Thin-film Composite Hollow Fiber Research Articles

Construction of a novel poly(amide-ester) thin film composite hollow fiber nanofiltration membrane with high water permeance

Highly permeable hollow fiber (HF) nanofiltration (NF) membrane is strongly desired since it could achieve efficient desalination with much less energy consumption. In this study, we used 4,4′,4′′-trihydroxytriphenylmethane (TP) as an aqueous co-monomer with piperazine (PIP) to react with trimesoyl chloride (TMC) to prepare a new internally pressurized poly(amide-ester) HF NF membrane. With the incorporation of TP molecules, the synthesized poly(amide-ester) separation layer achieved larger pore size and better hydrophilicity, giving the HF NF membrane excellent water permeance. Under optimum conditions, the HF NF membrane has a water permeance of 151 L m−2 h−1 MPa−1, which is 50 % higher than that of the control HF NF membrane, while maintaining a Na2SO4 rejection of 97.5 %. Moreover, it displays excellent desalination performance towards heavy metal salt solutions and high salinity solutions. It also maintains excellent desalination performance during a long-time filtration experiment, which indicates its good durability performance. In summary, this new poly(amide-ester) HF NF membrane shows good promise for the treatment of heavy metal and high-salinity wastewaters.

Scalable, Interfacially Synthesized, Covalent-Organic Framework (COF)-Based Thin-Film Composite (TFC) Hollow Fiber Membranes for Organic Solvent Nanofiltration (OSN).

Covalent organic frameworks have great potential for energy-efficient molecular sieving-based separation. However, it remains challenging to implement COFs as an alternative membrane material due to the lack of a scalable and cost-effective fabrication mechanism. This work depicts a new method for fabricating a scalable in situ COF hollow fiber (HF) membrane by an interfacial polymerization (IP) approach at room temperature. The 2D COF film was constructed on a polyacrylonitrile HF substrate using aldehyde (1,3,5-trimethylphloroglucinol, Tp) and amine (4,4'-azodianiline (Azo) and 4,4',4″-(1,3,5-triazine- 2,4,6-triyl) trianiline (Tta)) as precursors. The COF membrane on the PAN substrate showed 99% rejection of Direct red-80 with remarkable solvent permeance. The rejection analysis revealed that the structural aspects of the solute molecule play a major role in rejection rather than the molecular weight. We further optimized the precursor concentrations to improve the permeation performance of the resulting membrane. The durability study reveals excellent stability of the membrane toward organic solvents. This study also demonstrated the easy scalability of the membrane fabrication approach. The approach was further extrapolated to fabricate a cation-based COF membrane. These charged membranes exhibited an enhanced rejection performance. Finally, this approach can facilitate industrially challenging molecular sieving applications using COF-based membranes.

Hollow Fiber Membrane Modification by Interfacial Polymerization for Organic Solvent Nanofiltration

Hollow fiber (HF) organic solvent nanofiltration (OSN) membranes have recently attracted significant interest in the field of membrane technology. Their popularity stems from comparative advantages, such as high packing density, fouling resistance, and easier scalability for larger applications, unlike flat-sheet/spiral-wound OSN membranes, which may present challenges in these aspects. The combination of interfacial polymerization (IP) and HF configuration has opened up new opportunities for developing advanced membranes with enhanced separation performance that can be tailored for various OSN applications. The objective of this review is to discuss the latest advancements in developing thin film composite (TFC) HF membranes, with a focus on the IP method. Novel materials and processes are discussed in detail, emphasizing the fabrication of greener, interfacially polymerized HF OSN membranes. In addition, the commercial viability and limitations of TFC HF membranes are highlighted, providing perspectives on future research directions.

High-Degree Concentration Organic Solvent Forward Osmosis for Pharmaceutical Pre-Concentration.

Over half of the pharmaceutical industry's capital investments are related to the purification of active pharmaceutical ingredients (APIs). Thus, a cost-effective purification process with a highly concentrated solution is urgently required. In addition, the purification process should be nonthermal because most APIs and their intermediates are temperature-sensitive. This study investigated a high-degree concentration organic solvent forward osmosis (OSFO) membrane process. A polyketone-based thin-film composite hollow fiber membrane with a polyamide selective layer on the bore surface was used as the OSFO membrane to achieve a high tolerance for organic solvents and an effective concentration. MeOH, sucrose octaacetate (SoA), and 2M polyethylene glycol 400 (PEG-400)/MeOH solution were used as the solvent, model API, and a draw solution (DS), respectively. OSFO was performed at room temperature (23 ± 3 °C). Consequently, the 11 wt% SoA/MeOH solution was concentrated to 52 wt% without any SoA leakage into the DS. To our knowledge, there are no studies in which up to a 5 wt% concentration by OSFO has been demonstrated. However, the final feed solution contained 17 wt% PEG-400. This study demonstrates the promising potential of OSFO for pharmaceutical pre-concentration and the technical problems that need to be solved for social implementation.

Breaking The Permeance-Selectivity Tradeoff for Post-Combustion Carbon Capture: A Bio-Inspired Strategy to Form Ultrathin Hollow Fiber Membranes.

Thin film composite (TFC) hollow fiber membranes with ultrathin selective layer are desirable to maximize the gas permeance for practical applications. Herein, a bio-inspired strategy is proposed to fabricate sub-100-nm membranes via a tree-mimicking polymer network with amphipathic components featuring multifunctionalities. The hydrophobic polydimethylsiloxane (PDMS) brushes act as the roots that can strongly cling to the gutter layer, the PDMS crosslinkers function as the xylems to enable fast gas transport, and the hydrophilic ethylene-oxide moieties (brushes and mobile molecules) resemble tree leaves that selectively attract CO2 molecules. As a result, a ≈27nm-thick selective layer can be attached to the hollow fiber-supported PDMS gutter layer through a simple dip-coating method without any modification. Furthermore, a CO2 permeance of ≈2700 GPU and a CO2 /N2 selectivity of ≈21 that is beyond the permeance-selectivity upper bound for hollow fiber membranes is achieved. This bio-inspired concept can potentially open the possibility of scalable hollow fiber membranes production for commercial applications in post-combustion carbon capture and beyond.

Hollow fiber PSF fine porous supports with ultrahigh permeance for composite membrane fabrication: Novel inert bore liquid (IBL) spinning technique

The development of high-performance thin-film composite (TFC) hollow fiber membranes coated on top of porous supports is a hot topic both in industry and in science. However, it has been documented in recent literature that a porous support can hinder mass transfer through a composite membrane. Taking this into account, ultra-high permeable polysulfone (PSF) hollow fiber supports with an outer porous skin layer suitable for the fabrication of composite membranes were developed in this work. To address this ambitious challenge, the concept of spinning with an inert bore liquid (IBL) using wet air gap conditions was developed and successfully implemented. While the external non-solvent (water) ensures the formation of a thin porous skin layer, the inert bore liquid makes it possible to implement two important conditions for the formation of macropores on the lumen side of the hollow fiber: i) the coagulant enters only from the outer side of the dope solution layer, ii) there is no noticeable transport of the dope solution components into the inert bore liquid and vice versa. The following alkanes were studied as the IBL: pentane, hexane, heptane, and iso-octane. For example, using hexane and heptane as the bore liquids, PSF hollow fiber supports with high values of CO2 gas permeance, namely 20400 and 36700 GPU, respectively, were achieved. These values are an order of magnitude larger than the permeance of similar PSF supports reported in the literature. The presence of macropores on the lumen side of these hollow fibers was demonstrated by scanning electron microscopy. Composite membranes with a selective layer of polydecylmethylsiloxane (PDecMS) were coated and the separation of an eight-component mixture of C1-C4 hydrocarbons in a hollow fiber module was studied. Using a modified resistance model, it was shown that the absence of a skin layer on the lumen side of the hollow fiber reduced the support resistance and increased the contribution of the PDecMS selective layer to the total resistance of the composite membrane (for N2 and CO2: from 11.3% to 21.2 % and from 13 % to 20.5 %, respectively).

Tailoring the pore size of intermolecular cross-linked PIMs-based thin-film composite hollow fiber membranes using different length cross-linkers for organic solvent nanofiltration

Tailoring the pore size of intermolecular cross-linked PIMs-based thin-film composite hollow fiber membranes using different length cross-linkers for organic solvent nanofiltration

Incorporation of an Intermediate Polyelectrolyte Layer for Improved Interfacial Polymerization on PAI Hollow Fiber Membranes.

In a single-step spinning process, we create a thin-walled, robust hollow fiber support made of Torlon® polyamide-imide featuring an intermediate polyethyleneimine (PEI) lumen layer to facilitate the integration and covalent attachment of a dense selective layer. Subsequently, interfacial polymerization of m-phenylenediamine and trimesoyl chloride forms a dense selective polyamide (PA) layer on the inside of the hollow fiber. The resulting thin-film composite hollow fiber membranes show high NaCl rejections of around 96% with a pure water permeability of 1.2 LMH/bar. The high success rate of fabricating the thin-film composite hollow fiber membrane proves our hypothesis of a supporting effect of the intermediate PEI layer on separation layer formation. This work marks a step towards the development of a robust method for the large-scale manufacturing of thin-film composite hollow fiber membranes for reverse osmosis and nanofiltration.

Microfluidic preparation of thin film composite hollow fiber membrane modules for water nanofiltration: Up-scaling, reproducibility and MOF based layers

BackgroundThe commercialization of thin film composite (TFC) hollow fiber (HF) membranes remains challenging owing to issues associated with membrane manufacturing. MethodsTFC membranes were synthesized by microfluidic interfacial polymerization of polyamide (PA) on polysulfone hollow fiber (HF) membrane modules. A total of 33 HF membrane modules were prepared with different number of HFs (from 1 to 25) and different lengths (from 10 to 50 cm). They were evaluated in a nanofiltration operation in terms of water permeance and rose Bengal (RB) and MgSO4 rejections. Significant findingsAmong the 33 modules, 73% showed RB rejections higher than 95%, while 36% of the modules reached rejections above 99%. During the membrane synthesis, different parameters, such as PA monomer concentration, residence time and reaction time, were studied. As a result, the amount of monomer was reduced by ca. 80%. The versatility of microfluidics allowed incorporating hydrophilic metal-organic framework (MOF) ZIF-93 to produce HF modules with PA/MOF bilayered membranes (a continuous layer of MOF between the support and the PA film) which led to an important enhancement of the water permeance from 1.3 (bare PA membrane) to 5.3 L·m−2·h−1·bar−1 (PA/ZIF-93 HF membrane), maintaining RB rejection above 95%.

Inner-selective polyethersulfone-polydimethylsiloxane (PES-PDMS) thin film composite hollow fiber membrane for CO2/N2 separation at high pressures

Carbon dioxide (CO2) is the dominant greenhouse gas (GHG) and thus CO2 capture from flue gas of power plants, the main anthropogenic source of emission, is a key approach to mitigating the climate change. Thin-film composite (TFC) membranes have received extensive research attention recently as a promising post-combustion CO2 capture (CO2/N2) technology owing to its energy-efficiency, design versatility and upscaling potential. However, studies with the most industrially relevant membrane configuration, the hollow fibers, are rather limited for this application. Herein, we developed an inner-selective polyethersulfone-polydimethylsiloxane (PES-PDMS) TFC hollow fiber membrane by inner coating PDMS in the lumen of PES hollow fibers and then pressurizing the hollow fibers for CO2/N2 separation. The optimal PES-PDMS TFC membrane can achieve a CO2 permeance of 2150 GPU and a CO2/N2 selectivity of 20 when the operating pressure was between 20–22 bar, which holds good potential for post-combustion CO2 capture. The high separation performance arises from a combination of the stretched PES and PDMS layers. The micro-deformation of both layers under high pressures at the lumen side could possibly reduce the selective layer thickness. It may also induce polymer chain orientation, increase the fractional free volume, and potentially create free volume with smaller sizes, thus enhancing the CO₂ permeability and CO₂/N₂ selectivity from the PDMS and PES layers.

Pilot scale evaluation of thin film composite membranes for reducing wastewater volumes: osmotic concentration process

Gas operations generate large volumes of wastewater, necessitating efficient water management schemes. This study evaluates a forward osmosis (FO) pilot plant for volumes reduction of gas industry process water (PW). The osmotic pressure difference between seawater (40 g/L Total Dissolved Solids (TDS)) and low salinity (2 g/L TDS) PW is used for the osmotic concentration (OC). In the OC, PW volumes get reduced, while diluted draw solution (DS) is directly discharged, obviating the high-energy DS recovery step. A thin-film composite hollow fiber (HF) FO membrane was tested under FO mode using synthetic solutions to assess the performance on the OC unit. Subsequently, the pilot unit was subjected to PW feed for 48 h of continuous operation, primarily to evaluate water flux, reverse solute flux (RSF), and membrane fouling. The cleaning requirement to remove contaminants from the membrane surface was examined. The membrane achieved a water flux and RSF between 11.5 to 6.43 LMH and 38.57 to 9.45 mmol h−1 m−2, respectively at feed recovery rates between 60 and 90%. The membrane achieved a water flux of 10 LMH, which slightly decreased to 9.6 after 48 h of operation, mainly due to inorganic scaling. Lastly, cleaning with citric acid succeeded in recovering the initial water flux.

Effect of Molecular Weight and Chemical Structure of Terminal Groups on the Properties of Porous Hollow Fiber Polysulfone Membranes

For the first time, polysulfones (PSFs) were synthesized with chlorine and hydroxyl terminal groups and studied for the task of producing porous hollow fiber membranes. The synthesis was carried out in dimethylacetamide (DMAc) at various excesses of 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A) and 4,4'-dichlorodiphenylsulfone, as well as at an equimolar ratio of monomers in various aprotic solvents. The synthesized polymers were studied by nuclear magnetic resonance (NMR), differential scanning calorimetry, gel permeation chromatography (GPC), and the coagulation values of 2 wt.% PSF polymer solutions in N-methyl-2-pyrollidone were determined. According to GPC data, PSFs were obtained in a wide range of molecular weights Mw from 22 to 128 kg/mol. NMR analysis confirmed the presence of terminal groups of a certain type in accordance with the use of the corresponding monomer excess in the synthesis process. Based on the obtained results on the dynamic viscosity of dope solutions, promising samples of the synthesized PSF were selected to produce porous hollow fiber membranes. The selected polymers had predominantly -OH terminal groups and their molecular weight was in the range of 55-79 kg/mol. It was found that porous hollow fiber membrane from PSF with Mw 65 kg/mol (synthesized in DMAc with an excess of Bisphenol A 1%) has a high helium permeability of 45 m3/m2∙h∙bar and selectivity α (He/N2) = 2.3. This membrane is a good candidate to be used as a porous support for thin-film composite hollow fiber membrane fabrication.

Intermolecular cross-linked polymer of intrinsic microporosity-1 (PIM-1)-based thin-film composite hollow fiber membrane for organic solvent nanofiltration

Organic solvent nanofiltration (OSN) is a membrane-based organic solution separation process that has emerged as a viable alternative to energy- and solvent-intensive separation processes. Polymers of intrinsic microporosity (PIMs) are the targets of recent active research on OSN membrane materials because of their unique physicochemical properties, such as solution processability, chemical tunability, robust porosity, and high thermal stability. However, applying PIMs-based membranes in practical OSN applications is still challenging because of their limited organic solvent stability and inevitable decrease in performance. Meanwhile, despite the potential of thin-film composite hollow fiber membranes for OSN, only a few studies have been reported to date. In this study, we fabricated a PIMs-based thin-film composite hollow fiber membrane by dip-coating and improved its organic solvent stability by intermolecular cross-linking. The membrane exhibited pure ethanol permeance of 10.9 LMH/bar and a molecular weight cut-off of 952 g/mol in ethanol. The membrane displayed stable dye rejection performance (>95%) even after immersion in ethanol, acetone, and toluene for seven days. This study demonstrates that intermolecular cross-linking between PIMs polymer chains can improve the organic solvent stability of PIMs-based membranes and provides a desirable strategy to fabricate feasible organic solvent stable PIMs-based thin-film composite hollow fiber membranes for OSN applications.

TFC membrane with in-situ crosslinked ultrathin chitosan layer for efficient water/ethanol separation enabled by multiple supramolecular interactions

Chitosan (CS) membranes have been widely applied in water/ethanol separation via membrane-based pervaporation, but a bottleneck in the practical application always exists due to their severe swelling behavior in aqueous solution and consequently low permeation flux due to the large membrane thickness. Here, thin film composite (TFC) hollow fiber (HF) membrane with an in-situ-crosslinked ultrathin CS selective layer is developed via multiple supramolecular interaction-crosslinking strategy for efficient water/ethanol separation via pervaporation. With Fe3+-phytic acid (PhA) complex pre-deposited on the substrate, the subsequently introduced CS selective layer is in-situ crosslinked via multiple supramolecular interactions, including coordination, electrostatic, and hydrogen bonding interactions. By varying the cycle number of Fe3+/PhA assembly and the species of employed organophosphorus acid, the anti-swelling properties of the resultant TFC CS membrane is enhanced and the separation performance is maximized. The optimal TFC-CS-Fe2PhA2 membrane with two cycles of Fe3+/PhA assembly has a selective layer thickness of 60 ​nm and a corresponding ultrahigh flux of 2.87 ​kg/m2 h, coupled with a permeate water concentration of 99.5 ​wt% and good long-term stability for the dehydration of 85 ​wt% ethanol aqueous solution at 50 ​°C. The supramolecular interaction-crosslinking presented in this work provides an efficient and promising strategy for the construction of TFC CS membrane with excellent anti-swelling property and superior separation performance.

Optimization of Preparation Conditions of Poly(m-phenylene isophthalamide) PMIA Hollow Fiber Nanofiltration Membranes for Dye/Salt Wastewater Treatment.

Externally selective thin film composite (TFC) hollow fiber (HF) nanofiltration membranes (NFMs) hold great industrial application prospects because of their high surface area module. However, the complicated preparation process of the membrane has hindered its mass manufacture and application. In this work, PMIA TFC HF NFMs were successfully prepared by the interfacial polymerization (IP) of piperazine (PIP) with 1,3,5-benzenetricarbonyl trichloride (TMC). The effect of the membrane preparation conditions on their separation performance was systematically investigated. The characterized results showed the successful formation of a polyamide (PA) separation layer on PMIA HF substrates by the IP process. The as-prepared HF NFMs' performance under optimized conditions achieved the highest pure water permeability (18.20 L·m-2·h-1, 0.35 MPa) and superior salt rejection in the order: RNa2SO4 (98.30%) > RMgSO4 (94.60%) > RMgCl2 (61.48%) > RNaCl (19.24%). In addition, the as-prepared PMIA HF TFC NFMs exhibited desirable pressure resistance at various operating bars and Na2SO4 feed concentrations. Excellent separation performance of chromotrope 2B dye was also achieved. The as-prepared PMIA HF NFMs thus show great promise for printing and dyeing wastewater treatment.

Industrial scale thin-film composite membrane modules for salinity-gradient energy harvesting through pressure retarded osmosis

The current work highlights development of novel thin-film composite hollow fiber membranes for pressure retarded osmosis applications to harvest salinity gradient energy. The membranes were developed with a specific target of harnessing the salinity gradient energy between wastewater reverse osmosis retentate and seawater reverse osmosis brine via osmotic mixing. The hollow fiber membranes were prepared by coating a polyethersulfone substrate with a thin-film composite polyamide layer via interfacial polymerization, which were assembled into modules of different diameters for lab scale and pilot scale evaluation. As the module size increased from 1-in. to 2-in., and 4-in., the water permeability, tested against a 1000 mg/L sodium chloride solution at 15 bar, decreased from 2.6 L m−2 h−1 bar−1 to 2.0 L m−2 h−1 bar−1, and 1.2 L m−2 h−1 bar−1, respectively. The power density, measured in the lab-scale unit using 1 M sodium chloride draw solution, and DI water feed solution, also decreased from 9.1 W/m2 to 5.3 W/m2 with increasing module size. Pilot scale evaluation of the 4-and 8-in. modules on a 24 m3/day unit resulted in lower power densities of 2.5 W/m2 and 1.5 W/m2 which translated to 0.024 kWh/m3 and 0.05 kWh/m3 of salinity-gradient energy harvested, respectively.

Hollow fiber composite membranes of poly(paraterphenyl-3-bromo-1,1,1-trifluoroacetone) and PVA/glycine for ethanol dehydration

Thin film composite hollow fiber membranes (TFC-HFMs) usually have permeate flux of less than 2 kg m−2 h−1 for pervaporation (PV) dehydration of ethanol, as well as complicated and pragmatic preparation process, limiting their application in the PV. In this study, the TFC-HFMs with excellent PV performance are fabricated on newly-developed poly(paraterphenyl-3-bromo-1,1,1-trifluoroacetone) (PTB) hollow fiber supports. The PTB hollow fiber supports exhibit low mass transfer resistance as a result of high pure water permeance of 1.6 × 103 L m−2 h−1 bar−1, high porosity of 63.8% and mean pore size of 2.53 μm. Furthermore, self-assembly sandwich structure dense-selective layers are formed on the lumen side of PTB hollow fiber supports via heterostructured evolution that derives from a mixture of polyvinyl alcohol (PVA) and glycine (Gly). The resulting TFC-HFMs display the excellent separation performance. Especially, the TFC4.1-HFMs show a high permeate flux of 3.49 kg m−2 h−1, 91.1 wt% water in the permeate and excellent stability for dehydrating 85 wt% ethanol aqueous solution at 50 °C. The newly developed TFC-HFMs should have a wide application in the PV dehydration of ethanol due to simple preparation progress and efficient separation.

Tannic acid reinforced interfacial polymerization fabrication of internally pressurized thin-film composite hollow fiber reverse osmosis membranes with high performance

Internally pressurized thin-film composite (TFC) hollow fiber (HF) reverse osmosis (RO) membranes have the merits of easy scaling-up and no flow dead zone, etc. In this work, we used tannic acid (TA) as a reinforced additive in m-phenylenediamine (MPD) aqueous solution to assist the interfacial polymerization process to construct a polyamide separation skin layer with high separation performance on the inner surface of polysulfone hollow fiber substrate. Due to many phenolic hydroxyl groups on tannic acid molecules, they could form hydrogen bonds with MPD molecules and thus greatly hinders MPD diffusion towards the interface, and greatly helps to manipulate the interfacial polymerization process. In this way, we obtained a TA-reinforced TFC HF RO membrane having super hydrophilicity (contact angle of merely 26.4°), much thinner skin layer (about 100 nm in thickness), as well a much smoother surface (roughness of about 35 nm) under the optimized ultra-low concentration (100 mg L−1) for tannic acid in the MPD solution. The prepared TA-reinforced membrane achieves a water permeance of 20.4 L m−2 h−1 MPa−1, which is more than 50 % higher than that of the TA-free membrane, and a NaCl rejection of about 98 % with 2000 mg L−1 NaCl solution as feed. The TA-reinforced membrane has excellent fouling resistance, chlorine resistance, as well as long-term operation stability, thus showing a broad application prospect in brackish water desalination and tap water treatment.

Metal-assisted multiple-crosslinked thin film composite hollow fiber membrane for highly efficient bioethanol purification

Polyamide (PA)-based thin film composite (TFC) membranes have been extensively applied in various membrane-based separations. However, research works for bioethanol purification are relatively limited due to insufficient hydrophilicity and chain packing density of the PA selective layer by conventional interfacial polymerization. In this work, a new TFC hollow fiber (HF) membrane is fabricated by metal-assisted multiple crosslinking strategy, that is, metal-coordinated crosslinking of the pristine PA layer and coordination complexation between metal ions and phytic acid (PhA) for advanced water/ethanol separation. By tuning coordination abilities of metal ions with PA and PhA and the cycle number of PhA/metal ion assembly, PA-based TFC HF membrane is perfected. Additionally, a joint experiment/simulation characterization is deployed to reveal the coordination abilities of various metal ions with the pristine PA and grafted PhA. Ultimately, the synergistic effect between PA layer and PhA-metal ion complexes (i.e., 1 + 1 > 2 effect) is embodied in the separation performance of water/ethanol separation. The resulting TFC-Fe3+-PhA membrane with the strongest PhA-metal ion coordination ability exhibits the best water/ethanol separation performance, i.e., the separation factor of 1703 (34 times higher than pristine PA TFC HF membrane) and total flux of 1705 g/m2 h. This metal-assisted multiple crosslinking strategy is therefore believed to shed important lights on the development of next-generation high-performance TFC membranes for bioethanol purification.

Functionalized-MXene Thin-Film Nanocomposite Hollow Fiber Membranes for Enhanced PFAS Removal from Water.

Due to adverse health effects and the broad sources of per- and polyfluoroakyl substances (PFAS), PFAS removal is a critical research area in water purification. We demonstrate the functionalization of thin-film composite (TFC) hollow fiber nanofiltration (HFN) membranes by MXene nanosheets during the interfacial polymerization (IP) process for enhanced removal of perfluorooctane sulfonic acid (PFOS) from water. A MXene-polyamide (PA) selective layer was fabricated on top of a polysulfone (PSF) hollow fiber support via IP of trimesoyl chloride (TMC) and a mixture of piperazine (PIP) and MXene nanosheets to form MXene-PA thin-film nanocomposite (TFN) membranes. Incorporating MXene nanosheets during the IP process tuned the morphology and negative surface charge of the selective layer, resulting in enhanced PFOS rejection from 72% (bare TFC) to more than 96% (0.025 wt % MXene TFN), while the water permeability was also increased from 13.19 (bare TFC) to 29.26 LMH/bar (0.025 wt % MXene TFN). Our results demonstrate that both electrostatic interaction and size exclusion are the main factors governing the PFOS rejection, and both are determined by PA selective layer structural and chemical properties. The lamella structure and interlayer of MXene nanosheets inside the PA layer provided different transport mechanisms for water, ions, and PFAS molecules, resulting in enhanced water permeability and PFAS rejection due to traveling through the membrane by both diffusions through the PA layer and the MXene intralayer channels. MXene nanosheets showed very promising capability as a 2D additive for tuning the structural and chemical properties of the PA layer at the permeability-rejection tradeoff.