Glass Fiber Membrane Research Articles

Microplastics detection in some cosmetic samples by Accelerated Solvent Extraction and Micro-FTIR

Worldwide attention is focused on microplastics environmental pollution, primarily for its potential negative effects on biota and human health. It is of great importance to identify standardized analytical methods to have an objective feedback about this concern. The recent regulation regarding the intentionally added microplastics content and the attention for the unintentional microplastics release are the basis of this work, whose topic is the development of an analytical method for microbeads (spheres) and microparticles (fragments) determination in certain cosmetic samples, in particular creamy samples. The method is based on Accelerated Solvent Extraction technique to remove all the sample matrix ingredients. The final suspension was then filtered on silicon membrane, for the following quali-quantitative micro-FTIR analysis, and on glass fibre membranes, for the gravimetric analysis. The method was developed for a theoretical microplastics concentration of 0.025 % (w/w) and allows a good recovery percentage. Working both by gravimetric evaluation and by micro-FTIR analysis gives more confident results and guaranties a proper identification and characterization of the filtered materials.

Melamine-based nanoscale porous organic frameworks as multifunctional separator modifiers to mitigate the polysulfide shuttle effect in lithium–Sulfur batteries

The shuttling of polysulfides between electrodes in lithium-sulfur (Li-S) batteries significantly impairs cycle stability. This study explores the use of melamine-based nanoscale porous organic frameworks (POFs) as polysulfide reservoirs to modify glass fiber (GF) separators. Melamine was reacted with dibromoalkanes of varying carbon chain lengths (n = 4, 8, and 12) to produce a series of POF materials, POF-Cn, with different nanoscale pore sizes and solubilities. The POF composites, POF-Cn/SP/PVP, which include conductive carbon Super P (SP) and a polyvinylpyrrolidone (PVP) binder, were coated onto GF membranes to create modified separators for Li-S batteries. Batteries with these modified GF separators exhibited higher initial capacities, improved rate performance, and better long-term cycle stability compared to those with non-modified separators. Among the POF composites, POF-C8/SP/PVP exhibited the best performance, with an initial specific capacity of 1392 mAh g-1 at 0.1C and a high capacity retention of 90% after 300 cycles at 0.5C. The enhanced capacity, stability, and rate performance are attributed to the nanoporous structure of POF-C8 and its high nitrogen content, which effectively traps soluble LiPSs and reduces their diffusion toward the Li anode. The good solubility of POF-C8 facilitates uniform dispersion in the modifying layer, promoting efficient polysulfide trapping and maximizing their utilization in electrochemical reactions, aided by the conductive SP in the composite.

A versatile superhydrophilic/air-superoleophobic glass fiber membrane: Fabrication and application in oil/water separation

Superwetting materials have received extensive interest owing to their potential for efficient oil/water separation. Herein, a superhydrophilic-superoleophobic glass fiber membrane was fabricated through a simple spraying coating method. The membrane was coated with a composite layer of methyltrimethoxysilane (MTMS), fluorosurfactant (FS-50) and TiO2 nanoparticles. Accordingly, both hydrophilic groups (i.e., -OH) and oleophobic groups (i.e., fluorinated groups) were distributed on the membrane, and its surface roughness was improved by TiO2. The contact angles of water and oil on the coated membrane were 0° and 156.8° in air, respectively. By virtue of its selective permeability, it demonstrated separation efficiencies larger than 99.2 % for oil/water mixtures, which remained 98.7 % after 40 separation cycles. Furthermore, its separation efficiencies for oil-in-water emulsions were over 98.3 %, which remained 98 % after 10 separation cycles. Owing to its strong superoleophobicity, it displayed prominent anti-oil-fouling performance both in air and underwater. Besides, presence of TiO2 endowed it with photocatalytic capability, enabling it to recover from organic dye pollution. Moreover, the coated membrane maintained superoleophobic after 10 sandpaper-abrading or squeezing cycles. It also exhibited excellent stability under acid/alkali/salt conditions. The study provided new insights for constructing superwetting materials and an effective strategy for oil/water separation.

NiO nanosheets constructing honeycomb porous catalyst as an effective oxygen adsorption interlayer support for high performance lithium-oxygen batteries

Lithium-oxygen (LiO2) batteries are considered as a novel energy storage system as a result of its outstanding energy density. However, the challenge of oxygen corrosion is still restricting the practical application in LiO2 batteries. Here, we successfully acquire the NiO nanosheets constructing honeycomb porous catalysts as an effective oxygen adsorption interlayer support for high-performance LiO2 batteries. Honeycomb porous structures can store more oxygen and the defects in the exterior of NiO nanosheets can furnish more Lewis acid sites and catalytic sites to bind more O2− as a Lewis base for absorbing O2. Consequently, NiO nanosheets constructing honeycomb porous catalysts as interlayer is loading on the glass fiber membrane separator for LiO2 batteries in order to protect the anode from oxygen corrosion. The interlayer with 1.0 mg/cm2 NiO loading rate per unit area shows the outstanding electrochemical performance at a fixed 500 mAh/g specific discharge capacity and 0.1 mA/cm2 current density for 106 cycles in the LiO2 battery. This work provides an effective strategy to protect the Li metal anode in LiO2 batteries, at the same time, proposes a novel view for the efficient modification of separator.

Multifunctional Bionic Periosteum with Ion Sustained-Release for Bone Regeneration.

In this study, a novel bionic periosteum (BP)-bioactive glass fiber membrane (BGFM) is designed. The introduction of magnesium ion (Mg2+) and zinc ion (Zn2+) change the phase separation during the electrospinning (ES) jet stretching process. The fiber's pore structure transitions from connected to closed pores, resulting in a decrease in the rapid release of metal ions while also improving degradation via reducing filling quality. Additionally, the introduction of magnesium (Mg) and zinc (Zn) lead to the formation of negative charged tetrahedral units (MgO4 2- and ZnO4 2-) in the glass network. These units effectively trap positive charged metal ions, further inhibiting ion release. In vitro experiments reveal that the deigned bionic periosteum regulates the polarization of macrophages toward M2 type, thereby establishing a conducive immune environment for osteogenic differentiation. Bioinformatics analysis indicate that BP enhanced bone repair via the JAK-STAT signaling pathway. The slow release of metal ions from the bionic periosteum can directly enhance osteogenic differentiation and vascularization, thereby accelerating bone regeneration. Finally, the bionic periosteum exhibits remarkable capabilities in angiogenesis and osteogenesis, demonstrating its potential for bone repair in a rat calvarial defect model.

The Range of Influence across Commercial Glass Fiber Separators on the Cycling of the Zinc Metal Anode

Aqueous zinc-ion batteries (AZIBs) have attracted significant research attention due to their promising potential for large-scale energy storage applications in support of the rapid global growth of renewable wind and solar energy generation. However, challenges associated with the limited cycling life and low energy density of AZIBs persist as the critical limiting factors preventing their practical use in utility-scale energy storage applications [1]. Throughout zinc-ion research working to address these challenges, commercial glass fiber (GF) membranes are often used as the separator in studies investigating cathode, electrolyte, and anode designs [2]. Nevertheless, commercial GF membranes are available with a range of physicochemical properties, and the specific details of the selected membrane are often missing in published studies. In our work, we systematically compare Whatman™ GF separators (GF/A, GF/B, GF/C, GF/D, and GF/F) to assess the influence of the separator’s physicochemical properties (i.e., pore size and thickness) on the cycling life and cell-to-cell variability across multiple trials of Zn|Zn cells. Under constant current cycling, significant differences were observed in the cycling life and cell-to-cell consistency depending on the pore size and thickness of the GF separator [3]. In addition, our use of micro-computed X-ray tomography explores the associations between the separator’s pore size and zinc deposition morphology and provides visual identification of the failure mechanism corresponding with an overpotential collapse. The results of this work clarify the importance of GF separator selection and the separator’s influence to support the improvement of other cell components.

Load history dependency of stiffness properties of PTFE-coated glass fibre membranes

The aim of this contribution is to investigate whether the order of load ratios applied to a textile structure impacts the biaxial stiffness behaviour of the structural textile itself. These investigations are performed based on biaxial tests on an architectural woven glass fibre fabric, a representative of such membranes. The first part of the paper investigates the existence and extent of load history dependency in the material response. Biaxial test results show that effects of a previous load history on the weave geometry cannot be eliminated by further load cycling in all biaxial stress ratios. Moderate to strong effects are recognized in two stress ratios, although not in both weave directions.The second part of the paper examines how these effects influence material stiffness parameters and structural calculations. Two boundary value problems are investigated: a pressure chamber test and a roof structure. Parameters obtained by fitting biaxial tests with or without history are considered. By incorporating an adaptive load-ratio dependent scheme, highly predictive numerical results are obtained, showing that while the effect of load history may appear small in the biaxial tests and pressure chamber test, it can be significant in complex structural problems like roof structures.

Optimization of Total DNA Extraction from Dried Blood Samples.

While dried blood spots are a convenient source of genetic material, they are usually associated with a lower DNA yield than from a native sample. The study evaluated the DNA yield from dried blood samples prepared on glass fibre and cellulose membranes and investigated the reasons for the yield reduction. The extraction of total DNA from membrane-dried blood samples was optimized by spin-column extraction method. It was shown that preliminary short-term (20min) solubilization of a dried matrix in an aqueous medium, followed by standard extraction protocols for the mixture of the eluate with membranes, provides the highest DNA yield. The yield of DNA from a glass fibre membrane was 40-50% lower compared to a native sample, but on average, two times higher than from a conventional cellulose membrane (filter paper). The reduction of DNA yield when using a dried sample was found to be due to partial retention of nucleic acids by the membrane material during the lysis stage.

Amorphous FeSnOx Nanosheets with Hierarchical Vacancies for Room-Temperature Sodium-Sulfur Batteries.

Room-temperature sodium-sulfur (RT Na-S) batteries, noted for their low material costs and high energy density, are emerging as a promising alternative to lithium-ion batteries (LIBs) in various applications including power grids and standalone renewable energy systems. These batteries are commonly assembled with glass fiber membranes, which face significant challenges like the dissolution of polysulfides, sluggish sulfur conversion kinetics, and the growth of Na dendrites. Here, we develop an amorphous two-dimensional (2D) iron tin oxide (A-FeSnOx) nanosheet with hierarchical vacancies, including abundant oxygen vacancies (Ovs) and nano-sized perforations, that can be assembled into a multifunctional layer overlaying commercial separators for RT Na-S batteries. The Ovs offer strong adsorption and abundant catalytic sites for polysulfides, while the defect concentration is finely tuned to elucidate the polysulfides conversion mechanisms. The nano-sized perforations aid in regulating Na ions transport, resulting in uniform Na deposition. Moreover, the strategic addition of trace amounts of Ti3C2 (MXene) forms an amorphous/crystalline (A/C) interface that significantly improves the mechanical properties of the separator and suppresses dendrite growth. As a result, the task-specific layer achieves ultra-light (~0.1 mg cm-2), ultra-thin (~200 nm), and ultra-robust (modulus=4.9 GPa) characteristics. Consequently, the RT Na-S battery maintained a high capacity of 610.3 mAh g-1 and an average Coulombic efficiency of 99.9 % after 400 cycles at 0.5 C.

Amorphous FeSnOx Nanosheets with Hierarchical Vacancies for Room‐Temperature Sodium‐Sulfur Batteries

AbstractRoom‐temperature sodium‐sulfur (RT Na−S) batteries, noted for their low material costs and high energy density, are emerging as a promising alternative to lithium‐ion batteries (LIBs) in various applications including power grids and standalone renewable energy systems. These batteries are commonly assembled with glass fiber membranes, which face significant challenges like the dissolution of polysulfides, sluggish sulfur conversion kinetics, and the growth of Na dendrites. Here, we develop an amorphous two‐dimensional (2D) iron tin oxide (A‐FeSnOx) nanosheet with hierarchical vacancies, including abundant oxygen vacancies (Ovs) and nano‐sized perforations, that can be assembled into a multifunctional layer overlaying commercial separators for RT Na−S batteries. The Ovs offer strong adsorption and abundant catalytic sites for polysulfides, while the defect concentration is finely tuned to elucidate the polysulfides conversion mechanisms. The nano‐sized perforations aid in regulating Na ions transport, resulting in uniform Na deposition. Moreover, the strategic addition of trace amounts of Ti3C2 (MXene) forms an amorphous/crystalline (A/C) interface that significantly improves the mechanical properties of the separator and suppresses dendrite growth. As a result, the task‐specific layer achieves ultra‐light (~0.1 mg cm−2), ultra‐thin (~200 nm), and ultra‐robust (modulus=4.9 GPa) characteristics. Consequently, the RT Na−S battery maintained a high capacity of 610.3 mAh g−1 and an average Coulombic efficiency of 99.9 % after 400 cycles at 0.5 C.

High Performance Aqueous Zinc-Ion Batteries Developed by PANI Intercalation Strategy and Separator Engineering.

Aqueous zinc-ion batteries (ZIBs) have attracted burgeoning attention and emerged as prospective alternatives for scalable energy storage applications due to their unique merits such as high volumetric capacity, low cost, environmentally friendly, and reliable safety. Nevertheless, current ZIBs still suffer from some thorny issues, including low intrinsic electron conductivity, poor reversibility, zinc anode dendrites, and side reactions. Herein, conductive polyaniline (PANI) is intercalated as a pillar into the hydrated V2O5 (PAVO) to stabilize the structure of the cathode material. Meanwhile, graphene oxide (GO) was modified onto the glass fiber (GF) membrane through simple electrospinning and laser reduction methods to inhibit dendrite growth. As a result, the prepared cells present excellent electrochemical performance with enhanced specific capacity (362 mAh g-1 at 0.1 A g-1), significant rate capability (280 mAh g-1 at 10 A g-1), and admirable cycling stability (74% capacity retention after 4800 cycles at 5 A g-1). These findings provide key insights into the development of high-performance zinc-ion batteries.

Towards in vitro – In vivo correlation models for in situ forming drug implants

In vitro-In vivo correlation (IVIVC) is a main focus of the pharmaceutical industry, academia and the regulatory sectors, as this is an effective modelling tool to predict drug product in vivo performance based on in vitro release data and serve as a surrogate for bioequivalence studies, significantly reducing the need for clinical studies. Till now, IVIVCs have not been successfully developed for in situ forming implants due to the significantly different in vitro and in vivo drug release profiles that are typically achieved for these dosage forms. This is not unexpected considering the unique complexity of the drug release mechanisms of these products. Using risperidone in situ forming implants as a model, the current work focuses on: 1) identification of critical attributes of in vitro release testing methods that may contribute to differences in in vitro and in vivo drug release from in situ forming implants; and 2) optimization of the in vitro release method, with the aim of developing Level A IVIVCs for risperidone implants. Dissolution methods based on a novel Teflon shape controlling adapter along with a water non-dissolvable glass fiber membrane (GF/F) instead of a water dissolvable PVA film (named as GF/F-Teflon adapter and PVA-Teflon adapter, respectively), and an in-house fabricated Glass slide adapter were used to investigate the impact of: the surface-to-volume ratio, water uptake ratio, phase separation rate (measured by NMP release in 24 h post injection in vitro or in vivo), and mechanical pressure on the drug release patterns. The surface-to-volume ratio and water uptake were shown to be more critical in vitro release testing method attributes compared to the phase separation rate and mechanical pressure. The Glass slide adapter-based dissolution method, which allowed for the formation of depots with bio-mimicking surface-to-volume ratios and sufficient water uptake, has the ability to generate bio-relevant degradation profiles as well as in vitro release profiles for risperidone implants. For the first time, a Level A IVIVC (rabbit model) has been successfully developed for in situ forming implants. Release data for implant formulations with slightly different PLGA molecular weights (MWs) were used to develop the IVIVC. The predictability of the model passed external validation using the reference listed drug (RLD), Perseris®. IVIVC could not be developed when formulations with different PLGA molar ratios of lactic acid to glycolic acid (L/G) were included. The present work provides a comprehensive understanding of the impact of the testing method attributes on drug release from in situ forming implants, which is a valuable practice for level A IVIVC development.

Effect of membrane properties on the odor emanating from training aids for explosive-detecting canines.

Canines are widely used for real-time detection of explosives and have proven to be on par with instrumental methods. Canines are thought to rely largely upon detection of volatile chemical constituents of the explosives, though not necessarily the explosive itself. Hence, it is crucial to understand the odor available to them as generated by training aids. Previous studies have established that the Training Aid Delivery Device (TADD) developed by SciK9 is a reliable training aid that reduces cross-contamination and doubles as a storage device. A TADD comprises a standardized container, a synthetic membrane, a membrane holder, and a lid. In the work presented, activated charcoal strips were placed above and below the TADD membrane to determine the relative amounts of volatiles emitted by dynamite (i.e., ethylene glycol dinitrate (EGDN) and trinitroglycerin (NG)). The strips were eluted and the extracts tested using gas chromatography-mass spectrometry in negative ion chemical ionization mode. A series of t-tests at 95% confidence level were performed to determine any differences in vapor composition above and below the membranes. Nine synthetic membranes and six glass fiber membranes were tested in this study. It was expected that the relative concentration of volatiles would remain the same on both sides of the membrane; however, selective removal of nitroglycerin by some membranes was observed. Synthetic membranes with larger pore sizes showed no alteration in the vapor composition. Both synthetic and glass fiber membranes did not show a significant change in relative concentration of the other volatile compound in dynamite, i.e., EGDN. Out of all the membranes tested, three synthetic membranes and four glass fiber membranes showed selective alteration in odor availability of nitroglycerin in dynamite. For training purposes, membranes that do not alter the vapor composition should be used in the training aid.

Touchpad-based immunochromatographic strip for detecting the skin surface proteins

This study demonstrates, for the first time, the proof-of-concept of a novel immunosensor, a touchpad-based immunochromatographic strip, that non-invasively extracts and detects skin surface proteins. The strip was composed of a nitrocellulose membrane at the center, where a spot of anti-human IgG capture antibody was physically adsorbed. The capture antibody spot was covered with a glass fiber membrane impregnated with phosphate-buffered saline (PBS) to extract skin surface proteins, avoiding direct contact of the human skin with the capture antibodies. Skin surface IgG was detected in two steps: (1) touching the capture antibody via a glass fiber membrane containing PBS, and (2) dipping the strip into the Au-nanoparticle-labeled secondary antibody to visualize the existence of the captured skin surface IgG on the strip. We qualitatively demonstrated that using a very small amount of PBS while maintaining contact with the skin, skin surface proteins can be concentrated and detected, even with a relatively low-sensitivity immunochromatographic chip. This sensor is expected to be a potential biosensor for the non-invasive diagnosis of the integrity of human skin.

Membrane fouling during the harvesting of microalgae using static microfiltration

A challenge in the filtration of algal suspensions is the reduction in filtrate flow rate with time, associated with membrane fouling and filtercake formation. These two fouling mechanisms may occur simultaneously and have different effects on the scaling relationship of filtration rate with time, making quantitative predictions of the filtration behaviour complex. The foulants include suspended microalgal cells and their presumed Extracellular Polymeric Substances (EPS). To investigate this problem, we perform static microfiltration experiments to harvest oil-rich marine microalgae Nannochloropsis oculata. Batch filtration experiments of microalgal suspensions using glass-fibre membranes are conducted under filtration pressures varying between 0.5 and 200 kPa. Here we investigate the relative importance of potential fouling mechanisms, including pore plugging, entrance blocking, and filtercake formation. We examine variations in filtrate flux, using a novel approach involving numerical differentiation of the filtrate volume to identify how its scaling relationship with time and compare with the traditional root-time behaviour. These results are analysed with reference to the blocking filtration laws to determine the potential fouling mechanism. Rheology tests of both filtration feeds and filtrate are performed, and both optical and scanning electron microscopy are used to observe the filtercake. Our results show a significant drop in the filtrate flux after a spurt loss phase under pressure. The scaling analysis demonstrates a power law relationship between cumulative filtrate volume and time in the post-spurt phase. We show here, for the first time, that the scaling exponent varies with time, approaching a value close to 0.5 (i.e. the root-time behaviour) after a long period of time. Using the analysis, we conclude that the filtration process can be divided into various stages; a spurt loss phase when the pressure is initially applied, followed by a stage in which both internal and external filtercake formation occurs, and a final stage which is dominated by external filtercake formation (at which point root-time behaviour is observed). Furthermore, our findings suggest that fresh microalgal suspensions experienced a larger spurt loss compared to aged suspensions in microfiltration. This difference may be attributed to the limited production of EPS and microalgal debris during shorter cultivation periods. The microscopic observations reveal the invasion of microalgal cells into the membrane, which verifies the formation of an internal filtercake suggested by our scaling analysis. The contamination of the membrane increases with higher filtration pressures. Finally, we demonstrate that Fe3+ coagulant can be used to increase the microalgal particulate size before filtration, resulting in a much higher filtrate flux compared to uncoagulated suspensions. This result provides opportunities to reduce membrane contamination to a negligible level.

Interfacial redox modulation of polysulfides with ferrocene functionalized separator in Al–S batteries

Despite the bright future of aluminum-sulfur (Al–S) batteries due to the ultrahigh energy-to-price ratios, the development of this new energy storage system is plagued by the shutting of polysulfides and sluggish kinetics during redox conversions. Herein, ferrocene as efficient polysulfide mediators and electrocatalysts is covalently grafted onto glass fiber (GF) membranes, which serves as separators in Al–S batteries. Attributed to the strong chemisorption and catalytic effect of metallocene toward polysulfide conversions, Al–S cells assembled with the grafted separators deliver an ultrahigh initial capacity of 1347.9 mAh g−1 (at 200 mA g−1) and desirable rate performance (328.1 mAh g−1 at 500 mA g−1). As validated by theoretical calculations, effective polysulfide binding is achieved through beneficial cation-π interactions between Al3+ in polysulfides and the negatively charged cyclopentadienyl ligands in ferrocene, providing novel insights into the exploration of metal-sulfur chemistries for stable energy storage.

The engineering legacy of the FIFA World Cup Qatar 2022TM: Al Thumama Stadium

The structures of the Al Thumama Stadium, built for the FIFA World Cup Qatar 2022, can be categorised into four main building components. The permanent bowl structure with lower and middle tiers is mainly cast-in-place reinforced concrete with precast seating units. Structural steel was used for the upper tier stands, to be dismantled for legacy conversion after the tournament. The roof and façade system use steel and cable systems with a unique membrane cladding design derived from the cultural gahfiya symbol. The roof is a self-anchored tension–compression ring system based on the principle of a horizontal spoked wheel, with one compression ring along the outer perimeter and two tension rings along the oculus. The façade consists of lightweight double-layered and prestressed cable nets spanning between curved vertical beams. A translucent polytetrafluoroethylene-coated glass fibre membrane with highly transparent mesh inserts form the cladding of the stadium, providing its unique architectural design. This article gives an overview of the stadium's design and construction methodology.

Hydrophobicity and membrane distillation performance of glass fiber membranes modified by dip coating of pure PDMS

With growing concern for environmental issues associated with the use of chemicals and nanomaterials to achieve membrane hydrophobicity, polydimethylsiloxane has emerged as a promising and eco-friendly alternative. However, few studies have explored the application of pure PDMS solutions through dip coating to achieve hydrophobicity in membranes designed for membrane distillation; a process which demands the membranes possess specific porosity and pore size characteristics. This study explored how dip coating with different PDMS concentrations affected the hydrophobicity and physical properties of glass fiber membranes. Increasing the concentration of polydimethylsiloxane up to 15% resulted in a stepwise rise in hydrophobicity, but the functionality as a membrane was compromised when the concentration reached 20%. Hydrophobicity on the membrane surface was higher with 15% PDMS treatment than on the chemically grafted membrane, but the latter demonstrated superior performance in the membrane distillation process. Nevertheless, the study confirms the potential of the pure PDMS-coated membrane as a viable option for membrane distillation, with the possibility of enhancing performance through improvements in pore size and surface morphology.

First Record of Microplastic Contamination in the Non-Native Dark False Mussel Mytilopsis leucophaeata (Bivalvia: Dreissenidae) in a Coastal Urban Lagoon.

Microplastic contamination is a global concern due to its conspicuous presence in aquatic ecosystems and its toxic nature to environmental and human health. False mussels are among the most notable fresh- and brackish water invaders. The invasive Mytilopsis leucophaeata in Rodrigo de Freitas Lagoon-RFL (Rio de Janeiro, Brazil) is the most abundant macrofaunal invertebrate, widely established and distributed throughout the lagoon. This study aimed to assess microplastic contamination in this invasive filter feeder and evaluate its potential use as a bioindicator. Agglomerates (~100 mussels) were manually collected using a stainless-steel spatula in ten sampling areas distributed throughout the whole lagoon and kept frozen. In the laboratory, 60 individuals were sorted by area for soft-tissue digestion. Each pool of 10 soft-tissue mussels (n = 6 by area) was wet-weighted and then placed in a 150-mL decontaminated glass beaker with 50 mL of 10% KOH. Samples were heated (40 °C) for 48 h, and digested samples were filtered in glass-fiber membranes. Microplastics were found in all samples of mussels (n = 60) from RFL; the particles were mostly lower than 100 µm with a mean concentration (±SD) of 35.96 ± 47.64 MPs g wet-weight-1. Microplastics were distinguished in seven shapes with different occurrences in samples (%): fiber (43.3%); fragment (34.3%); film (16.3%); sponge/foam (4.9%); pellet (0.57%), rope/filaments (0.17%); and undefined (0.4%). Thirteen colors of microplastics were found, but transparent (54.94%), black (10.77%), and white (9.36%) were the most common. Mytilopsis leucophaeata were useful to assess microplastic contamination in RFL and might be preferentially used in other invaded brackish systems instead of native and often threatened bivalves. Our results confirm the effective application of bivalves as an indicator of coastal microplastic pollution.

Biopolymer-Based Protective Layer for Stable and Highly Reversible Zinc Metal Anodes

Zinc (Zn) metal has attracted considerable attention because of its natural abundance and stability in aqueous environments compared with lithium/sodium metal anodes. Moreover, Zn metal as anode showed a high theoretical capacity (820 mAh g−1), high energy per volume (5855 mA cm−3), and low operational potential (–0.78 V vs SHE) in electrochemical systems. However, Zn metal suffers from dendrite growth and poor plating/stripping reversibility, resulting from inhomogeneous Zn ion flux and contamination by generally used glass fiber membranes (GFs) as separators. Although studies to inhibit dendritic Zn growth have been conducted, dendritic Zn remains still a major problem during long-term cycling under practical rate and capacity conditions. In this context, it is essential to investigate Zn deposition behavior from initial nucleation to Zn growth morphologies after long-term cycling.Among the problematic factors pointed out by researchers, the irregular pore distribution of GFs causes uneven Zn ion flux. Moreover, the detached fibers after cycling contaminate the Zn anode surface, resulting in nonuniform Zn deposition and trapping of Zn metal in the separator. To stabilize Zn metal anodes, introducing a protective layer can be an effective strategy to construct ion channels with abundant functional groups for high affinity with Zn metaland protect from direct contact with GFs. Organic polymers are suitable candidates for construction of protective layer which tolerates the volume changes of Zn metal and exhibit good chemical compatibility with Zn metal.Polysaccharides are favorable for use as gel polymers, separators, and binders owing to their cost-effectiveness and good electrochemical properties. Besides, they contain various oxygen-containing groups, resulting in relatively high ionic conductivity. However, it is not sufficient to fabricate membranes for the stabilization of Zn metal using polysaccharide alone because of insufficient ion conductive properties. This problem can be solved by blending polymers with high ionic conductivities such as poly(ethylene oxide) (PEO), poly(vinylidene difluoride), and poly(vinyl chloride). Notably, PEO has mainly been used in gel polymer electrolytes. The hydroxyl groups of PEO can facilitate the transport of metal ions and ether linkages can enhance the affinity with cations, resulting high ionic conductivity.In this study, we designed a functional protective layer by blending polysaccharide and PEO and investigated Zn deposition behavior from the formation of initial nucleation to Zn growth process after long-term cycling. The protective layer, fabricated by a one-pot method, featured highly dispersed blending polymers by phase separation and contained uniformly distributed oxygen-containing functional groups. Moreover, we demonstrated that the protective layer induced the formation of regular Zn nucleation sites and smooth Zn deposition after long-term cycling under the realistic conditions required for high-energy metal battery systems. Using the Zn||Cu and Zn||Zn cells stabilized by the protective layer under low capacity (0.1 mAh cm−2), we confirmed that homogeneous initial Zn deposition patterns were induced by ex situ SEM images of Cu and Zn electrodes. Subsequently, smooth and dense Zn growth was confirmed under fast Zn plating/stripping conditions, indicating that protective layer can induce basal plane (002) dominant deposition to mitigate dendrite formation and protect physically and chemically from GFs.Based on the morphological Zn deposition behavior, we successfully fabricated a functional protective layer and significantly enhanced the electrochemical performance of Zn metal battery systems. The Zn||Cu cells with a functional protective layer showed significantly increased long-term cycling above 3850 cycles (more than 160 days) at high rate and capacity condition (2 mA cm−2 and 1 mAh cm−2). In addition, the durability of protective layer was confirmed by a high-rate test (at 10 mA cm−2). These results are consistent with those of the Zn||Zn symmetric cell tests under harsh conditions of 5 mA cm−2 and 5 mAh cm−2. Furthermore, full cell with the protective layer using vanadium disulfides as the cathode exhibited enhanced cyclability over 1000 cycles with 87 % capacity retention compared to the bare full cell that short-circuited at the 340th cycle.Our work demonstrated that there are two important factors affecting the durability of Zn anodes: (i) Zn metal surface should be protected by a smooth and dense layer with high affinity to Zn metal and ions and (ii) physical and chemical contamination from GFs. Figure 1