Interfacial Polymerization Approach Research Articles

The role of membrane filtration in wastewater treatment

AbstractWater is vital for the sustainable growth of human communities. Due to the greatest population and significant economic development, demands on water and purification have significantly risen. Classical wastewater treatment procedures have made some progress over the years in purifying effluents for disposal, but they fall lacking in the way they deeply control emerging harmful substances. The potential to reuse treated wastewater for home, agricultural, and industrial needs depends on breakthroughs in purifying technologies. One of the most recent breakthroughs to be implemented effectively in reducing contaminants to desirable levels is membrane technology. Nanofiltration, microfiltration, reverse osmosis, ultrafiltration, and membrane bioreactors are examples of widely utilized membrane processes depending on features such as size or charge. Over traditional treatment, membrane technology offers various benefits. This review article discusses a number of membrane‐related topics, including membrane categorizing, application in various fields, benefits, and drawbacks. Furthermore, offers an outlook of the filtering membranes that will be used in the future. Smart membranes have gained interest because of their tunable permeability and selectivity characteristics. Technological advancements in the media that are utilized in activated growth membrane bioreactors. Modified interfacial polymerization approaches have been investigated in addition to adsorptive ultrafiltration mixed matrix membranes to enhance the performance of the polyamide thin‐film composite and thin‐film nanocomposite membranes.

Insights into micro-structure and separation mechanism of benzimidazole-linked polymer membrane for H2/CO2 separation

Separation of hydrogen from carbon dioxide for sustainable H2 production and CO2 capture still faces great challenges due to the smaller size of H2 and higher condensability of CO2. Herein, a high-performance benzimidazole-linked polymer (BILP) membrane for hydrogen separation was directly prepared on α-Al2O3 substrate through a facile interfacial polymerization approach at room temperature. The separation performance of the BILP membrane were regulated by controlling the reaction time and the microstructure was systematically characterized. Molecular simulations were performed to deep understand the separation mechanism in the BILP membrane. The best performance membrane displays an extraordinary mixed gas selectivity of 40 for H2/CO2 together with outstanding H2 permeance of 250 gas permeation units (GPU) at 473 K, far exceeding the Robeson’s upper bound. Besides, the membrane can withstand high temperature and pressure, and also shows good H2/N2 and H2/CH4 selectivity. The excellent separation performance, coupled with high temperature and pressure resistance and easy preparation, render BILP membranes great potential for economic H2 purification, H2 recovery, and natural gas treatment.

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.

Molecular-level manipulation of polyamide membranes for high-performance H2/CO2 separation

The preparation of high-performance H2/CO2 polymer separation membranes is an urgent need to reduce the global greenhouse effect. Here, polyamide (PA) membranes with excellent H2/CO2 separation performance are produced using a facile interfacial polymerization (IP) plus heat treatment approach. The synergistic effect of the substrate-confinement and the control of the d-spacing and crosslinking degree of PA membranes creates sufficient H2 selective channels. The effects of test parameters such as feed temperature and feed pressure on membrane performance were investigated. The ultra-high H2/CO2 selectivity of 110 with excellent H2 permeance of 180 GPU is observed at 150 °C and feed pressure of 2 bar. In addition, PA membranes have high-pressure resistance (16 bar), high-temperature resistance (300 °C), and attractive durability (210 h). The excellent performance and facile preparation process make them expected to be one of the most promising membranes for H2/CO2 separation.

A novel ZIF-L/PEI thin film nanocomposite membrane for removing perfluoroalkyl substances (PFASs) from water: Enhanced retention and high flux

Membrane separation technology is widely recognized as an effective method for removing perfluoroalkyl substances (PFASs) in water treatment. ZIF-L, a metal-organic framework (MOF) family characterized by its mat-like cavities and leaf-like morphology, has garnered considerable interest and has been extensively employed in fabricating thin-film nanocomposite (TFN) membranes. In this study, a robust, high-performance TFN membrane to remove PFASs in a nanofiltration (NF) process was created through an interfacial polymerization approach on the surface of polysulfone (PSF), incorporating ZIF-L within the selective layer. The TFN membrane modified by adding 5 wt% ZIF-L (relative to the weight of ethylene imine polymer (PEI)) exhibits 2.3 times higher water flux (up to 47.56 L·m−2·h−1·bar−1) than the pristine thin film composite membrane (20.46 L·m−2·h−1·bar−1), and the rejection for typical PFASs were above 95 % (98.47 % for perfluorooctanesulfonic acid (PFOS) and 95.85 % for perfluorooctanoic acid (PFOA)). The effectiveness of the ZIF-L/PEI TFN membrane in retaining representative PFASs was examined under various conditions, including different pressures, feed concentrations, aqueous environments, and salt ions. Notably, the experiments demonstrated that even after contamination with humic acid (HA), >88 % of the water flux could be restored by washing. Additionally, density functional theory (DFT) calculations were employed to predict the distinct intermolecular interactions between PFASs and ZIF-L as well as PEI. These calculations provide additional insights into the interception mechanism of TFN membranes towards PFASs. Based on this study, TFN membranes incorporating MOF as nanofillers show great potential as an effective method for purifying PFASs from aqueous environments and possess superior environmental sustainability and cost-effectiveness.

Electronanofiltration Membranes with a Bilayer Charged Structure Enable High Li+/Mg2+ Selectivity.

Achieving separation of lithium and magnesium with similar radii is crucial for the current lithium extraction technology from salt lakes, which usually possess a high lithium-to-magnesium ratio. Herein, we proposed the facile sequential interfacial polymerization (SIP) approach to construct electronanofiltration membranes (ENFMs) with a bilayer charged structure consisting of a high positively charged surface and a negatively charged sublayer. The trimesoyl chloride (TMC) concentration was adjusted to enhance the -COOH content and negative charge of the polyamide sublayer to promote Li+ migration, and then the quaternized polyethylenimine was introduced to the membrane surface by the SIP process to increase the positive charge density on the surface of the ENFMs, which would block the migration of Mg2+ and enhance the Li+/Mg2+ selectivity of the ENFMs. The optimal quaternary-modified ENFMs achieved outstanding selectivity for Li+/Mg2+ (49.85) and high Li+ flux (4.10 × 10-8 mol cm-2 s-1) at a current density of 10 mA cm-2. Moreover, in simulated brines with low lithium concentration and high Mg2+/Li+ ratio, the optimal ENFMs also displayed elevated Li+/Mg2+ selectivity (>45), highlighting the substantial promise of the membranes for practical applications.

Janus membranes with simultaneous flux enhancement and fouling/wetting resistance prepared by a modified interfacial polymerization process for membrane distillation

Conventional membrane distillation (MD) membranes are hydrophobic and challenged by severe membrane fouling and wetting. Current surface modification strategies for anti-fouling and anti-wetting purposes, usually complex and time-consuming, often compromise the MD flux. Herein, we propose a modified interfacial polymerization (mIP) approach to fabricate Janus membranes with rapid and robust MD performance. In the mIP process, a dry hydrophobic substrate is first immersed in an oil-phase monomer solution and then in contact with an aqueous monomer solution to trigger the mIP reaction. The as-fabricated Janus membrane (e.g., IP2@PTFE) comprised an ultrathin, underwater oleophobic, and defect-free polyamide (PA) layer and a porous polytetrafluoroethylene (PTFE) substrate. Compared with the unmodified PTFE membrane, the vacuum MD flux of the IP2@PTFE membrane held a 177.4 % increase when tackling a NaCl solution (3.5 wt%) at 60 °C. When the NaCl solution contained sodium dodecyl sulfate (SDS) surfactant or/and mineral oil, the IP2@PTFE membrane exhibited fouling and wetting resistance simultaneously; conversely, severe oil fouling and quick SDS-induced wetting occurred on the pristine PTFE membrane. The mIP process does not require any pretreatment of the hydrophobic substrate, so it is facile and scalable. We believe that this study will facilitate the design of robust MD membranes.

A Rapid Self-Pumping Organohydrogel Dressing with Hydrophilic Fractal Microchannels to Promote Burn Wound Healing.

Burn wounds pose great challenges for conventional dressings because massive exudates oversecreted from swollen tissues and blisters seriously delay wound healing. Herein, a self-pumping organohydrogel dressing with hydrophilic fractal microchannels is reported that can rapidly drain excessive exudates with ≈30 times enhancement in efficiency compared with the pure hydrogel, and effectively promote burn wound healing. A creaming-assistant emulsion interfacial polymerization approach is proposed to create the hydrophilic fractal hydrogel microchannels in the self-pumping organohydrogel through a dynamic floating-colliding-coalescing process of organogel precursor droplets. In a murine burn wound model, the rapid self-pumping organohydrogel dressings can markedly reduce dermal cavity by ≈42.5%, accelerate blood vessel regeneration by ≈6.6 times, and hair follicle regeneration by ≈13.5 times, compared with the commercial dressing (Tegaderm). This study paves an avenue for designing high-performance functional burn wound dressings.

Nano-wrinkled polyamide membrane preparation via heterogeneous surface-regulated interfacial polymerization for enhanced desalination performance

Nano-wrinkled morphology and ultrathin thickness are desirable membrane structures in polyamide membranes, particularly for high-performance applications in desalination and wastewater treatment. In this study, we present the fabrication of a nano-wrinkled polyamide membrane with ultrathin thickness on a heterogeneous surface that features hydrophilic UiO-66-NH2 nanoparticles embedded on a hydrophobic polyethersulfone surface using a heterogeneous surface regulated interfacial polymerization approach. The presence of the heterogeneous surface induces the formation of aqueous phase microphases under the organic phase due to the unbalanced interfacial tension, which serves as a template for the formation of the polyamide film. This results in the creation of a nano-wrinkled polyamide layer upon drying. Furthermore, the hydrogen bonding interaction between the UiO-66-NH2 and piperazine (PIP) slows down the PIP release, which contributes to the ultrathin thickness of the polyamide layer. The polyamide membrane obtained in this study exhibits a pure water permeance (PWP) of 26.1 L bar−1·h−1·m−2 and a Na2SO4 rejection of 97.5 %. The PWP is 6.15 times higher than that of a control membrane fabricated through conventional interfacial polymerization. Our work offers a novel approach to tailor the structure of polyamide membranes via heterogeneous surface regulated interfacial polymerization, which has potential applications in environmental desalination.

Fabrication of highly positively charged nanofiltration membranes by novel interfacial polymerization: Accelerating Mg2+ removal and Li+ enrichment

Li+, a vital green energy source, is mainly extracted from salt lakes, which also contain high concentration of Mg2+. Therefore, there is an imminent need for separation of Li+ and Mg2+. Recent innovations highlight the great potential of positively charged nanofiltration (NF) membranes for separating Mg2+ and Li+. Typically, positively charged NF membranes are prepared by the interfacial polymerization approach, where the most commonly applied aqueous phase monomer is polyethyleneimine (PEI). In this work, a new class of polyallylamine (PAA)-based NF membrane with a high density of positive charge, was developed to achieve high perm-selectivity for separating Mg2+ and Li+. The results indicated that the abundant primary amine (-NH2) groups on the PAA molecular chain endowed the NF membrane with a highly hydrophilic and positively charged polyamide layer. The resulting NF membrane exhibited superior Mg2+/Li+ separation ability with a high separation factor SMg2+/Li+ of 82.8 and a water permeance of 7.39 L/(m2hbar). It is also noteworthy that the SMg2+/Li+ value is more than 4 times higher than that of the previously reported PEI-based membrane. Moreover, our work also provides a new potential candidate for the future development of positive charged NF membranes.

FO membrane fabricated by layer-by-layer interfacial polymerisation and grafted sulfonamide group for improving chlorine resistance and water permeability

This study presents a layer-by-layer interfacial polymerization approach to enhance the chlorine resistance and water permeability of thin-film composite (TFC) polyamide (PA) forward osmosis membranes. The PA film was prepared by self-polymerization using 3,5-Dihydroxybenzoic acid (DHBA) and trimesoyl chloride (TMC) with addition of 4-amino-benzene sulfonamide (4-ABSA), which is a sulfonamide monomer, on a polysulfone (PSF) support layer. The cross-linking structure and surface characterisation of the DHBA-ABSA membrane was studied systematically. FTIR results showed the successful grafting of the sulfonamide group on the membrane surface. Compared with the MPD-TMC membrane, the water flux of three modified membranes—DHBA, ABSA, and DHBA with ABSA—improved by 27.6%, 44.0%, and 67.6%, respectively, and reverse salt flux decreased by 9.9%, 12.3%, and 16.2%, respectively. Furthermore, the chlorine-stability test using 200 ppm NaClO indicated stable long-term performance under different pH values. The stable sulfonamide structure of ABSA with N-H group effectively prevented chlorine from directly attacking the active layer and improve the chlorine-stability of the membrane. In addition, the abundant hydrophilic groups on ABSA and DHBA monomers formed a hydration layer with water molecules on the membrane surface through hydrogen bonding, which enhanced the permeability of the TFC-PA membranes. The findings of this study demonstrate the DHBA-ABSA membrane's wider application potential in water and wastewater treatment processes.

Conducting polymer host–guest hydrogels with bicontinuous electron/ion transport for boosted thickness–independent supercapacitance

The development of conducting polymer hydrogels with 3D ordering and hierarchical geometry is urgent yet challenging for the design of electrochemical/electronic systems with combined features of hydrogel structures and pseudocapacitive organic materials. Herein, a host–guest hybrid gel electrode that is composed of a polypyrrole (PPy) aerogel and its skeleton-surface-constrained Fe3+-coordinated poly(acrylic acid) (Fe-PAA) hydrogel is fabricated, which can readily work as a highly elastic and self-healable electrode for an all-gel-state supercapacitor with thickness-independent capacitive performance. An interfacial polymerization approach by restraining oxidative nucleation and promoting secondary growth reactions is presented for preparing the pseudocapacitive PPy aerogel as a host component with good elasticity. Upon an impregnation with the ionically conductive and self-healable Fe-PAA hydrogel as a guest component, the resultant PPy aerogel-hosting hydrogels (PAHH) exhibit a remarkable thickness-independent supercapacitance owing to the enhanced electron/ion transport kinetics induced by a bicontinuous electron/ion-conducting network. A proof-of-concept all-solid-state supercapacitor based on the host–guest hybrid electrodes demonstrates a remarkable remarkably high areal capacitance of 2033 mF cm−2 and extremely steady retention undergoing a 60 % compression deformation and cutting damage with high self-healing performance. The host–guest geometry design for the development of bicontinuous electron/ion conductive transport in conducting polymer-based electrodes might boost unprecedented electron and ion transport in high-mass-loading thick electrodes for smart energy storage devices.

Lignin-based Nanofiltration Membrane with High Permeability, Acid-alkali and Chlorine Resistances toward the Removal of Multivalent Salts and Dyes

Abstract A lignin-based nanofiltration membrane was fabricated using aminated lignin and trimesoyl chloride as raw materials by an interfacial polymerization approach. The obtained membrane possesses excellent pure water permeability (31.2 L m−2 h−1 bar−1), high retention rates (>95%) to multivalent salts (EDTA and sodium citrate) and organic dyes (brilliant blue R and congo red), satisfactory acid-alkali and chlorine resistances, and separation-performance stability. It also shows better retention capability and alkaline stability than those of a membrane fabricated with pristine alkali lignin due to the high crosslinking degree.

Facile synthesis of porphyrin-based PAF membrane for hydrogen purification

Available online Hydrogen (H2) is a promising clean energy source and its separation and purification from fossil fuels and natural gas is of great significance. Microporous continuous membrane separation is an efficient and energy-saving separation method, in which membranes with a pore size less than 1 nm can better achieve size-dependent sieving of H2. Porous aromatic framework (PAF) continuous membranes are expected to exhibit high-efficiency gas separation due to their highly connected channels as well as structural stability and channel design. Synthesis of continuous PAF membranes using facile methods remains a challenge. Here, we synthesized ultrathin continuous porphyrin-based PAF (ppPAF) membrane using an interfacial polymerization approach. The design introduced rigid porphyrin groups, resulting in a pore size of 0.7 nm for the ppPAF membrane. The ppPAF membrane showed a H2 permeance of 709.2 gas permeation units (GPU), with a H2/CO2 selectivity of 78.8. The ppPAF membrane showed a H2/CH4 selectivity of 93.3, with a H2 permeance of 624.8GPU. Our results provide new ideas for the synthesis of continuous PAF films.

Semi-aromatic polyamide membrane incorporated with yolk-shell mesoporous hybrid nanospheres for ultrahigh permeability and improving comprehensive property

In this report, yolk-shell (YS) organic-inorganic hybrid nanospheres (YSHNs) with radially ordered mesopores were synthesized by a co-assembly strategy using 1,2-bis(triethoxysilyl)ethane and tetraethoxysilane as precursors, and cetyltrimethylammonium bromide as a soft template. Then, Silver nanoparticles (AgNPs) were uniformly embedded in the hollow cavities of the YSHNs. The semi-aromatic polyamide (SAP) based nanocomposite membrane was fabricated using 1,3,5-cyclohexane tricarbonyl chloride as an organic phase, meta-phenylene diamine as an aqueous phase, and the mesoporous YS hybrid nanospheres as nanoadditives by an interfacial polymerization approach. The results show that the YS nanospheres were successfully incorporated into the polyamide (PA) separation layer, and the membrane becomes very hydrophilic. The membrane incorporated with the aminated YS mesoporous nanospheres exhibits ultrahigh pure water permeability (PWP, 9.34 L m−2 h−1 bar−1) and comparable NaCl rejection (96.1%), which is dramatically higher than the membrane with common mesoporous nanospheres. It is because that the hollow cavity of the YS nanosphere further decreases the membrane resistance, and the aminated spherical surface improves the interfacial compatibility between the PA matrix and the YS nanospheres. Furthermore, the flexible YS hybrid structure and the mesoporous core could play an important buffering for avoiding the shell fracture under a high operation pressure. The chlorine resistance of the YS-nanosphere incorporated membrane is significantly improved compared to the pristine SAP membrane in a strong chlorination strength (5500 ppm h, pH = 5). The confined AgNPs in the YS mesostructure endow the membrane with a sustainable antibiofouling property. Moreover, the polylysine modification improves the membrane fouling resistance and performance stability.

Performance regulation of a thin film composite (TFC) NF membrane by low-temperature interfacial polymerization assisted by the volatilization of n-hexane

Reducing the thickness of the polyamide (PA) layer has been confirmed as a feasible strategy to improve the permeability of the thin film composite (TFC) nanofiltration (NF) membrane. In this study, a novel interfacial polymerization (IP) approach assisted by the volatilization of n-hexane was proposed to promote the formation of a thinner PA layer, in which a small amount of n-hexane was added onto the substrate membrane after aqueous phase immersion and before the organic phase coating, then the temperature of the substrate membrane together with the water-soluble monomer solution would be decreased due to the volatilization of n-hexane. The infrared thermographies demonstrated that 7.8 μL cm−2n-hexane dosage was the most efficient, which can sharply decrease the surface temperature from room temperature (25 °C) to 7.9 °C. The TFC membranes prepared at the lower temperature presented much higher permeability. When PIP concentration was 0.3% w/v, TMC concentration was 0.1% w/v and IP reaction time was 40 s, the PA layer formed at this low temperature was smoother and more hydrophilic. Its thickness was reduced from 26.97 nm to 11.98 nm and water permeability was increased by 50% to 36.7 L m−2 h−1 bar−1 while maintaining Na2SO4 rejection of 96.5%.

Capillary-Assisted Fabrication of Thin-Film Nanocomposite Membranes for Improved Solute-Solute Separation.

Efficient separation of harmful contaminants (e.g., per- and polyfluoroalkyl substances, PFASs) from valuable components (water and nutrients) is essential to the resource recovery from domestic wastewater for agricultural purposes. Such selective recovery requires precise separation at the angstrom scale. Although nanofiltration (NF) has the potential to achieve solute-solute separation, the state-of-the-art polyamide (PA) membranes are typically constrained by limited precision of solute-solute selectivity and their well-documented permeability-selectivity trade-off. Herein, we present a novel capillary-assisted interfacial polymerization (CAIP) approach to generate metal-organic framework (MOF)-PA nanocomposite membranes with reduced surface charges and more uniform pore sizes that favor solute selectivity by enhanced size exclusion. By uniquely regulating the PA-MOF interactions using the capillary force, CAIP results in effective exposure of MOF nanochannels on the membrane surface and a PA matrix with a high cross-linking gradient in the vertical direction, both of which contribute to an exceptional water permeance of ∼18.7 LMH/bar and an unprecedentedly high selectivity between nutrient ions and PFASs. Our CAIP approach breaks new ground for utilizing nanoparticles with nanochannels in fabricating the next-generation, fit-for-purpose NF membranes for improved solute-solute separations.

Fabrication of organic solvent nanofiltration membrane using commercial PVDF substrate via interfacial polymerization on top of metal-organic frameworks interlayer

Interfacial polymerization (IP) is a rapid and convenient approach to fabricating thin-film composite (TFC) membranes with high permeance and satisfactory rejection for organic solvent nanofiltration (OSN). However, it is normally difficult to directly conduct the IP approach on the commercial membrane substrate (particularly, in the microfiltration range) because the monomers on the substrate are unevenly distributed during the IP reaction. In the current work, Cu-TCPP nanosheets were in-situ grown on commercial PVDF microfiltration substrate (pore size of 0.45 μm) by using preinstalled Cu2O nanoparticles as a copper ion source. The Cu-TCPP nanosheets covered the large pores and penetrated the surface layer of the PVDF substrate. The obtained PVDF/i-Cu-TCPP was then used as a substrate to conduct the IP and to fabricate the PVDF/i-Cu-TCPP/PA membrane. It was found that i-Cu-TCPP which serves as an interlayer could store the aqueous solution of the amine and was critical to the formation of a thin and defect-free polyamide separation layer. In comparison, loading of the Cu-TCPP on the PVDF substrate by filtration led to the formation of PVDF/e-Cu-TCPP/PA, which however exhibited inferior separation performance as compared to the PVDF/i-Cu-TCPP/PA membrane. More importantly, the PVDF/i-Cu-TCPP/PA membrane exhibited higher tensile strength (6.0 vs. 2.8 MPa) compared to the PVDF/e-Cu-TCPP/PA membrane, due to the enhanced interaction (adhesion) between the PVDF substrate and the i-Cu-TCPP interlayer. Under optimal synthetic conditions, the permeance of the PVDF/i-Cu-TCPP/PA membrane was almost 4 times that of the PVDF/PA membrane (1.93 vs. 0.49 L m-2 h-1 bar-1) without compromising rejection (>96%). The optimal TFC membrane also showed excellent OSN performance towards various organic solvents and good long-term stability to VB12/ethanol mixtures (50 h). Furthermore, the concentration test of erythromycin in methanol solution indicated that the PVDF/i-Cu-TCPP/PA membrane has great potential in the pharmaceutical industry for drug concentration and organic solvent recovery.

Separation of textile wastewater using a highly permeable resveratrol-based loose nanofiltration membrane with excellent anti-fouling performance

A precise separation of organic dyes and inorganic salts is a prerequisite for zero liquid discharge of saline textile wastewater. The development of loose nanofiltration (LNF) membranes with customized nanoscale pores and high water permeance is expected to address this challenge. Herein, a new LNF membrane is reported, fabricated via a scalable interfacial polymerization (IP) approach between resveratrol and trimesoyl chloride (TMC) on a Kevlar substrate. The optimal resveratrol/TMC membrane exhibited an ultra-high pure water permeance (121.1 L−1 m−2h−1 bar−1), high dye rejection (99.4% for 200 ppm of Congo Red), and low salt rejection (4.2% for NaCl and 9.8% for Na2SO4). The chemical compositions, surface properties, and morphologies of the LNF membranes were characterized to elucidate their structure–property-performance relationships. The homogeneous diffusion of resveratrol to the water/hexane interface and the appropriate stoichiometry of the two monomers contribute to the formation of an ultra-thin (35–45 nm) and hydrophilic composite membrane, which allows the membrane to attain a high water permeance. The LNF membrane additionally maintains excellent anti-fouling properties during filtration of organic dye solutions, primarily as a result of the high hydrophilicity, negative charge density, and smoothness of the membrane surface. Importantly, the novel LNF membrane also retains stability after washing with ethanol and acetone, owing to the cross-linked polyphenol ester and the rigid phenyl backbone of the membrane surface. These results reveal the huge potential of applying resveratrol-based LNF membranes for the treatment of saline textile wastewater.

Preparation of nanocomposite Fe3O4@SiO2-PA for effective removal of Sb(III) from aqueous solutions: Kinetics, equilibrium and thermodynamic evaluation

ABSTRACT Silica-coated magnetite (Fe3O4@SiO2) was functionalized with polyamide through a simple interfacial polymerization approach to synthesize a magnetic nanocomposite utilized for Sb(III) separation from aqueous solutions. The physical and chemical properties of Fe3O4@SiO2-polyamide (Fe3O4@SiO2-PA) nanocomposites were comprehensively studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), Magnetic property, and Brunauer-Emmett-Teller (BET) analysis methods. It was revealed by characterizations that polyamide polymer was uniformly grafted onto Fe3O4@SiO2 nanocomposites. The as-synthesized Fe3O4@SiO2-PA nanocomposites could be easily recovered from aqueous solutions by magnetic separation in 60 s. The adsorption data of Sb(III) were well fitted by Langmuir isotherm equation, and the maximum adsorption capacity for Sb(III) is 193.5 mg/g. The kinetics of adsorption data were well fitted by using the pseudo-second-order model, with the determination coefficients of 0.996 at 20°C. The negative of change exothermic enthalpy ΔH (−70.4 kJ·mol-1) and Gibbs free energy ΔG (−175.1 kJ·mol-1) rendered the possibility of adsorption activity under given temperature parameters. By taking into account satisfactory adsorption efficiency it was concluded that the remediation of water pollution from Sb(III) could be achieved with such a great promising strategy.