Ultrathin Selective Layer Research Articles

Structural optimization of separation layer and porous PES substrate for enhanced pervaporation desalination performance

Pervaporation membranes with water-selective properties hold great potential for desalination and brine concentration applications. In this study, a modified PES porous membrane with smaller pore sizes and enhanced interfacial support was used as the substrate. Ultrathin selective layers were fabricated on its surface via atomized spray coating, resulting in high-performance pervaporation membranes for desalination analysis. The study compares the effects of PVA and PEI on membrane performance under different crosslinking systems. At 82 °C, using a 3.5 wt.% sodium chloride solution, the PES composite membrane with a PEI/SPTA selective layer achieved a maximum flux of 180.35 ± 13.8 kg m-² h⁻¹, with a salt rejection rate of 99.97% ± 0.2. Even at a higher brine concentration of 20 wt.%, the membrane maintained a flux of 49.77 ± 7.3 kg m-² h⁻¹ at 72 °C. The membrane's high salt rejection and stable performance under complex operating conditions demonstrate that pervaporation composite membranes prepared with low-surface-porosity substrates offer enhanced cycle stability and industrial potential in real-world desalination and concentration applications.

Poly-(aminoethyl piperazine) membranes with ultra-thin selective layers prepared via a rate-retarded interfacial polymerization method

New monomers have been exploring to fabricate interfacial polymerized thin film composite membranes for decades. N-aminoethyl piperazine (AEP), an aliphatic amine with a heterocyclic structure, was used in this work as an amine monomer to synthesize nanofiltration membranes. Due to the high reactivity nature of AEP, a rate-retarded interfacial polymerization method was applied, which was realized by applying ultra-low AEP concentration (0.07 wt%), low reaction temperature (4 °C monomer solutions), and ice-water quench. The resulting AEP membrane had much better performance (3–4 times permeance and closed rejections) compared with the membranes prepared by the hot water post-treatment and the oven heat treatment. At lower monomer concentrations, an NF membrane with a selective layer thickness of only around 20 nm was prepared by the rate-retarded interfacial polymerization method. The membranes had a negatively charged surface with "willow leaf" like morphology. The MWCO was around 200 g mol−1, and the water permeance was up to 22.8 L m−2 h−1 bar−1, which is comparable with the commercial polyamide membrane NF270. Therefore, AEP is a very competitive alternative monomer for NF membrane synthesis.

Bis-tris-based polyester nanofiltration membranes fabricated via one-step interfacial polymerization for desalination

To obtain high-performance polyester (PE) nanofiltration (NF) membranes for desalination, most PE NF membranes are fabricated with high aqueous monomer concentration, or high reaction temperature, or long reaction time. The interfacial polymerization (IP) reaction rate between hydroxyl groups and acyl chloride groups is promoted but the cost of membrane fabrication is also increased. In this work, Bis-tris (bis(2-hydroxyethyl)-amino-tris(hydroxymethyl)methane) with rich hydroxyl groups is first utilized as an aqueous monomer to fabricate PE membranes under conventional IP conditions. The fabricated Bis-tris PE membranes feature strong hydrophilicity, excellent electronegativity, and ultra-thin selective layers, which are conducive to improving desalination performance. The optimized Bis-tris PE membrane shows excellent water permeance of 22.5 L m−2 h−1 bar−1 and a satisfactory Na2SO4 rejection of 96.9 %. Additionally, the Bis-tris PE membrane displays superior long-term stability and chlorine resistance under 96 h cross-flow filtration. This research enlightens the promising potential of Bis-tris as a novel and economic aqueous monomer for the fabrication of high-performance PE NF membranes.

Large-Area Ultrathin Metal-Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations.

Ultrathin continuous metal-organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic-imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large-area fabrication. Here, we propose a ligand back diffusion-assisted bipolymer-directed metal ion distribution strategy for preparing large-area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross-linked two-dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large-area ultrathin MOF membranes. We report the practical fabrication of three representative defect-free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50-130 nm), including ZIFs and carboxylate-linker MOFs. Among these, the ZIF-8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale-up practicality, MOF membranes were prepared and incorporated into spiral-wound membrane modules with an active area of 4,800 cm2. The ZIF-8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Large‐Area Ultrathin Metal–Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations

AbstractUltrathin continuous metal–organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic‐imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large‐area fabrication. Here, we propose a ligand back diffusion‐assisted bipolymer‐directed metal ion distribution strategy for preparing large‐area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross‐linked two‐dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large‐area ultrathin MOF membranes. We report the practical fabrication of three representative defect‐free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50–130 nm), including ZIFs and carboxylate‐linker MOFs. Among these, the ZIF‐8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale‐up practicality, MOF membranes were prepared and incorporated into spiral‐wound membrane modules with an active area of 4,800 cm2. The ZIF‐8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Carbon Molecular Sieve Membranes with Ultra-Thin Selective Skin Layer by Pyrolysis of Porous Hollow Fibers.

Translating carbon molecular sieve (CMS) membranes into highly scalable hollow fiber geometry with ultra-thin selective layer (<1µm) for gas separation remains as great challenge. The porous support layer of precursor hollow fiber membranes is prone to collapse during pyrolysis, which induces thick skin layer (15-50µm) of CMS hollow fiber membranes. Here, a novel strategy is present to obtain an ultra-thin selective skin layer by carbonization of hollow fiber membranes with porous skin. P84-based defect-free CMS hollow fiber membranes with ultra-thin selective skin layer (0.9µm) for gas separation are prepared without any coating or complex chemical pretreatment. Compared with the carbon membranes derived from defect-free fibers, the H2 permeance (93.9 GPU) of CMS membranes derived from the porous fibers increases ≈1353% with comparable selectivity of H2/CH4 (143) and higher H2/N2 (120). Furthermore, the porous fibers are pre-aged near the Tg in N2 conditions before carbonization, and the H2 permeance of the derived CMS hollow fiber membranes reached 147 GPU (increased 2180%). It is a new facile way to prepare CMS hollow fiber membranes with ultra-thin selective layer by porous fibers, demonstrating its versatile potential in gas separation or organic liquids separation.

Porous rGO/networked cellulose composite membranes: Towards enhanced nanofiltration performance of rGO-based membranes

Graphene-based materials have been widely used for the fabrication of superior separation membranes for water treatment and purification. In particular, reduced graphene oxide (rGO), which has better water stability than graphene oxide (GO), has been demonstrated to be a good building block. However, rGO laminates are characterized by narrow interlayer spacing leading to dense packing and consequently lower flux limiting their direct utilization for membrane development. In this study, we report the fabrication of networked cellulose (NC)/porous rGO composite membranes with enhanced separation performance. We observed a synergistic effect due to the incorporation of NC and the presence of nano-pores on the rGO sheets. Firstly, in addition to the enhanced hydrophilicity and mechanical stability, the presence of NC with networked fibers reduced the horizontal transport resistance within the interlayer channels due to the formation of voids and wrinkles. Secondly, in-plane pores created by H2O2 oxidation of GO effectively contributed to additional transport channels providing shortened transport length for water molecules. Results showed that composite membranes maintained stable long-term performance with a pure water permeance up to 25.1 ± 2.2 Lm−2h−1bar−1 and salt rejection of 70.2 %, 63.08 %, 17.13 % and 25.62 %, for Na2SO4, MgSO4, MgCl2 and NaCl respectively. Unlike many previously reported rGO membranes that rely on ultra-thin selective layers, this work demonstrates an effective strategy for fabricating superior rGO membranes for water treatment and desalination.

PDMS-based artificial lung membranes with enhanced permeation to overcome the bottleneck in CO2/O2 selectivity

Artificial lung membranes are the heart for extracorporeal oxygenation. Hereinto, the nonporous PDMS-based membranes have excellent biocompatibility, and also isolation ability to both blood and harmful matters. Nevertheless, their CO2/O2 selectivity, in the conventional cases using pure-oxygen sweeping stream, is not enough to accomplish sufficient CO2 removal in balance with O2 addition. In this work, the oxygenation mode using oxygen-enriched stream, faithfully based on the permeation mechanism, is established to overcome this bottleneck. To neutralize the negative impacts caused by lowering oxygen content and its partial pressure, PDMS-based composite membranes with ultra-thin selective layer to enhance mass transfer have been fabricated successfully. The experiments manifest that the selective layer, on the basic condition that the composite structure is stable enough to make surface modification and realistic utilization, is decreased to 376 nm on the porous substrates. O2 and CO2 permeation rates through the ultimate membrane samples have been enhanced to 502 GPU and 4117 GPU, respectively. In this instance, the essential oxygenation could be sustained with O2 partial pressure less than 446 mmHg in the sweeping stream. The minimum membrane area for a common treatment case is 0.05 square meters. Once the membrane area is increased to 0.18 square meters, the sterile air after purification could be directly used for oxygenation. In comparison to the oxygenation devices being used currently, membrane area can be saved by about 90 %, which is highly significant to reduce the injuring influence on blood cells. All in all, the artificial lung membranes with ultra-thin PDMS coating layer have promising future in realistic utilization.

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.

Design of ultrathin cross-linked poly(ethylene oxide) selective layer for high-performance CO2 capture

Cross-linked poly(ethylene oxide) (PEO) is a highly promising membrane material for CO2 capture, as it allows fast and selective CO2 transport. However, the facile fabrication of an ultrathin cross-linked PEO selective layer for thin-film composite (TFC) membrane to achieve high CO2 separation performance remains challenging. To address this issue, we reported the design of a soluble high-permeability cross-linked PEO polymer and the fabrication of it into an ultrathin CO2-selective layer through a simple coating technique. The as-synthesized cross-linked PEO polymer contains abundant poly(dimethylsiloxane) (PDMS) segments, leading to highly improved free volume and affinity towards CO2, which result in high CO2 diffusivity, solubility, and consequently high CO2 permeability (528 Barrer). TFC membranes with an ultrathin selective layer (∼128 nm) were successfully fabricated using the PEO polymer, leading to superior CO2 capture performance (CO2 permeance = 2650 GPU, CO2/N2 = 20) for CO2/N2 mixture separation in a long-term stability test, exceeding the target performance for carbon capture. Given their high separation performance, excellent stability, and scalable fabrication route, our PEO-based membranes hold great promise for post-combustion CO2 capture.

Zwitterionic polyamide membranes via in-situ interfacial polymerization modification for efficient pervaporation dehydration

Thin-film composite membranes (TFC) comprised of polyamide have emerged as a promising candidate in molecular separations due to their ultrathin selective layer and controllable structure. However, improving selectivity while retaining satisfactory permeability of TFC membranes remains a great challenge. Herein, zwitterionic polyamide membranes have been fabricated for pervaporation dehydration via in-situ interfacial polymerization modification (in-situ IPM) strategy. In-situ amination of the substrates can improve the interface compatibility between the selectivity layer and the substrate through fourier transform infrared spectroscopy (FTIR) characterization, making the membranes more stable to resist the structural evolution in liquid conditions. The zwitterion modification afterwards endows the membranes with dense structure and improved hydrophilicity through X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and contact angle measurements. The optimized zwitterionic polyamide membrane with well-defined structure realizes superior separation performance with a separation factor of 3870 while maintaining a high permeation flux of 4380 g m−2 h−1 when processing 90 wt% ethanol aqueous solution at 76 °C, outperforming most reported TFC membranes. Moreover, the zwitterionic polyamide membrane also exhibits stable separation performance under the successive test. This work would provide a feasible scheme for the design of efficient TFC membranes for pervaporation dehydration.

Enhanced Osmotic Energy Conversion through an Asymmetric Nanochannel Array Membrane with an Ultrathin Selective Layer

Enhanced Osmotic Energy Conversion through an Asymmetric Nanochannel Array Membrane with an Ultrathin Selective Layer

Ultrathin Polyamide Nanofilms with Controlled Microporosity for Enhanced Solvent Permeation.

Organic solvent nanofiltration (OSN) technology shows reduced energy consumption by almost 90% with great potential in achieving low-carbon separation applications. Polyamide nanofilms with controlled intrinsic and extrinsic structures (e.g., thickness and porosity) are important for achieving such a goal but are technically challenging. Herein, ultrathin polyamide nanofilms with controlled microporosity and morphology were synthesized via a molecular layer deposition method for OSN. The key is that the polyamide synthesis is controlled in a homogenous organic phase, rather than an interface, not only involving no monomer kinetic diffusion but also broadening the applicability of amine monomers. The particular nonplanar and rigid amine monomers were superbly used to increase microporosity and the nanofilm was linearly controlled at the nanometer scale to decrease thickness. The composite membrane with the polyamide nanofilms as separation layers displayed highly superior performance to current counterparts. The ethanol and methanol permeances were up to 5.5 and 14.6 L m-2 h-1 bar-1, respectively, but the molecular weight cutoff was tailored as low as 300 Da. Such separation performance remained almost unchanged during a long-term operation. This work demonstrates a promising alternative that could synergistically control the physicochemical structures of ultrathin selective layers to fabricate high-performance OSN membranes for efficient separations.

Ultrathin membrane with robust and superior CO2 permeance by precision control of multilayer structures

Reducing CO2 emissions in the atmosphere is an urgent task to resolve serious environmental issues including global warming. Polymer-based ultrathin film composite (UTFC) membranes are an attractive strategy compared with other CO2 separation technologies due to their lower environmental impacts, higher cost-efficiency, and ease of scale-up. However, improving the gas separation performance with a simplified fabrication process is still needed for practical uses. The key to designing a high-performing gas separation composite membrane is the development of a highly gas-permeable gutter layer and ultrathin high-selective top layer. While the top layers in nanoscale thicknesses have been recently developed, achieving high gas permeance is still challenging due to the existing less controlled gutter layer. Gutter layers afford a uniform and highly permeable base to which an ultrathin selective layer can be coated, minimising the gas permeance loss while maintaining the gas selectivity. Polydimethylsiloxane (PDMS) is a common and widely used material for gutter layers due to its inherent high gas permeability. However, the CO2 permeance of these films is limited to between 1,500 and 5,000 GPU as the current uncontrollable fabrication methods tend to produce thicker layers. Here we report a new fabrication method with precise thickness control, which results in ultrathin gutter layers showing consistent CO2 permeance with 13,920 ± 1,770 GPU without any reduction in CO2/N2 selectivity. When this gutter layer was coated with a selective layer of PolyActive™ (PA), the resultant PAN/PDMS/PA composite membranes outperformed previously reported UTFC membranes with a CO2 permeance of 3,555 GPU and CO2/N2 selectivity of 40.

Polydopamine functionalized graphene oxide membrane with the sandwich structure for osmotic energy conversion.

Ion-selective membrane is the key component for osmotic energy conversion. Nanofluid channels based on two-dimensional materials have advantages of facile preparation, tunable channel size, and easy upscaling, which is promising for efficient osmotic energy harvesting. However, further improvement of the output power is hindered by the low ion sensitivity for the limited charge density. Herein, we demonstrate the preparation of a cation-selective polydopamine-coated graphene oxide composite membrane with the sandwich structure by a simple interfacial polymerization technique, which greatly improves the surface charge density and further generates a power density of 3.4W/m2 under river water and seawater. The GO membrane is firstly fabricated to function as the supporting layer and provide the reaction sites. And the ultrathin selective layer of the polydopamine membrane is chemically bonded with the GO layer by the in-situ polymerization on both sides of the GO membrane. The sandwiched nanofluidic membrane with ultrahigh charge density exhibits both high cation selectivity and ionic conductivity, benefiting the performance of osmotic energy conversion. The economic, easy-prepared method of the sandwiched nanofluidic membrane provides a promising strategy for high-performance osmotic energy conversion.

Development and Investigation of Hierarchically Structured Thin-Film Nanocomposite Membranes from Polyamide/Chitosan Succinate Embedded with a Metal-Organic Framework (Fe-BTC) for Pervaporation.

Thin-film composite membranes (TFC) obtained by the formation of a selective layer on a porous membrane-substrate via interfacial polymerization (IP) are indispensable for separation procedures in reverse osmosis, nanofiltration, pervaporation, and gas separation. Achieving high selectivity and permeability for TFC membranes is still one of the main challenges in membrane science and technology. This study focuses on the development of thin film nanocomposite (TFN) membranes with a hierarchically structured polyamide (PA)/chitosan succinate (ChS) selective layer embedded with a metal–organic framework of iron 1,3,5-benzenetricarboxylate (Fe-BTC) for the enhanced pervaporation dehydration of isopropanol. The aim of this work was to study the effect of Fe-BTC incorporation into the ChS interlayer and PA selective layer, obtained via IP, on the structure, properties, and performance of pervaporation TFN membranes. The structure and hydrophilicity of the developed TFN membranes were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM), along with water contact angle measurements. The developed TFN membranes were studied in the pervaporation dehydration of isopropanol (12–30 wt % water). It was found that incorporation of Fe-BTC into the ChS interlayer yielded the formation of a smoother, more uniform, and defect-free PA ultrathin selective layer via IP, due to the amorpho-crystalline structure of particles serving as the amine storage reservoir and led to an increase in membrane selectivity toward water, and a slight decrease in permeation flux compared to the ChS interlayered TFC membranes. The best pervaporation performance was demonstrated by the TFN membrane with a ChS-Fe-BTC interlayer and the addition of 0.03 wt % Fe-BTC in the PA layer, yielding a permeation flux of 197–826 g·m−2·h−1 and 98.50–99.99 wt % water in the permeate, in the pervaporation separation of isopropanol/water mixtures (12–30 wt % water).

Ultra-permeable intercalated metal-induced microporous polymer nano-dots rooted smart membrane for environmental remediation

Energy efficient CO2 separation using ultrathin smart membranes must possess efficient permeation performance, higher surface area and hydrostatic stability at industrially relevant high pressures. However, ultrathin membranes are susceptible to lower surface area, plasticization and swelling which reduces the performance at higher pressure under humidified conditions. This paper evaluates the routes for the potential intercalated effect of metal-induced microporous polymers (MMPs) dots into a cellulose-based polymer matrix to enhance promising properties, including the surface area, CO2 permeation performance, plasticization resistance and hydrostatic stability of ultrathin smart membranes at high pressure. The MMP dots-rooted smart membrane demonstrated 55 nm thickness of ultrathin selective layer with a higher surface of 220 cm2. The enhancement of CO2 permeability from 14.1 to 108.9 Barrer and CO2/CH4 ideal selectivity from 11.8 to 31.1 was observed due to the integration of MMP dots into the cellulose polymer. This result could be due to enhancement of nitrogen lone pair electron interactions with CO2 followed by amines group which improved the CO2 adsorption on the membrane surface. The MMP dots-rooted membrane demonstrated plasticization resistance up to 26 bar pressure, as compared to a pristine polymer membrane which is a percentage increase of 160% under humidified conditions. The resulting ultrathin smart membrane exhibited stable performance for a duration of 200 h under humidified conditions which confirmed the higher hydrostatic stability of the membrane. These findings confirmed the potential of MMP dots materials for the development of an industrial scale CO2 separation process using intercalated membranes.

PDMS thin-film composite membrane fabricated by ultraviolet crosslinking acryloyloxy-terminated monomers

Polydimethylsiloxane (PDMS), as a representative membrane material with superior permeability, attracts great attention in gas separation, pervaporation and nanofiltration. However, the fabrication of defect-free ultrathin PDMS membrane remains great challenge mainly due to the difficulty in controlling the processability and substrate pore penetration of casting solution. In this work, for the first time, we employed PDMS monomer terminated with acryloyloxy groups (AC-PDMS) to implement fabrication of thin-film composite (TFC) membrane. The ultraviolet (UV) reactivity between acryloyloxy groups induced fast curing of AC-PDMS casting solution, thereby realizing formation of ultrathin selective layer (∼260 nm) and inhibition of substrate pore penetration. By optimizing the UV wavelength, irradiation time and polymer concentration, the resulting AC-PDMS TFC membrane achieved attractive CO2 permeance of 9635 GPU, with CO2/N2 selectivity of 11.5. Furthermore, chain crosslinking and packing behavior, fabrication of TFC membrane and transport property of AC-PDMS were compared with conventional hydroxyl-terminated PDMS (OH-PDMS). Together with the potential in scalable fabrication, the strategy based on UV crosslinking acryloyloxy-terminated monomers provides a new avenue to produce ultrathin PDMS membranes toward practical application in molecular separation.

Ultra-thin microporous membranes based on macrocyclic pillar[n]arene for efficient organic solvent nanofiltration

Organic solvent nanofiltration (OSN) is a green, environmentally friendly and sustainable separation technology. High-performance OSN membranes are expected to play a critical role in the field of chemical separation involving organic solvents. However, traditional OSN membranes suffer from the constraints on perm-selectivity. Herein, we introduced macrocyclic molecules with intrinsic angstrom-size cavity, pillar[n]arene (P[n]a, n = 5, 6), as a novel aqueous monomer to react with trimesoyl chloride (TMC) to prepare highly perm-selective thin-film composite (TFC) OSN membranes through interfacial polymerization. The prepared TFC-P[n]a membranes exhibit ultra-thin selective layer thickness of sub-10 nm and possess permanent intrinsic microporous structure, which endows the membrane with high perm-selectivity. Especially, the TFC-P[6]a membrane exhibits a high methanol permeance (8.10 L m−2 h−1 bar−1) and a low molecular weight cut-off (MWCO) of 300 g mol−1. In addition, the prepared TFC-P[n]a membranes exhibit molecule sieving function and could discriminate molecules with similar molecular weights but different shapes. Our work provides an insight of material design for the preparation of next-generation high-performance organic solvent nanofiltration membranes.

Metal-organophosphate biphasic interfacial coordination reaction synthesizing nanofiltration membranes with the ultrathin selective layer, excellent acid-resistance and antifouling performance

Phytate as a natural strongly charged organophosphate has recently attracted much attention in diverse fields including membrane separations towards water-energy-food nexus. However, the ideal phytate-based nanofiltration membrane with defect-free and ultrathin selective layer for highly-efficient water treatment is still much challengeable due to the typical aggregation of metal ions and uncontrolled reaction between metal ion and organophosphate via conventional coating method. Herein, metal-organophosphate biphasic interfacial coordination reaction is proposed to construct ultrathin (13.4 nm) selective layer of phytate-based nanofiltration membranes with high permeance and excellent stability by controllable coordination assembly. Iron acetylacetonate (Fe(acac)3) as an organic phase monomer with powerful electron-gaining ability is exploited to avoid the aggregation of traditional Fe(III) in aqueous phase, which can also coordinate with phytic acid (PA) to ensure a defect-free ultra-thin selective layer. The architecture of the phytate-based selective layer can be well regulated by optimizing the coordination metal source, the concentration of PA and Fe(acac)3, reaction time, so as to achieve the ultrahigh permeation flux of 190 L m−2 h−1 with excellent dye rejection (99.6%). Most interestingly, our phytate-based nanofiltration membranes with plenty of hydrophilic phosphate groups on the surface and high binding energy of P–O–Fe bond (−315.1 kJ mol−1) exhibited the long-term separation stability, excellent acid-resistance and anti-pollution ability, realizing the stable membrane separation process under harsh conditions.