Composite Fiber Membranes Research Articles

Flexible Highly Thermally Conductive PCM Film Prepared by Centrifugal Electrospinning for Wearable Thermal Management

Personal thermal management materials integrated with phase-change materials have significant potential to satisfy human thermal comfort needs and save energy through the efficient storage and utilization of thermal energy. However, conventional organic phase-change materials in a solid state suffer from rigidity, low thermal conductivity, and leakage, making their application challenging. In this work, polyethylene glycol (PEG) was chosen as the phase-change material to provide the energy storage density, polyethylene oxide (PEO) was chosen to provide the backbone structure of the three-dimensional polymer network and cross-linked with the PEG to provide flexibility, and carbon nanotubes (CNTs) were used to improve the mechanical and thermal conductivity of the material. The thermal conductivity of the composite fiber membranes was boosted by 77.1% when CNTs were added at 4 wt%. Water-resistant modification of the composite fiber membranes was successfully performed using glutaraldehyde-saturated steam. The resulting composite fiber membranes had a reasonable range of phase transition temperatures, and the CC4PCF-55 membranes had melting and freezing latent heats of 66.71 J/g and 64.74 J/g, respectively. The results of this study prove that the green CC4PCF-55 composite fiber membranes have excellent flexibility, with good thermal energy storage capacity and thermal conductivity and, therefore, high potential in the field of flexible wearable thermal management textiles.

Reduction in Olfactory Discomfort in Inhabited Premises from Areas with Mofettas through Cellulosic Derivative-Polypropylene Hollow Fiber Composite Membranes.

Hydrogen sulfide is present in active or extinct volcanic areas (mofettas). The habitable premises in these areas are affected by the presence of hydrogen sulfide, which, even in low concentrations, gives off a bad to unbearable smell. If the living spaces considered are closed enclosures, then a system can be designed to reduce the concentration of hydrogen sulfide. This paper presents a membrane-based way to reduce the hydrogen sulfide concentration to acceptable limits using a cellulosic derivative-propylene hollow fiber-based composite membrane module. The cellulosic derivatives considered were: carboxymethyl-cellulose (NaCMC), P1; cellulose acetate (CA), P2; methyl 2-hydroxyethyl-cellulose (MHEC), P3; and hydroxyethyl-cellulose (HEC), P4. In the permeation module, hydrogen sulfide is captured with a solution of cadmium that forms cadmium sulfide, usable as a luminescent substance. The composite membranes were characterized by SEM, EDAX, FTIR, FTIR 2D maps, thermal analysis (TG and DSC), and from the perspective of hydrogen sulfide air removal performance. To determine the process performances, the variables were as follows: the nature of the cellulosic derivative-polypropylene hollow fiber composite membrane, the concentration of hydrogen sulfide in the polluted air, the flow rate of polluted air, and the pH of the cadmium nitrate solution. The pertraction efficiency was highest for the sodium carboxymethyl-cellulose (NaCMC)-polypropylene hollow fiber membrane, with a hydrogen sulfide concentration in the polluted air of 20 ppm, a polluted air flow rate (QH2S) of 50 L/min, and a pH of 2 and 4. The hydrogen sulfide flux rates, for membrane P1, fall between 0.25 × 10-7 mol·m2·s-1 for the values of QH2S = 150 L/min, CH2S = 20 ppm, and pH = 2 and 0.67 × 10-7 mol·m-2·s-1 for the values of QH2S = 50 L/min, CH2S = 60 ppm, and pH = 2. The paper proposes a simple air purification system containing hydrogen sulfide, using a module with composite cellulosic derivative-polypropylene hollow fiber membranes.

Electrospun porous polyacrylonitrile/polyvinylpyrrolidone nanofiber membrane with ultra-hydrophilic and high moisture-permeability for dust personal protection

The serious dust pollution in coal mine working environment can cause occupational lung diseases and other diseases, affecting the life and health of miners. Therefore, the prospect of developing an air filtration membrane with high filtration performance is of remarkable significance. This study prepared a porous Polyacrylonitrile (PAN) /Polyvinylpyrrolidone (PVP) nanofiber membrane based on Electrospinning and post-treatment technology used for downhole personal protection. The prepared porous nanofiber membrane increased the specific surface area by 133.63 % and the porosity by 391.02 % (compared with the pure PAN nanofiber membrane), and was able to achieve a high filtration efficiency of 98.76 % and a low pressure drop of 165 Pa at an air flow rate of 85 L/min. Meanwhile, this study conducted contact angle and moisture permeability tests on the prepared composite fiber membrane. After 1 second of water droplets falling on the fiber membrane, it had a 14° contact angle (strong hydrophilicity), and the moisture permeability reached 4256.677 cm3/m2·d·Pa, which could discharge the water vapor generated by respiration in time. In addition, given the complex and irregular pore distribution of electrospun nanofibers, the fractal correlation dimension of nanofiber membrane pores was studied through fractal theory, and the relationship between the fractal dimension of fiber pores and respiratory resistance was discussed. Based on this, the nanofiber membrane prepared in this study can be widely used in individual protection in mines.

Design and fabrication of PPTA-braid-reinforced PFA/GE hollow fiber composite membranes

Due to the effects of the rapid development of modern society and fresh water resource pollution, water shortage has further accelerated, which is becoming a very urgent problem. Herein, the poly (p-phenylene terephthalamide)-(PPTA-) braid-reinforced (PBR) poly(tetrafluoroethylene-co-perfluoropropylvinylether)/graphene (PFA/GE) hollow fiber composite membranes (HFCMs) were prepared by dipping coating-thermal sintering coupling technique with a green process. GE is an emerging type of two-dimensional functional nanoparticle with a tunable passageway for oil molecules. The influences of the GE concentration in the casting solution on the structure and performance of the PBR−PFA/GE HFCMs were investigated. The results showed that the addition of GE produced a finger-like pore structure suitable for oil channels. Meanwhile, the roughness and contact angle of the composite membrane increased accordingly, and the water contact angle increased from 115° to 120°. The permeation fluxes of kerosene also increased obviously with the increase of GE contents, and the maximum flux of M-3 reached as high as 217.66 L·m−2·h−1. The application of the lubricating oil flux test under working conditions of 60–150 °C has demonstrated the high-temperature oil permeability resistance of the composite membrane. Even after long-term use, its separation efficiency for water-in-oil emulsions still remains above 99.5 %. In addition, the membrane separation-efficiency both up to 99.9 % for activated carbon and silica dioxide (SiO2) in kerosene. Overall, the PBR-PFA/GE HFCMs with excellent lipophilicity presented great potential for oily wastewater treatment at high temperatures.

Sandwich-structured bimodal fiber/bead-on-string fiber composite membrane for comfortable PM0.3 filter

Particulate matter (PM) pollution causes critical harm to human health and global environment. However, the protective respirators attain high-performance filtration of the most permeable PM0.3 by tight stacking of fibers and seriously compromising their wearing comfort. Herein, a fluffy sandwich-structured membrane (SSM) composed of bimodal fibrous layers and bead-on-string fibrous layer is designed to endow the air filter with both high-performance filtration and superior thermal-wet comfort. Based on the electrospinning technique, the bimodal fibers made of nano-/submicron-fibers (about 46 nm and 155 nm) are formed by inducing the jet splitting while the bead-on-string fibers consisting of submicron-fibers (≈ 120 nm) and micro-beads (≈ 3.37 μm) are prepared through manipulating the Rayleigh instability of jets. Due to the structural design of small pores and low packing density, the SSM exhibits excellent PM0.3 removal of 99.8%, low filtration resistance of 65 Pa, and high quality factor of 0.097 Pa-1. It also shows long-term filtration stability and durability under high humidity conditions. Moreover, the SSM simultaneously possesses superior thermal-wet comfort of heat dissipation, air permeability of 164 mm·s-1, and water vapor transmission of 7.6 kg·m-2·d-1. This work may offer a novel insight for exploiting high-performance and comfortable personal protective materials.

Fabrication of hollow fiber composite membranes via opposite transmission reaction method for dye/salt separation

The separation layer prepared by the conventional coating-crosslinking method is typically thick and prone to forming defective macropores, significantly affecting the water permeability and dye/salt separation performance of membranes. This work presented a novel method to prepare hollow fiber composite membranes for dye/salt separation based on the opposite transmission reaction of crosslinker. In this method, the macromolecule in situ reacted with a small‐molecule crosslinker at the openings of membrane pore channels, forming a separation layer with discontinuous sheet-like and granular structure. Compared to the conventional forward coating-crosslinking method, the separation layer prepared by the opposite transmission reaction method exhibited an ultra-thin thickness of 29.1 nm. Consequently, the composite membrane exhibited a high water permeability of 72.7 L·m−2·h−1·bar−1, which was 2.3 times higher than that of conventional methods. Moreover, the prepared composite membrane presented a more uniformed pore structure, completely retaining the VBB (100%) with a low Na2SO4 rejection of 4.3%, demonstrating excellent dye/salt separation performance. Additionally, the prepared composite membrane exhibited superior anti-fouling properties compared to that prepared by the conventional method. Therefore, the opposite transmission reaction method proposed in this study held promising applications in the preparation of hollow fiber composite membranes for efficient dye/salt separation.

Preparation and Characterization of Novel Multifunctional Wound Dressing by Near-Field Direct-Writing Electrospinning and Its Application.

Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as insufficient breathability, poor moisture retention performance, and single function. Herein, a novel multifunctional wound dressing was prepared to utilize near-field direct-writing electrospinning technology, in which calf skin collagen type I (CSC-I) and polycaprolactone (PCL) were used as the composite matrix, Hexafluoroisopropanol (HFIP) as the solvent, and erythromycin (ERY) as an anti-infective drug component. The results show that the micro/nanofiber membranes prepared by near-field direct-writing electrospinning technology can all present a complete mesh structure, excellent thermal stability, and good moisturizing properties. Moreover, the composite fiber membrane loaded with ERY not only had obvious antibacterial properties against E. coli and S. thermophilus but also a better slow-release function of drugs (it is rare to have both in traditional wound dressings). Therefore, this experimental design can provide relevant theories and an experimental foundation for preparing a new type of medical dressing with drug loading and has good guiding significance for the application and promotion of near-field direct-writing electrospinning in medical dressings.

Stretchability-adjustable Janus composite fiber membrane for passive radiant cooling and heating

Stretchability-adjustable Janus composite fiber membrane for passive radiant cooling and heating

Fabricating rapid proton conduction pathways with sepiolite nanorod-based ionogel/Nafion composites via electrospinning

The major limitation of conventional sulfonated polymer proton-exchange membranes (PEMs) is their strong reliance on water molecules for proton conduction, causing a significant reduction in proton conductivity under low-humidity conditions. In this study, a one-dimensional ionogel (IL@Sep) confined within sepiolite (Sep) nanorods was prepared using ionic liquid (1-butyl-3-methylimidazolium trifluoromethanesulfonate) and supercritical CO2. Subsequently, IL@Sep was blended with a Nafion solution, and electrospinning was used to fabricate the composite fiber PEM suitable for low-humidity environments. The results revealed that the electrospun (ES)-Nafion/IL@Sep composite fiber membrane exhibited significantly enhanced mechanical properties, water absorption, and proton conductivity. At an IL@Sep content of 2 wt%, the Nafion/2IL@Sep membrane exhibited a proton conductivity of 231 mS cm−1 at 80 °C/98 % relative humidity (RH) and 113 mS cm−1 at 80 °C/40 % RH. Moreover, the single-cell assembled with this composite membrane exhibited good gas tightness and achieved a peak power density of 779 mW cm−2 at 60 °C/80 % RH, which was ∼1.45 times that of the Nafion 212 membrane single-cell. This study indicates that electrospinning-assisted ionogel-modified ES-Nafion/IL@Sep composite fiber membranes have potential suitability for use in proton-exchange membrane fuel cells under varying humidity conditions.

Enhancing thin-film composite polyethersulfone hollow fiber membranes through alkali-induced interfacial polymerization modification for effective separation of monovalent/divalent salts

Amidst the escalating global water scarcity issues, finding better ways to sustainably treat brackish water and seawater while simultaneously recovering resources becomes increasingly important. In this work, we investigated the fabrication strategies to produce polyethersulfone hollow fiber membranes (PES HFMs) with robust characteristics and uniformly arranged shape. The presence of an air gap (AG) in the dry-wet spinning process facilitates the chain orientation due to the gravitational force and elongational stretch and moisture-induced early phase inversion, therefore preventing corrugations on the shell side. We extensively studied the correlation between HFM spinning parameters and the appearance and disappearance of buckling effects. Moreover, it was proven that the addition of N-methyl-2-pyrrolidone (NMP) to the bore fluid composition prolongs the demixing process, overcoming the HFMs' delamination issue. After optimizing the spinning conditions, a facile alkali-induced interfacial polymerization (IP) was employed to enhance the formation of a selective polyamide (PA) layer on PES HFM substrates. The final membrane made by this modification process, denoted as PES-IP-BOH, exhibits a Na2SO4 rejection higher than 96 %, while maintaining low rejections for other monovalent salts. Accordingly, it achieved a high ideal selectivity of >23 for the selective separation of monovalent and divalent salts.

Design of PVDF hollow fiber membranes with stable crystalline and porous structure by solvent‐free method

AbstractOne of the critical principles of green chemistry and environmental sustainability is to avoid using harmful solvents in chemical processes. In this study, a novel solvent‐free method was employed to prepare poly (vinylidene fluoride) (PVDF) hollow fiber composite membranes with stable crystalline and porous structures. Utilizing the cold‐hot stretching method, the crystalline structure and orientation of PVDF were effectively redesigned, resulting in improved mechanical and penetration properties of the membrane. Additionally, an investigation into the internal crystalline structure of the PVDF hollow fiber membrane was conducted, focusing on crystalline changes induced by ion‐dipole interactions. Results indicated that the addition of neutral ion‐dipole functional particles (N‐P) promoted the conversion of α crystalline to β crystalline, leading to stable β crystalline and controllable pore sizes in the prepared PVDF hollow fiber membrane. Furthermore, the internal crystalline structure significantly contributed to enhancing the membrane's mechanical properties and penetration performance. Notably, a PVDF hollow fiber with high β crystalline content was achieved through 150% cold‐hot stretching and the addition of 20. wt% N‐P further enhanced the β‐crystalline content in the membrane. This study presents a promising approach for reducing solvent consumption and minimizing environmental impact in the field of environment‐friendly membrane fabrication.

Construction of PDMS@ZIF-8 composite membrane on PVDF hollow fiber inner surface for ultrafast ethanol/water separation

Construction of ultra-thin and defect-free separation membrane on inner surface of hollow fiber supports is significant but challenging for molecular separation. In this study, the highly permeable PDMS@ZIF-8/PVDF composite membranes were successfully fabricated upon the inner-surface of polyvinylidene fluoride (PVDF) hollow fiber membrane for pervaporation (PV) ethanol/water separation. The efficient preparation of hierarchical PDMS@ZIF-8/PVDF composite membranes benefited from the precise regulation of ZIF-8 layer through interfacial synthesis and sequential coating of PDMS matrix. The thickness of the PDMS layer was only 16 ± 2 nm, which admirably eliminated the non-selective defects in ZIF-8 layer. Owning to the optimal combination of MOF layer and ultra-thin polymer layer, the as-prepared membrane exhibited the excellent ethanol flux of 1.34 kg m−2 h−1 with an ethanol concentration in permeate of 31.3 wt% for separating 5 wt% ethanol aqueous solution at 40 °C. The separation performance of the resultant membrane was superior to that of the other ethanol selective PV membranes. These findings herein provided a new way for preparing high-performance hollow fiber composite membranes for PV separation.

Functionalized-MXene-based imprinted MOFs composite membranes for the selective separation of ribavirin

The evident decrease for membrane-treated performance in response to multi-component mixture greatly limited its application. Here, we prepared blended nanomolecularly imprinted composite fiber membranes (CXPM-MIMs) with in situ growth of imprinted MOFs on carboxyl functionalized MXene. Through the carboxylate-assisted coordination pathway, a chelation site is provided by the carboxylate-modified MXene to coordinate with NH2-UiO-66, creating a tightly linked NH2-UiO-66/carboxylate-functionalized MXene heterostructure. The key role of the modified carboxyl group can be identified so that it can help to create a strong coordination bond between the two materials. Conventional MOFs typically lack selectivity and specificity. Here, we present a molecularly imprinted nanocomposite MOFs membrane material that exhibits selective adsorption and molecular separation capabilities. Imprinted UiO-66 (Ce) based on diamino-terephthalic acid was synthesized with water as the only solvent without adding any regulator or additive. By adding ribavirin molecules to multicomponent MOFs using a molecular imprinting technique and carrying out adsorption tests (isothermal and kinetic) as well as selectivity testing, we were able to demonstrate this adsorption-separation mechanism. The valuable testing outcomes shown that the as-prepared CXPM-MIMs performed excellently in terms of pemselectivity for ribavirin (RBV) (permselectivity factor β = 4.89, 10.14, 9.23) in addition to exhibiting perfect specific adsorption ability (58.3 mg g−1). The strong permselectivity and particular identification capacity of CXPM-MIMs demonstrated their tremendous potential in the treatment of RBV contamination.

Synthesis of Polystyrene Fiber Membranes Prepared by Electrospinning: Effect of AgNO3 on the Microstructure

<p>Polystyrene (PS) is commonly employed in insulation, packaging, filters, and medical equipment, with recent studies exploring its potential in fiber membrane production. The electrospinning technique is discussed to synthesize PS fiber membranes with high porosity and controllable diameter. Additionally, incorporating silver nitrate into PS composite fibers is explored for enhanced functionalities such as catalytic activity, high electrical conductivity, and antibacterial activity. However, PS composite fiber membranes with silver nitrate (AgNO<sub>3</sub>) metal variations are rarely observed. This research aims to modify the microstructure of PS fiber membranes produced using electrospinning by adding silver nitrate (AgNO<sub>3</sub>) with varying concentrations. PS-Ag fiber membranes are produced using N,N-dimethylformamide (DMF) solvent, which serves as a solvent and a reducing agent for Ag. The results show that the effect of Ag affected the diameter of the PS-Ag fiber membrane, with an average diameter of around 3.67 - 6.93 micrometers. Degradation occurred in these samples at a strong broadening peak near ~1300 cm<sup>-1</sup> until ~1600 cm<sup>-1</sup> from the Raman results. The FTIR results show that the wavelength of ~3500 cm<sup>-1</sup> indicated the presence of OH. The presence of OH indicates that the PS-Ag fiber membrane has the potential for water filtration application</p>

Robust design of reinforced superhydrophobic FEP-SiO2@PTFE hollow fiber membrane for waste lubricating oils treatment

The shortage of petroleum resources brings the regeneration of used lubricating oils (ULOs) to a major issue, and hence the superhydrophobic membranes attract extensive attention derived from lotus-effect and capillary forces. In this paper, a superhydrophobic FEP-SiO2@PTFE hollow fiber composite membrane (HFCM) based on a facile step-by-step adhesive bonding method with a water contact angle up to 154.1°. The multilayered structure with superhydrophobic separation layer, microporous structure transition layer, and high strength supporting layer could be constructed. The lubricant permeate flux of membrane was as high as 814.5 L·m−2·h−1·bar−1 at 100 °C, with separation efficiencies of 99.3 % and 98.9 % for lubricants containing activated carbon and SiO2, respectively. Meanwhile, the flux of the membrane was stabilized at 430.9 L·m−2·h−1·bar−1 after 200 h of operation, and showed an initial permeation of 680.1 L·m−2·h−1·bar−1 after 5 cycles. Prominent mechanical properties and thermal-resistance (breaking strength of about 165.0 MPa, thermal decomposition temperature was up to 380℃) are another excellent performance of the membrane. As a result, the membrane provided another preferred option for the recycling of heavy oils, such as ULOs, at high temperatures or in various harsh environments.

Preparation of polystyrene and silane-modified nano-silica superhydrophobic and superoleophilic three-dimensional composite fiber membranes for efficient oil absorption and oil-water separation

Oily solid waste and wastewater are two kinds of contaminants that seriously endanger the environment and the general public. Recently, superhydrophobic and superoleophilic materials have attracted extensive attention owing to their exceptional oil-water separation capabilities. In this study, we demonstrated a simple, low-cost, and high-economic efficiency method to prepare nanosilica (SiO2) from dye diatomite filter aid waste (DDW) and silanize it with octadecyltrichlorosilane (OTS) to form hydrophobic nanosilica (hSiO2) by solution impregnation. Polystyrene/hydrophobic nanosilica (PS/hSiO2) composite fiber membranes with a rough surface and low surface energy were prepared by electrospinning. The prepared PS/hSiO2 water contact angle can reach 166.6°, showing superhydrophobicity and excellent adsorption capacity for various common oils. The maximum oil absorption capacity for transformer oil can reach 136.4 g/g. Importantly, the oil absorption process of the nanocomposite is selective, fast, and efficient, and it can be used for the purification of oil-contaminated water. In addition, it also demonstrates remarkable durability and stability in strong acid and alkali solutions. This strategy of making oil-water separation materials from solid waste may offer a straightforward, cost-effective, and environmentally sustainable option for the treatment of solid waste, industrial oil wastewater treatment, and marine oil spill cleanup.

Electrospun 3D Curly Electret Nanofiber Air Filters for Particulate Pollutants

Amidst rapid industrialization and urbanization, air pollution has emerged as a global environmental challenge. Traditional air filtration materials face challenges in effectively filtering PM0.3 and often result in discomfort due to high air resistance when used for personal protection, as well as excessive energy consumption in industrial air purification applications. This study initially utilized extremely high environmental humidity to induce fiber formation, resulting in the preparation of a fluffy fiber membrane with a three-dimensional curly morphology, which increased the porosity to 96.93%, significantly reducing air resistance during filtration. Subsequently, rutile TiO2 with a high dielectric constant was introduced, exploiting the low pressure drop characteristic of the fluffy 3D curly fiber membrane combined with the electret effect of TiO2 nanoparticles to notably improve the issue of excessive pressure drops while maintaining filtration efficiency. The microstructure, morphology, and element distribution of the fibers were analyzed using FESEM and EDS. FTIR and XRD were employed to examine the functional groups and crystal structure within the fibers. The electret effect and filtration performance of the fiber membrane were investigated using an electrostatic tester and a particulate filtration efficiency tester. The results demonstrated that inducing fiber formation under high-humidity conditions could produce fibers with a 3D curly structure. The fiber membrane was highly fluffy, significantly reducing the pressure drop. Introducing an appropriate amount of titanium dioxide markedly improved the electrostatic effect of the fiber membrane, enhancing the filtration performance of the 3D curly PVDF/TiO2 composite fiber membrane. With a 0.5% addition of TiO2 nanoparticles, the filtration efficiency of the fiber membrane reached approximately 99.197%, with a pressure drop of about 49.83 Pa. This study offers a new approach to developing efficient, low-resistance air filtration materials, showcasing the potential of material innovation in addressing air quality challenges within the sustainable development framework.

Advancing rehabilitation: Knittable fiber-shaped sensors for monitoring rotator cuff injury recovery

The integration of sensors into clothes offers significant convenience for monitoring the rehabilitation of patients. However, conventional flat sensors face challenges in achieving seamless integration due to their incompatibility with clothing. Here, we created a knittable fiber-shaped capacitive pressure sensor designed for long-term monitoring of shoulder movements of patients with rotator cuff injuries. This innovative sensor incorporates copper wires and silver conductive fibers as electrodes, with a polyvinylidene fluoride (PVDF) composite fiber membrane containing zeolite imidazolate framework (ZIF-8) particles as the dielectric layer. The resultant sensor can be seamlessly while non-invasively incorporated into the garment of patents due to its exceptionally flexibility. After optimizing the number of Cu wires (4) and electrospinning time of PVDF (8 min), the knittable sensor showed a sensitivity of 0.04 kPa−1 in the range of 2–8 kPa, 10 times higher than that without ZIF-8 (0.003 kPa−1). Beyond its applications in monitoring shoulder movement across various directions and degrees, this sensor has proven its ability in monitoring breath or recording weight when encompassed into a mask or a carpet, respectively. Via integrated in daily wearings, this sensor holds immense potential in the fields of rehabilitation monitoring and personal health management due to its remarkable sensitivity and flexibility.

Stabilized superhydrophobic composite membranes prepared by electrospinning for oil–water separation

AbstractIn dealing with the oil–water separation process, improving the oil–water selectivity of the membrane surface and increasing the porosity within the membrane are effective means to achieve durable and efficient oil–water separation. Therefore, polystyrene/polyacrylonitrile‐polyvinylidene fluoride/Polydimethylsiloxane Fe3O4 nanoparticles (PS/PAN‐PVDF/PDMS@Fe3O4) composite membranes with superhydrophobicity and lipophilicity were prepared by electrospinning technique. By controlling the filling concentration of Fe3O4 nanoparticles, a stable superhydrophobic and lipophilic rough structure was constructed, and micro–nano multilayer rough voids existed inside the membrane. The results showed that the composite fiber membrane exhibited exceptional superhydrophobicity (156.2°), thermal stability (338°C), mechanical properties (tensile strength of 3.0 MPa, elongation of 33.9%), and oil adsorption capacity (30–100 g/g). Moreover, even under corrosive environments, this composite fiber membrane maintained its superhydrophobic properties (above 152°) and achieved high oil–water separation efficiency (above 97%). Remarkably, after 40 cycles, the composite membrane could sustain a separation flux of 5000 L m−2 h−1. Consequently, the composite fiber membrane manufactured using this strategy exhibits promising potential for applications in oil–water separation.

Activated carbon-decorated electrospun polystyrene fibers for highly efficient removal of hazardous crystal violet dye from water

This study focuses on the synthesis of activated carbon (AC) from pomegranate peels biowaste and successful incorporation into polystyrene fibers (PSFs) by electrospinning process, yielding composite electrospun fiber membrane known as AC-PSFs. To gain insights into the characteristics of the fabricated electrospun fiber composite, a comprehensive characterization was conducted. To verify the role of AC in enhancing adsorption performance of PSFs to remove cationic crystal violet dye (CV) from aqueous solutions, batch adsorption technique was used. Notably, the AC-PSFs composite, containing 10% of AC, exhibited 465% high adsorption capacity compared to neat PSFs. The maximum Langmuir adsorption capacities obtained for CV dye was 65.14, 67.16 and 71.28 mg/g for PSFs and 388, 394.61 and 402.78 mg/g for AC-PSFs, at a temperature of 298, 303, and 308 K, respectively. The adsorption of CV dye onto PSFs and AC-PSFs closely followed the Langmuir isotherm model, while the kinetic adsorption fitted well with PSO model. AC-PSFs is a highly reusable adsorbent, retaining a 99% removal efficiency after using it for ten consecutive cycles, exemplifying its significant potential for long-term applications. Furthermore, the fabricated AC-PSFs composite offers the advantages of facile fabrication, excellent reusability, and easy handle, thereby establishing itself as a promising adsorbent for the efficient removal of cationic dyes from polluted water.