M-phenylenediamine Research Articles

Dual optimization strategy assisted m-phenylenediamine-based hypercrosslinked polymer loaded ultrafine bimetallic nanoparticles for efficient formic acid dehydrogenation

Heterogeneous catalysts based on Pd play a vital role in enabling efficient formic acid decomposition (FAD). Nevertheless, the performance of Pd-based catalysts is constrained by inherent challenges, such as Pd particles’ tendency to aggregate and possess localized electronic structures. Therefore, there is an urgent need to develop an effective strategy to simultaneously overcome these challenges. In response to this, we synthesized knitting hypercrosslinked polymers (HCPs) using m-phenylenediamine (MPD) as the aromatic monomer. A dual-optimization approach was proposed, aiming to mitigate the adverse effects of excessive coordination and maximize the involvement of residual Fe3+ in the bimetallic synergistic effect. Experimental findings, DFT calculations, and ab initio molecular dynamics simulations (AIMDs) collectively suggest that reducing the coordination effect leads to enhanced nitrogen exposure in the HCPs, consequently reducing the size of Pd species. Furthermore, the incorporation of residual Fe3+ into Pd forms Pd-Fe bimetallic species, which then adjusts the catalytic reaction barrier and enhances catalytic activity. Notably, the optimized Pd@MHCP-2 catalyst exhibited exceptional performance in the FAD reaction at 323 K, achieving a remarkable turnover frequency (TOF) value of 1486 h−1. This research introduces a novel perspective for the design and development of next-generation Pd-based catalysts.

Mussel-inspired co-deposition of catechol-amine and graphene oxide (GO) modified anion exchange membranes (AEMs) for antifouling

Mussel-inspired co-deposition has many applications in surface modification of polymer membranes. Organic fouling of ion exchange membranes is one of the common issues that hinder electrodialysis treatment of industrial wastewater. In this work, anion exchange membranes were surface-modified by the mussel-inspired co-deposition of catechol-amine and graphene oxide (GO) nanosheets. Results showed that co-deposition with catechol (CA) and m-phenylenediamine (MPD) as reactant monomers rapidly generated modifying layer on the AEM surface. And the addition of GO into co-deposition helped improve the homogeneity and reduce polymer particle aggregation. The synergistic effect of catechol-amine and GO nanosheets was beneficial to form uniform modifying layer with improved hydrophilicity and negative charge density of membrane surface. In eletrodialysis experiments with sodium dodecyl benzene sulfonate (SDBS) as model foulants, GO-CA-MPD-3h modified AEM maintained high desalination rate close to that without folants, indicating good modifying antifouling performance. Mussel-inspired co-deposition of catecholamines and functional materials give new insights into membrane modificatin through a feasible and cost-effective method

Catechol/m-Phenylenediamine Modified Sol-Gel Coating with Enhanced Long-Lasting Anticorrosion Performance on 3003 Al Alloy.

Aluminum alloys, characterized by their low density and high mechanical strength, are widely applied in the manufacturing sector. However, the application of aluminum alloys in extreme environments presents severe corrosion challenges. Sol-gel organic coating techniques have garnered significant attention due to their excellent stability, barrier properties, and cost-effectiveness, as well as their simpler processing. Nevertheless, conventional sol-gel coatings are unable to withstand the corrosive effects of high-chloride and high-halide ion environments such as marine conditions, owing to their inherent structural defects. Therefore, this study proposes the utilization of a simple method to synthesize catechol (CA) and meta-phenylenediamine (MPD)-derived catecholamine compounds to modify sol-gel coatings. Surface characteristics of the modified coatings were analyzed using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The thickness of the modified coating was approximately 6.8 μm. The CA/MPD-modified substance effectively densifies the sol-gel coating, enhancing its corrosion protection performance. A 3.5 wt% NaCl solution was used to simulate a marine environment, and electrochemical impedance spectroscopy (EIS) was conducted using an electrochemical workstation to evaluate the coating's protective properties over a long-term period. The results indicate that the modified coating provides protection for 3003 aluminum alloy for a minimum of 30 days under corrosive conditions, outperforming unmodified sol-gel coatings in terms of corrosion resistance.

Development of Polyamide-Modified Membranes for Solar-Driven Seawater Desalination System

In response to the escalating global water crisis, this study introduces the development of polyamide-modified membranes (PA-PES, PA-PP, and PA-PTFE) through interfacial polymerization to enhance the efficiency of a passive solar desalination system. FTIR analysis and morphological characterization showed that a thin polyamide film formed above the modified membranes using m-phenylene diamine (MPD) and trimesoyl chloride (TMC). Notable improvements were observed in its productivity and distillate salinity by integrating these modified membranes into the membrane distiller of the system. Mainly, the PA-PES membrane achieved productivity of 764.56 ml/m2-h and reduced salinity to as low as 2 g NaCl/L. Despite challenges in salinity reduction, possibly due to residual chlorides, this study demonstrates the potential of polyamide-modified membranes in advancing solar-driven desalination, offering a promising solution to mitigate global water scarcity. This research paves the way for further advancements in sustainable desalination technology, emphasizing the need for continued optimization and exploration of membrane-based systems.

Interfacial oligomer splicing toward 3D silicon-centered polyimine nanofilm for rapid molecule/ion differentiation

3D porous organic polymers —renowned for rich interpenetrated, hierarchical pores and exceptional structural durability— showcase the potential for precise membrane-based separations. However, the challenge lies in processing these chemically stable polymers into a selective thin film under mild conditions. Herein, an interfacial oligomer splicing (IOS) approach via Schiff-base reactions is presented to create 3D silicon-centered porous polyimine (PPIn) nanofilms. The pre-synthesized oligomers from 4,4′,4″,4‴-silanetetrayltetrabenzaldehyde (TFS) and m-phenylenediamine (MPD) with high steric hindrance and hydrophobic character are precisely confined at the oil boundary, initiating IOS to yield an amorphous nanofilm on a Kevlar hydrogel surface. These silicon-centered 3D nanofilms exhibited an exceptional thermal and mechanical stability, while offering abundant low-resistance transport nanochannels. The nanofilm backbone, composed of rigid nonplanar aromatic skeleton and robust imine linkage, contributed to open and interpenetrated selective nanochannels, corroborated by both experimental and simulation and results. It was shown that 83-nm-thick PPIn nanofilms grown on the hydrogel achieved high-efficient molecule/ion differentiation, evident in excellent dye retention (>99.0 %), high NaCl permeation (92.8 %), and remarkable water permeability (74.3 L m−2 h−1 bar−1). This study establishes an innovative IOS approach for fabricating silicon-centered 3D-POP membranes and underscores their potential for efficient molecule/ion differentiation.

Ni(II)/Yb(III)-metallogels for distinctive fluorescent ‘turn-on’ detection of m-phenylenediamine: Toward construction of multiple logic gates

New versatile Schiff base gelator (HL) and its highly selective Ni(II)-and Yb(III)-based metallogels 1–2 have been synthesized and characterized by spectral techniques. Gelator HL in presence of triethylamine (Et3N) with Ni(NO3)2·6H2O and anhydrous Yb(NO3)3 in DMF/MeOH(1:1) solvents forms MG1 and MG2 supramolecular gels, respectively at room temperature (rt). Rheological results show thermal stability up to 100 ℃ and structurally rigid nature of MG1 and MG2. Remarkably, MG1 and MG2 were examined for identification of cations, anions, nitroaromatics and aromatic amines (AAs) but unable to recognize any analytes except for m-phenylenediamine (MPD) by using MG1. Metallogel MG1 shows highly selective response to MPD environmental pollutant with a limit of detection (LoD) of 7.58 × 10-7 M, without any interference of competing analytes. Interestingly, depending upon fascinating fluorescent On-Off-On switching behavior, molecular logic device has been fabricated with AND and IMPLICATION-logic gates function by employing the chemical inputs (i) HB, Ni(II) (MG1), Yb(III) (MG2) and (ii) HB, MG1 and MPD based on emission change at different wavelengths as output signal.

Synthesis and characterization of linear hybrid aliphatic/aromatic copolyurea via one‐step feeding method

AbstractThe combination of aromatic and aliphatic structures can endow polyurea with distinct performance advantages. A one‐step feeding method is used to synthesize linear hybrid aliphatic/aromatic copolyureas by varying the ratio of m‐phenylenediamine (MPD) and polyoxypropylenediamine (D2000) reacting with 4,4′‐diphenylmethane diisocyanate (MDI). Real‐time Fourier‐transform infrared spectrometer monitoring reveals that D2000 exhibits higher reactivity than MPD. Consequently, in the MDI/MPD/D2000 system, D2000 initially reacts with MDI to form an isocyanate‐terminated prepolymer, which subsequently reacts with MPD. Compared with the two‐step feeding method, this approach successfully eliminates biuret formation and enhances tensile strength. Additionally, decreasing the molar ratio of D2000 to MPD (λm) reduces the size and degree of microphase separation in the polyurea by increasing the ordered hydrogen bonding and benzene conjugation, leading to an increase in tensile strength. Specifically, as λm decreases from 70 mol% to 30 mol%, the degree of microphase separation decreases from 0.47 to 0.2, causing the tensile strength to rise from 28 to 48 MPa. Further reducing λm to 30 mol% decreases the degree of microphase separation to 0.16, resulting in an increase in tensile strength to 78 MPa.

Anomalous mass transfer behavior of organic molecules in crosslinked graphene oxide membranes induced by intermolecular forces

Membrane-based technology has a wide application for many separation practices, nevertheless, the precise separation of organic molecules using a membrane remains challenging. To get a deeper understanding of the nanoconfined mass transport of the organic molecules, pristine and crosslinked graphene oxide (GO) membranes were synthesized, and their transport properties were systemically studied. With m-phenylenediamine (MPD) crosslinked, the flux of the organics across the GO-MPD membrane was approximately 5-fold lower than that of the pristine GO membrane, though the GO-MPD membrane retains a relatively large pore size. Computational simulations implied the occurrence of strong intermolecular forces between the organics and the GO-MPD membrane, which significantly affected the partitioning and diffusion of the organics. We propose that the synergetic effect of “capacity and strength” needs to be considered when organic transport impacts are examined. By combining a low sorption capacity with strong intermolecular forces between organic molecules and the membrane, the transport of organic molecules across the membrane could be slowed down or inhibited, and vice versa. Our work offers a more comprehensive framework at the nanoscale that deepens the understanding of organic molecule mass transfer, which aids in the designing of high-selective membrane materials for separation practices involving organic molecules.

Tough epoxy resin systems for cryogenic applications

This work presents the development of new epoxy systems that combine high fracture toughness at cryogenic temperatures (▪) with a slow curing reaction (long pot life) and a glass transition temperature between ▪ and ▪, ensuring good mechanical performance at room temperature. This was achieved by incorporating varying amounts and types of short-chain alkylamines into epoxy networks based on bisphenol A diglycidyl ether (DGEBA) crosslinked with metaphenylene diamine (MPD). This modification enhanced the cryogenic fracture toughness of the base system, DGEBA crosslinked with MPD, from 2 to ▪. It has been suggested that the significantly improved cryogenic fracture toughness in systems with flexible aliphatic chain extenders might result from nano- or micro-phase separation, but X-ray scattering and dynamic mechanical spectroscopy did not provide conclusive evidence for this hypothesis.The required slow curing reaction was achieved by using a sterically hindered alkylamine (2-heptylamine) as chain extender, which increased the pot life more than twofold, resulting in resin formulations that combine a high cryogenic fracture toughness, a low viscosity and a long processing window at room temperature.

Tuning polyamide membrane chemistry for enhanced desalination using Boc-protected ethylenediamine and its in situ Boc-deprotection

The scarcity of freshwater resources, driven by rapid population growth and industrialization, underscores the urgent need for advanced desalination technologies. This research aims to meet this critical demand by enhancing the performance of polyamide membranes through innovative chemical tuning of the active layer. By strategically using Boc-protected ethylenediamine (EDA), we can precisely control the membrane’s surface properties. One amino group in EDA is protected with a Boc group, allowing the other to participate in the interfacial polymerization (IP) reaction with meta-phenylenediamine (MPD) and trimesoyl chloride (TMC). This inclusion of Boc-protected EDA enables in situ tuning of the active layer chemistry during polymerization. Subsequent removal of the Boc protection generates hydrophilic ammonium groups on the membrane surface, enhancing its desalination capabilities. As a result, three distinct membranes were fabricated and thoroughly characterized: MPD-TMC (control), MPD-TMC-EDA-Boc, and MPD-TMC-EDA-Deboc. At 20 bar and 2000 ppm NaCl feed, the MPD-TMC-EDA-Deboc membrane demonstrated superior desalination performance with a salt rejection of 98 ± 0.5% and a permeate flux of 25 L m−2 h−1; an increase of 25% compared to the control membrane. For the seawater nanofiltration (NF) permeate with a TDS of 33,700 ppm, a salt rejection of 97% and a permeate flux of 23 L m−2 h−1 was recorded at 20 bar. The MPD-TMC-EDA-Deboc membrane showed enhanced antifouling performance (95 ± 1% flux recovery) compared to the control MPD-TMC membrane with 93 ± 1% flux recovery. The Boc-protection/deprotection strategy demonstrated the high potential of this approach to significantly enhance the performance of polyamide membranes for desalination applications.

On the role of the porous support membrane in seawater reverse osmosis membrane synthesis, properties and performance

In this study, we explore the role of the polysulfone (PSU) support membrane skin-layer and whole-body pore morphology on the physical-chemical properties and separation performance of hand-cast polyamide-PSU (PA-PSU) composite seawater reverse osmosis (SWRO) membranes. We tailor the support membrane pore morphology by varying the PSU concentration and the coagulation bath temperature. In order to isolate the impacts of the PSU support, all of the porous supports are coated using identical m-phenylene diamine (MPD) and trimesoyl chloride (TMC) solution compositions, reaction conditions, and post-treatments. As PSU concentration increases, PSU support membrane pore size, surface and body porosity, water permeability, MPD mass uptake (by the PSU support), and PA-PSU composite membrane water permeability decrease, while MPD and TMC conversion, PA film mass and thickness, crosslinking degree (XD), and PA-PSU composite membrane NaCl rejection increase. As PSU support membrane coagulation bath temperature increases, support membrane pore size, surface and body porosity, MPD uptake, PA film mass, thickness and XD, MPD and TMC conversion, and NaCl rejection increase, while composite PA-PSU membrane water and NaCl permeability decrease. Composite membrane permeabilities were 70–90 percent of the (theoretical) unsupported PA film permeabilities due to the high XD and low PA coating film thickness. Composite PA-PSU membrane water/salt permeabilities both correlate most strongly with PA coating film mass/thickness and XD, which in turn correlate most strongly with TMC conversion. The key to increasing water permeability is lower PA film mass/thickness and XD with higher support membrane surface pore size and porosity. In contrast, the key to increasing NaCl rejection is higher PA film mass/thickness and XD with lower support membrane surface pore size and porosity.

Low MWCO non-polyamide nanofiltration membranes synthesized in aqueous by coupling with catechol-amine chemistry and the oxidation-induced self-polymerization of m-phenylenediamine

Catechol-amine coatings offer versatile routes for surface modifications and nanofiltration (NF) membrane preparations. However, the formation of the selective layer is time-consuming and often deficient, rendering it unsuitable for large-scale applications. In this work, oxidation-induced self-polymerization and catechol-amine chemistry were combined to rapidly construct nanofiltration membranes in an aqueous medium. M-phenylenediamine (MPD) underwent oxidation and self-polymerized on a polysulfone (PSF) support. The addition of sodium periodate facilitated the subsequent tannic acid (TA) coating. The catechol-amine reaction between oxidized TA and poly-MPD forms crosslinked poly TA-MPD complexes, offering the resulting membrane a high selectivity. The role of NaIO4 in the selective layer formation and the influences of the synthesis parameters on the membrane performance were discussed. Utilizing the facile method enabled the achievement of a low molecular weight cut-off (MWCO) NF membrane (180 Da). The membrane exhibited a high water permeance (10.9 Lm−2h−1bar−1) and good salt rejections (93 % for Na2SO4). The filtration of the bovine serum acid (BSA) solution demonstrated the membrane has good antifouling performance with a flux recovery ratio (FRR) of 95.1 %. The proposed method offers a straightforward and rapid approach to fabricating low MWCO NF membranes in an aqueous medium, which has potential in large-scale applications.

Hollow fiber thin-film composite membrane regulated by macrocyclic polyamine molecules for high performance organic solvent nanofiltration

Organic solvent nanofiltration (OSN) technology has the potential to separate and purify organic solvents in high efficiency. The self-supporting structure and ease scaling-up merit of hollow fiber (HF) type membrane make it an attractive option for OSN application. Nevertheless, low solvent permeance is one of technical limitation in conventional HF OSN membranes due to their excessively dense separation layer and limited free volume. Herein, we propose a straightforward methodology to fabricate HF thin-film composite (TFC) OSN membranes having exceptional solvent permeance and solute rejection. This methodology is conducted through the incorporation of macrocyclic molecules, 1,4,7,10-tetraazacyclododecane (Cyclen), into the aqueous monomer solution of m-Phenylenediamine (MPD) during the interfacial polymerization to modulate the separation layer. In this way, the average pore size of the separation layer could be precisely enlarged and narrowed on a sub-nanometer scale. Consequently, the Cyclen-modulated HF TFC OSN membrane exhibits excellent separation performance, with a pure methanol permeance of 76.7 L m−2 h−1 MPa−1 and a pure ethanol permeance of 26.5 L m−2 h−1 MPa−1, which is nearly 60 % increase compared with the baseline TFC membrane, while the Rhodamine B (RDB) rejection only shows a neglectable decrease from 99.7 % to 99.6 % at optimal fabrication conditions. Furthermore, the optimal membrane exhibits remarkable solvent resistance, withstanding a 35 d immersion in N, N-dimethylformamide (DMF) at room temperature without a significant decline in RDB rejection. Additionally, the optimal membrane shows higher than 99 % rejection for Rifampicin (823 Da), which is considerable potential for applications in the separation and recovery of pharmaceuticals. In summary, incorporating macrocyclic polyamine Cyclen into the polyamide layer is a viable method for regulating the physical structure and strengthening the performance of HF OSN membrane.

Impact of cationic surfactants molecular structure on physicochemical structure and properties of polyamide reverse osmosis membrane via tailoring interfacial polymerization

Surfactants assisted interfacial polymerization (IP) has been demonstrated as an effective method to finely tailor the structure and performance of polyamide (PA) reverse osmosis (RO) membranes. However, little is done to illustrate how molecular structure of cationic surfactants affects IP and the amounts of surfactants incorporated into PA. In this study, three types of quaternary ammonium cationic surfactants were employed to assist the IP process and to fabricate RO membranes. Results show that these three cationic surfactants can not only significantly accelerate m-phenylenediamine (MPD) diffusion from aqueous phase into oil phase and promote the PA crosslinking, but also can be incorporated into PA to affect the surface properties (hydrophilicity, charge properties). Benzyl dimethyl phenyl ammonium chloride (BDMPAC) having two benzene rings had been found to be incorporated into PA with the highest amount because of its similar benzene structure as PA. Moreover, benzalkonium chloride (BAC) with the longest aliphatic tail induced a pronounced Marangoni convection during IP, resulting in an enlarged surface area of PA with large leaves and abundant internal/backside voids, and thus the highest water permeance. This study demonstrates a facile and simple way of using cationic surfactants to engineer the high-performance polyamide RO membrane.

Optimized preparation route for polyamide top-coated forward osmosis membrane for enhanced water flux using industrial wastewater as feed.

The forward osmosis (FO) process has recently gained significant interest in treating wastewater, brackish/seawater and concentrating feedstocks for various operations, including desalination. The study investigates the effect of different synthesis conditions of the polyamide-based thin-film composite (TFC) FO membranes on the membranes' final performance. Taguchi statistical analyses were used to fabricate and optimize the polyamide TFC FO membrane. The process parameters as factors were the amount of polyethersulfone (PES), polyethylene glycol 400 (PEG-400), polyvinyl pyrrolidone (PVP), m-phenylenediamine (MPD), and trimesoyl chloride (TMC), and TMC reaction-time (RT). The Taguchi method was adopted to investigate the optimal conditions and the significance of individual factors using an L16 (45) orthogonal array. Another Taguchi analysis (Taguchi 2) was adopted to investigate the influence of other important parameters like optimal conditions for MPD, TMC, and TMC reaction-time factors using an L9 (33) orthogonal array. Confirmation tests validated a maximum water flux of 46.4 ± 2.32 L/m2·h with a specific combination of control factors for membrane synthesis: PES/PEG/PVP/MPD/TMC/TMC RT-16/7/0.5/1/0.05/30. These tests demonstrated a high-water flux of 7.05 ± 0.35 L/m2·h when exposed to industrial wastewater (secondary effluent) as the feed solution (FS) and fertilizer as the draw solution (DS) in the FO process. The R2 values were more than 90%. The experimental validation confirmed the models' predictive ability with different FSs, including industrial wastewater.

Foam fractionation for the separation and enrichment of trace m-phenylenediamine and o-phenylenediamine in solution

In this study, a foam fractionation technique was developed for the separation and enrichment of the trace m-phenylenediamine (MPD) and o-phenylenediamine (OPD) in solution. Firstly, a self-designed foam fractionation device was assembled and built, followed by a comprehensive characterization on gas types, foam fractionation column parameters, and porous sieve plate material used in the apparatus. Subsequently, the most crucial parameters for the separation and enrichment, such as surfactant species, solution pH, electrolyte categories, and gas flow rate, were identified and optimized. The mechanisms of key processes during foam fractionation under the influence of these parameters were thoroughly discussed. Other influencing factors, such as surfactant concentration, foam collection time, and solution volume in the fractionation column, were optimized using response surface methodology (RSM). Under these optimal conditions, maximal enrichment ratios of 138.2 and 85.5 were achieved for MPD and OPD, respectively. Finally, foam fractionation coupled with high-performance liquid chromatography (HPLC) was employed to detect MPD and OPD in the solution. The results demonstrated limits of detection (LOD) of 1.5 × 10−2 μg/L and 1.5 μg/L for MPD and OPD, with relative standard deviation (RSD) values of 4.1 % and 3.9 %. When testing various actual samples, the recoveries were in the range from 92.0 % or greater in all cases. The method exhibited advantages of high sensitivity, precision, and accuracy, attributed to the high enrichment efficiency of foam fractionation. In conclusion, the foam fractionation method established in this study offers simplicity in apparatus, operational convenience, environmental friendliness (minimized use of organic solvents), and high enrichment efficiency. It proves valuable for the quantitative analysis of trace amounts of MPD and OPD in solution, presenting a novel approach for the detection of trace organic compounds in solutions.

Controlling amine monomers via UiO-66-NH2 defect sites to enhance forward osmosis membrane performance for lithium recovery

The excessive thickness of the separation layer and the presence of cracks cause low water flux and poor lithium recovery in conventional forward osmosis (FO) membranes. According to the influence of the diffusion behavior of amine monomers in interfacial polymerization, the use of an interlayer optimizes the separation layer structure of traditional thin-film composite FO membrane. However, it is difficult to accurately control the separation layer structure by simply adjusting the amount of the interlayer material loaded. Herein, FO membranes with defect-containing metal–organic framework (MOF) interlayers were constructed. By adjusting the concentrations of competitive ligands, the MOFs showed different degrees of linker loss, which exposed the metal ions in the MOFs to different extents. The defective sites of the constructed MOFs increased the interaction between the interlayer and m-phenylenediamine (MPD), and density functional theory (DFT) simulations also revealed an increase in the binding energy of the two materials. Therefore, MPD attachment and diffusion were controlled by changing the proportion of defects in the MOFs, thereby finely regulating the separation layer structure. Additionally, tannic acid (TA) was predeposited to improve the stability of the interlayer. The prepared membrane exhibited water fluxes of 33.84 and 65.81 LMH and reverse salt fluxes of 0.58 and 2.38 gMH in the active layer facing feed solution (AL-FS) and active layer facing draw solution (AL-DS) modes, respectively. Excellent lithium ion recovery and fouling resistance was also demonstrated in battery wastewater treatment.

Effects of substrate (track-etched filter) properties on the performance of forward osmosis membranes

Highly permeable membranes can improve the validity of water treatment using forward osmosis (FO) membranes. This study aims to identify the effects of substrate (track-etched (TE) filter) properties on the permeability of FO membranes. The polyamide active layer properties of three types of TE filters with similarly-sized pore diameters (0.2 μm) were observed to be equivalent regardless of the substrate porosity (13.7%–15.8 %) and substrate thickness (10–25 μm). Under the same fabrication protocol using 1.5 wt% m-phenylenediamine (MPD) solution with 0.25 wt% sodium dodecyl sulfate (SDS) addition, the increased porosity of the TE filter increased water flux. This suggested that further reduction in thickness and increase in porosity can enhance the water flux. The addition of SDS to an MPD solution was crucial in maximizing the water flux of TE filter-based FO membranes, and the other approaches (no surfactant addition or the addition of Tween80 or hexadecyltrimethylammonium bromide) produced lower water flux. The optimized fabrication protocol presented the highest water flux of 43 L/m2h and reverse salt flux of 10 g/m2h with the draw (1.0 M NaCl) and feed (pure water) solutions. This study determined the best approach for forming a highly permeable PA active layer on TE filters.

Thin-film composite membranes with contorted monomer for high-flux isothermal refining

The development of isothermal refining processes is important because of the high energy demands of crude oil separation. Membrane technology provides separation efficiency and low carbon footprint. This efficiency can be fine-tuned and enhanced by modifying the chemistry of the membrane selective layer. Herein, we describe the fabrication of membranes by interfacial polymerization using a combination of contorted fluorinated monomer bearing six fluorine atoms and trimesoyl chloride in the organic phase. A fluorinated m-phenylene diamine was added to the aqueous phase. This approach produces membranes with high surface roughness, increases their hydrophobicity and promotes the transport of hydrocarbons with high selectivity and toluene permeance (15.6 L m−2 h−1 bar−1). Successful evaluations were conducted for the fractionation of crude oil, confirming the potential for application in the petrochemical industry.

Optimizing ionic conductivity and ion selectivity in zinc-polyiodide flow batteries with composite polyamide-porous separators

Owing to their superior theoretical energy capacity, zinc-polyiodide flow batteries (ZIFBs) are well-known energy storage devices. The practicality of ZIFBs depends on the development of cost-effective separators that can demonstrate both excellent ionic conductivity and selective ion permeability. Herein, an economical polymer blend comprising poly (ether sulfone) (PES) and sulfonated poly (ether ether ketone) (sPEEK) is fabricated via a phase inversion technique. Due to the formation of a sponge-like structure, the porous substrate indicates high ionic conductivity. Furthermore, the selected porous substrate is coated with a thin-film polyamide, synthesized from m-phenylenediamine (MPD) and 1,3,5-benzene tricarbonyl trichloride (TMC) via interfacial polymerization (IP). This polyamide layer can efficiently mitigate the undesired migration of triiodide ions, while maintaining high ionic conductivity. This innovative approach yields a composite separator having a deftly tunable structure. Using such a separator, ZIFBs can operate stably with high coulombic efficiency (CE) of 91 % over 100 cycles at a current density of 10 mAh cm−2. Overall, this study explores the trade-off between ionic conductivity and ion permeability. It is seen that by adjusting their morphology, the physical characteristics of the composite separators can be improved, ensuring stable and efficient operation of ZIFBs.