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Charcoal based graphene oxide-copper oxide (GO-CuO) nanohybrids were successfully synthesized via the co-precipitation method. It was then used to improve polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane properties and performance. The PVDF/GO-CuO UF nanocomposite membranes containing different contents of the synthesized GO-CuO nanohybrids were prepared via the phase inversion method. It was found that hydrophilicity of PVDF membrane containing 0.2 wt% of the synthesized GO-CuO nanohybrids increases than the neat PVDF membrane, so that its water contact angle (WCA) decreases from 80.68 ± 1.23° for the neat PVDF membrane to 60.53 ± 5.25° for the modified membrane containing 0.2 wt% of the synthesized GO-CuO nanohybrids. On the other hand, compared to the neat PVDF membrane, pure water flux (PWF) of this modified nanocomposite membrane increases by about 77% (from 101.1 ± 1.82 to 178.87 ± 1.47 LMH) and exhibits 94.28 ± 0.93% rejection of bovine serum albumin (BSA). This improvement is due to increased hydrophilicity, porosity, average membrane pore size, and decreased membrane surface roughness. The results of fouling measurements showed 42%, 60%, and 8% reduction in total fouling ratio (R t), irreversible fouling ratio (R ir), and reversible fouling ratio (R r), respectively. This indicated that antifouling properties of the modified membrane is significantly improved. It was found that the fabricated PVDF/GO-CuO nanocomposite membrane exhibits better performance than the neat PVDF membrane. Also, the results showed that this membrane also exhibits better properties and performance than the PVDF/GO and PVDF/CuO nanocomposite membranes. Therefore, it can be concluded that the fabricated PVDF/GO-CuO nanocomposite membrane has excellent potential for water and wastewater treatment applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigated the effects of different braid materials (polyethylene terephthalate, nylon 6, and their hybrid), weaving frequencies of the braids (7, 9, 11, 13 Hz), and concentrations of polyether sulfone solution (15% and 18 wt%) on braid angles, braid thickness, and bursting resistance. The results showed that for all types of single and hybrid braids, the braid angle decreases with increasing spinning frequency. When spinning frequency was increased from 7 to 13 Hz, the average wall thickness of polyethylene terephthalate, nylon 6, and the hybrid braids increased by approximately 50%, 65%, and 60%, respectively. The bursting pressure results were obtained in the range of 9.3 to 20.2 bars. The Fourier transform infrared spectroscopy results revealed no chemical bond between the braids and the polyether sulfone layer. Optical and electron microscope analyses revealed formation of uniform thickness of the polyether sulfone layers on the surface of the braids, as well as the penetration of polyether sulfone into the gaps between the filaments. The analyses also showed macroscopic adhesion of polyether sulfone to the braids and provided information on the amount and size of the pores in the polymer layers. The results showed that the selection of appropriate weaving frequency, braid materials, and polyether sulfone layer concentration are important as controllable parameters for producing polymeric hollow fiber composites with excellent burst pressure resistance. [ABSTRACT FROM AUTHOR]

• Real industrial mixtures of 12 components were separated by PV using MSE membranes. • Aromatics were recovered from their mixture with alicyclics/aliphatics/alcohols. • Methanol contamination negatively affects aromatic recovery via coupling effect. • Membrane plasticization by aromatics is intensified by methanol contamination. • Benzene has stronger coupling effects on n-hexane/cyclohexane compared to toluene. The pervaporation separation of aromatics from real industrial multicomponent mixtures containing 12 aromatic/alicyclic/aliphatic/alcoholic compounds was investigated using MSE polymer membranes. The effects of operating parameters including temperature, flow rate, permeate pressure, total aromatic content, and methanol contamination on PV performance were investigated. The behavior of the membrane in terms of swelling, plasticization and coupling effect in contact with real industrial multicomponent feed was evaluated and the work was completed by finding how the operating parameters influence the mass transfer mechanisms, component activity, dominant and limiting transfer phenomena, and coupling effect. The results showed that methanol contamination weakened the positive influences of increasing temperature and reducing permeate pressure. The coupling effects between benzene/toluene as fast-permeating components on n-hexane/cyclohexane as slow-permeating components in the presence of methanol were investigated. The results revealed that benzene has a stronger kinetic coupling effect on n-hexane and cyclohexane than toluene has. Furthermore, the coupling effect is more effective on n-hexane than cyclohexane. The results also showed that the presence of a second fast-permeating component (methanol) typically enhances the permeation of slow-permeating species. In general, the coupling effect had a negative effect on the PV performance in this work which favors the aromatic recovery. [ABSTRACT FROM AUTHOR]

In emergency treatment research, the focus on chitosan-based products for wound healing has been consistent. This study specifically explores a dressing made by mixing chitosan (CS) and poly (vinyl alcohol) PVA. Using electrospinning technology, nanofiber membranes of CS and PVA are created with the assistance of non-toxic and hydrophilic polyethylene oxide (PEO). The outcome is a new nanofibrous membrane loaded with mupirocin, designed for healing burn wounds. The study delves into the influence of PVA, CS, and PEO concentrations on the structural and chemical characteristics of the mats. This comprehensive exploration involves techniques such as Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM) imaging, Fourier Transform Infrared Spectrometry (FTIR analysis), and Contact angle measurements. Additionally, the research evaluates the antibacterial performance and biomedical behavior of the developed scaffolds. PEO proves beneficial in the electrospinning process, contributing to smoother fibers. Meanwhile, the addition of CS and mupirocin leads to formation of the thinner nanofibers (251 ± 5 μm and 263 ± 4 μm, respectively) and scaffolds with higher swelling (up to ∼3.5 times at 90 min). Notably, the (MTT) assay confirms the non-cytotoxicity of the fabricated nanofibers, with proliferations exceeding ∼85% for all samples. The crosslinked samples released the drug more slowly than the non-crosslinked dressings, with 80% of the scaffolds releasing the drug within 24 h. The in-vivo investigations suggested that the drug-containing scaffolds performed reliably and showed promise as a medical dressing for treating burn wounds. • Mupirocin was incorporated into the nanofibers made from the blending of PEO, PVA, and CS. • This exploration involves techniques such as SEM, AFM imaging, FTIR analysis, and Contact angle measurements. • The developed nanofiber membranes exhibited no cytotoxicity. • The drug loaded nanofibers showed excellent antibacterial and wound healing behaviors. [ABSTRACT FROM AUTHOR]

An infected skin wound caused by external injury remains a serious challenge. Electrospun drug-loaded nanofibers with antibacterial properties based on biopolymers have been widely explored for wound healing. In this study, the double-layer CS/PVA/mupirocin (CPM) + CS/PVA/bupivacaine (CPB) mats were prepared by electrospinning method (20 % polymer weight) and then crosslinked with glutaraldehyde (GA) to optimize the water-resistant and biodegradation properties for wound dressing applications. The morphology of mats was characterized as defect-free and interconnected nanofibers by Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Fourier Transform Infrared Spectrometry (FTIR) analysis also assessed the chemical structural properties. The porosity, surface wettability, and swelling degree of the dual-drug loaded mats were improved by about 20 %, 12°, and 200 % of the CS/PVA sample to provide a moist environment for efficient wound breathing and repairing. This highly porous mat facilitated the wound exudates absorption and air permeability excellently, reducing the chance of bacterial infections by inhibiting the growth of S. aureus bacterial colonies with a zone of 71.3 mm diameter. In vitro drug release results showed a high-burst release of 80 % and a continuous release profile for bupivacaine and mupirocin, respectively. MTT assay and in vivo tests indicated >90 % of cell viability and improvement in cell proliferation. It triply accelerated wound closure compared to the control group, reaching nearly full closure after 21 days as a potential clinical wound treatment. [Display omitted] • Drug release of the antibiotic/anesthetic-loaded CS/PVA bilayer nanofiber mats was tuned. • The composition, morphology, and thermal stability of each layer were characterized. • CS/PVA/bupivacaine (CPB) instantly alleviated pain with antibacterial activity. • CS/PVA/mupirocin (CPM) provided antibiotic activity in cell proliferation. • Promising results were obtained using the optimum sample for skin wound repair. [ABSTRACT FROM AUTHOR]

Polymeric membranes have been commercially used in wastewater treatment and desalination. Polymeric membranes efficiency decreases with time due to fouling, thermal and mechanical instability, chemical degradation and also swelling phenomenon occurrence. Among polymers, sulfone-based polymers have been research interest of membrane manufacturers. However, their intrinsic hydrophobic nature causes fouling under aqueous filtration. Polymer nanocomposite membranes (PNMs) with improved properties and performance than polymeric membranes have attracted much attention all over the world. Size and type of nanofillers, degree of aggregation/dispersion, nanofillers quantity incorporated into the polymeric matrices and compatibility between polymers and nanofillers are the main factors that can considerably affect the PNMs performance and properties. Carbon nanotubes (CNTs) with unique physicochemical properties could be used to improve the PNMs performances in terms of permeability and antifouling properties. Also, it has been reported that by incorporation of CNTs in the polymer matrices, hydrophilicity/hydrophobicity, pore size, porosity, mechanical and thermal stability, surface charge, solute rejection, roughness and other physicochemical properties of the PNMs could be improved, significantly. Effective CNTs functionalization could lead to the improved PNMs characteristics. This article presents an overview of current progresses in fabrication and characterization of CNTs-based PNMs used in various membrane separation processes for water treatment applications with particular emphasis on their challenges and advances. Also, effects of CNTs and their functionalization on structure, performance and properties of the CNTs-based PNMs are deeply investigated. [ABSTRACT FROM AUTHOR]

Herein, hybrid adsorptive nanofiltration (NF) hollow fiber (HF) membranes with the charge-patterned structure were fabricated and characterized for enhanced boron removal application. Mg–Al layer double hydroxide (LDH) and bentonite nanoparticles (NPs) were used as adsorbents in the support layer, while pristine and novel amine modified UiO-66 metal-organic frameworks (MOFs) were used to synthesize thin-film nanocomposite polyamide (PA) selective layer. UiO-66 was modified using triethylamine (TEA) and polyethylene imine (PEI) and the modification was approved through FTIR, DLS, and FESEM analyses. Prior to the performance evaluation of the fabricated membranes, the feasibility of boron removal by PA, and pristine and modified UiO-66 was investigated using molecular dynamics (MD) simulation and the diffusion coefficients were estimated. The structure of the fabricated thin film composite (TFC) and thin film nanocomposite (TFN) membranes were characterized by AFM, zeta potential and FESEM analyses showing agglomeration of the MOFs at 0.1 wt%. Membrane performance in boron removal was evaluated through brackish water condition at 4 bar in neutral and alkaline pH. The results showed that the contribution of the adsorptive support is 8 and 4% for the supports containing LDH and bentonite, respectively. Boron removal of the UiO-66 TFN membrane was achieved up to 58%, while the charge-patterned UiO-66/PEI TFN membrane was able to remove boron up to 87 and 91% at neutral and alkaline pH conditions. [Display omitted] • Hollow fiber membranes with charge-patterned UiO-66 incorporated thin-film nanocomposite selective layer were fabricated. • Pristine and modified UiO-66 nanoparticles incorporation in selective layer was able to increase boron removal efficiency. • The fabricated membranes were able to provide 87% and 91% boron removal at neutral and alkaline pH, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antifouling hollow fiber membranes with inner-selective layer were synthesized via facile fabrication method. • High water flux and low reverse salt flux were obtained through OMBR application where wastewater was used as feed flow. • Hollow fiber membranes consisted of antimicrobial outer skin layer and porous medium for enhance wastewater treatment. • Specific performance index (SPI), as a new concept was introduced which is believed to have the potential to be used as a unique FO membrane characteristic. Forward osmosis (FO) hollow-fiber membranes were prepared by in situ thin layer assembly of polyethyleneimine (PEI) on antifouling PES-based porous nanocomposite membranes during membrane formation by spinning and phase inversion, via incorporation of surface-modified silver nanoparticles (NPs) in the dope solution and addition of PEI in the bore liquid; after cross-linking with glutaraldehyde the FO selective layer was obtained at the lumen surface while the shell surface had ultrafilter (UF) properties. This design enabled the utilization of the FO membranes in active layer facing draw solution (DS) orientation to employ maximum effective osmotic pressure, while the UF layer in combination with the antibacterial NPs was supposed to reduce fouling by the wastewater used as feed solution (FS). The quality of the active layer assembly was characterized using atomic force microscopy and scanning electron microscopy analyses, as well as salt rejection, structural parameter (S), and molecular weight cut-off (MWCO) measurements. The separation performance of these membranes was evaluated in an osmotic membrane bioreactor (OMBR) system, showing for the best FO nanocomposite membranes less than 10% fouling and flux reduction over 5 cycles of operation over a total period of 5 days. The best-suited membrane showed promising separation performance in the OMBR system by providing 43.4 LMH water flux and only around 0.2 g/l specific reverse salt flux (SRSF) with 1 M NaCl and DI water serving as DS and feed, respectively. This study focused also on distinctive performance criteria in combined FO and OMBR systems, such as the membrane's potential in a pretreatment step of brine streams (used as DS) to provide proper feed composition for RO units and introduced a new specific performance index (SPI) for better characterization of FO membranes which summarizes all essential characteristics of the membrane application, instead of using existing structural parameter equations for membrane characterization. The best-suited FO membrane offered an SPI of 778.2 gl−1 m−2 h−1, meaning 778.2 g/l reduction of TDS in DS per unit membrane surface area per hour. [ABSTRACT FROM AUTHOR]

This study focused on removal of boron from water via hybrid nanofiltration (NF) thin film composite (TFC) hollow fiber (HF) membranes. To do so, nanocomposite polyvinyl chloride (PVC) HF membranes containing bentonite and layered double hydroxide (LDH) nanoparticles as natural and synthetic adsorbents were fabricated as the adsorptive support layers with high efficiency in boron removal. The phase inversion behavior of dope solutions and mechanical strength of the adsorptive nanocomposite PVC HF membranes were investigated and the results showed that LDH interacts better with PVC polymeric chains than bentonite. It was found that LDH with smaller pores and better adsorption capability in comparison with bentonite results in more hydrophilic membranes with better performance. On the other hand, bentonite tends to become agglomerated at above 1.5 wt%. Moreover, the fabricated membranes containing LDH have lower MWCO and more uniform pore size distribution which make them better options as support for the TFC layer formation to fabricate NF TFC membranes. The selective TFC layer was then fabricated via interfacial polymerization of m-phenylenediamine (MPD) and 1,3,5- benzenetricarbonyl trichloride (TMC) on the outer layer of the nanocomposite PVC HF membranes. Boron removal, and recovery and reusability of the fabricated NF TFC membranes were investigated by Na₂CO₃ solution. It was found that the NF TFC membranes containing LDH with boron removal of more than 83.6% and water flux of 16.1 L/m2.h at 4 bar operational pressure exhibit better performance than the NF TFC membranes containing bentonite. [Display omitted] • Nanofiltration (NF) hollow fiber membranes with adsorptive support layer were fabricated. • The fabricated NF membranes were used for boron removal from water. • Natural bentonite and LDH nanoclays were used as adsorbents in support layer. • Boron removal and adsorption recovery of the fabricated membranes were studied in five cycles. • Over 83% boron removal was achieved by the fabricated adsorptive NF membranes. [ABSTRACT FROM AUTHOR]

In this work, charcoal based nanomaterial (charcoal-NM) with two-dimensional structure, high oxygen and nitrogen content (functional groups) and excellent colloidal dispersion property was synthesized and used to prepare ultrafiltration polyethersulfone (PES) mixed-matrix membranes (MMMs), via phase-inversion method. The charcoal-NM can be dispersed in water and organic solvents without sonication and its colloidal dispersion shows high stability for a long time. The influences of the charcoal-NM on morphology, antifouling behavior, pure water flux (PWF) and hydrophilicity of the fabricated MMMs were studied, and the optimum membrane was selected. Antifouling investigations were done by Bovine serum albumin (BSA) as fouling agent. It was found that incorporation of the charcoal-NM into the PES matrix causes formation of channels with vertical alignment in the membrane structure and enhancing the membrane hydrophilicity and therefore leads to improved flux recovery ratio (FRR), PWF and antifouling properties of the MMMs. The fabricated MMM with 0.6 wt% charcoal-NM was selected as the optimal membrane (with PWF of 410.16 LMH, FRR of 95.43% and BSA rejection of 95.89%). This work showed that the charcoal-NM with low cost and excellent dispersion property can be used as an effective nanofiller for MMMs preparation for environmental applications. [Display omitted] • Charcoal based nanomaterial (charcoal-NM) was synthesized and used as nanofiller. • Charcoal-NM with abundant O and N containing functional groups showed high hydrophilicity. • Charcoal-NM could be dispersed in solvent easily without sonication and modification. • Ultrafiltration polyethersulfone/charcoal-NM MMMs was fabricated, successfully. • The fabricated membranes exhibited enhanced water flux and antifouling properties. [ABSTRACT FROM AUTHOR]

Amino group grafted halloysite nanotubes (Hal-NH 2 s) were used to enhance adsorption/filtration performance of chitosan (CS)/poly (vinyl alcohol) (PVA) electrospun nanofibers by coating on the polymeric membrane as well as embedding them into the polymer solution. The novel cactus-like nanofibers exerted considerably higher Cd(II) and Pb(II) adsorption capacity than other functionalized materials. The compositional changes of functionalized Hals were verified by Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD). Morphology of Hal-NH 2 loaded nanofibers was characterized as well as thermal/mechanical properties. Impacts of potentially affecting parameters including Hal-NH 2 loading, pH, temperature, contact time, and initial concentration of heavy metal ions were optimized in the adsorption process. According to the well-fitted Langmuir model, the maximum adsorption capacity of Cd(II) and Pb(II) ions at 120 min were measured to be 454.5 and 476.2 mg/g for the Hal-NH 2 entrapped nanofibers, while for the Hal-NH 2 coated nanofibers, higher values of 516.3 and 551.6 mg/g were measured, respectively. Kinetics of the adsorption process was also studied, indicating that a pseudo-second-order model was fitted on the experimental data. In contrast to the Hal-NH 2 coated nanofibers, the Hal-NH 2 entrapped nanofibers were considered stable, and their adsorption capacity remained almost intact after five adsorption/desorption cycles. These affinity membranes revealed promising Cd(II) and Pb(II) ions removal, and uniform permeation flux, indicating their ability to be the next generation of adsorptive filters. [Display omitted] • Novel electrospun chitosan/PVA-aminated Hal adsorptive membranes were fabricated. • Adding aminated Hal improved thermal and mechanical properties of chitosan/PVA. • Pb(II) and Cd(II) adsorption were enhanced about twice compared to chitosan/PVA ENMs. • Nanocomposite membrane containing 7wt% aminated Hal exhibited the best performance. • ENMs offered enhanced ion metal removal (up to 90%) with high flux performance. [ABSTRACT FROM AUTHOR]

Rational manipulation of the thin film composite (TFC) membranes properties and their surface structures are important to optimize forward osmosis (FO) performance. In this study, a facile approach is proposed for fabricating a hydrophilic and high-flux TFC membrane. Through this strategy, dopamine (DA) was mixed into m -phenylenediamine (MPD) as an aqueous solution followed by interfacial polymerization (IP) reaction with trimesoyl chloride (TMC) on a fabricated polyvinyl chloride (PVC) substrate. For the first time, the simultaneous effects of the DA concentration and the co-deposition time on the membrane morphology and FO properties were systematically investigated to explore the optimum condition. After evaluating the as-prepared membranes, the membranes with the DA concentration of 0.1 g/L and 120 min co-deposition time of PDA and MPD showed high water flux (24.40 L/m2.h) and acceptable reverse salt flux (RSF) compared with the control membrane without DA incorporation (15.95 L/m2.h) using deionized (DI) water as the feed solution (FS) and 1 M NaCl as the draw solution (DS) in the FO mode. Moreover, the optimum membranes exhibited excellent performance in the seawater desalination test. This study demonstrated that incorporation of DA during the IP reaction can be an effective and facile strategy for tailoring the membrane structure and obtaining high-performance FO membranes with outstanding performance for desalination purposes. [Display omitted] • A novel high-flux DA incorporated TFC membrane was produced. • The simultaneous effects of DA concentration and co-deposition time of PDA and MPD were investigated. • DA concentration of 0.1 g/L and 120 min co-deposition time of PDA and MPD in the IP reaction were found as the optimum condition for the membrane synthesis. • The modified membrane showed higher water flux in comparison with the control membrane. • DA incorporated TFC membrane was found as a suitable candidate for desalination application. [ABSTRACT FROM AUTHOR]

In this work, metal-organic framework derived porous carbon (MOFDPC) nanoparticles (NPs) were synthesized and incorporated into cellulose acetate (CA) polymeric matrix to prepare biodegradable CA/MOFDPC adsorptive membranes via phase inversion method. Polyethylene glycol (PEG) was used as pore former agent. Performance of the prepared membranes was evaluated in methylene blue (MB) removal from aqueous solution via continuous adsorption experiments. The physicochemical properties of the fabricated membranes were characterized by contact angle measurement, SEM, FTIR, AFM, TGA and tensile strength analysis. At first, the effects of PEG concentration and MOFDPC NPs loading were investigated. It was found that the best performance is obtained for the prepared membrane containing 15 wt% PEG and 2 wt% of MOFDPC NPs as the optimal adsorptive membrane. Then, the effects of solution pH, initial MB concentration and operating pressure on the MB removal capability of the prepared optimal adsorptive membrane were investigated. Reusability of the optimal adsorptive membrane was studied via subsequent adsorption/desorption cycles. Its long-term behavior was also studied. The obtained results showed that the prepared biodegradable CA/MOFDPC adsorptive membrane with MB removal percentage of 98.2% and permeate flux of 76.03 LMH and excellent reusability and long-term behavior can be potentially utilized for wastewater treatment applications especially MB removal. [Display omitted] • CA/MOFDPC adsorptive membranes were prepared via phase inversion method. • Membrane performance was evaluated in MB removal from aqueous solution. • Membrane containing 2 wt% of MOFDPC NPs exhibited the best performance. • The MB removal percentage of 98.2% and permeate flux of 76.03 LMH were achieved. • Effects of solution pH, initial MB concentration and pressure were also investigated. [ABSTRACT FROM AUTHOR]

Biopolymer-based electrospun mats, mimicking the extracellular matrix, have been extensively explored in biomedical applications. This study compares Achillea millefolium (AM) and Viola (V) extracts for developing a biocompatible wound dressing. The extracts were incorporated into a Chitosan/polyvinyl alcohol (CS/PVA) matrix via electrospinning. Crosslinking with Carbonyldiimidazole (CDI) improved chemical stability, water resistance, and biodegradability. The resulting mats exhibited flawless interconnected nanofibers, confirming the presence of AM and Viola extracts as analyzed via FTIR. Significant differences were observed between these two herbal extracts, particularly in mechanical properties, with tensile strengths of 6.9 MPa for AM and 17.2 MPa for Viola. Viola extract demonstrated robust antibacterial properties, producing an 8.2 mm inhibition zone against Staphylococcus aureus , compared to AM's 30 %. The release of therapeutic agents indicated an initial rapid phase, followed by a controlled 72 h release at a consistent rate. Notably, Viola extract led to 80.9 % wound closure on the 10th day, surpassing AM extract at 63.7 %. In contrast, the control group achieved only 32.1 % closure. This comparative study underscores the distinct advantages of AM and Viola extracts in wound dressing applications. While AM presents specific strengths, Viola extract exhibits superior mechanical properties, antibacterial efficacy, and accelerated wound closure, suggesting its potential with significant clinical implications. [Display omitted] • Achillea millefolium (AM) and Viola (V) extracts were obtained. • CS/PVA/AM (CPAM) and CS/PVA/V (CPV) mats were fabricated by electrospinning. • Morphology and in-vitro behavior were studied after Carbonyldiimidazole crosslinking. • The mat's antibacterial activity was significantly improved by adding the Viola extract. • The optimized dressings showed favorable biocompatibility and wound regeneration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PAN/FCS-NaY TNAM was fabricated with a sandwich-like composite structure. • The PAN/FCS-NaY TNAM was studied for Cu(II) and Pb(II) dynamic adsorption. • The loaded zeolite increased the adsorption capacity of the nanofibrous membrane. • High ions removal (94%<) was achieved at the optimum feed concentration, pH, and time. • Dynamic metal ions adsorption was modeled using dynamic filtration prediction models. In this study, an innovative PAN/FCS-NaY TNAM was fabricated using an electrospinning technique for Cu(II) and Pb(II) removal from contaminated water. Top and bottom fibrous layers (M1) were fabricated using a combination of FCS and PAN blends. Middle layer (M2) was electrospun from pure PAN solution and loaded with NaY zeolite particles. The physicochemical properties of the material and fibrous samples were investigated through SEM, FTIR-ATR, DSC, AFM, DMTA analysis, and contact angle measurement. The effective parameters, including initial ions concentration, time, reusability, and pH on the dynamic adsorption performance of the prepared membrane and its stability in the aqueous medium for Cu(II) and Pb(II) ions removal were investigated at a pressure of 0.006 bar. Dynamic metal ions adsorption was modeled using dynamic filtration prediction models such as Thomas and Yoon-Nelson. The fabricated nanostructure fibrous membranes with the removal percentage of Cu(II) and Pb(II) ions (94.6% and 98.7%, respectively) under the optimal operating conditions (initial concentration: 50 ppm, time: 10 min, and pH: 4.6), high compatibility in modeling dynamic filtration (R2 > 0.99), high pure water flux (298 LMH), suitable reusability (four-cycle without significant reduction in adsorption) as well as long-term stability, can be as potential filters in water treatment applications. [ABSTRACT FROM AUTHOR]

Environmental protection and resource recovery require efficient separation of salts and heavy metal ions from wastewater. A new hollow fiber nanofiltration membrane (HFNM) with a highly positive charge was developed via Hyperbranched polyethyleneimine (HPEI) self-assembly and methyl iodide (MeI) quaternization on a polyethersulfone (PES) with carboxylic-PES (CPES) substrate. Effects of different layers on surface charge and roughness, wettability, and mechanical stability were evaluated. MgCl 2 and ZnCl 2 as representative of salts and heavy-metal ions, respectively, were used to investigate separating properties of the membranes in terms of feed temperature and concentrations, operating pressures, antifouling properties, and long-term stability. The relationship between salt/ions rejection and water flux, pore size, and surface positive charge degree was explained by comparing the structures and properties of the membranes. The 1 wt. % HPEI and 0.5 wt. % GA solutions for 30 min crosslinking at pH of 11 and then 5 wt. % MeI solution could lead to the formation of the optimum membrane. Based on high hydrophilicity, low surface roughness, Donnan exclusion, and steric hindrance, the membrane could effectively exhibit superb rejection rates of Zn2+ (99.8 %), and Mg2+ (98.6 %), while showing high flux values (24.47 and 33.54 L m − 2 h − 1). The high flux rate (around 25.41 L m − 2 h − 1) during 4 cycles of regeneration, and high ions rejection (>98 %) were retained even after an 8-hour consistent operation. The prepared membrane, with high durability and structural stability, can introduce an effective solution for water purification from divalent ions. [Display omitted] • An HPEI-assembled PES/CPES hollow fiber membrane was prepared as the first layer. • The second layer of methyl iodide was formed as high positive charge density. • This nano-filter exhibited high ion/salt retention and high permeability performance. • Rejection order of R(Zn2+) > R(Cd2+) > R(Cu2+) and R(Mg2+) > R(Cd2+) was achieved. • This double-positively-charged membrane showed long-term stability and good antifouling performance. [ABSTRACT FROM AUTHOR]

Membrane bioreactors (MBRs) as biotechnology-based wastewater treatment processes have recently attracted lots of attentions. However, membrane fouling/biofouling as a significant obstacle has prevented MBRs from being widely used. The phase inversion method was used to fabricate a novel MIL-101(Cr) (MCPs)/polyethersulfone (PES) composite membrane. Adding MCPs up to 0.4 wt% significantly improved the membrane surface hydrophilicity and increased the membrane porosity, pore size, and fouling/biofouling formation resistance. Pure water flux of the optimal composite membrane increased by about 198.61% compared to the neat one. It also showed the lowest total fouling ratio (Rt: 48.79%) and irreversible fouling ratio (Rir: 10.43%), and the highest flux recovery ratio (FRR: 89.54%) and protein rejection (99%). Its COD removal efficiency for acetate as synthesis wastewater was about 75%. Performance of the optimal composite membrane was also evaluated at varied mixed liquor suspended solids (MLSS) concentrations of 8000, 10,000, and 12,000 mg/L. Increasing MLSS concentration decreased permeation flux due to rising sludge viscosity and fouling/biofouling formation. The results gave useful insights into preparation of hydrophilic composite membranes through blending of MCPs and PES to treat organic wastewaters using the MBR applications. [ABSTRACT FROM AUTHOR]

In membrane bioreactor (MBR) application, there are considerably influencing factors on membrane performance over time making serious problems, including reduced permeation flux and rejection percentage as well as formed thick fouling/biofouling layer. This study provided a new preparation strategy to fabricate extraordinary superhydrophilic CuO/PVDF nanocomposite membranes with micro/nano hierarchical structure, using a wet micro-pattern casting knife with simultaneous bombardment of hydrophilic CuO nanoparticles/non-solvent solution via cold spray coating (s-NIPs method). When compared to the neat membrane, the main characteristics of the superhydrophilic membrane enhanced such as surface area (70%) and pure water flux (PWF) (400%). Protein rejection (PR) and chemical oxygen demand (COD) removal were also obtained as about 96.7% and 97.8% at constant mixed liquor suspended solids (MLSS = 6000 mg/l) in a submerged aerobic MBR, fed by the synthesized sodium acetate wastewater (compared to the neat case: 78% and 91%), respectively. Furthermore, its excellent antifouling/biofouling properties were proved via significantly less formation of biofilm and adherence of extracellular polymeric substances (EPSs) and soluble microbial products (SMPs) on the membrane surface. Low variation of sludge flux and COD removal by increasing MLSS from 6000 (348 LMH and 96.7%) to 12000 mg/L (200 LMH and 94.2%) proved the significant impact of the preparation method on the membrane performance. Stability of the F–CuO coated layer caused superhydrophilicity and antibacterial properties to be maintained under long-period. The obtained results demonstrated potential of the fast, facile, simple, and one-step preparation method without compromising the membrane separation ability, while simultaneously providing superhydrophilicity, antibacterial activity, and ultra-low fouling/biofouling formation. [Display omitted] • Superhydrophilic membrane was prepared with micro/nano hierarchical structure. • Stable layer of antibacterial CuO NPs was coated on membrane surface by cold spray deposition. • Implementation of hierarchical structure increased active surface area up to 70%. • Optimal membrane exhibited highest PWF with ultra-low fouling/biofouling formation. • FRR, COD removal, and protein rejection were increased up to 94, 98 and 97%. [ABSTRACT FROM AUTHOR]

The core of this study was fabrication of novel cellulose acetate/pluronic F-127 (CA/PF-127) composite membranes for forward osmosis (FO) applications. Performance and structure of the FO membranes under the influence of different applicator clearance gaps (ACGs) along with PF-127 wt.% contents were examined during the non-solvent phase separation (NIPS) method. Scanning electron microscopy, water contact angle, atomic force microscopy and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis were used to characterize the membrane properties. The best performance was attributed to the lower thickness and the higher porosity. The lower structural parameter, which reduces the internal concentration polarization (ICP), led to the highest water flux. The values of 10.58 (L/m2.h) and 0.39 (g/L) were obtained as water flux and specific reverse salt flux (SRSF) of the optimal FO membrane, which was synthesized by 20 wt.% of CA, 79.00 wt.% of N-methyl-2-pyrrolidone (NMP), 1.0 wt.% of PF-127 and 100 µm of ACG, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Negatively charged CPES/PES blend HF UF membranes were fabricated. • The UF flux increased 250% using CPES/PES blend, losing 8% rejection. • The UF membrane WCA reduced from 76° to 42°, using CPES/PES blend. • The UF membrane FRR improved from 59% to 86% using CPES/PES blend. • The best membrane was used as substrate for HPEI thin-film layer assembly to achieve NF membrane. • The NF rejection increased up to 95% from 81% for the NF membrane prepared with the neat PES substrate. In this work, carboxylic polyethersulfone (CPES) was synthesized through acetylation and oxidation of polyethersulfone (PES). The success rate of the reaction and the formation of CPES were analyzed by fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Negatively charged CPES/PES blend hollow fiber ultrafiltration (UF) membranes were fabricated via the wet-spinning method. Surface and structural properties of the membranes were characterized by scanning electron microscopy (SEM), water contact angle (WCA), and atomic force microscopy (AFM). significant improvement of the membranes' hydrophilicity due to the presence of the CPES was approved through the decrease of WCA from 76°(neat PES) to 42°. The permeability was increased up to about three times of the neat PES membrane, while the rejection was not affected that much and just decreased from 94% to 86%. Membrane's antifouling properties were significantly improved according to the flux recovery ratio (FRR) of more than 90%. The best-suited hollow fiber membrane was used as a substrate for hyperbranched polyethyleneimine (HPEI) thin-film layer assembly to achieve nanofiltration (NF) membrane. It was shown that the presence of the CPES improved the layer assembly of the HPEI and thus the M g C l 2 rejection in NF membranes. In this case, the salt rejection increased up to 95% for the best-suited membrane from 81% for the membrane with a neat PES substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Asymmetric nanofiltration PVC hollow fiber membranes were fabricated via dry-wet spinning technique. • Delayed demixing was achieved by addition of high molecular weigh PVP. • Volatile solvent evaporation resulted in dense selective layer. • The effect of fabrication parameters were investigated in order to introduce best-suited membrane. • The effect of DS concentration and temperature were studied by means of Flux and SRSF. PVC hollow fiber (HF) membrane for forward osmosis (FO) application as a potential candidate for water desalination was fabricated by altering the spinning conditions. High molecular weight polyvinylpyrrolidone (PVP) was used as a blending additive to control the phase inversion process by increasing viscosity leading to delayed demixing as observed on the ternary phase diagram and confirmed by the simulation results, and forming dense barrier layer structure by providing chain entanglements with the PVC matrix. PVP/PVC ratio of 5/100 was proved to offer suited membrane morphology and selective layer. Different air gap distances and bore fluid flow rates were investigated to achieve proper fabrication parameters. The prepared membranes presented high flux and salt rejection in nanofiltration (NF) and FO tests. The best-suited membrane demonstrated the structural parameter of 389 µm with a narrow pore size distribution and a molecular weight cut-off of 490 Da. In different draw solution (DS) concentrations, it was observed that the membranes perform well in all conditions. Considering the PVC-PVP chain entanglements and mobility and the possibility of PVP being washed away, the membranes' performance at different temperatures indicated that 25–45 °C would be the safe operating range for the fabricated membranes with stable values of 31.0–33.4 LMH and 0.17–0.18 (FO mode) and 33.0–33.4 LMH and 0.23–0.24 (PRO mode) for water flux and specific reverse salt flux. [ABSTRACT FROM AUTHOR]

In this research, a novel biodegradable cellulose acetate (CA)-based nanocomposite adsorbent filled with metal-organic framework-derived porous carbon (MOF-DPC) nanoparticles was fabricated through the phase inversion method for methylene blue (MB) removal from aqueous solution. The MOF-DPC nanoparticles were synthesized via one-step carbonization of MOF-5 at 1000 ​°C under an argon environment. The synthesized MOF-DPC nanoparticles were characterized by HR-TEM, SEM, BET, XRD, Raman, and FTIR analyses, while the fabricated CA/MOF-DPC adsorbent by FTIR and TGA analyses. The effects of various parameters such as MOF-DPC loading (0–2 ​wt%), solution pH (3–11), initial MB concentration (5–200 ​mg ​L−1), solution temperature (25–65 ​°C), and contact time (0–960 ​min) on decolorization behavior of the fabricated CA/MOF-DPC adsorbent were investigated. A high removal efficiency (87.72%) and an acceptable adsorption capacity (41.36 ​mg ​g−1) were achieved at the optimum conditions (2 ​wt% MOF-DPC loading, pH value of 11, MB concentration of 50 ​mg ​L−1, temperature of 65 ​°C and contact time of 6 ​h). The kinetic and equilibrium data were fitted well by the pseudo-second-order kinetic model (R 2 ​= ​0.9945) and the Freundlich adsorption isotherm model (R2 ​= ​0.9886), respectively. The thermodynamic investigations confirmed that the adsorption is endothermic and spontaneous at higher temperatures. This study has recommended the fabricated CA/MOF-DPC nanocomposite as a promising adsorbent for the treatment of wastewaters. [Display omitted] • MOF-DPC nanoparticles were synthesized via carbonization of MOF-5 at 1000 ​°C. • CA/MOF-DPC nanocomposite was synthesized for MB removal from aqueous solution. • Effects of adsorption parameters were studied and optimum conditions were determined. • Kinetic and equilibrium data were studied by various isotherm and kinetic models. • Adsorption capacity of 41.36 ​mg/g and removal efficiency of 82.72% were achieved. [ABSTRACT FROM AUTHOR]