Carbon Fiber Membrane Research Articles

Preparation of CoNi‐LDH‐Modified Polypropylene‐Based Carbon Fiber Membranes for Flexible Supercapacitors

ABSTRACTThe rapid development of flexible electronic devices has placed higher demands on the development of high‐performance flexible supercapacitors. In this work, a safe and simple method was developed to prepare cobalt–nickel layered double hydroxide (CoNi‐LDH) flexible electrodes. Metal–organic framework (MOF)‐derived CoNi‐LDH was successfully grown on the surface of polypropylene nonwoven flexible carbon fiber membranes through plasma oxidation treatment, grafting of cobalt‐based MOFs, and room‐temperature etching in Ni2+ solution. The prepared flexible modified carbon fiber membrane (CPO‐CoNi‐40‐0.5) has good mechanical properties with a tensile strength of 159.26 ± 63.03 kPa. In addition, the CPO‐CoNi‐40‐0.5 electrode has a high specific capacitance of 580 F g−1 at 1 A g−1. The assembled supercapacitor maintains 99% of the initial specific capacity after 7000 cycles and 98% of the initial specific capacity when it is folded at 90°, showing excellent long cycle stability and bending resistance. This paper provides a new way to promote the development of high‐performance and low‐cost flexible electrodes.

Silver enhanced 3D carbon nanofiber membrane via electrospinning for high performance lithium metal anodes

A silver (Ag) enhanced 3D carbon nanofiber membrane (Ag@CNFM) was synthesized through a combination of electrospinning and heat treatment techniques, with polyacrylonitrile, polyvinylpyrrolidone, and silver nitrate as precursors playing different roles in this process. Additionally, Ag-enhanced 3D carbon fiber membrane composite anodes were obtained by electrodeposition at a current density of 1 mA cm−2 for 10 h with a total deposition capacity of 10 mAh cm−2. The composite materials (denoted as Ag@CNFM/Li) working in symmetrical cells exhibited 1.2 mV overpotential after charging and discharging over 2000 h at 5 mA cm−2. Ag@CNFM/Li fulfilled a high discharge specific capacity of 109.66 mAh g−1 after 200 cycles at a current density of 0.5 C and 141. 59 mAh g−1 after 150 cycles at a current density of 1 C with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) working as counter electrode, maintaining a capacity retention of 87.37% and 72.8%. Even at a higher current density of 5 C, Ag@CNFM/Li retained a discharge specific capacity of 85.05 and 159.14 mAh g−1 with a capacity retention of 61.54% and 79.7% in LFP and NCM811 full cells, respectively.

Lithium-Oxygen-Battery Using Lightweight Gas-Diffusion Current Collector

Introduction There is a growing demand for high-energy-density storage devices owing to the increasing number of mobile device applications. On the other hand, an energy-density of currently mainstream lithium-ion batteries (LIBs) has almost reached its theoretical limit, and there is a strong desire for a next-generation batteries that use high-capacity materials based on designs different from conventional ones. Lithium oxygen batteries (LOBs), comprising gas phase oxygen and lithium metal foil as the positive and negative electrode materials, have received great attention as next generation energy storage devices owing to their superior theoretical energy densities. These days, there has been considerable technological progress in the field of LOBs, however, the progress on gas diffusion layer (GDL) has not been sufficient despite their importance in providing an oxygen supply needed to achieve practical power densities. The current mainstream design of LOBs uses a carbon fiber-based GDL which are used in polymer electrolyte fuel cells, but its heavy-weight makes it hardly to apply to high energy-dense LOBs. A new material design is required to achieve practical power density with minimal weight load.In this study we demonstrated a gas-diffusible current collector that combines the function of oxygen mass transport and electron transfer by a Ni-coated polymer fiber mesh and investigated its applicability in LOBs. Experimental Method A Ni-coated polymer fiber mesh, which is a gas-diffusible current collector, was obtained by electroless plating of 0.5 μm of Ni onto a 0.8 mg/cm2 mesh comprised a 27 μm diameter PET fiber. The LOB cell was fabricated with the following configuration. Cathode active material: a self-standing KB-based membrane (270 mm thick, 5.4 mg/cm2 carbon-loaded), Anode active material: Li foil (20 μm thick), Separator: polyolefin-based separator (20 μm thick), Electrolyte: 0.5 M LiTFSI + 0.5 M LiNO3 + 0.2 M LiBr in TEGDME, GDL: a carbon fiber membrane (200 μm thick) or the Ni-coated PET mesh, positive electrode current collector: SUS-304 foil (20 μm thick). And a ceramic-based, solid-state separator (LICGC, 90 μm thick), which was sandwiched between polyolefin separator, was used to protect the lithium negative electrode. Result and Discussion First, we investigated the effect of the mass loading of the GDL and positive electrode current collector on the energy density of a LOB. A 200 μm carbon fiber membrane (8.4 mg/ cm2) and a 30 μm SUS mesh (3.5 mg/cm2) were used as a GDL and a cathode current collector and total weight of GDL and cathode current collector reached 11.9 mg/cm2. On the other hand, the weight of the Ni-coated polymer fiber mesh is only 1.4 mg/cm2 (PET fibers: 0.8 mg/cm2, Ni coating layer: 0.6 mg/cm2). Therefore, when this material is used as a gas diffusible current collector, a weight reduction of about 10 mg/cm2 can be achieved. (Based on our calculations [1], it’s equivalent to an increase of approximately 150 Wh/kg in a LOB). These results illustrate the importance of a gas-diffusible current collector in high-energy-density LOBs. Then we fabricated the following two LOB cells and evaluated their battery performance. (i) Cell A: carbon fiber membrane GDL and SUS mesh current collector (total weight 11.9 mg/cm2), (ii) Cell B: Ni-coated PET fiber mesh gas-diffusible current collector (total weight 1.4 mg/cm2). The schematic illustration of LOB cells is shown in Figure a, b. Figure c, d shows the discharge profiles of the LOB cells at 0.4 mA/cm2 current density and 4.0 mAh/cm2 areal capacity and this result indicated that the gas-diffusible current collector possesses an oxygen transport ability equivalent to that of a conventional carbon fiber membrane, albeit with a smaller thickness and less weight. We also conducted a cycling test at current density of at 0.4 mA/cm2 current density and 4.0 mAh/cm2 areal capacity. These two cells displayed stable discharging/charging and showed an equivalent cycle-life performance. These results indicated that equivalent LOB performance can be achieved even when using a lightweight gas-diffusible current collector instead of a conventional thick, heavy carbon fiber membrane. We believe that the concept of an ultralightweight gas diffusible current collector demonstrated in this study opens future directions in the search for metal air batteries with high energy-density and power densities.[1] M. Shuntaro et al., ACS Appl. Energy Mater. 2023, 6, 1906−1912 Figure 1

Activation of peroxymonosulfate over recyclable Co3O4/rice straw lignin-based carbon fiber flexible membrane for the degradation of organic pollutants

Heterogeneous composite catalysts have gained significant attention in recent years due to their cleanliness, high efficiency, and stable performance. However, the difficulty of recovery and high cost have always limited the development of heterogeneous composite catalysts. Herein, flexible lignin-based carbon fiber (LCF) membranes with easy recovery and low cost were prepared by electrospinning and carbonization using rice straw lignin waste and polyacrylonitrile (PAN). Following in-situ sedimentation and annealing treatment, Co3O4 nanoparticles were successfully anchored on the surface of LCF to achieve Co3O4/LCF composite membrane, which was utilized for activating peroxymonosulfate (PMS) with an impressive 83 % degradation efficiency of tetracycline (TC) within 30 min, the mineralization rate of TC reached 67 % within 90 min, and displayed exceptional degradation capabilities even with interfering substances. Based on the quenching experiments, electron paramagnetic resonance (EPR), electrochemical tests and X-ray photoelectron spectroscopy (XPS), both radical and non-radical pathways were involved for TC degradation, and non-radical pathway was identified as the primary route. Active sites such as CO, graphite N, pyridinic N, and the Co2+/Co3+ redox cycle played the crucial roles during the degradation process. Density functional theory (DFT) and high-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses demonstrated the proposal of a plausible degradation pathway for TC.

Hybrid Nanoalloy‐Cluster‐Single Atom Sites Based Aerophilic Carbon Fiber Membranes as Binder‐Free Cathodes for Ultra‐Long‐Life Zn‐air Batteries

AbstractHigh‐efficient and durable electrocatalysts for oxygen reduction and oxygen evolution reaction (ORR/OER) are desirable to Zn‐air batteries (ZABs). However, most of catalysts in powder form with sole active sites remain challenging in achieving the satisfactory bifunctional catalysis and suffer from peeling off during the long‐term operation. Herein, hybrid CoFe active sites are constructed containing nanoalloys (≈10 nm), clusters (< 2 nm), and single atoms on aerophilic carbon fiber membranes as binder‐free air cathodes for ultra‐long‐life ZABs. In particular, the high air‐permeability of membranes (0.2 s) can prevent the active sites from blocking by O2 bubbles and promote the mass transfer. The theoretical and experimental results confirm that the hydrophilic CoFe2O4/CoFeOOH sites reconstructed on the surface of CoFe nanoalloys are mainly responsible for OER. While for single atoms and clusters on nitrogen (N)‐doped carbon matrix, they play a synergetic role in optimizing the adsorption energy to enhance ORR activity. Thus, the as‐prepared catalysts exhibit an ultra‐low ORR/OER potential gap (0.64 V). When further assembled as freestanding air‐electrodes, it exhibits an outstanding cycling lifespan of 1200 and 155 h in liquid‐ and quasi‐solid‐state ZABs respectively, which are fivefold and twofold higher than those of powder‐based cathodes (240/67 h).

Co-MOF-derived N-doped carbon nanosheet arrays on biomass carbon fiber membrane for highly sensitive detection of luteolin

Rapid and accurate determination of luteolin (LU) content is important for drug dosage control, treatment and prevention of disease. Traditional chromatographic and spectroscopic methods are gradually replaced by more sensitive and rapid electrochemical detection. 3D carbonized eggshell fiber membrane (3D CEFM) with good electrical conductivity and mechanical stability is prepared at high temperatures. To enhance the sensing performance of LU, nitrogen-doped carbon nanosheet arrays/3D CEFM (Co-NC NSAs/3D CEFM) derived from ZIF-67 nanosheet arrays (ZIF-67 NSAs) are prepared on the surface of 3D CEFM. Due to the synergistic effect, the Co-NC NSAs (thickness ∼ 1 μm, height ∼ 3 μm) provides a shorter electron transport path, while the 3D CEFM (pore size ∼5 μm) offers good electrical conductivity and a large solution contact area. Co-NC NSAs/3D CEFM electrode has a sensitivity of 1.31 μA·μM−1·cm−2 in the 0–60 μM LU and a limit of detection (LOD) of 0.04 μM (S/N = 3). Meanwhile, the electrode demonstrated recoveries of 98.0 % to 103.5 % in real samples, with a relative standard deviation (RSD) of 1.2 to 2.3 %. These results indicate that the electrode has significant potential for practical applications.

Coordination-based synthesis of Fe single-atom anchored nitrogen-doped carbon nanofibrous membrane for CO2 electroreduction with nearly 100% CO selectivity

Carbon-based materials with single-atom (SA) transition metals coordinated with nitrogen (M-Nx) have attracted extensive attention due to their superior electrochemical CO2 reduction reaction (CO2RR) performance. However, the uncontrolled recombination of metal atoms during the typical high-temperature synthesis process in M-Nx causes deterioration of CO2RR activity. Herein, by using electrospinning, we propose a novel strategy for constructing a highly active and selective SA Fe-modified N-doped porous carbon fiber membrane catalyst (Fe-N-CF). This carbon membrane has an interconnected three-dimensional structure and a hierarchical porous structure, which can not only confine Fe to be single atom as active centers, but also provide a diffusion channel for CO2 molecules. Relying on its special structure and stable mechanical properties, Fe-N-CF is directly used for CO2RR, which presents an excellent selectivity (CO Faradaic efficiency of 97%) and stability. DFT calculations reveals that the synthesized Fe-N4-C can significantly reduce the energy barrier for intermediate COOH* formation and CO desorption. This work highlights the specific advantages of using electrospinning method to prepare the optimal SA catalysts.

Bio-inspired superhydrophobic fiber membrane for oil-water separation and non-destructive transport of liquids in corrosive environments

Conventional polymer separation membranes or coatings suffer from poor separation performance and serious failure in highly corrosive environments, due to their low chemical and mechanical stability. Herein, a simple electrospraying and electrospinning strategy was used to prepare flexible superhydrophobic carbon fiber membranes (FSCFM). The wettability of FSCFM was improved by forming a lotus leaf-like hierarchical rough structure on its surface. The FSCFM exhibited an excellent permeation flux of immiscible oil-water mixtures (up to 15,800 L m−2 h−1) and water-in-oil emulsions (over 5500 L m−2 h−1), while the separation efficiencies were always kept at more than 99 % after 25 consecutive separations. Even in corrosive environments, its separation performance did not show any degradation. Notably, except for recovering floating oil under external driving forces with excellent cyclic stabilities, FSCFM was also able to transport various corrosive solutions with high efficiencies (99.9 %). After multiple mechanical damages and bending cycles, the FSCFM remained superhydrophobic. It could also maintain its repellency in strong acids/bases, high salt solutions and even under high-temperature environments (94.5 °C). These superior properties make it a strong candidate for oil-water mixture/emulsion separation and non-destructive transport of highly corrosive fluids.

Flexible carbon fiber membrane derived from polypropylene for symmetric quasi-solid-state supercapacitors

The high-value recycling of disposable masks (DMMs) for energy storage applications is an effective way to deal with the overcapacity of waste plastics. In this work, we focus on developing a novel approach for flexible carbon fiber membrane electrodes that utilizes polypropylene nonwoven derived from DDMs. Herein, polypropylene nonwoven is transformed into flexible carbon fiber membrane (CPPK) via sulfuric acid sulfonation, potassium hydroxide (KOH) solution impregnation, and high-temperature carbonization. The KOH solution impregnation activation method offers distinct advantages over the traditional blending process by enhancing the uniformity of the pore structure, thereby improving the flexibility of CPPK. As a result, the as prepared CPPK shows no structural failure even after undergoing approximately one hundred times folds with nearly 180°. Furthermore, CPPK electrodes demonstrate a high specific capacitance of 194 F g−1 at 0.5 A g−1. Besides, symmetric quasi-solid-state supercapacitors (SSCs) comprised with CPPK deliver a great energy density of 10.50 Wh·kg−1 at a power density of 200 W kg−1, as well as excellent bending stability. This study provides a new perspective on developing flexible carbon materials derived from polypropylene nonwoven whether from the point of view of recycling waste plastics or mass production of industry.

Electro-activation of peroxymonosulfate using a carbon fiber membrane anode for high-efficient degradation of antibiotic wastewater: The dominant role of singlet oxygen

A flow-through peroxymonosulfate (PMS) electro-activation system with a polyacrylonitrile-based carbon fiber (PCF) membrane anode (denoted as E-PCF-PMS system) was developed. The introduction of the PCF membrane anode enabled the flow-through electrocatalytical system to achieve a remarkable tetracycline (TC) removal of 96.0 ± 0.2 % within 15 min, with a degradation rate of 0.273 min−1. Scavenging investigations revealed that singlet oxygen (1O2) was the dominant reactive oxygen species for TC degradation in the E-PCF-PMS system, and this finding was confirmed by electron paramagnetic resonance tests. Potential degradation pathways of TC were identified according to the detected intermediates and calculations of density functional theory, and a decreasing trend in the toxicity of TC intermediates was discovered. Thanks to the 1O2-dominated pathway, the constructed E-PCF-PMS system could achieve efficient TC degradation under different concentrations of several common anions (Cl−, NO3−, HPO42−, and HCO3−) and humic acid (HA). General applicability and reusability tests demonstrated the excellent practicability of the proposed system. The PMS electro-activation system offers a potential technique for high-efficient degradation of contaminants in water and wastewater.

Construction of Fe Nanoclusters/Nanoparticles to Engineer FeN4 Sites on Multichannel Porous Carbon Fibers for Boosting Oxygen Reduction Reaction

AbstractFe–N–C catalysts are emerging as promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR), while they still suffer from sluggish reaction kinetics due to the discontented binding affinity between the Fe‐N4 sites and oxygen‐containing intermediates, and unsatisfactory stability. Herein, a flexible multichannel carbon fiber membrane immobilized with atomically dispersed Fe‐N4 sites and neighboring Fe nanoclusters/nanoparticles (FeN4‐FeNCP@MCF) is synthesized. The optimized geometric and electronic structures of the Fe atomic sites brought by adjacent Fe nanoclusters/nanoparticles and hierarchically porous structure of the carbon matrix endow FeN4‐FeNCP@MCF with outstanding ORR activity and stability, considerably outperforming its counterpart with FeN4 sites only and the commercial Pt/C catalyst. Liquid and solid‐state flexible zinc–air batteries employing FeN4‐FeNCP@MCF both exhibit outstanding durability. Theoretical calculation reveals that the Fe nanoclusters can trigger remarkable electron redistribution of the FeN4 sites and modulate the hybridization of central Fe 3d and O 2p orbitals, facilitating the activation of O2 molecules and optimizing the adsorption capacity of oxygen‐containing intermediates on FeN4 sites, and thus accelerating the ORR kinetic. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with nanoclusters/nanoparticles for efficient ORR catalysis.

“Graphene Bubble Bridging” Enabled Flexible Multifunctional Carbon Fiber Membrane Toward K+ Storage Devices

AbstractWidespread integration of carbon‐based membranes into prevailing fields like energy storage and material engineering is thwarted by a lack of functionality, customization, and compatibility, making the development of such carbon‐based membranes urgency yet challenging. Herein, a “graphene bubble bridging” strategy is adopted to fabricate the multifunctional carbon fiber membrane, in which graphene bubbles with optimized assembling not only endow the carbon fiber with superior flexibility and integrity by embedded bridging function, but also enhance the fast electron transport capability and electrolyte wettability. Few‐layer MoSSe nanosheets with expanded interlayer spacing as a typical energy storage material contribute to plentiful ion intercalation/deintercalation that can be well buffered within the robust fibers. The interlaced carbon fibers enable a self‐supporting framework that ensures good conductivity and mechanical stability as well. Such functional, customized, and compatible membranes with synergies can boost the attributes of advanced K+ storage devices, such as flexible K‐ion capacitors and K‐based dual‐ion batteries. This work can afford new insights for designing flexible electrode in the energy storage field, as well as various types of conformations that can bring more opportunities on developing flexible functional membranes for other fields (e.g., catalysts, electromagnetic shielding).

Anti-dissolving Fe2N6 site-based carbon fiber membranes for binder-free Zn–air batteries with a 200-day lifespan

The anti-dissolving Fe2N6 structure enables ZABs to operate over 200 days (record-breaking 14 500 cycles).

Characterization and Mechanism Analysis of Flexible UV Irradiated PAN-Based Carbon Fiber Membranes Prepared

Characterization and Mechanism Analysis of Flexible UV Irradiated PAN-Based Carbon Fiber Membranes Prepared

Electrosynthesis of α‐Amino Acids from NO and other NOx species over CoFe alloy‐decorated Self‐standing Carbon Fiber Membranes

AbstractThe conversion of industrial exhaust gases of nitrogen oxides into high‐value products is significantly meaningful for global environment and human health. And green synthesis of amino acids is vital for biomedical research and sustainable development of mankind. Herein, we demonstrate an innovative approach for converting nitric oxide (NO) to a series of α‐amino acids (over 13 kinds) through electrosynthesis with α‐keto acids over self‐standing carbon fiber membrane with CoFe alloy. The essential leucine exhibits a high yield of 115.4 μmol h−1 corresponding a Faradaic efficiency of 32.4 %, and gram yield of products can be obtained within 24 hours in lab as well as an ultra‐long stability (>240 h) of the membrane catalyst, which could convert NO into NH2OH rapidly attacking α‐keto acid and subsequent hydrogenation to form amino acid. In addition, this method is also suitable for other nitrogen sources including gaseous NO2 or liquidus NO3− and NO2−. Therefore, this work not only presents promising prospects for converting nitrogen oxides from exhaust gas and nitrate‐laden waste water into high‐value products, but also has significant implications for synthetizing amino acids in biomedical and catalytic science.

Electrosynthesis of α-Amino Acids from NO and other NOx species over CoFe alloy-decorated Self-standing Carbon Fiber Membranes.

The conversion of industrial exhaust gases of nitrogen oxides into high-value products is significantly meaningful for global environment and human health. And green synthesis of amino acids is vital for biomedical research and sustainable development of mankind. Herein, we demonstrate an innovative approach for converting nitric oxide (NO) to a series of α-amino acids (over 13 kinds) through electrosynthesis with α-keto acids over self-standing carbon fiber membrane with CoFe alloy. The essential leucine exhibits a high yield of 115.4 μmol h-1 corresponding a Faradaic efficiency of 32.4 %, and gram yield of products can be obtained within 24 hours in lab as well as an ultra-long stability (>240 h) of the membrane catalyst, which could convert NO into NH2 OH rapidly attacking α-keto acid and subsequent hydrogenation to form amino acid. In addition, this method is also suitable for other nitrogen sources including gaseous NO2 or liquidus NO3 - and NO2 - . Therefore, this work not only presents promising prospects for converting nitrogen oxides from exhaust gas and nitrate-laden waste water into high-value products, but also has significant implications for synthetizing amino acids in biomedical and catalytic science.

Self-assembly of gold nanoparticles on three-dimensional eggshell biological carbon fiber membranes: Non-enzymatic detection of rutin

A highly selective electrochemical sensing platform based on gold nanoparticles@three-dimensional carbonized eggshell fiber membrane (Au NPs@3D CEFM) was developed for non-enzymatic detection of rutin in the presence of ascorbic acid, dopamine and uric acid. The porous 3D connected-network CEFM with a pore size of ∼5 µm was prepared. Au NPs (∼10 nm) were uniformly anchored on the surface of the 3D CEFM by self-assembly. The porous 3D CEFM acts as a conductive platform and the regular small-sized Au NPs provide more active sites to significantly enhance the catalytic and selective properties of Au NPs@ 3D CEFM. Under the optimal conditions, the Au NPs@ 3D CEFM/ITO electrode exhibits an excellent sensitivity of 3.08 μA·μM−1·cm−2 and a low detection limit of 0.014 µM (S/N = 3) for the detection of rutin in 0–60 µM. Meanwhile, the electrode is also effectively used for the determination of rutin in actual biological samples and the recoveries for spiked samples ranged from 92.3% to 106.8%.

An iron-doped carbon fiber membrane as the microbe-electrode interaction accelerator for wastewater energy conversion

Bioelectrochemical systems (BESs) can achieve energy and resource recovery from wastewater. Accelerating electron transfer at the microbe-anode interface is vital for high-efficient wastewater energy conversion in BESs. Here, we fabricated an iron-doped carbon fiber membrane (Fe-CFM) anode with the stable and uniform distribution of iron oxides to boost electron transfer and microbial adhesion. This Fe-CEM anode efficiently accelerated the electron transfer with a small charge transfer resistance of 2.3 Ω. It achieved excellent energy conversion with a maximum power density of 3222 ± 384 mW m−2 and a maximum current density of 20.4 A m−2 assembled with the filtration composite anode and Co single atom air cathode in BES, which were 28% and 58% higher than those of the commercial carbon fiber cloth anode. The electricity generation could be significantly improved with the appropriate iron content. Our results demonstrate that this Fe-CFM has remarkable application potential in wastewater energy conversion.

Synthesis of Bi2WO6/g-C3N4 heterojunction on activated carbon fiber membrane as a thin-film photocatalyst for treating antibiotic wastewater

Photocatalysts usually exist in powder form, which limits their practical application in photocatalytic degradation of antibiotics in wastewater. To solve this problem. Here, we report the construction of Z-scheme Bi 2 WO 6 /g-C 3 N 4 on activated carbon fiber membrane (ACF) as a thin-film photocatalyst. The catalyst was characterized by XRD, SEM, XPS and other means. Chlortetracycline was used as a model pollutant to study the photocatalytic activity of the sample. According to the results of XPS and XRD, the composite material was successfully prepared. Ultraviolet diffuse reflectance characterization showed that the edge and intensity of the absorption band of the composite material were enhanced. The photodegradation experiment of chlortetracycline shows that 10% Bi 2 WO 6 /g-C 3 N 4 /ACF (area: 4 × 4 cm 2 ) has the best photocatalytic activity. Cycling experiments have proved that the 10% Bi 2 WO 6 /g-C 3 N 4 /ACF composite material has a stable degradation ability during the photodegradation process. Therefore, Bi 2 WO 6 /g-C 3 N 4 /ACF can be used as a recyclable, large surface area photocatalyst to eliminate water Antibiotics in the environment.

Waste-derived carbon fiber membrane with hierarchical structures for enhanced oil-in-water emulsion separation: Performance and mechanisms

A superhydrophilic and underwater superoleophobic membrane based on waste-derived carbon fibers was prepared with the assistance of tannic acid and (3-Aminopropyl)triethoxysilane. The surface morphology, chemistry, roughness and wettability of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, water contact angle (WCA) and underwater oil contact angle (UWOCA) measurements, respectively. Carbon fibers enabled the construction of micro-nano hierarchical structures on the membrane surface, which significantly increased the membrane surface roughness (2.1 times higher than the control) and effective surface area (1.6 times higher than the control). The carbon fiber membrane exhibited superhydrophilicity (WCA = 0°) with ultrafast water spreading in air and underwater superoleophobicity (UWOCA = 157.2°) with little oil adhesion. The carbon fiber membrane showed effective surfactant stabilized oil-in-water emulsion separation using various oils (permeation flux up to 713 Lm-2h-1 and separation efficiency up to 99.8%). We also proposed an integrated model to elucidate how the superhydrophilic and underwater superoleophobic property and surface roughness interact with the size exclusion mechanism by considering dynamic flows near the membrane surface, which further reveals the anti-fouling and self-cleaning properties of our carbon fiber membrane. Our model provides new insights into developing specially-wettable membranes with high fouling resistance for wide wastewater treatment applications based on surface wettability and roughness.