Search

The water-entry process of solid and hollow hyperelastic spheres was numerically simulated using the arbitrary Lagrange--Euler method, based on the finite element analysis software LS-DYNA. The effect of the different initial velocities on the cavity evolution and deformation of the sphere in a range of low Froude (Fr) numbers was investigated. The evolution of the cavity, deformation of the hyperelastic sphere and parameters at the time of cavity closure were analysed. In addition, the difference in the water-entry process between solid and hollow spheres was given. The numerical results shows that the size of the cavity, fluctuation on the cavity profile, closure time and closure depth increased with Fr and that the closure time was proportional to Fr1/2 for both solid and hollow spheres. However, the relationship between the closure depth and Fr of the hollow sphere differed from that of the solid one. Within the investigated low Froude numbers, whether for the solid or hollow spheres, the deformation amplitude increased with the Froude number. However, the deformation period remained nearly the same for different conditions. Under the same physical and motion parameters, the hollow sphere exhibited larger deformations compared with the solid sphere. The deformation period for the hollow sphere was also longer than that for the solid one. [ABSTRACT FROM AUTHOR]

The electroelastomer cylindrical actuators, a typical representation of soft actuators, have recently aroused increasing interest owing to their advantages in flexibility, deformability, and spatial utilization rate. Proprioception is crucial for controlling and monitoring the shape and position of these actuators. However, most existing flexible sensors have a modulus mismatch with the actuation unit, hindering the free movement of these actuators. Herein, a low-modulus strain sensor based on laser-induced cellular graphitic flakes (CGF) onto the surface of hollow TPU fibers (HTF) is present. Through the electrostatic self-assembly technology, the flexible sensor features a unique hybrid sensing unit including soft HTF as substrate and rigid CGF as conductive path. As a result, the sensor simultaneously possesses desirable modulus (~0.155 MPa), a gauge factor of 220.3 (25% < ε < 50%), fast response/recovery behaviors (31/62 ms), and a low detection limit (0.1% strain). Integrating the sensor onto the electroelastomer cylindrical actuators enables precise measurement of deformation modes, directions, and quantity. As proof-of-concept demonstrations, a prototype soft robot with high-precision perception is successfully designed, achieving real-time detection of its deformations during the crawling process. Thus, the proposed scheme sheds new light on the development of intelligent soft robots. [ABSTRACT FROM AUTHOR]

This study examines the semi-analytical expression of a hollow cylindrical fiber membrane bioreactor catalyzed by an immobilized enzyme (lipase), focusing on the dynamic kinetic resolution (DKR) of racemic (R)- and (S)-ibuprofen ester through the homotopy perturbation method (HPM). This method effectively solves the coupled non-linear system of second-order ordinary differential equations (ODEs), incorporating the mass transfer associated with the DKR reaction rate. The DKR rate equations are computed utilizing both enantiomers, which represent the enzymatic hydrolysis of the substrate within the barrier's support matrix, where the racemization term is negligible. Additionally, the corresponding racemization of the unreacted substrate outside the membrane is considered, where the enzymatic hydrolysis term is negligible. The dimensionless steady-state solution for the dynamics of the mean integrated effectiveness factor (MIEF) related to convective hydrolysis-racemization phenomena quantifies the local effectiveness factor, which impacts the Thiele modulus and the bulk initial concentrations of a substance within the membrane layer. The Bodenstein number is a critical parameter that optimizes reaction conditions, enhances mixing efficiency, and mitigates mass transfer limitations. The normalized values from the sensitivity analysis are analyzed to identify the key parameters of the present system. The conversion efficiency and limitations of the proposed model utilizing HPM are presented. Our proposed solution compares the semi-analytical expression with the simulated numerical results of BVP-4c using the built-in solver in MATLAB R2023b software, demonstrating good agreement across all values of the reaction parameters. The agreement between semi-analytical and numerical computations demonstrates the validity of these approximation methods. The findings provide significant insights for enhancing membrane reactor design and improving the efficiency of industrial processes for racemic ibuprofen ester production. [ABSTRACT FROM AUTHOR]

Gelatin, a natural protein, is extensively used in the food, pharmaceutical, and cosmetics industries. However, purifying gelatin to meet the specific requirements of various industries remains a considerable challenge. Ceramic membrane separation technology, renowned for its high permeability, excellent anti-fouling properties, and long lifespan, has been widely applied in the food, biotechnology, and water purification industries. In this study, a sol-gel method was employed to fabricate a gradient multilayer TiO 2 -modified coating on the surface of an α-Al 2 O 3 porous ceramic membrane. The viscosity of the TiO 2 sols was adjusted by varying the concentrations of polyethylene glycol (PEG 2000) and aging times. The results indicated that coating the C-P5^5 composite membrane with a sol containing 5 wt% PEG, aged for different durations (2, 5, 10, 15, and 18 d), effectively reduced the weight-average molecular weight (M w) of the permeate from the feed solution of 52.4 kDa–11.9 kDa. However, the C-P10^5 composite membrane, with a 10 wt% PEG content and aged for the same durations, yielded a permeate gelatin M w of 13.6 kDa. The composite membrane with excellent anti-fouling and photocatalytic self-cleaning properties holds promise for innovative applications in gelatin purification and bio-separation processes. [Display omitted] [ABSTRACT FROM AUTHOR]

The Co-CoTe nanostructure assembled hollow fibers with highly efficient catalytic performance promote the development of high-performance ZAB. [Display omitted] • The theoretical evaluations on Co-CoTe heterostructure reveal its large work function difference and BIEF. • Co-CoTe heterostructures in tiny carbon nanotube assemble the Co-CoTe@HFS hollow fibers. • The Co-CoTe@HFS has good flexibility and superior oxygen catalytic properties. • The full ZAB with Co-CoTe@HFS cathode achieves high performance in diverse environments. The design of highly efficient catalysts to enhance the kinetics of oxygen reduction (OER) and oxygen evolution (ORR) reactions is the key issue for the development of high-performance Zn-air battery. In this work, we report the design of Co-CoTe heterostructured fibers as the bifunctional oxygen catalyst for Zn-air battery. Firstly, the theoretical analysis was carried out on Co-CoTe heterostructure. The large work function difference is favorable to construct strong interfacial built-in electric field (BIEF), and the low energy barrier endows high catalytic activities. Moreover, the in-situ grown carbon shell was designed to build "core–shell" Co-CoTe/C unit to realize its high performance. They assemble the Co-CoTe@HFS fiber with good self-supporting and flexible features. Taken the advantages of the strong BIEF, the "core–shell" basic unit, and the freestanding substrate, the Co-CoTe@HFS fiber achieves the good electrocatalytic properties and high reliability. The full Zn-air battery (ZAB) with the Co/CoTe@HFS air cathode achieves the high peak power density and cycling stability over long-term cycling. Therefore, this work provides a clue to design bifunctional oxygen catalysts for high-performance ZABs. [ABSTRACT FROM AUTHOR]

This paper describes the fabrication of ceramic Nb2O5 hollow fibers covered by a thin graphene oxide (GO) layer using the vacuum‐assisted dip‐coating process for the efficient photocatalysis degradation of methylene blue (MB) under UVC light irradiation. Pristine and GO‐coated Nb2O5 hollow fibers were evaluated for photocatalytic degradation at different initial dye concentrations and pH values. A photodegradation of 66.4% of the dye molecules was achieved using the pristine Nb2O5 hollow fibers at 57.4 ± 0.1 mg mL1, initial MB concentration of 10 mg L−1, and pH of 11. Under the same experimental conditions, the GO‐coated Nb2O5 hollow fibers degraded 100% of the MB molecules. Additionally, the GO‐coated Nb2O5 hollow fibers were successfully reused for four reaction cycles and exhibited suitable long‐term stability. Thus, the proposed ceramic Nb2O5 hollow fibers with a surface decorated by a GO layer presented suitable characteristics for use as a photocatalyst in MB degradation. [ABSTRACT FROM AUTHOR]

Introduction: Biological invasions may promote the onset of systemic inflammatory response syndrome in patients eligible for continuous renal replacement therapy (CRRT), leading to poor prognosis. Hence, we aimed to examine the inflammatory reactions in circulation using vitamin E‐coated polysulfone hollow fiber membrane (ViLIFE). Methods: Lipopolysaccharides were intravenously administered to pigs (2 μg/kg/30 min) to establish an acute inflammation model. Extracorporeal circulation was performed for 6 h in continuous venovenous hemodiafiltration mode using a hemofilter for CRRT filled with a polysulfone hollow fiber membrane or ViLIFE, and the differences in inflammatory reactions were evaluated. Results: The ViLIFE group exhibited low platelet and cytokine levels (p < 0.05 vs. sham‐CRRT group). Additionally, the ViLIFE group had lower lactate and high mobility group box 1 levels than the other groups. Conclusion: ViLIFE represents a promising CRRT modality that can inhibit the inflammatory response in circulation and inhibit further biological invasions. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A multifunctional hollow fibre was prepared by the modification of polyethersulfone (PES) with laccase (Lac) and phosphorus-doped graphitic carbon nitride (P-gC3N4) for the removal of ciprofloxacin and sulfamethoxazole. The properties and structure elucidation of the prepared membranes were evaluated using contact angle analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), correlative light electron microscopy (CLEM), atomic force microscopy (AFM), tensile strength, water-intake capacity, and pure water flux. The modified multifunctional hollow fibre membranes showed increased root mean square surface roughness from 50 nm for neat PES to 104 nm, which contributed to the significantly higher water flux of 90 L.m−2h−1 compared to 54 L.m−2h−1 for pristine PES. The hydrophilicity also improved after modification as the contact angle reduced from 72° ± 1.01° to 42° ± 2.26°. The modified hollow fibre membranes showed an enhanced removal of ciprofloxacin (77%) and sulfamethoxazole (80%). Moreover, antifouling properties towards bovine serum albumin were 89% for FRR, 7% for Rr, 9% for Rir and 17% for Rt. Regeneration studies showed that the multifunctional hollow fibre membrane obtained a high removal percentage of 79% towards sulfamethoxazole after five cycles. Hence, this work proposes a new system that can be successfully utilized in the treatment of emerging pharmaceutical pollutants in water. [ABSTRACT FROM AUTHOR]

Membrane processes are being considered for carbon dioxide capture from concentrated point sources. The processes often use hollow fiber membranes. Modules are formed by gathering fibers together in a bundle. The fibers may be supplied individually or in small groups (i.e. tows) for module fabrication. The use of tows can introduce nonuniform fiber packing due to the size and spacing of the tows. The potential for flow maldistribution and its detrimental effect on module performance is evaluated by solving the governing conservation equations. For the first time, the performance of a module formed from fiber tows is evaluated. Two performance metrics are reported: 1) recovery and 2) required area as a function of carbon dioxide removal. The effects of tow size and tow spacing are evaluated. The results indicate performance is better for smaller tows. Furthermore, lower packings, both intra- and inter-tow, are preferred. The concept of an equivalent planar bundle (EPB) for fiber tow modules is introduced to potentially reduce simulation time and costs. The simple procedure for creating the EPB is validated by comparing the performance metrics calculated using the EPB to the results obtained from full simulations. [ABSTRACT FROM AUTHOR]

The composition of biogas consists mainly of CH4 (~60%) and CO2 (40%). To be considered a clean fuel, CH4 concentration in biogas must be increased to over 95%. In this study, membranes which were stacked in a chamber were utilized to purify biogas by passing biogas over them. These membranes were composed of polyethersulfone hollow fiber substrate coated with a "selective layer" made of cellulose nanocrystals (CNC‐0–2 wt) in polyvinyl alcohol (PVA) and l‐arginine as a CO2 carrier. Of the different CNC concentrations in PVA‐LA, CNC1/PVA‐LA (1.0 wt% CNC in PVA‐LA) displayed the lowest water contact angle of 17° (corresponding to higher moisture absorbing ability). With further increase in CNC concentration, even though CNC1.5/PVA‐LA showed the higher crystallinity (66%), and water contact angle increased (20°); reducing the chances of facilitated transport of CO2 through it. Biogas separation experiments were conducted at 90% RH and different feed pressures (0.8–1 bar) for various CNC concentrations. Increasing the CNC concentration led to a thicker selective layer, enhancing the CO2 permeability and selectivity up to CNC1/PVA‐LA. However, with the further addition of CNC, both permeability and selectivity decreased. At 90% RH and 1 bar feed pressure, the CNC1/PVA‐LA setup demonstrated a CO2 permeability of 20,522 Barrer and a selectivity of 33, making it suitable for low‐pressure biogas storage systems with lower energy requirements. [ABSTRACT FROM AUTHOR]

Mamyshev oscillator (MO) represents a powerful mode‐locking technique to produce high energy and ultrashort pulses from a fiber system. However, it is challenging to achieve low repetition rates directly from an oscillator while fully exploiting the outstanding characteristics of MOs due to the constraint of large dispersion and high nonlinearity of conventional solid‐core fibers. Here, a new method of combining a low‐dispersion and low‐nonlinearity hollow‐core fiber (HCF) with the MO is proposed to overcome the problem, achieving a reduction in repetition rate from 20 to 1 MHz and realizing sub‐50 fs pulses. Furthermore, the HCF provides anomalous dispersion and offers chirp management in the 1 MHz MO, effectively improving the pulse energy from 381 nJ (20 MHz all‐normal‐dispersion MO) to 514 nJ. The influence of intracavity chirp management is investigated by numerical simulations. To the best of our knowledge, it is the first time of realizing high‐energy sub‐50 fs pulses at 1 MHz repetition rate directly from an oscillator. The maximum peak power of the output pulses is more than 100 times higher than the previously reported low‐repetition ultrafast fiber lasers. This high‐performance laser has good potential for applications such as high‐precision micromachining, high‐order nonlinear microscopy imaging, and femtosecond‐laser‐assisted chemical ionization mass spectroscopy. [ABSTRACT FROM AUTHOR]

Hemodialysis is crucial for patients with end‐stage renal disease, yet evaluating its operating parameters often requires complex mathematical models. To simplify this process, user‐friendly modules have been developed to accurately assess key parameters with minimal inputs, enabling users to track disease prognosis. These modules incorporate governing equations and allow straightforward analysis. Validation against experimental data from polymer membrane studies demonstrated that at a blood flow rate of 300 mL min−1, the model predicted a clearance of 262 mL min−1, showing 7% difference from the actual value of 281 mL min−1. At a dialysate flow of 400 mL min−1, the model's predicted clearance was 286.47 mL min−1, with only a 1% difference compared to previous model. The module also showed 40% higher clearance in counter‐current flow compared to co‐current, with a 47% difference at 400 mL min−1 dialysate flow. Increasing the hollow fibre length from 27 to 50 cm led to a 4% clearance increase. Additionally, increasing residual renal clearance by 0.5 mL min−1 doubled the standard Kt V−1 Kt/V, and similar effects were seen by increasing weekly hemodialysis sessions. The app allows simulations, plots, and comparisons with minimal inputs and can be integrated into MATLAB or other platforms, benefiting both patients and researchers in prognosis and treatment analysis. [ABSTRACT FROM AUTHOR]

The influence of the molecular weight and chemical structure of polyphenylene sulfone (PPSU) end groups on the formation of the porous structure of ultrafiltration (UF) hollow fiber membranes was investigated. Polymers with a molecular weight ranging from 67 to 81 kg/mol and with a hydroxyl-to-chlorine end group ratio ranging from 0.43 to 17.0 were synthesized. The excess of end groups was achieved during polymer synthesis by adding one of the following monomers: hydroxyl (excess DHBP) or chlorine (excess DCDPS). For the first time, it was found that the stability of PPSU solutions is determined not by the molecular weight of the polymer, but by the chemical structure of its end groups. The stability of polymer solutions increases with the increasing proportion of chlorine groups. The SEM method showed that with the increasing molar fraction of chlorine end groups in the polymer, a more open porous structure forms on the outer surface of the hollow fiber membranes derived from it. The maximum UF permeance of the hollow fiber membranes for water was achieved with the PPSU sample containing the highest chlorine end group content, amounting to 136 L/(m2·h·bar), with a high rejection of the model substance Blue Dextran (at 94.7%). This represents the best result currently reported among unmodified PPSU hollow fiber membranes. [ABSTRACT FROM AUTHOR]

Hollow fiber membrane humidifiers are used in mobile proton exchange membrane (PEM) fuel cell systems to humidify the supply air of the fuel cell and thereby to achieve a sufficient level of humidification of the PEM. A hollow fiber humidifier contains a large amount of hollow fiber membrane that transfers water from the moisture-laden exhaust gas of the fuel cell to the dry supply air along a concentration gradient. In this study, the effect of fiber placement on the water transfer inside hollow fiber bundles is investigated in detail using a validated CFD model of a membrane humidifier. To analyze the effects of fiber positioning, 80 simulations using humidifiers with different fiber numbers and placements are carried out and analyzed for two operating points. Two statistical metrics, the wrap-around discrepancy and a distance-based metric called MaxiMin, are used to assess the uniformity and space-filling properties of the fiber placements. Correlations of the uniformity of fiber placement and the water transfer inside hollow fiber bundles are then identified. Furthermore, it is demonstrated that both, the wrap-around discrepancy and the MaxiMin, can be used as optimization criterion for the fiber placement inside humidifiers to maximize water transfer rates. The optimization leads to an average improvement of 5 % in water transfer compared to a median random fiber distribution. [ABSTRACT FROM AUTHOR]

The article discusses the development of a method to improve the hemocompatibility of artificial lungs used in extracorporeal membrane oxygenation (ECMO) by endothelializing the hollow fiber membranes (HFMs) with endothelial cells (ECs). The study utilized a clickable coating on the HFMs for efficient binding of metabolically labeled ECs, resulting in improved endothelialization and reduced blood coagulation and platelet activation. The research highlights the potential of using glycoengineered ECs, including hiPSC-ECs, for patient-specific treatment options in improving the hemocompatibility of artificial lungs. [Extracted from the article]

Hollow fiber liquid-phase microextraction is commonly used in analytical chemistry, providing high clean-up and pre-concentration factors. However, a major issue with this method is the long extraction time. The objective of this project is to reduce the extraction time by inducing different types of fluid motion in the sample solution. Three methods were employed: agitation using a magnetic stir bar in the horizontal position (conventional method), utilization of an air pump, and agitation using a magnetic stir bar in the vertical position for the pre-concentration and determination of non-steroidal anti-inflammatory drugs (naproxen, ibuprofen, and mefenamic acid) in biological samples via high-performance liquid chromatography with ultraviolet absorbance detection. The results demonstrated a significant reduction in extraction time and limit of detection when the air pump was employed compared to the conventional method of stirring with a magnetic stir bar in the horizontal position. Moreover, the mentioned parameters were even lower when stirring solutions were accomplished using a vertically-positioned magnetic stir bar, surpassing the method utilizing the air pump for agitation. Furthermore, the relative standard deviations were also lower when a vertically-positioned magnetic stir bar was used compared to the conventional method with a horizontally-positioned magnetic stir bar, while those of the air pump-assisted agitation method fell between the values of the aforementioned methods. [ABSTRACT FROM AUTHOR]

The environmental and ecological concerns drive researchers to synthesize functional materials using components from natural resources. Nanocellulose (NC), derived from plants, marine animals, or microorganisms, is a green material attracting attention due to its abundance, biocompatibility, and biodegradability. NC’s interstice properties enable the synthesis of functional nanocomposites in forms like aerogels, foams, paper, sheets, or hollow filaments. This review briefly describes NC classification and production while comprehensively presenting its mechanical, rheological, optical, and electrical properties, offering foundational knowledge for future research. Additionally, it highlights recent developments in NC-based products across fields such as papermaking, water treatment, civil engineering, electronics, cosmetics, food, and medicine. For the first time, this paper explores recent advances in NC molecular simulation, providing insights into structure, arrangement, and interactions through molecular dynamic simulation. Finally, future prospects for NC-based applications are discussed to encourage studies addressing current challenges. [ABSTRACT FROM AUTHOR]

A novel and innovative method was developed to fabricate defect-free composite hollow fiber (HF) membranes using drop-casting under continuous flow. The synthesized Pebax-1657—based membranes were examined for gas separation processes, focusing on the separation of CO2 from CH4 and CO gases. The separation performance of the membranes was rigorously assessed under realistic binary gas mixture conditions to evaluate their selectivity and performance. The effect of pressure on separation performance was systematically investigated, with transmembrane pressures up to 10 bar being applied at a temperature of 298 K. Remarkable CO2/CH4 selectivities of up to 110 and CO2/CO selectivities of up to 48 were achieved, demonstrating the robustness and effectiveness of these composite HF membranes, suggesting their suitability for high-performance gas separation processes under varying operational conditions. Overall, this study introduces a novel approach for scaling up the fabrication of HF membranes and provides valuable insights into their application in CO2 separation technologies, offering the potential for advancements in areas such as natural gas processing and carbon capture from CO-containing streams. [ABSTRACT FROM AUTHOR]

In order to explore the preparation process and properties of hemp composite fiber membrane, hemp/polyacrylomtrile composite fiber membrane was prepared by electrospinning method. The electrospinning process was optimized with the ratio of cellulose solution, receiving distance, voltage and pushing speed as the indexes. The adsorption of methylene blue dye on the composite fiber membrane was optimized by single factor test. The results show that the best process for preparing hemp/polyacrylomtrile composite fiber membrane was as follows; cellulose solution ratio of 10%, receiving distance of 20 cm, spinning voltage of 20 kV and liquid pushing speed of 1.5 mL/h. The surface of the prepared fiber membrane was flat and the porosity was 80.8%. The breaking strength was (12.36 ± 2.31) cN, and the elongation at break was (23.65 ± 3.26) %. The optimum conditions for dye adsorption were heating temperature of 40 °C, methylene blue concentration of 20 mg/L, pH value of 9, heating time of 9 h, and the adsorption rate of dye was 93.3%. [ABSTRACT FROM AUTHOR]

Fibers from milkweed, which grows in Quebec (Canada), offer a distinct and outstanding advantage compared to other natural fibers: their ultra-lightweight hollow structure provides excellent acoustic and thermal insulation properties for the automobile industry. To highlight the properties of milkweed fibers and reduce the use of synthetic materials in vehicles, nonwoven carpeting made from a blend of milkweed fibers and polylactic acid (PLA) fibers was produced using the air-laid process. Some of the nonwovens were compressed to investigate the effects of increased mass per unit area on their thermal, acoustic, and mechanical properties. The nonwovens' mass per unit area, thermal insulation, sound absorption coefficient, airflow resistivity, compression, and resistance to moisture were evaluated and compared to other carpets made of natural and synthetic fibers. The findings indicate that milkweed and PLA carpets have lower thermal conductivity values of 37.45 (mW/m·K), (mW/m·K) less than carpets made from cotton and polypropylene. At low frequencies, none of the carpets absorbed sound. At high frequencies, milkweed and PLA carpets showed sound absorption values of at least 0.6, which provide better acoustic insulation than nonwoven materials made from jute and polyethylene (PE) fibers. Milkweed and PLA carpets exhibited better compression values than polypropylene (PP) carpets. [ABSTRACT FROM AUTHOR]

[Display omitted] For sodium-ion batteries, nickel telluride (NiTe 2) is an excellent anode material. However, significant volume changes and slow kinetics compromise its structural stability and its capacity for high-current reactions. To increase sodium storage performance, NiTe 2 nanoparticles are synthesized in situ within hollow porous carbon spheres (NiTe 2 @HPCS) through a "drop-dry" process, vacuum-assisted adsorption, and vapor tellurization. Then, a large number of NiTe 2 @HPCS particles are densely encapsulated in carbon fibers (CFs) via electrospinning and carbonization (NiTe 2 @HPCS/CF). In coin-type half cells, NiTe 2 @HPCS/CF exhibits a high and stable capacity of 432 mAh g−1 after 500 cycles at 1.0 A g−1. When half cells are operated at 5.0 and 10.0 A g−1, the lifespan reaches 1000 cycles and the capacities sustain at 332 and 195 mAh g−1. The cycled electrode materials preserve the intact composite structure, demonstrating remarkable robustness. Kinetic investigation affirms swift electron and Na+ conduction within NiTe 2 @HPCS/CF. Furthermore, in Na 3 V 2 (PO 4) 3 //NiTe 2 @HPCS/CF full cells, NiTe 2 @HPCS/CF also exhibits favorable cycling stability. At 1.0 and 5.0 A g−1 after 300 and 500 cycles, reversible capacities reach 299 and 172 mAh g−1, respectively. The outstanding performance is associated with the unique dual carbon encapsulation structure: HPCSs effectively confine NiTe 2 nanoparticles, maintaining their high electrochemical activity and promoting the sodiation/de-sodiation reactions. CFs further reinforce structural stability and electron conduction of NiTe 2. [ABSTRACT FROM AUTHOR]

Improperly managed solidwaste dumpsites are a potential time bomb as these can pose serious deleterious hazards to the neighbouring communities. This was the case in Maseru Lesotho one warm afternoon when the dumpsite caught fire with no clear human activity, producing dark smoke that covered the residential area around the site. The current study reports the use of simple passive samplers composed of polypropylene hollow fibre membranes impregnated with dodecane for screening of polycyclic aromatic hydrocarbons in this dumpsite fire smoke. The fibres were suspended at different sampling locations at the dumpsite and inside and outside the surrounding households and left there to sample for 6 hours after which 1-cm pieces were placed in headspace vials for desorption and further analysed by gas chromatography and mass spectrometry. The detected compounds were annotated using the NIST 2017 MS library comparison and the following compounds were found: acenaphthene, naphthalene, biphenylene, flourene, phenanthrene, flouranthene, benzoflouranthene, pyrene and clopentapyrene. Given there were no standards available, the compounds could not be quantified. Nonetheless, the results demonstrated the potential for a simple hollow-fibre liquidphase microextraction technique for use in the screening of PAHs in smoke. Most importantly, they reflect the importance of negative impact of the dumpsite smoke being so rich in these compounds that have been classified as carcinogens. [ABSTRACT FROM AUTHOR]

Cryopreservation enhances the availability of "off-the-shelf" cell therapies. However, the choice between tissue culture polystyrene (TCP) and hollow fiber system (HFB) system for adipose-derived stem cell (ASC) production remains a critical decision, with implications for scalability, reproducibility, and the clinical efficacy. Therefore, the characteristics of ASCs expanded in TCP and HFB and cryopreserved were compared. TCP and HFB cultures were established, and cells were cryopreserved. Surface markers were analyzed to identify immunophenotypic changes and subpopulations. Clonogenicity, differentiation capability, and proliferation potentials were determined along with surrogate tests on wound healing. The expressions of the most markers were consistent before and after thawing for both systems. However, CD105 expression of TCP cells was significantly decreased by the freeze-thawing procedure. Also, CD274 was significantly less expressed on HFB-expanded cells before freezing, however, post-thawing, the proportion of CD274 positive cells was comparable to TCP cells. Besides, two expansions supported different subpopulations, influencing the heterogeneity within ASC cultures. Despite this heterogeneity, no statistical differences were observed as for ASC functional characteristics and the effects on fibroblasts. This study highlighted freeze-thaw does not interfere with the production of fully functional ASCs in either system, although it drives some differential changes in the subpopulations between systems. [ABSTRACT FROM AUTHOR]

This study presents an innovative methane gas sensor design based on anti-resonant hollow-core fiber (AR-HCF) technology, optimized for high-precision detection at 3.3 . Our numerical analysis explores the geometric optimization of the AR-HCF's structural parameters, incorporating real-world component specifications. The proposed design features a 65 diameter hollow core surrounded by seven silica rings. We achieved significant improvements in confinement loss and optical power distribution through progressive structural modifications. The optimized structure demonstrated a confinement loss of and over 95% optical power confinement in the hollow core. Our model predicts a relative sensitivity of , a response time of 5.4 s, and a theoretical detection threshold of 2.24 ppm. The limit of detection (LoD) was estimated to be 3.8 ppbv, and the normalized noise equivalent absorption (NNEA) coefficient was . The sensor response exhibited excellent linearity over its operating range, with an R2 value of 0.9917 in the critical concentration range. These findings highlight the potential of our AR-HCF-based methane sensor design for real-time gas monitoring applications. [ABSTRACT FROM AUTHOR]

Recently, hollow fiber polyelectrolyte multilayer membranes (PEMMs) have shown great potential for removing organic micropollutants from wastewater streams. Currently, these PEMMs are made with the selective layer on the inside of the hollow fiber. However, to reduce the physical footprint of PEMM modules, it would be beneficial to have the selective layer on the outside. This will lead to an increased surface area per fiber and enable the use of smaller mechanically stronger fibers, which further increases the surface area per membrane module. To prove that the concept of an outer‐skinned PEMM is feasible, the dry‐jet wet‐spinning process is used to fabricate charged outer‐skinned hollow fiber supports, and they are coated through the layer‐by‐layer self‐assembly process to form a PEMM. Scanning electron microscopy images of the hollow fibers confirm the existence of an asymmetric structure with an outer skin, while fluorescence imaging confirms that the polyelectrolyte multilayer is located on the outside of the hollow fiber. Filtration experiments showed that the PEMMs exhibited nanofiltration properties similar to the conventional inner‐skinned PEMMs. Overall, these membranes show a 3.8x increase in active membrane surface area to volume ratio compared to commercial PEMMs, clearly highlighting the benefits in terms of footprint. [ABSTRACT FROM AUTHOR]

ABSTRACT Ready‐made or commercial hollow fiber (HF) membranes have limited performance for removing humic acid (HA) from water streams unless they undergo surface modification. Alternatively, a membrane can be tailor‐made specifically for HA removal by developing a new formulation and adjusting its fabrication parameters. In this study, to enhance the performance and antifouling properties of HF membranes, a hybrid membrane was developed by blending polyethersulfone (PES) with cellulose nanocrystals (CNC) and multiwalled carbon nanotubes (MWCNT). The effect of air gap length during the dry–wet spinning process was investigated, ranging from 3 cm to 12 cm, to regulate the properties of the hybrid membrane. The membranes were evaluated in terms of morphology (FESEM and AFM), porosity, and hydrophilicity (contact angle). Water flux, HA rejection, and flux recovery ratio (FRR) were also measured. The air gap length significantly influenced the fiber structure, with the finger‐like structure expanding from the outer surface to the center of the fiber as the air gap extended up to 9 cm. This increase in air gap length resulted in a significant reduction in porosity, decreasing from 75.59% to 43.45%, while simultaneously enhancing the contact angle from 78° to 89.60°. The membrane produced at a 9 cm air gap length exhibited the best performance, with a pure water flux of 15.83 LMH, HA rejection over 95%, and a high FRR of 98.78%. The synergistic effect of combining CNC with MWCNT and simply adjusting the air gap distance proves to be an effective approach for preparing custom‐made HF membranes for HA removal. [ABSTRACT FROM AUTHOR]

Copyright of Membrane Science & Technology (10078924) is the property of Membrane Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] • A novel non-radical-dominated MOF-derived PMS catalytic membrane was proposed. • The MOF-derived heterojunction structure facilitated an enhanced electron transfer mechanism. • The formation of the heterostructure and the efficient cycling of Ni2+/Co3+ contributed to a remarkable non-radical process. • The M−NNCO−THFM demonstrated broad pH adaptability, excellent stability in complex water matrices, and good reusability. Traditional peroxymonosulfate (PMS) catalytic membranes dominated by radical pathways often face interference from complex components in water bodies. Herein, we employed a controlled electro-deposition technique to coat a Ni-Co metal–organic framework (MOF) precursor onto titanium hollow fiber membrane (THFM), followed by high-temperature calcination to synthesize a MOF-derived NiO-NiCo 2 O 4 /THFM (M−NNCO−THFM) PMS catalytic membrane. Then, the M−NNCO−THFM filtration integrated with PMS activation (MFPA process) for water treatment. Experimental results demonstrated that the M−NNCO−THFM MFPA process successfully achieved complete phenol (PE) removal via a non-radical-dominated degradation pathway, involving singlet oxygen (1O 2) and electron transfer, while exhibiting wide pH adaptability and exceptional stability in complex water matrices. Mechanism analysis revealed that the electron transfer process was significantly enhanced by the MOF-derived heterojunction structure, which increased the flat-band potential from 0.39 eV to 0.56 eV, thereby facilitating efficient electron transfer for PE removal. The non-radical 1O 2 pathway was primarily due to the cycling of metal valence states (Ni2+/Co3+), leading to the reduction of Co2+ and its reaction with PMS, resulting in the generation of reactive species. Furthermore, electrochemical measurements indicated that the M−NNCO−THFM exhibited lower charge transfer resistance and enhanced charge transfer efficiency compared to non-MOF-derived NNCO-THFM, corresponding to the superior catalytic performance and electrochemically active surface area of M−NNCO−THFM. [ABSTRACT FROM AUTHOR]

Compared to the traditional open mixing process used for the production of the rubber composites, wet mixing process is a lower shear force mixing method. This article revealed the influence of the open mixing process and the wet mixing process on the microstructure, density, mechanical properties, and ablation performance of ethylene propylene diene monomer (EPDM) rubber/fiber/hollow glass microsphere composite system. The results showed that the wet mixing process increased the fiber length by more than 300% compared to the open mixing process, while the fragmentation rate of the hollow glass beads was reduced by 94.4%, these effectively maintained the structural integrity of the fibers and the hollow glass microsphere filler. By using the wet mixing process, the density of EPDM composite materials can be reduced by about 20%, and the tensile strength and ablation resistance of these composites were also significantly improved. Compared to polyimide fiber and aramid fiber short fibers, the wet mixing process of solution‐based rubber had a more significant effect on improving the length and ablation resistance of phenolic fiber and carbon fiber fibers which having poor shear strength. [ABSTRACT FROM AUTHOR]

With increasing water scarcity, high‐salt wastewater recovery is gaining more attention. To this end, high efficiency hollow‐fiber‐type loose nanofiltration (HF‐LNF) membranes have recently emerged. However, most conventional polymeric membranes are limited to the laboratory stage due to material‐specific complexities and low permeance. Herein, a straightforward synthesis strategy is presented for the lab‐scale kilogram production of poly(biphenyl‐trifluoroacetophenone) (PBT) polymer and a one‐step spinning process for the pilot‐scale (650 m length) PBT HF‐LNF membranes. Due to the slight hydrophobicity and high molecular weight of linear PBT polymer, as well as the addition of hydrophilic additives, the thermodynamic stability becomes lower, resulting in the formation of uniform 1 nm micropores. These micropores induce selective rejections for dye (>99.9%) and salt (<5%), thereby enabling effective dye/salt deep separation. The permeance is also enhanced greatly (97.3 L m−2 h−1 bar−1), approximately five times higher than most reported HF‐LNF membranes and commercial nanofiltration membranes. This upscaling strategy bridges lab research and industrial production, potentially advancing HF‐LNF technology. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate the coherent random laser emission by combining CdSe/ZnS colloidal quantum dots with hollow optical fiber. Through the localized surface plasmon resonance induced by Ag nanoparticles (NPs), well-distinguished discrete spikes are observed from the Ag modified hollow fiber loaded with CdSe/ZnS QDs solution. In addition, coherent random laser action with low threshold is also realized in the hollow optical fiber filled with high packing-density CdSe/ZnS QDs even if the Ag NPs is not introduced. The self-assembled clusters of CdSe/ZnS QDs serve as the optical gain media as well as the strong scattering centers. The angle measurement experiments show that the directional emission of random laser can be adjusted by using different pumping manners. This facile, inexpensive, low pump threshold random laser could be widely used in photonic devices and display imaging. [ABSTRACT FROM AUTHOR]

Permeance‐selectivity trade‐off and high temperature resilience are key challenges in development of membranes for post‐combustion carbon capture. While mixed matrix membranes (MMMs) consisting of polymers and metal–organic frameworks (MOFs) offer the potential to address the challenges, they are limited by the low loading of MOFs in the thin film layer. Herein, we propose an inverse synthesis strategy to form polymer‐MOF networks by copolymerizing monomers with functionalized UiO‐66 nanoparticles. This process yields a finely dispersed, easily processable solution, enabling defect‐free, thin polymer‐MOF coatings with up to 40 wt % MOF loading within the polyethylene oxide‐based polymers on polyacrylonitrile supports. The membrane with 40 wt % MOF demonstrated a 212 % increment in CO2 permeance at 25 °C and maintained a selectivity of 20 at 60 °C, which is attributed to the stable diffusivity selectivity of MOFs at high temperature. Furthermore, the membrane was evaluated with mixed gas and 83 % relative humidity (RH) at 60 °C, achieving a CO2 permeance up to 2793 GPU and a CO2/N2 selectivity of 21.6. This work offers insights into the design of practical mixed matrix membranes, which not only paves the way towards energy efficient carbon capture from flue gas, but also provides more possibilities for other applications. [ABSTRACT FROM AUTHOR]

Sustainable separation processes are crucial for industries like chemicals and pharmaceuticals and membrane technology stands out for its low energy consumption. However, membrane fabrication typically involves large amounts of solvents, which are facing tighter scrutiny due to environmental regulations. This work tackles the quest to replace toxic solvents and proposes thymol and its mixtures with other natural components as green solvents. Thymol, despite being solid at room temperature, forms homogeneous liquid solutions with a high-performance polyetherimide, exhibiting behavior analogous to deep eutectic mixtures observed for small molecules. Through spectroscopic, thermal, and rheological analyses, we elucidate the role of hydrogen bonding between carbonyl and hydroxyl groups in these solutions. We utilized the findings for membrane fabrication. Hollow fibers were spun in continuous machines using the green solvent dope solutions. These fibers coated with polyphenols were assessed for air dehumidification, showcasing the successful translation of fundamental investigation into membrane production and application. [ABSTRACT FROM AUTHOR]

ABSTRACT Dense polymeric hollow fiber membrane–based gas separation modules are becoming increasingly important in various industrial fields due to their higher efficiency compared to other gas separation processes. Modeling the membranes gas separation process and analyzing the governing mathematical equations such as the solution–diffusion model are crucial for optimizing module performance and making the process cost‐effective. Herein, we introduce an improved methodology for solving the mathematical model of polymeric hollow fiber gas separation membranes focusing on a simpler and more accurate solution strategy. Unlike previous solving methods, the model characteristic functions (feed flow, permeate flow, feed composition, permeate composition within the porous support layer, and bulk permeate composition) better adhere to boundary conditions at the module inlet and closed‐end. The improved solving algorithm provides a more accurate solution, with a maximum mean squared error of 7.3441 × 10−5 and minimum R2$$ {R}^2 $$ of 0.8853, outperforming previous complex methods. The corrected algorithm also features improved speed, completing calculations in under 0.015 s, faster than any reported values. The model's response to changes in geometric and operating conditions is evaluated through an extensive sensitivity test, which is conducted by statistical analysis and numerical solutions. Numerical solution approach allows for a wider range of possibilities of interactions compared to statistical analysis and enables inspection of a wider response surface. Additionally, the response equation is estimated for permeate purity, stagecut, and retentate purity, and the process is optimized for different goals. Performance of membrane gas separation is highly sensitive to the membrane sizing and feed concentration, as these factors significantly influence the separation driving force. Therefore, this study presents an improved solving strategy and a detailed description of the effect of various parameters on the model response, along with a comprehensive comparison to statistical analysis and process optimization possibilities. [ABSTRACT FROM AUTHOR]

• The countercurrent hollow fiber membrane module is proposed for cold water generation. • A 3-D numerical model is developed accounting for irregular fiber filling. • Channeling effect and flow dead zones degrade the heat and moisture transport. • Irregular fiber filling increases the air side heat transfer resistance by >158 %. • Irregular fiber filling offers the potential to improve energy efficiency under certain conditions. The countercurrent hollow fiber membrane-based evaporative water cooler (MEWC) offers an eco-friendly and compact solution for cold water generation. This study introduces a random sequential addition algorithm to model the real-world irregular fiber filling within the MEWC. Inspired by the honeycomb structure, the developed 3-D numerical model adopts a calculation unit featuring a hexagonal prism comprising multiple fibers. Validation against experimental data reveals an average relative error of 2.81 % concerning outlet water temperature. The effects of fiber filling patterns (regular layout and random layout) on the velocity and temperature fields of the MEWC are investigated. Comparisons of outlet water temperature, cooling efficiency, consumptive electric power ratio, and heat and mass transfer resistance composition between these layouts under various operating conditions are conducted. The results indicate that the random layout fosters severe channeling effect and large flow dead zones, impairing air side heat and moisture transfer. The random layout exhibits over 15.9 % reduction in cooling efficiency and 36.3 % decrease in consumptive electric power ratio compared to the regular layout. Irregular fiber filling leads to a notable 158.6 % increase in air side heat transfer resistance and a 35.9 % rise in mass transfer resistance. Although irregular filling compromises the cooling performance, it demonstrates potential for energy savings under certain conditions. Design schemes should be carefully tailored to meet specific application requirements by considering these trade-offs. [ABSTRACT FROM AUTHOR]

A novel and effective adsorbent based on magnetic polymeric ionic liquid nanocomposite-coated hollow fiber membrane (MPILNC-HFM) was developed and applied for magnetic solid phase extraction of Pb (II) and Cu (II) from environmental water and fruit juice samples with microinjection sampling-flame atomic absorption spectrometry (MIS-FAAS). During extraction process, the adsorbent coated on the surface of the hollow fiber can be removed from the solution using tweezers without using a magnet. Additionally, the need to use a centrifuge during adsorption and desorption steps is also eliminated, thereby increasing the speed, simplicity, and efficiency of the extraction process. The nanocomposite characterized through Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive x-ray (EDX) analyses to ensure its applicability. The experimental parameters were optimized by applying one-variable-at the-time (OVAT) approach. Under optimal conditions, limits of detection were achieved 16.5 µg L−1 for Pb (II) and 20.4 µg L−1 for Cu (II), respectively, with relative standard deviations up to 7.9% and relative recoveries in the range of 91.8%–02.2%. [ABSTRACT FROM AUTHOR]

Anion-doped perovskite membranes with a hollow fiber geometry have excellent oxygen separation performance. However, during the fabrication process of hollow fiber membranes, soaking the precursor in deionized water leads to elemental dissolution, especially anion dissolution. To prevent metal and anion element dissolution, an improved one-step thermal processing approach was proposed in which saturated solutions were used as internal and external coagulation baths, effectively controlling the stoichiometric ratio. Compared with using deionized water as internal and external coagulation baths, using a fluorine-containing saturated solution increased the oxygen flux of the membrane by 21% at 900 °C. The oxygen permeability of the fluorine-doped oxide membrane reached 6 mL cm−2 min−1 at 900 °C, with an oxygen flux exceeding 1 mL cm−2 min−1 at 700 °C, meeting commercial oxygen separation membrane standards. Anion doping and stability enhancement strategies could further advance the development and practical use of oxygen separation membranes. [ABSTRACT FROM AUTHOR]

This study explores the layer-by-layer (LBL) modification of polyacrylonitrile (PAN) hollow fibers for effective Mg2+/Li+ separation. It employs an LBL method of surface modification using polyelectrolytes, specifically aiming to enhance ion selectivity and improve the efficiency of lithium extraction from brines or lithium battery wastes, which is critical for battery recycling and other industrial applications. The modification process involves coating the hydrolyzed PAN fibers with alternating layers of positively charged polyelectrolytes, such as poly(allylamine hydrochloride) (PAH), polyethyleneimine (PEI), or poly(diallyldimethylammonium chloride) (PDADMAC) and negatively charged polyelectrolytes, such as poly(styrene sulfonate) (PSS), to form polyelectrolyte multilayers (PEMs). This study evaluates the modified membranes in Mg2+ and Li+ salt solutions, demonstrating significant improvements in selectivity for Mg2+/Li+ separation. PAH was identified as the optimal positively charged polyelectrolyte. PAN hollow fibers modified with ten bilayers of PAH/PSS achieved rejection rates of 95.4% for Mg2+ ions and 34.8% for Li+ ions, and a permeance of 0.39 LMH/bar. This highlights the potential of LBL techniques for effectively addressing the challenges of ion separation across a variety of applications. [ABSTRACT FROM AUTHOR]

Liquid phase microextraction techniques are considered as the miniaturized version of traditional liquid-liquid extraction, which use only several microliters of a proper solvent to extract the analytes from sample. In these methods, the target analytes are migrated into a water-immiscible organic solvent (acceptor phase) from an aqueous sample (donor phase). They are mainly classified into three main groups including (a) single-drop microextraction, (b) dispersive liquid–liquid microextraction, and (c) hollow fiber-liquid phase microextraction. These techniques have been successfully applied to the assessment of different analytes in food samples, pharmaceuticals, beverages, and so on. This review mainly focuses on up-to-date information on the application of liquid phase microextraction techniques in dairy products. The advantages and disadvantages of the developed liquid phase microextraction methods were discussed. [ABSTRACT FROM AUTHOR]

Here, we report a numerical study of supercontinuum generation in an antiresonant optical fiber with a hollow core filled with a mixture of deuterium (D2) and hydrogen (H2). For 1 ps pulses at a wavelength of 1.03 μm with different chirp values, we demonstrate a possibility of obtaining a mid-IR coherent supercontinuum with a spectral width of 2300 nm, initiated by cascade processes at resonance frequencies of vibrational and rotational levels of D2 and H2. We show that an increase in the chirped pulse duration to 25 ps while maintaining the energy and spectral width allows increasing the quantum conversion efficiency in the mid-IR from 10 to 50% and expanding the range of optimal fiber lengths at which a high degree of supercontinuum coherence is achieved. [ABSTRACT FROM AUTHOR]

This paper employs five different general-purpose optimization methods to perform parameter optimization on single-layer hollow antiresonant fibers. It provides guidance on the establishment of hyperparameters for various optimization methods, with the aim of further defining and standardizing the necessary conditions and convergence criteria for applying optimization algorithms to specialty optical fibers. Through numerical experiments, the study ultimately obtains the converged optimal performance and the range of optimized parameter guidance for single-layer, double-layer, and triple-layer antiresonant fibers with different topological structures. [ABSTRACT FROM AUTHOR]

The antimicrobial concentration–time profile in humans affects antimicrobial activity, and as such, it is critical for preclinical infection models to simulate human-like dynamic concentration–time profiles for maximal translatability. This review discusses the setup, principle, and application of various dynamic in vitro PK/PD infection models commonly used in the development and optimisation of antimicrobial treatment regimens. It covers the commonly used dynamic in vitro infection models, including the one-compartment model, hollow fibre infection model, biofilm model, bladder infection model, and aspergillus infection model. It summarises the mathematical methods for the simulation of the pharmacokinetic profile of single or multiple antimicrobials when using the serial or parallel configurations of in vitro systems. Dynamic in vitro models offer reliable pharmacokinetic/pharmacodynamic data to help define the initial dosing regimens of new antimicrobials that can be developed further in clinical trials. They can also help in the optimisation of dosing regimens for existing antimicrobials, especially in the presence of emerging antimicrobial resistance. In conclusion, dynamic in vitro infection models replicate the interactions that occur between microorganisms and dynamic antimicrobial exposures in the human body to generate data highly predictive of the clinical efficacy. They are particularly useful for the development new treatment strategies against antimicrobial-resistant pathogens. [ABSTRACT FROM AUTHOR]

This study explores the design, dynamic behavior, and controllability of a hybrid membrane-distillation process for propane/propylene separation, offering a novel comparison with traditional single distillation columns. Our key innovation lies in integrating hollow fiber membrane technology with distillation to significantly improve process efficiency, reducing energy consumption and operational costs. Using rigorous economic and dynamic simulations, the hybrid process demonstrates superior performance, achieving a 12.6 % reduction in total annual cost (TAC) compared to the conventional distillation system. Advanced control methodologies, including Singular Value Decomposition (SVD) and condition number analysis, are applied to assess and optimize the controllability of the hybrid structure under disturbances such as fluctuations in feed composition and flow rates. The results highlight the hybrid process's ability to maintain high product purity and faster dynamic response, offering a robust solution for large-scale propane/propylene separation in the petrochemical industry. This work provides crucial insights into improving both operational efficiency and control robustness in industrial separation processes. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metal‒organic frameworks (MOFs) are nanoporous crystalline materials with enormous potential for further development into a new class of high-performance membranes. However, the preparation of defect-free and water-stable MOF membranes with high permselectivity and good structural integrity remains a challenge. Herein, we demonstrate a dual-source seeding (DS) approach to produce high-performance, water-stable MOF-303 membranes with hollow fiber (HF) geometry and preferentially tailored crystallographic orientation. By controlling the nucleation site density during secondary growth, MOF-303 membranes with a preferred crystallographic orientation (CPO) on the (011) plane were fabricated. The MOF-303 membrane with CPO on (011) provides straight one-dimensional permeation channels with a superior water flux of 18 kg m−2 h−1 in pervaporative water/ethanol separation, which is higher than that of most of the reported zeolite membranes and 1–2 orders of magnitude greater than that of previously reported MOF membranes. The straight water permeation channels also offer a promising water permeance of 15 L m−2 h−1 bar−1 and a molecular weight cut-off (MWCO ≈ 269) for dye nanofiltration. These results provide a concept for developing ultrapermeable MOF membranes with good selectivity and structural integrity for pervaporation and nanofiltration. Metal-organic frameworks can be used to develop high-performance membranes. Here, authors demonstrate a dual-source seeding method to fabricate MOF-303 hollow fiber membranes with controlled crystallographic orientation, superior water flux, selectivity, and structural stability for pervaporation and nanofiltration. [ABSTRACT FROM AUTHOR]

In recent years, numerous studies have focused on the use of mixed ionic-electronic conducting oxides for coupled oxygen separation and catalytic reactions in membrane reactors. A promising strategy for the efficient fabrication of oxygen separation membranes involves modification of the membrane surface via exsolved metal nanoparticles decoration. Here, we present a detailed characterization of the structural and transport properties of a novel membrane material La 0.4 Sr 0.6 Fe 0.95 Nb 0.05 O 3−δ (LSFNb5). The exsolution of Fe nanoparticles was observed after heating of LSFNb5 in a reducing atmosphere (5 % Н 2 /Ar) and was confirmed by X-ray diffraction analysis, Mössbauer spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The formation of Fe nanoparticles on the surface of LSFNb5 hollow fiber membrane in the reduction process leads to the enhancement of oxygen fluxes and reduces the apparent activation energy. Kinetic parameters for oxygen transport through LSFNb5 hollow fiber membrane estimated using two different models, are in good agreement with the experimental results. Furthermore, LSFNb5 hollow fiber membrane demonstrates stable performance both before and after surface treatment. [ABSTRACT FROM AUTHOR]

The hydrogen-based membrane biofilm reactor (H2-MBfR) is an emerging biological nitrogen removal technology characterized by high efficiency, energy-saving capability, and environmental friendliness. The technology achieves denitrification and denitrogenation of microorganisms by passing hydrogen as an electron donor from inside to outside through the hollow fibre membrane module, and eventually the hydrogen reachs the biofilm attached to the surface of the fibre membrane. H2-MBfR has obtained favourable outcomes in the treatment of secondary biochemical effluent and low concentration nitrogen polluted water source. The experiment was optimized by s single-factor testing and response surface methodology-based optimization (RSM), and the optimal operational conditions were obtained as follows: an influent flow rate of 2 mL/min, hydrogen pressure of 0.04 MPa, and influent nitrate concentration of 24.29 mg/L. Under these conditions, a high nitrate removal rate of 98.25% was achieved. In addition, Proteobacteria and Bacteroidetes were the dominant bacteria in all stages, and the genus Hydrogenophaga was sufficiently enriched, occurring at 13.0%–49.0% throughout the reactor operation. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway for nitrate reduction and inorganic carbon utilization by microorganisms in the H2-MBfR was explored through comparison with the KEGG database. The results provided a mechanistic explanation for the denitrification and carbon sequestration capacity of the H2-MBfR. [ABSTRACT FROM AUTHOR]