\n\n \n \n \n \n \n \n Design of Electrified Fiber Sorbents for Direct Air Capture with Electrically-Driven Temperature Vacuum Swing Adsorption.\n \n \n \n \n\n\n \n Lee, Y. H.; Lee, J. H.; Joo, H.; Massen-Hane, M.; Park, I.; Rho, S.; Jamal, A.; Alan Hatton, T.; and Koh, D.\n\n\n \n\n\n\n
Advanced Materials, 37(45): e04542. 2025.\n
_eprint: https://advanced.onlinelibrary.wiley.com/doi/pdf/10.1002/adma.202504542\n\n
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\n\n \n \n Paper\n \n \n\n \n \n doi\n \n \n\n \n link\n \n \n\n bibtex\n \n\n \n \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{lee_design_2025,\n\ttitle = {Design of {Electrified} {Fiber} {Sorbents} for {Direct} {Air} {Capture} with {Electrically}-{Driven} {Temperature} {Vacuum} {Swing} {Adsorption}},\n\tvolume = {37},\n\tcopyright = {© 2025 The Author(s). Advanced Materials published by Wiley-VCH GmbH},\n\tissn = {1521-4095},\n\turl = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202504542},\n\tdoi = {10.1002/adma.202504542},\n\tabstract = {Joule heating is becoming accepted as a highly efficient regeneration technique for temperature vacuum swing adsorption in direct air capture (DAC). This acknowledgment arises from its ability to rapidly generate and transfer heat, along with the convenience of obtaining electrical power from renewable sources. This study presents a unique electrified fiber sorbent (i.e., e-fiber) design that facilitates Joule heating, enabling energy-efficient electrically-driven temperature-vacuum swing adsorption (e-TVSA) for DAC. The e-fiber sorbent is produced via a dip coating technique, in which a silver composite solution is applied to the surface of an open-porous polymer matrix. The resulting ultra-thin, interconnected porous conductive layer on the fiber surface not only minimizes the increase in diffusion resistance even after the surface coating process but also offers exceptionally low electrical resistance (0.5 Ω cm−1). The e-fiber sorbent module achieves a desorption temperature of 110 °C in 80 s at 3 V. Notably, only a 5\\% reduction in capacity is recorded following repeated cycles of e-TVSA at a CO2 concentration of 400 ppm. The complicated nature of heat transfer processes is clarified caused by Joule heating in the e-fiber sorbent module through detailed case studies conducted with computational simulations, offering insights for design optimization and system engineering.},\n\tlanguage = {en},\n\tnumber = {45},\n\turldate = {2025-12-26},\n\tjournal = {Advanced Materials},\n\tauthor = {Lee, Young Hun and Lee, Jung Hun and Joo, Hwajoo and Massen-Hane, Michael and Park, Injun and Rho, Soohyeon and Jamal, Aqil and Alan Hatton, T. and Koh, Dong-Yeun},\n\tyear = {2025},\n\tnote = {\\_eprint: https://advanced.onlinelibrary.wiley.com/doi/pdf/10.1002/adma.202504542},\n\tkeywords = {Joule heating, direct air capture, dry-jet wet-quench spinning, electrically-driven temperature-vacuum swing adsorption (e-TVSA), electrified fiber sorbents},\n\tpages = {e04542},\n}\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
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\n Joule heating is becoming accepted as a highly efficient regeneration technique for temperature vacuum swing adsorption in direct air capture (DAC). This acknowledgment arises from its ability to rapidly generate and transfer heat, along with the convenience of obtaining electrical power from renewable sources. This study presents a unique electrified fiber sorbent (i.e., e-fiber) design that facilitates Joule heating, enabling energy-efficient electrically-driven temperature-vacuum swing adsorption (e-TVSA) for DAC. The e-fiber sorbent is produced via a dip coating technique, in which a silver composite solution is applied to the surface of an open-porous polymer matrix. The resulting ultra-thin, interconnected porous conductive layer on the fiber surface not only minimizes the increase in diffusion resistance even after the surface coating process but also offers exceptionally low electrical resistance (0.5 Ω cm−1). The e-fiber sorbent module achieves a desorption temperature of 110 °C in 80 s at 3 V. Notably, only a 5% reduction in capacity is recorded following repeated cycles of e-TVSA at a CO2 concentration of 400 ppm. The complicated nature of heat transfer processes is clarified caused by Joule heating in the e-fiber sorbent module through detailed case studies conducted with computational simulations, offering insights for design optimization and system engineering.\n
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\n\n \n \n \n \n \n \n A strategic design of iCVD copolymers for high-performance organic solvent nanofiltration membranes with tunable permeance and selectivity.\n \n \n \n \n\n\n \n Choi, J.; Kim, D.; Choi, K.; Seo, H.; Jang, M.; So, H.; Im, S. G.; Yoo, Y.; and Koh, D.\n\n\n \n\n\n\n
Chemical Engineering Journal, 524: 169165. November 2025.\n
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\n\n \n \n Paper\n \n \n\n \n \n doi\n \n \n\n \n link\n \n \n\n bibtex\n \n\n \n \n \n abstract \n \n\n \n\n \n \n \n \n \n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n\n\n\n
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@article{choi_strategic_2025,\n\ttitle = {A strategic design of {iCVD} copolymers for high-performance organic solvent nanofiltration membranes with tunable permeance and selectivity},\n\tvolume = {524},\n\tissn = {1385-8947},\n\turl = {https://www.sciencedirect.com/science/article/pii/S1385894725100089},\n\tdoi = {10.1016/j.cej.2025.169165},\n\tabstract = {Organic solvent nanofiltration (OSN) holds promise for reducing industrial solvent waste, yet membrane materials still face a critical challenge: achieving both robust permeance and high solute rejection. Herein, we introduce a molecular design strategy for high-performance OSN membranes with adjustable monomer composition using initiated chemical vapor deposition (iCVD). Vapor phase copolymerization between a rigid, highly cross-linkable monomer (1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane) and relatively soft, bulky monomer (cyclohexyl methacrylate) allowed the formation of an active layer with exquisitely tailored copolymer composition for high-performance OSN membrane. By precisely adjusting the ratio of monomers, both the solvent permeance and solute selectivity of the thin film copolymer membranes could be controlled precisely, overcoming the conventional trade-off, which is hard to achieve in solution processing. Notably, the copolymer membrane with the highest permeance ({\\textasciitilde}2.43 L m−2 h−1 bar−1) achieved up to a 6.5-fold increase in acetone permeance without compromising the molecular weight cut-off ({\\textasciitilde}370 g mol−1) with the optimized copolymer composition. Such findings highlight the potential of the molecularly designed copolymer membrane as a promising selective layer in OSN processes, providing scalable, defect-free, and high-performance separation solutions, particularly for the pharmaceutical and chemical industries.},\n\turldate = {2025-12-26},\n\tjournal = {Chemical Engineering Journal},\n\tauthor = {Choi, Jihoon and Kim, Daehun and Choi, Keonwoo and Seo, Hyeokjun and Jang, Min-Jun and So, Hyoseok and Im, Sung Gap and Yoo, Youngmin and Koh, Dong-Yeun},\n\tmonth = nov,\n\tyear = {2025},\n\tkeywords = {Copolymerization, Initiated chemical vapor deposition (iCVD), Molecular weight cut-off, Organic solvent nanofiltration (OSN), Solvent permeance},\n\tpages = {169165},\n}\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
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\n Organic solvent nanofiltration (OSN) holds promise for reducing industrial solvent waste, yet membrane materials still face a critical challenge: achieving both robust permeance and high solute rejection. Herein, we introduce a molecular design strategy for high-performance OSN membranes with adjustable monomer composition using initiated chemical vapor deposition (iCVD). Vapor phase copolymerization between a rigid, highly cross-linkable monomer (1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane) and relatively soft, bulky monomer (cyclohexyl methacrylate) allowed the formation of an active layer with exquisitely tailored copolymer composition for high-performance OSN membrane. By precisely adjusting the ratio of monomers, both the solvent permeance and solute selectivity of the thin film copolymer membranes could be controlled precisely, overcoming the conventional trade-off, which is hard to achieve in solution processing. Notably, the copolymer membrane with the highest permeance (~2.43 L m−2 h−1 bar−1) achieved up to a 6.5-fold increase in acetone permeance without compromising the molecular weight cut-off (~370 g mol−1) with the optimized copolymer composition. Such findings highlight the potential of the molecularly designed copolymer membrane as a promising selective layer in OSN processes, providing scalable, defect-free, and high-performance separation solutions, particularly for the pharmaceutical and chemical industries.\n
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