Hydrothermal synthesized UV-resistance and transparent coating composited superoloephilic electrospun membrane for high efficiency oily wastewater treatment

Chitosan-based aerogels: A new paradigm of advanced green materials for remediation of contaminated water

Chitosan (CS) aerogels are highly porous (∼99 %), exhibit ultralow density, and are excellent sorbents for removing ionic pollutants and oils/organic solvents from water. Their abundant hydroxyl and amino groups facilitate the adsorption of ionic pollutants through electrostatic interaction, complexation and chelation mechanisms. Selection of suitable surface wettability is the way to separate oils/organic solvents from water. This review summarizes the most recent developments in improving the adsorption performance, mechanical strength and regeneration of CS aerogels. The structure of the paper follows the extraction of chitosan, preparation and sorption characteristics of CS aerogels for heavy metal ions, organic dyes, and oils/organic solvents, sequentially. A detailed analysis of the parameters that influence the adsorption/absorption performance of CS aerogels is carried out and their effective control for improving the performance is suggested. The analysis of research outcomes of the recently published data came up with some interesting facts that the unidirectional pore structure and characteristics of the functional group of the aerogel and pH of the adsorbate have led to the enhanced adsorption performance of the CS aerogel. Finally, the excerpts of the literature survey highlighting the difficulties and potential of CS aerogels for water remediation are proposed.

Intertwisted superhydrophilic and superhydrophobic collagen fibers enabled anti-fouling high-performance separation of emulsion wastewater

Oil-contaminated wastewater has been one of the most concerned environmental issues. Superwetting materials-enabled remediation of oil contamination in wastewater faces the critical challenge of fouling problems due to the formation of intercepted phase. Herein, high-performance separation of emulsions wastewater was accomplished by developing collagen fibers (CFs)-derived water-oil dual-channels that were comprised of intertwisted superhydrophilic and superhydrophobic CFs. The dual-channels relied on the superhydrophilic CFs to accomplish efficient demulsifying, which played the role as water-channel to enable fast transportation of water, while the superhydrophobic CFs served as the oil-transport channel to permit oil transportation. The mutual repellency between water-channel and oil-channel was essential to guarantee the stability of established dual-channels. The unique dual-channel separation mechanism fundamentally resolved the intercepted phase-caused fouling problem frequently engaged by the superwetting materials that provided single-channel separation capability. Long-lasting (1440 min) anti-fouling separations were achieved by the superwetting CFs-derived dual-channels with separation efficiency high up to 99.99%, and more than 4-fold of stable separation flux as compared with that of superhydrophilic CFs with single-channel separation capability. Our investigations demonstrated a novel strategy by using superwetting CFs to develop water-oil dual-channels for achieving high-performance anti-fouling separation of emulsions wastewater. ENVIRONMENTAL IMPLICATION: Industrial processes discard a large amount of emulsion wastewater, which seriously imperils the aquatic ecosystem. This work demonstrated a conceptual-new strategy to achieve effective remediation of emulsion wastewater via the water-oil dual-channels established by the intertwisted superhydrophilic and superhydrophobic collagen fibers (CFs). The superhydrophilic CFs enabled efficient demulsification of emulsions and played the role of water-channel for the rapid transportation of water, while the superhydrophobic CFs worked as oil-channel to permit the efficient transportation of oil pollutants. Consequently, the long-term (1440 min) anti-fouling high-performance separation of emulsion wastewater was achieved.

Highly efficient removal of emulsified oil from oily wastewater by microfiltration carbon membranes made from phenolic resin/coal

Oily wastewater treatment is a major problem for a large variety of industrial sectors. Membrane filtration is quite promising for oil-in-water emulsion treatment by virtue of numerous eminent advantages. Here, microfiltration carbon membranes (MCMs) were prepared by the blends of phenolic resin (PR)/coal as precursor materials for efficient removal of emulsified oil from oily wastewater. The functional groups, porous structure, microstructure, morphology and hydrophilicity of the MCMs were analysed by Fourier transform infrared spectroscopy, bubble-pressure method, X-ray diffraction, scanning electron microscope and water contact angle, respectively. The effect of coal amount in precursor materials on the structure and properties of MCMs was mainly investigated. Under operation at 0.02 MPa for trans-membrane pressure and 6 mL min-1 for feed flowrate, the optimal oil rejection and water permeation flux are correspondingly attained to 99.1% and 21,388.5 kg m-2 h-1 MPa-1 for MCMs made by the precursor containing 25% coal. Besides, the anti-fouling ability of the as-prepared MCMs is greatly improved in comparison with the one merely made by PR. In summary, the result indicates that the as-prepared MCMs are very promising for oily wastewater treatment.

Preparation of Newly Polymer-Coated Microbial Pellets and Their Adsorption and Degradation Properties for Oil-Containing Wastewater

Water is the lifeblood of everything on earth, nourishing and nurturing all forms of life, while also contributing to the development of civilization. However, with the rapid development of economic construction, especially the accelerated process of modern industrialization, the pollution of oily sewage is becoming increasingly serious, affecting the ecological balance and human health. The efficient elimination of pollutants in sewage is, therefore, particularly urgent. In this paper, a core-shell microbial reactor (MPFA@CNF-SA-AM) was fabricated by using nanocellulose and sodium alginate (SA) particles embedded with microorganisms as the core and lipophilic and hydrophobic fly ash as the outer shell layer. Compared with that of free microorganisms and cellulose and SA aerogel pellets loading with microorganisms (CNF-SA-AM), which has a degradation efficiency of 60.69 and 82.89%, respectively, the MPFA@CNF-SA-AM possesses a highest degradation efficiency of 90.60% within 240 h. So that this self-floating microbial reactor has selective adsorption properties to achieve oil-water separation in oily wastewater and high effective degradation of organic pollutants with low cost. The adsorption curves of MPFA@CNF-SA-AM for diesel and n-hexadecane were studied. The results showed that the adsorption follows the Freundlich model and is a multimolecular layer of physical adsorption. In addition, the degradation mechanism of diesel oil was studied by gas chromatography-mass spectrometry. The results showed that diesel oil was selectively adsorbed to the interior of MPFA@CNF-SA-AM, and it was degraded by enzymes in microorganisms into n-hexadecanol, n-hexadecaldehyde, and n-hexadecanoic acid in turn, and finally converted to water and carbon dioxide. Compared with existing oily wastewater treatment methods, this green and pollution-free dual-functional core-shell microbial reactor has the characteristics of easy preparation, high efficiency, flexibility, and large-scale degradation. It provides a new, effective green choice for oily wastewater purification and on-site oil spill accidents.

A comprehensive review on state-of-the-art antifouling super(wetting and anti-wetting) membranes for oily wastewater treatment

One of the most dangerous types of pollution to the environment is oily wastewater, which is produced from a number of industrial sources and can cause damage to the environment, people, and creatures. To overcome this issue, membrane technology as an advanced method has been considered for treating oily wastewater due to its stability, high removal efficiency, and simplicity in scaling up. Membrane fouling, or the accumulation of oil droplets at or within the membrane pores, compromises the efficiency of membrane separation and water flux. In the last decade, the fabrication of membranes with specific wettability to reduce fouling has received much consideration. The purpose of this article is to offer a literature overview of all fabricated anti-fouling super(wetting and anti-wetting) membranes for applicable membrane processes for the separation of immiscible and emulsified oil/water mixtures. In this review, we first explain membrane fouling and discuss methods for preventing it. Afterwards, in all membrane separation processes, including pressure-driven, gravity-driven, and thermal-driven, membranes based on the form and density of oil are categorized as oil-removing or water-removing with special wettability, and then their wettability modification with different materials is particularly discussed. Finally, the prospect of anti-fouling membrane fabrication in the future is presented.

Fabricated magnetic adsorption - Forward osmosis membrane hybrid system for hydroponic irrigation from rich arsenic-containing heavy metal water stream

Solidification of soluble arsenic from extremely acidic water and direct use of recovery water have been the major challenges in global water management, with the urgent need for new treatment system development. Thus, magnetic adsorption - fertilizer drawn forward osmosis (FDFO) hybrid system with a novel adsorbent and fertilizer mixture to solve the drawbacks of each process was developed with the ultimate goals of metal removal and direct reuse for hydroponic irrigation. Magnetic metal-organic framework-based adsorbent (CMM) was synthesized with various promising capabilities, i.e., wide pH range efficiency, strong pH adjustment, good stability, fast adsorption (1 h), and oxidation (40 min), high capacity (175 and 126 mg/g for As(III), As(V)), strong magnetization (75 emu/g), complete separation by a magnet, excellent interference-tolerance and reusability. In the FDFO system, a massive water volume (50 times higher than the initial draw solution with suitable nutrients for hydroponics irrigation with acceptable NaCl levels was obtained for the first time up to now. However, low As(III) rejection (50%) required the FDFO process to improve more. After integrating with magnetic adsorption, nearly 100% of As was removed. The pH of feed solutions adjusted from extremely acidic to close to neutral conditions further solidified metal by precipitation and membrane separation processes, leading to almost no detection of metals in the final draw solution. Also, favorable nutrients and excellent reusability were obtained. This hybrid process would generally offer an environmentally sustainable and high efficiency for decontaminating As-containing heavy metal water for hydroponic irrigation.

Design and assembly of Ag-decorated Bi2O3 @ 3D MXene Schottky heterojunction for the highly permeable and multiple-antifouling of fibrous membrane in the purification of complex emulsified oil pollutants

Membrane separation technology has potential for purifying emulsified oily wastewater. However, the oils, soluble organic substances, and microorganisms can cause complex membrane fouling problems, thereby reducing the separation efficiency and service life. Herein, a highly permeable and multiple-antifouling composite membrane was prepared using porous PAN fibrous mat as support backbone for the assembly of Ag-decorated Bi₂O₃ @ 3D MXene Schottky heterojunction and hydrophilic TA as the adhesive. The unique arrangement of 3D MXene heterojunction and hydrophilic functionalization effectively broke through the limitation of separation flux and synergistically enhanced the anti-fouling performance of membrane. Such fibrous composite membrane achieved an exceedingly high permeability (2717-3328 L·m^-2·h^-1) for various emulsified oils, while ensuring excellent oil/water emulsion retention rate (99.59%) and good cycle stability. Meanwhile, the composite membrane displayed favorable photocatalytic degradation performance toward degrading MeB (96.1%) and antibacterial ability. Furthermore, the MD simulation and free radical trapping experiments were carried out to unravel the molecular interactions during the separation process and the photocatalytic mechanism of composite membrane, respectively. Overall, the combination of photocatalytic self-cleaning, anti-oil adhesion, and antibacterial effect renders the membrane high permeability and multiple-antifouling performance, which provides a new strategy for dealing with complex oily wastewater in petrochemical industry.

A Selective Review of Ceramic, Glass and Glass-Ceramic Protective Coatings: General Properties and Specific Characteristics for Solar Cell Applications

A review on ceramics, glasses and glass-ceramics as thin film protective coatings for solar cells is given. The different preparation techniques and the physical and chemical properties are presented in a comparative way. This study is useful for technologies involving solar cells and solar panel cell development at the industrial scale, because protective coatings and encapsulation play a major role in increasing the lifetime of solar panels and environmental protection. The aim of this review article is to give a summary of existing ceramic, glass, and glass-ceramic protective coatings and how they apply to solar cell technology: silicon, organic or perovskite cells. Moreover, some of these ceramic, glass or glass-ceramic layers were found to have dual functionality, such as providing anti-reflectivity or scratch resistance to give a two-fold improvement to the lifetime and efficiency of the solar cell.

Fluorosensing of benzaldehydes by CuI-graphene: A spectroscopy, thermodynamics and docking supported phenomenon

Benzaldehyde and 4-methyl benzaldehyde constitute a major part of the harmful volatile organic compounds (VOCs) found in the environment. Hence, rapid and selective detection of benzaldehyde derivatives are required to minimize the environmental degradation as well as the potential hazards on human health. In this study, the surface of the graphene nanoplatelets were functionalized with CuI nanoparticles for specific and selective detection of benzaldehyde derivatives by fluorescence spectroscopy. CuI-Gr nanoparticles exhibited higher efficiency towards the detection of benzaldehyde derivatives as compared to pristine CuI nanoparticles with detection limit (LOD) 2 ppm and 6 ppm for benzaldehyde and 4-methyl benzaldehyde respectively in aqueous medium. The LOD values for the detection of benzaldehyde and 4-methyl benzaldehyde by pristine CuI nanoparticles were poor and found to be 11 ppm and 15 ppm respectively. Fluorescence intensity of CuI-Gr nanoparticles were found to be quenched with increasing concentration (0-0.01 mg/mL) of the benzaldehyde and 4-methyl benzaldehyde. This novel graphene-based sensor was also found to be highly selective for the benzaldehyde derivatives as no changes in signal were detected in presence of other VOCs like formaldehyde and acetaldehyde.

A susceptible coordination hybrid based terbium sensibilization coupled ESIPT effects for pattern discrimination of analogues

Multianalyte detection and analogue discrimination are extremely valuable frontier areas for their wide applications in environmental, medical, clinical and industrial analyses. Nowadays, researchers rack their brains on how to develop excellent multianalyte chemosensors that have presented huge challenges in designing high-efficient fluorescent sensing materials and constructing high-throughput detection methods. In this paper, we propose a novel strategy to utilize the dual-emission fluorescent detection platform as a lab-on-a-molecule, arising from the disalicylaldehyde-coordinated hybrid H₂Q_j3/Tb based terbium sensibilization coupled excited-state intramolecular proton transfer effects. Using the statistical analysis (PCA and HCA) for sensing signals of three fluorescence channels (431, 543 and 583 nm), we demonstrate this elaborate chemosensor with multianalyte detection of three species (solvents, anions and cations) and pattern discrimination of analogues. As a result, the H₂Q_j3/Tb shows great lab-on-a-molecule characters for each set of species, resulting in the easier identification of many critical analytes (e.g., H₂O, NO₂^- and Fe³⁺) and discrimination of analogues. In addition, it is also proven to be able to provide reliable content determination for an analyte, especially the NO₂^- (LOD = 0.37 μM), and discrimination for mixed analogues. A combination of easy-to-implement preparation procedure and data analysis technique makes this work promising for not only designing similar lanthanide-based materials but also realizing more high-efficient multianalyte sensing systems towards various potential applications.

Customization of surface wettability of nano-SiO2 by coating Trimethoxy(vinyl)silane modifier for oil-water separation: Fabrication of metal-based functional superwetting nanomaterial, characterizations and performance evaluation

The wettability of nano-SiO₂ surface was transformed from the inherent hydrophilicity to functional superhyderophobicity by coating Trimethoxy (vinyl)silane modifier, and the resultant surface showed contrasting wettability for water and oil (Superhydrophobic and Superoleophilic), which is a desired characteristic for the membranes used in oil-water separation. Initially Trimethoxy (vinyl)silane coated SiO₂ nanoparticles (TMVS@SiO₂) were synthesized by hydrolysis and poly-condensation reactions, and this nano dispersion was spray coated on the annealed stainless-steel mesh surface, whose resulting hierarchical surface texture brought about the desired wettability, with the water-surface-air (θ_WA) and oil-surface-air (θ_OA) interfacial contact angles of 150° and 0° respectively. In addition to the wettability studies (contact angles), FTIR, morphological, and elemental characterizations of the TMVS@SiO₂ coated surfaces were carried out to understand the alterations that have taken place on the TMVS@SiO₂ surface that in turn rendered superhydrophobicity and superoleophilicity to the surface. The FTIR absorption peaks indicate that after modifying SiO₂ with TMVS, the -OH groups on SiO₂ surface are clearly replaced by -CH₃. The morphological studies indicated that modification of SiO₂ leads to better cross-linking between coating composition and nanoparticles and EDS spectra and elemental mapping of the modified surface showed the presence of Si, O and C elements. Finally, this surface was tested for its efficiency and stability as a membrane in the process of separating oil and water from the oily water using gravity driven method. The oil-water separation efficiency was estimated to be 99% for this membrane and also it was found to be quite stable as the surface effectively retained this oil-water separation efficiency even after 10 cycles of separation process.

Virucidal PVP-Copper Salt Composites against Coronavirus Produced by Electrospinning and Electrospraying

Electrospinning technology was used to produced polyvinylpyrrolidone (PVP)-copper salt composites with structural differences, and their virucidal activity against coronavirus was investigated. The solutions were prepared with 20, 13.3, 10, and 6.6% w/v PVP containing 3, 1.0, 0.6, and 0.2% w/v Cu (II), respectively. The rheological properties and electrical conductivity contributing to the formation of the morphologies of the composite materials were observed by scanning electron microscopy (SEM). SEM images revealed the formation of electrospun PVP-copper salt ultrafine composite fibers (0.80 ± 0.35 µm) and electrosprayed PVP-copper salt composite microparticles (1.50 ± 0.70 µm). Energy-dispersive X-ray spectroscopy (EDS) evidenced the incorporation of copper into the produced composite materials. IR spectra confirmed the chemical composition and showed an interaction of Cu (II) ions with oxygen in the PVP resonant ring. Virucidal composite fibers inactivated 99.999% of coronavirus within 5 min of contact time, with moderate cytotoxicity to L929 cells, whereas the virucidal composite microparticles presented with a virucidal efficiency of 99.999% within 1440 min of exposure, with low cytotoxicity to L929 cells (mouse fibroblast). This produced virucidal composite materials have the potential to be applied in respirators, personal protective equipment, self-cleaning surfaces, and to fabric coat personal protective equipment against SARS-CoV-2, viral outbreaks, or pandemics.

Chiral Luminescent Sensor Eu-BTB@d-Carnitine Applied in the Highly Effective Ratiometric Sensing of Curing Drugs and Biomarkers for Diabetes and Hypertension

Chiral drugs are of great significance in drug development and life science because one pair of enantiomers has a different combination mode with target biological active sites, leading to a vast difference in physical activity. Metal-organic framework (MOF)-based chiral hybrid materials with specific chiral sites have excellent applications in the highly effective sensing of drug enantiomers. Sitagliptin and clonidine are effective curing drugs for controlling diabetes and hypertension, while insulin and norepinephrine are the biomarkers of these two diseases. Excessive use of sitagliptin and clonidine can cause side effects such as stomach pain, nausea, and headaches. Herein, through post-synthetic strategy, MOF-based chiral hybrid material Eu-BTB@d-carnitine (H₃BTB = 1,3,5-benzenetrisbenzoic acid) was synthesized. Eu-BTB@d-carnitine has dual emission peaks at 417 and 616 nm when excited at 330 nm. Eu-BTB@d-carnitine can be applied in luminescent recognition toward sitagliptin and clonidine with high sensitivity and low detection limit (for sitagliptin detection, K_sv is 7.43 × 10⁶ [M^-1]; for clonidine detection, K_sv is 9.09 × 10⁶ [M^-1]; limit of detection (LOD) for sitagliptin is 10.21 nM, and LOD of clonidine is 8.34 nM). In addition, Eu-BTB@d-carnitine can further realize highly sensitive detection of insulin in human fluids with a high K_sv (2.08 × 10⁶ [M^-1]) and a low LOD (15.48 nM). On the other hand, norepinephrine also can be successfully discriminated by the hybrid luminescent platform of Eu-BTB@d-carnitine and clonidine with a high K_sv value of 4.79 × 10⁶ [M^-1] and a low LOD of 8.37 nM. As a result, the chiral hybrid material Eu-BTB@d-carnitine can be successfully applied in the highly effective ratiometric sensing of curing drugs and biomarkers for diabetes and hypertension.

Collagen fiber membrane as multi-functional support enabled rational design of ultrahigh-flux separation membrane for the remediation of oil contamination in water

Membrane separation is a promising approach for the remediation of oil contamination in water. High-flux separation of membrane relies on the rational design of ultrathin active layer to significantly reduce mass transfer distance for achieving high separation flux, while the ultrathin active layer is usually fragile with poor mechanical strength, which has to be supported on a support. Herein, we employed collagen fiber membrane (CFM) as multi-functional support for the in-situ growth of polyacrylonitrile (PAN) layer by electrospinning to prepare the high-performance PAN/CFM composite membrane. Due to the amphiphilic nature and strong capillary effect, CFM played the role as multi-functional support to provide separation effectiveness and boosted separation flux. The PAN/CFM composite membrane enabled ultrahigh separation flux (e.g., 51751.59 L m^-2 h^-1 bar^-1) to a variety of oil-in-water emulsion, which was one order of magnitude higher than that of commercial polyethersulfone membrane and 1.86-fold to that of cellulose acetate membrane. Furthermore, the PAN/CFM composite membrane retained high separation flux (e.g., 11046.97 L m^-2 h^-1 bar^-1) during the 5th separation cycle, providing appreciable anti-fouling capability. Therefore, our findings provided a promising way to effectively resolve the problem of oil contamination in water.

Solvo-thermal synthesis of a unique cluster-based nano-porous zinc(II) luminescent metal-organic framework for highly sensitive detection of anthrax biomarker and dichromate

In this work a flexible multi-dentate 4,4'-(1H-1,2,4-triazole-1-yl) methylene-bis(benzonic acid) (H₂L) ligand has been employed, a unique cluster-based nano-porous luminescent zinc(II) metal-organic framework {[Zn(μ₆-L)]·(DMAC)₂}_n (1) (DMAC = Dimethylacetamide) has been isolated under solvo-thermal conditions. The H₂L ligand adopts hexa-dentate coordination modes via one triazole nitrogen atom and four aromatic carboxylate oxygen atoms, which bridge the neighboring six-coordinated Zn^II centers, leading to a three-dimensional (3D) nano-porous metal organic framework. A PLATON program analysis suggests the total potential solvent area volume is 2028.9 Å³, which occupy 62.5% percent of the unit cell volume (3248.4 Å³). PXRD Patterns of the as-synthesized samples 1 have been determined confirming the purity of the bulky samples. Photo-luminescent properties indicate strong fluorescent emissions of 1 at the room temperature. Further photo-luminescent measurements show that 1 can exhibit highly sensitive real-time luminescence sensing of anthrax biomarker dipicolinic acid (DPA) with high quenching efficiency (K_SV = 1.48 × 10⁵ M^-1) and low detection limit (0.298 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive luminescence sensing for Cr₂O₇^2- ions in aqueous solutions with high quenching efficiency K_SV = 1.22 × 10⁴ L·mol^-1 and low detection limit (0.023 μM (S/N = 3)). Therefore 1 can be used a unique multi-functional 3D cluster-based metal organic material in sensitive detection and effective detection of environment pollutants and biomarker molecules.

Review of the Recent Advances in Electrospun Nanofibers Applications in Water Purification

Recently, nanofibers have come to be considered one of the sustainable routes with enormous applicability in different fields, such as wastewater treatment. Electrospun nanofibers can be fabricated from various materials, such as synthetic and natural polymers, and contribute to the synthesis of novel nanomaterials and nanocomposites. Therefore, they have promising properties, such as an interconnected porous structure, light weight, high porosity, and large surface area, and are easily modified with other polymeric materials or nanomaterials to enhance their suitability for specific applications. As such, this review surveys recent progress made in the use of electrospun nanofibers to purify polluted water, wherein the distinctive characteristics of this type of nanofiber are essential when using them to remove organic and inorganic pollutants from wastewater, as well as for oil/water (O/W) separation.

High-performance TFNC membrane with adsorption assisted for removal of Pb(II) and other contaminants

Rapid and thorough removal of heavy metal ions in wastewater is critical for the urgent need of clean water. Herein, we prepared a high-performance thin film nanofibrous composite (TFNC) membrane consisting of a polyacrylonitrile (PAN)-UiO-66-(COOH)₂ composite nanofibrous substrate (CPAN) and a calcium alginate (CaAlg) skin layer. Owing to abundant adsorption sites of UiO-66-(COOH)₂ MOF, the optimal CPAN-2 nanofibrous substrate showed excellent adsorption capacity for lead ions. The maximum Pb²⁺ adsorption capacity of CPAN-2 substrate calculated by Langmuir isotherm model was 254.5 mg/g. Meanwhile, due to the relatively loose structure of CaAlg skin layer, this TFNC membrane showed high water permeate flux about 50 L m^-2h^-1 at 0.1 MPa, and the rejection for dyes was higher than 95%. Therefore, CaAlg/CPAN TFNC membranes were appropriate for dynamic adsorption/filtration to remove Pb²⁺. Compared with original CaAlg/PAN membrane, the optimal CaAlg/CPAN TFNC membrane showed much better ability to treat Pb(II)-containing wastewater and had good recyclability. Most importantly, the CaAlg/CPAN TFNC membrane could treat 7659 L m^-2 wastewater containing single lead ions under WHO drinking water standard, and effectively deal with more simulated lead-containing wastewater. This work could provide a substitutable solution for effective removal of heavy metal ions and other various contaminants in wastewater.

Multi-Component Nanofiber Composite Membrane Enabled High PM0.3 Removal Efficiency and Oil/Water Separation Performance in Complex Environment

Currently, industrial waste gas and oily wastewater are usually at high temperature and contain corrosive components (e.g., acid, alkali, oxidant, or high salt, etc.), presenting great challenges on filtration/separation materials. Here, a multi-purpose Poly(m-phenylene isophthalamide)/polyacrylonitrile/silica (PMIA/PAN/SiO₂) nanofiber composite membrane with a high yield was prepared simply via electrospinning to satisfy the demands of air filtration and oil/water separation in complex environments. Under the synergy of PMIA, PAN and SiO₂, the composite membrane possesses high PM_0.3 removal capacity of 99.69%, robust purification ability against real smoke PM_2.5, effective oil/water separation performance of > 99.6%, superior high temperature stability (about 250 °C) and excellent chemical resistance, showing the potential application in filtration/separation process under complex conditions. Moreover, the influence mechanism of SiO₂ NPs on mechanical properties and filtration performance was systematically investigated through experiments and simulations, paving the way for future intensive research. This study provides an option for the facile and effective preparation of high-performance filtration/separation membranes applied in the field of dust filtration and oily wastewater separation, even in harsh environments.

A thermoresponsive CA-PNIPAM-based electrospun nanofibrous membrane for oil/water separation

The prepared electrospun CA-P fibrous membrane/mat has the potential ability for high-efficiency oil/water separation.

Chemical upcycling of polylactide (PLA) and its use in fabricating PLA-based super-hydrophobic and oleophilic electrospun nanofibers for oil absorption and oil/water separation

Circular design and fabrication of PLA nanofiber filters from PLA wastes for effective oil decontamination and oil/water separation.

Robust and durable liquid-repellent surfaces

This review provides a comprehensive summary of characterization, design, fabrication, and application of robust and durable liquid-repellent surfaces.

Highly polymerized linear polyimide /H3PW12O40 photocatalyst with full visible light region absorption

The degree of polymerization in polyimides has significant effects on their photoelectric properties. Increase the degree of polymerization in polyimide can improve its light absorption capability as well as reduce the recombination rate of photogenerated electrons and holes. However, it is difficult to promote the polymerization of polyimides by conventional approaches, such as increasing the polymerization temperature since polyimides are susceptible to high temperature and can be decomposed. In this paper, a suitable proportion of phosphotungstic acid was introduced to increase the degree of polymerization of polyimide at a lower polymerization temperature, so as to improve the light absorption capability of the composite and inhibit the recombination of electron and hole. The p-phenylenediamine based polyimide with the one-dimensional linear polymer chain has excellent charge transfer ability, so the POM-π effect formed with phosphotungstic acid is stronger, correspondingly, the light absorption capacity of the composite photocatalyst formed is stronger than that of the cross-linked polyimide/phosphotungstic acid.

Exploring Reusability of Disposable Face Masks: Effects of Disinfection Methods on Filtration Efficiency, Breathability, and Fluid Resistance

To curb the spread of the COVID-19 virus, the use of face masks such as disposable surgical masks and N95 respirators is being encouraged and even enforced in some countries. The widespread use of masks has resulted in global shortages and individuals are reusing them. This calls for proper disinfection of the masks while retaining their protective capability. In this study, the killing efficiency of ultraviolet-C (UV-C) irradiation, dry heat, and steam sterilization against bacteria (Staphylococcus aureus), fungi (Candida albicans), and nonpathogenic virus (Salmonella virus P22) is investigated. UV-C irradiation for 10 min in a commercial UV sterilizer effectively disinfects surgical masks. N95 respirators require dry heat at 100 °C for hours while steam treatment works within 5 min. To address the question on safe reuse of the disinfected masks, their bacteria filtration efficiency, particle filtration efficiency, breathability, and fluid resistance are assessed. These performance factors are unaffected after 5 cycles of steam (10 min per cycle) and 10 cycles of dry heat at 100 °C (40 min per cycle) for N95 respirators, and 10 cycles of UV-C irradiation for surgical masks (10 min per side per cycle). These findings provide insights into formulating the standard procedures for reusing masks without compromising their protective ability.

Recent progress in cellulose-based electrospun nanofibers as multifunctional materials

Cellulose, the most abundant natural polymer, has good biocompatibility, biodegradability, and non-toxicity, which make it and its derivatives promising candidates for the fabrication of multifunctional materials, while maintaining sustainability and environmental friendliness. The combination of electrospinning technology and cellulose (and its derivatives) provides a feasible approach to produce nanostructured porous materials with promising functionalities, flexibility, renewability and biodegradability. At the same time, it enables value-added applications of cellulose and its derivatives that are derived from nature or even biomass waste. This review summarizes and discusses the latest progress in cellulose-based electrospun nanofibers, including their construction methods and conditions, various available raw materials, and applications in multiple areas (water treatment, biomaterials, sensors, electro-conductive materials, active packaging, and so on), which are followed by the conclusion and prospects associated with future opportunities and challenges in this active research area.

The preparation of electrospun PVDF/TBAC multi morphology nanofiber membrane and its application in direct contact membrane distillation

Microporous membrane with a hydrophobic surface, high porosity and narrow pore size distribution is the ideal membrane distillation (MD) membrane. The electrospun membranes for MD is a new type and effective way to seawater desalination. Herein, a novel polyvinylidene fluoride (PVDF)/ tetrabutylammonium chloride (TBAC) electrospun nanofiber membrane (ENMs) fabricated apply to for direct contact membrane distillation (DCMD). Combine with the spinning condition, the characteristic and content of TBAC significant effect on the multi morphology structure of nanofiber. Therefore, the porous structure and morphology of PVDF/TBAC ENMs can be well-designed by optimizing relative humidity and TBAC concentration in spinning process, three different structure nanofiber membranes were obtained. Lab-scale setup was used to test membrane separation performance. The result indicated that the ultrafine ENMs with 0.025 mol/L TBAC presented a steady water flux of about 20.6 L/(m² h) and a high-efficiency salt rejection rate of over 99%. PVDF/TBAC ENMs are expected to provide a solution for development of efficient water treatment membrane. This article is protected by copyright. All rights reserved.