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Detection sensitivity of aquatic species using environmental DNA (eDNA) generally decreases in turbid water but is poorly characterized. In this study, eDNA detection targeted delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish associated with turbid water. eDNA sampling in the field was first paired with a trawl survey. Species-specific detection using a Taqman qPCR assay showed concordance between the methods, but a weak eDNA signal. Informed by the results of field sampling, an experiment was designed to assess how turbidity and filtration methods influence detection of a rare target. Water from non-turbid (5 NTU) and turbid (50 NTU) estuarine sites was spiked with small volumes (0.5 and 1 mL) of water from a delta smelt tank to generate low eDNA concentrations. Samples were filtered using four filter types: cartridge filters (pore size 0.45 μm) and 47 mm filters (glass fiber, pore size 1.6 μm and polycarbonate, pore sizes 5 and 10 μm). Prefiltration was also tested as an addition to the filtration protocol for turbid water samples. eDNA copy numbers were analyzed using a censored data method for qPCR data. The assay limits and lack of PCR inhibition indicated an optimized assay. Glass fiber filters yielded the highest detection rates and eDNA copies in non-turbid and turbid water. Prefiltration improved detection in turbid water only when used with cartridge and polycarbonate filters. Statistical analysis identified turbidity as a significant effect on detection probability and eDNA copies detected; filter type and an interaction between filter type and prefilter were significant effects on eDNA copies detected, suggesting that particulate-filter interactions can affect detection sensitivity. Pilot experiments and transparent criteria for positive detection could improve eDNA surveys of rare species in turbid environments.

In recent years, the demand for filter media has increased dramatically, driven by the need to manufacture personal protective equipment and for various applications in the industrial and civil sectors. Nanofiber‐based membranes are proposed as potential alternatives to commercial filtration devices. This study presents the design and implementation of an innovative pre‐industrial electrospinning setup, combining a negatively charged spinneret and a positively charged counter‐electrode, capable of producing polyvinylidene fluoride (PVDF) nanofibers with an average diameter of 410 nm and electrostatic surface potential values 3.7 times higher compared to a conventional electrospinning process, eliminating the need for further post‐treatment. These properties are essential for improving mechanical and electrostatic filtration of small particles, including infectious droplets. The surface potential of the membranes is also long‐lasting, as evidenced by tests one year after manufacture. As a case‐study, these filters are used to manufacture surgical masks, reporting excellent performance in terms of bacterial filtration efficiency (BFE) up to 99.9%, and breathability (29.8±4.5 Pa cm−2) when compared to commercially available meltblown polypropylene (PP) face masks, and also complied with the stringent European standard (EN14683:2019) for type‐II surgical masks. Furthermore, the pre‐industrial setup allows for increased production capacity of up to 42 000 m2 per year, suitable for large‐scale production. [ABSTRACT FROM AUTHOR]

With the inherent demand for hydrophobic materials in processes such as membrane distillation and unidirectional moisture conduction, the preparation and application development of profiles such as modified cellulose acetate membranes that have both hydrophobic functions and biological properties have become a research hotspot. Compared with the petrochemical polymer materials used in conventional hydrophobic membrane preparation, cellulose acetate, as the most important cellulose derivative, exhibits many advantages, such as a high natural abundance, good film forming, and easy modification and biodegradability, and it is a promising polymer raw material for environmental purification. This paper focuses on the research progress of the hydrophobic cellulose acetate preparation process and its current application in the water-treatment and resource-utilization fields. It provides a detailed introduction and comparison of the technical characteristics, existing problems, and development trends of micro- and nanostructure and chemical functional surface construction in the hydrophobic modification of cellulose acetate. Further review was conducted and elaborated on the applications of hydrophobic cellulose acetate membranes and other profiles in oil–water separation, brine desalination, water-repellent protective materials, and other separation/filtration fields. Based on the analysis of the technological and performance advantages of profile products such as hydrophobic cellulose acetate membranes, it is noted that key issues need to be addressed and urgently resolved for the further development of hydrophobic cellulose acetate membranes. This will provide a reference basis for the expansion and application of high-performance cellulose acetate membrane products in the environmental field. [ABSTRACT FROM AUTHOR]

Polymer-based wastewater disinfection, which is typically performed using chemical oxidation or irradiation, can result in various toxic byproducts and corrosion under harsh environments. This study introduces a robust bio-adsorbent prepared from naturally abundant polydopamine-modified medical stone (MS@PDA) for the high-efficiency removal of bacteria from water. The PDA nanocoating can be easily applied through an in situ self-polymerization process, resulting in a considerably high bacterial adsorption capacity of 6.6 k pcs mm−2 for Staphylococcus aureus. A cyclic flow-through dynamic filtration and a disinfection system was implemented using an MS@PDA porous filter with an average pore size of 21.8 ± 1.4 µm and porosity of ~83%, achieving a 5.2–6.0-fold enhancement in the cumulative removal efficiency for MS@PDA2. The underlying mechanisms were elucidated through the synergistic effects of interfacial bio-adsorption and size-dependent interception. Notably, the bacteria captured on the surface could be killed using the enhanced photothermal effects of the PDA nanocoating and the inherent antimicrobial properties of the mineral stone. Thus, this study not only provides a new type of advanced bio-adsorbent but also provides new perspectives on an efficient and cost-effective approach for sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]

This study investigates the influence of particle shape on the void space morphology and topology in granular materials. Numerical samples with spherical and ellipsoidal particle shapes were generated using the discrete element method. A segmentation algorithm was used to extract the pore space characteristics. The results reveal that particle shape significantly affects both constriction and pore sizes, with distinctive features according to flatness index or elongation ratio, the former being more significant than the latter. The obtained results were validated by conducting numerical filtration tests, which illustrated a direct correlation between the constriction properties derived from the pore space extraction and the blockage rate of fine particles in the filtration tests. The study revealed the importance of considering particle shape in filter design, emphasising its significant impact on pore space characteristics and filtration performance. [ABSTRACT FROM AUTHOR]

Ultrafine particulate matter and airborne microorganisms present in the atmosphere significantly affect human health, leading to serious respiratory diseases. Among these particulates are bioaerosols, which include viruses, bacteria, and fungi. When inhaled, these microorganisms can cause diseases, such as influenza, tuberculosis, and COVID-19. Therefore, the development of bifunctional membranes that can simultaneously filter particulate matter (PM) and inhibit microorganism growth is essential. Electrospun filters, known for their high surface area, are effective in capturing these airborne particles. This study presents a novel approach by incorporating various surfactants into electrospun filters made from 8% polyacrylonitrile (PAN). The surfactants used include cetyltrimethylammonium bromide (CTAB), widely cited in the literature for bactericidal filtering applications, as well as sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC), which are rarely used in electrospun filters for this purpose. The addition of surfactants enhanced the filter performance, capturing particles smaller than 250 nm with over 99% efficiency for particles between 6.38 and 242 nm. The pressure drop across the filters ranged from 111.4 ± 1.2 to 204.4 ± 1.1 Pa. Moreover, the incorporation of surfactants not only improved hydrophobic and hydrophilic properties—where hydrophobic nanofibers performed better for filtration—but also significantly increased antimicrobial activity against Staphylococcus aureus (97.25 ± 0.95%) and Escherichia coli (94.52 ± 2.37%). These filters not only capture particles but also inactivate pathogens, contributing to a healthier environment. Filters with biocidal properties are particularly useful in hospitals, laboratories, and other settings where air sterility is critical. [ABSTRACT FROM AUTHOR]

Nanofiber membranes receive considerable interest recently because of their distinctive structural features, facile preparation, as well as high filtering efficiency. Due to ever‐increasing air pollution, membranes made from biodegradable materials can play a crucial part in providing purified air with minimum concerns of environmental issues after the membrane's end of service life. The purpose of this systematic review is to assess the performance of biodegradable electrospun nanofibrous membrane filters toward air sub‐micron particles. To identify relevant studies, a systematic search is carried out in major scientific search engines including PubMed, Scopus, and the Web of Science. Data extraction is used to collect the necessary information on the membranes' structural properties, as well as filtration performance metrics such as efficiency, pressure drop, and quality factor. Among the electrospun membranes derived from biodegradable polymers, the polyvinyl alcohol (PVA)‐based electrospun membranes are more effective in filtration efficiency in capturing sub‐micron particles. The results highlight that these types of membranes are effective in filtration with low energy consumption, making them more apt for air purification. The use of such membranes can supply both high filtering performance and protection of the environment. [ABSTRACT FROM AUTHOR]

Low‐cost ceramic membrane support is important for the filtration performance of a asymmetry filtration membrane. In this study, the oil‐based drilling cutting pyrolysis residues (ODPRs) were used as raw materials incorporating with fly ash, and carbon particles were used as pore‐forming agents to prepare high‐flux low‐cost ceramic membrane supports. Besides the strength of the supports was decreased with increased carbon particles addition and size, the porosity, pore size and consequently the Darcey permeability k1 and pure water permeability of the support were increased with the increased carbon particle addition and size. The chemical stability of the support was deteriorated with the increased carbon particles addition. A leaching test on the support with 10% 12 µm carbon particle addition indicates that the support obtained by using the ODPRs incorporating with fly ash as raw materials is safe for aqueous filtration. This study showcased the utilization of ODPRs as a primary resource to manufacture a high‐permeability support for water filtration. This approach aligns with the principles of sustainable development, following a waste‐to‐product‐to‐environment pathway. [ABSTRACT FROM AUTHOR]

The selection of an appropriate fabric for technical applications, such as protective masks, hinges on a thorough understanding of the fabric's physical and mechanical properties. This study addresses the challenge of selecting the optimal material structure for the upper layer of a protective mask, aiming to ensure adequate breathability while providing effective filtration against airborne particles and contaminants. We assessed and compared the physical–mechanical properties of five polymer spun-bond nonwoven fabrics from different suppliers. Our comprehensive evaluation included, as follows: a visual inspection; light permeability analysis; mass and thickness measurements; elongation and tensile strength tests; breathing resistance assessments; and filter penetration tests with paraffin oil. The results revealed significant variations in performance among the samples, with one fabric consistently outperforming the others across multiple parameters. Notably, this top-performing fabric met or exceeded the EN 149:2001+A1:2009 standard for breathing resistance and filtration efficiency and, in combination with additional filter layers, met the requirements or exceeded class FFP2 (filtering face piece). This study underscores the importance of meticulous material selection and quality control in optimizing PPE (personal protective equipment) performance and user safety, providing valuable insights for mask manufacturers and healthcare professionals. [ABSTRACT FROM AUTHOR]

The vacuum preloading technique is extensively employed for ground improvement, particularly for slurry ground characterized by high‐water content and low strength. Such ground frequently exhibits a delay in pore water pressure dissipation when treated with prefabricated vertical drains. To clarify the drainage and consolidation behaviour of high‐water content slurry ground under vacuum preloading, this study proposed a two‐stage combined model that integrates both filtration and consolidation processes. Initially, an axisymmetric filtration model was used to describe the formation of the soil column through the radial migration and compaction of the particles. The end‐of‐filtration radial distributions of void ratio, permeability coefficient, and effective pressure served as initial conditions for the consolidation stage analysis. This stage was depicted using a large strain consolidation model based on the free strain condition. The results showed the necessity of incorporating the filtration stage to capture the overall drainage mechanism and characteristics of slurry ground with vacuum preloading treatment. [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic autoimmune disease with a long disease course and frequent relapse characteristics. It is now recognised to be associated with epidermal environments of inflammatory cytokines. However, its pathogenesis is still not completely clear. We found the haemorheology of psoriatic patients to be abnormal, and ageing and deformed erythrocytes increased in the blood. The abnormal erythrocytes were more likely to induce psoriasis, which was confirmed in a mouse model induced by different blood components of psoriatic patients/healthy volunteers. Spleen filtration dysfunction, which caused abnormal erythrocytes, was also more likely to induce psoriasis, which was confirmed in a mouse model induced by splenectomy. The mechanism was the weakening of the 'eat me' function of spleen macrophages phagocytizing ageing and deformed erythrocytes, resulting in the dysfunction of spleen filtration and the increase of ageing and deformed erythrocytes in the body. Additionally, the decreased oxygen‐carrying capacity and the declined antioxidant capacity of those erythrocytes led to the hypoxia environment, making psoriasis more likely to be induced. These findings demonstrate that spleen filtration dysfunction contributes to the pathogenesis of psoriasis and suggest that improving it may be an effective therapy for psoriasis and control its relapse. [ABSTRACT FROM AUTHOR]

Filter use in experiments is often unspecified, potentially affecting results. In this study, six different filters were investigated for technetium and iodine. Technetium was evaluated at pH 2.5, 6, and 11 for two concentrations. Three oxidation states of iodine (iodide, molecular iodine, and iodate) were evaluated at pH 7 for two concentration levels. The results obtained were analyzed using a t-test to determine if it was statistically different than an unfiltered sample. The experimental results are combined with a literature review highlighting the inconsistency of filter reporting in manuscripts, as well as not accounting for analyte loss on filters used. [ABSTRACT FROM AUTHOR]

Background: An October, 2021 review of Public Health Ontario's COVID-19 guidance for congregate settings such as shelters and long-term care homes demonstrated that this guidance did not include references to ventilation or filtration. In April 2022, an interdisciplinary team with expertise in indoor air quality (IAQ), engineering, epidemiology, community programming and knowledge translation launched a virtual ventilation and filtration consultation program for community spaces in Toronto, Ontario. The program gives people working in community spaces direct access to IAQ experts through 25-min online appointments. The program aims to help reduce the risk of COVID-19 transmission in community spaces, and was designed to help compensate for gaps in public health guidance and action. Methods: Representatives from participating organizations (n. 27) received a link to an online survey via email in April 2023. Survey questions explored the impacts of the program on topics such as: purchase and use of portable air filters; maintenance and use of bathroom fans; and, maintenance and modification of HVAC systems. Survey participation was anonymous, and no demographic information was collected from participants. Results: Representatives from 11 organizations completed the survey (40%). Of those who responded, nine (82%) made changes as a result of the program, with eight (73%) making two or more changes such as purchasing portable air filters and increasing routine maintenance of HVAC systems. Conclusions: When presented with brief access to expert support and tailored plain language guidance, people working in community spaces increased their use of ventilation and filtration strategies for COVID-19 infection prevention and control. [ABSTRACT FROM AUTHOR]

With the increase in air pollutants and bacteria hazards, conventional melt-blown cloth of polypropylene (PP), which is widely used as the filtering medium, can no longer meet people's needs due to its insufficient filtration efficiency, lack of antibacterial function, etc. In this study, the nanoparticles of the zinc and cobalt imidazolate framework (ZnCo-ZIF) were synthesized and directly incorporated into polylactide (PLA) to prepare PLA/ZnCo-ZIF fibrous membranes through electrospinning methodology. The addition of ZnCo-ZIF resulted in a decrease in the average diameter of fiber from 1.01 μm of pure PLA membrane to 0.72 μm of PLA/ZnCo-ZIF (3 wt%) membrane. The PM filtration and antimicrobial properties of PLA/ZnCo-ZIF fibrous membranes were tested. The PLA/ZnCo-ZIF (2 wt%) membrane displayed great filtration ability, and the filtration efficiencies for PM2.5 and PM10 were 90.88% and 93.00%, compared to 75.76% and 79.37% of PP melt-blown cloth. In addition, the antibacterial rates of the PLA/ZnCo-ZIF (3 wt%) membrane reached 100% and 93.24% against E. coli and S. aureus, which were higher than 85.80% and 90.59% of the PLA/ZIF-8 (3 wt%) membrane. The prepared membranes could be used in the field of masks instead of PP melt-blown fabric, and they solved the problem of the non-degradability and non-functionalization of melt-blown fabric. [ABSTRACT FROM AUTHOR]

Different composition of mixed matrix membranes comprising Polyvinylidene fluoride (PVDF) as base polymer, Polyvinylpyrrolidone and Montmorillonite clay as additive was fabricated by phase inversion technique using N, N-Dimethylacetamide as a solvent. Furnished membrane samples were characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) for phase identification, functional group analysis, thermal stability, determination of surface morphology and textural features which show that PVP and MMT successfully modified PVDF membrane and resulted in PVDF/PVP/MMT mixed matrix membrane. Different membrane characteristics such as pure water flux, water content, porosity, shrinkage ratio, fouling recovery ratio and solute rejection were studied and calculated. The contemporary membrane (PPM5) having 5 wt. % of MMT represented the increase in pure water flux, porosity, and fouling recovery ratio from 13.8 Lm−2h−1, 33% and 52% to 19.8 Lm−2h−1, 85%, and 87%, respectively. The PPM5 also shows a reduction in shrinkage ratio from 19% to 7% and improved hydrophilicity which results in a solute rejection factor of 83% and 87% for Pb(II) and Cd(II), respectively, in comparison to other fabricated membranes. These membranes provide an economical and effective solution for wastewater treatment. [ABSTRACT FROM AUTHOR]

Image denoising is crucial for enhancing image quality, especially in medical applications where noise can significantly impact the accuracy of analysis and interpretation. This paper presents the development of an adaptive Gaussian filter-based denoising technique that effectively enhances images corrupted by various types of noise. By incorporating the adaptive adjustment of filter parameters based on local image characteristics, the proposed method achieves superior denoising performance. The algorithm analyzes the noisy image to estimate the noise characteristics, dynamically adjusting the Gaussian filter parameters to ensure optimal preservation of image details while effectively suppressing noise artifacts. Optimized strategies for parameter selection and filtering operations are employed to ensure computational efficiency. A comparative analysis demonstrates that the adaptive Gaussian filter outperforms traditional methods, achieving a higher Peak Signal-to-Noise Ratio (PSNR) and a lower Root Mean Square Error (RMSE). The technique also exhibits robustness against different noise distributions, making it a versatile solution for various image enhancement applications. These findings highlight the potential of the adaptive Gaussian filter to significantly improve image quality, facilitating more accurate and reliable analysis across diverse domains. [ABSTRACT FROM AUTHOR]

Oil pollution and the energy crisis make oil-water separation an urgent for human need. The widespread use of materials with a single emulsion separation capability is limited. Multifunctional on-demand separation materials can adapt to a wide range of application scenarios, thus having a wider range of applications. The underoil superhydrophilic surface is of great significance for realizing the on-demand separation of oil/water emulsions through the removal of water in the oil and oil in the water. A 3D porous emulsion separation material based on the superhydrophilic principle of sphagnum moss was designed. The material was prepared in a simple step by taking advantage of the adhesion of polydopamine and the introduction of the as-prepared superhydrophilic BaSO4 nanoparticles to achieve superhydrophilicity with a water contact angle (WCA) of 0° and an oil contact angle (OCA) of 157.3°, resulting in excellent separation performance for both water-in-oil and oil-in-water emulsions. Underoil superhydrophilic porous composite (OSPC) can complete two kinds of emulsion separations by filtration or adsorption. It adsorbs water from water-in-oil emulsion to achieve separation, with a good adsorption capacity of 74.38 g/g and efficiency up to 99%. It can also filter oil-in-water emulsions with an efficiency of 99.92%. The separation efficiencies are all almost unchanged after ten separation cycles. Furthermore, the material has excellent flame retardancy, which reduces the possibility of secondary disasters. The three-dimensional porous sponge has excellent on-demand separation performance for multiple emulsions. It provides a new preparation strategy for underoil superhydrophilic materials and a new idea for the design direction of special wetting materials for the on-demand separation of oil/water emulsions. [ABSTRACT FROM AUTHOR]

Dewatering fine-grained materials is a common procedure in various industries. Nevertheless, the theory regarding the dewatering of fine-grained materials is largely confined to laboratory studies and some empirical and semi-empirical formulas. Most studies primarily concentrate on describing macroscopic phenomena. A positive pressure filtration device is introduced, and the effect of particle size during the process of filtration and dehydration is analyzed. The results show that the positive pressure horizontal filtration process is accompanied by interfering sedimentation, which results in the characteristic of a coarse filter cake at the lower part and a fine filter cake at the upper part. In the case of dewatering flotation coal filtration, high pressure assists in overcoming the adhesive force and surface tension of water, facilitating water discharge. The “air drainage” effect leads to variations in moisture levels in different parts. This study theoretically analyzes the positive pressure filtration sedimentation and its impact on particle size, the retention mechanism of capillary dewatering and coarse and heavy particles, as well as the air pressure dewatering mechanism. This study is of great significance for the design and development of new equipment for dewatering fine-grained materials with independent intellectual property rights. [ABSTRACT FROM AUTHOR]

In this study, we present a successful application of the Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) for simulating the complex phenomenon of multi-particle arch formation within high-concentration packed-bed environments. We investigate the roles of physical forces in this phenomenon, shedding light on aspects that are challenging to explore through experimentation. Our research is motivated by the desire to comprehend the conditions and parameters influencing the formation, stability, disruption, and reformation of multi-particle sand arches within filter openings. This arching phenomenon serves as an efficient particle retention mechanism, particularly in heavy oil production wells. We delve into factors like particle size, shape, and particle size distribution that may impact multi-particle arch performance. Additionally, we explore the physics behind multi-particle arching by examining the effects of various physical forces on arch performance. Utilizing a Computational Fluid Dynamics–Discrete Element Model, we investigate the multi-particle arching phenomenon under steady-state flow conditions in packed-bed environments. Our approach employs the unresolved coupling method in STAR-CCM+ (Siemens PLM). We test various filter slot geometries, including straight slots, keystone slots, wire-wrapped screens (WWS), and seamed slots, all under laminar flow conditions. Our findings highlight the significance of gravity, inter-particle forces, and interactions between the filter wall and the particles in multi-particle arch formation at both the slot opening and microscale levels. We confirm that a multi-particle arch can be formed within a specific slot width. Interestingly, while maintaining a constant slot width, we observe that the slot length has an insignificant effect on multi-particle arch formation and stability. In summary, our CFD–DEM model successfully simulates and predicts multi-particle arch formation, stabilization, breakage, and reformation, allowing for comprehensive testing of the effects of various parameters. This research offers valuable insights into a complex phenomenon that is crucial in packed-bed filtration systems. [ABSTRACT FROM AUTHOR]

The conventional approach to generate pores in ceramic membranes involves the incorporation of a pore-forming element. However, this method tends to diminish the mechanical properties of the membranes and poses challenges in effectively regulating both pore size and membrane porosity. In this work, low-cost ceramic filtering membranes with enhanced mechanical strength have been successfully prepared mainly from abundant clays and without the need for pore-forming agents. The Porosity and pore size were controlled by adding a finely-grained clay (d 90 = 22 μm) by-product to coarse clay (d 90 = 50 μm) within a specified range of 33–66 wt%. The microstructure evolution of prepared membranes was examined by XRF, FTIR, XRD, SEM, and DTA-TGA analysis, while the technological properties were evaluated by permeability, porosity, density, and mechanical measurements. The findings indicated that the increase in the amount of finely grained clay mixed with coarse clay and the sintering temperature had a synergistic effect on the porosity and pore size of the obtained membranes. The incorporation of finely-grained clays, accompanied by an elevation in sintering temperature, led to a reduction in porosity from 31.3 ± 0.7 % to 6.2 ± 0.5 % and pore size, along with the crystallization of the α-mullite (12 %) and anorthite (30 %) phase with a quartz phase and an improvement in mechanical strength reaching up to 251 ± 3 MPa. A formulation comprising 33 wt% of finely-grained clay by-products and 67 wt% of coarse clay, sintered at 1000 °C, emerged as a promising ultrafiltering membrane with enhanced mechanical strength reaching 120 ± 1 MPa, and a permeability of 1000 L/h.m2 at 1 bar. [ABSTRACT FROM AUTHOR]

The growing production and use of plastics significantly contribute to microplastics (MPs) contamination in the environment. Humans are exposed to MPs primarily through the gastrointestinal route, as these particles are present in beverages and food, e.g., sugar. Effective isolation and identification of MPs from food is essential for their elimination. This study aimed to evaluate factors influencing the isolation of MPs from sucrose solutions to determine optimal conditions for the process. Polyethylene particles were used to test separation methods involving chemical digestion with acids and filtration through membrane filters made of nylon, mixed cellulose ester, and cellulose acetate with pore sizes of 0.8 and 10 µm. The effects of temperature and acid type and its concentration on plastic particles were examined using scanning electron microscopy and µ-Raman spectroscopy. The results indicate that increased temperature reduces solution viscosity and sucrose adherence to MPs' particles, while higher acid concentrations accelerate sucrose hydrolysis. The optimal conditions for MPs' isolation were found to be 5% HCl at 70 °C for 5 min, followed by filtration using an efficient membrane system. These conditions ensure a high recovery and fast filtration without altering MPs' surface properties, providing a reliable basis for further analysis of MPs in food. [ABSTRACT FROM AUTHOR]

In this study, the synthesis of poly(vinylidene fluoride) composite membranes incorporated with titania (TiO2) nanoparticles and graphene oxide (GO) was demonstrated. The effect of GO on the surface morphology of the membrane was observed by scanning electron microscopy, indicating the typical membrane looseness and porosity caused by GO. The chemical properties and composition of the membrane were confirmed by X-ray diffraction and Fourier transform infrared spectroscopy, indicating the as-prepared membrane materials with reasonably doped TiO2 and GO. The effect of the amount of doped GO on the microstructure and performance of the PVDF/TiO2/GO membrane was systematically investigated. GO enhances the flux of the PVDF membrane in the early filtration stage and enhances the retention of pollutants. In addition, it was found that the synergistic filtration of large and small molecules improved the removal of small molecule contaminants. Therefore, the results of this study offered a new technology for the synergistic treatment of dye wastewater with macromolecule pollutants. [ABSTRACT FROM AUTHOR]

This study focuses on the construction of polyvinyl chloride microcrystalline nanocellulose (PVC/NC@TALCM) nanocomposite membranes with titanium gamma aluminate (TGAL) for the adsorption and filtration of the cationic dye MB. The adsorption ability of the nanocomposite membrane was investigated by varying the dosage of the adsorbent, pH, and dye concentration. The PVC-MCNC@TGAL membrane, loaded with 5% titanium aluminate at pH 10, demonstrated a 98.6% removal efficiency for the MB dye using a dead-end filtration system. The adsorption kinetics study revealed that the adsorption process followed pseudo-second-order kinetics, indicating a chemisorption process. The Freundlich isotherm model was found to be more suitable than the Langmuir model based on the R2 value. Finally, the PVC-MCNC@TGAL nanocomposite membrane was found to be a cost-effective and eco-friendly adsorbent for the removal of MB from industrial wastewater. Additionally, the self-cleaning property of the membrane contributes to sustainability by reducing the usage of chemicals. [ABSTRACT FROM AUTHOR]

A new mode of combustion of granular mixtures Zr + 0.5C in a co-current argon flow with the formation of a finger-like front instability was discovered. The observed phenomena were explained under the assumption of a decrease in the permeability of synthesis products due to significant shrinkage of the sample in the longitudinal direction, which prevented the filtration of argon through the products. Redirection of the gas flow into the gap between the granules and the side surface of the cylindrical reactor contributed to the formation of a finger. It was shown that a decrease in the sample size in the longitudinal direction is provided by the pressure drop of argon, and a decrease in the cross-section occurs under the action of surface tension forces due to a transverse temperature gradient. [ABSTRACT FROM AUTHOR]

For the marine industry biofouling has a negative reputation. On ship hulls, the accumulation of these unwanted plants and animals can lead to increased drag, fuel consumption, and greenhouse gas emissions. Offshore platforms are also subject to biofouling which can result in corrosion and hydrodynamic loading, thus shortening their lifespan. While the harmful impacts of biofouling are commonly reported throughout the literature, biofouling can also benefit both aquatic and human populations. Common biofouling organisms act as natural filtration systems, thus improving water quality. Many of the same flora and fauna serve as a food source, and structures could be designed to lessen the impacts of fouling on hydrodynamic forces. In addition, microfouling species commonly found in biofilms have the potential to be harnessed as biofuel sources and can be a component of the carbon cycle. The following review discusses the benefits of biofouling and why ecological engineering initiatives may aid in ecosystem restoration versus the use of antifouling techniques for preventative growth. [ABSTRACT FROM AUTHOR]

The object of research was the territory of a planned construction of the second stage of a tailings storage facility for flotation tailings of a mining and processing complex based on a gold ore field. To comply with legislative and regulatory requirements regarding environmental protection, a set of works was performed, including laboratory and computational filtration studies. Recommendations were developed based on them to prevent filtration through the flotation tailings storage bed. [ABSTRACT FROM AUTHOR]

Nanofibre-based membranes have shown great potential for removing textile wastewater due to their high porosity and surface area. However, nanofibre membranes exhibit lower dye removal efficiency. Hence, this study aims to improve the dye removal performance of nanofibre membranes by incorporating zeolites. The research involved fabricating composite membranes by electrospinning polyvinyl alcohol (PVA) nanofibres incorporated with zeolites. Mechanical strength was enhanced by placing the PVA/zeolite nanofibre membrane between fusible nonwoven interfacing and woven polyester fabric, followed by heat treatment. Morphological analysis revealed the uniform dispersion of zeolite particles within the PVA nanofibres. EDX analysis confirmed the successful incorporation of zeolites into the fibres. Among all membrane samples, the PZ-0.75 membrane exhibited the highest pure water flux (PWF) with approximately 1358.57 L·m−2·min−1 for distilled water and 499.85 L·m−2·min−1 for batik wastewater. Turbidity of batik wastewater increased proportionally with zeolite concentration, with removal rates of 84.79%, 78.8%, 76.96%, and 74.19% for PZ-0.75, PZ-0.5, PZ-0.25, and PVA membranes, respectively. Furthermore, the UV/Vis spectrophotometer demonstrated that dye removal efficiency increased from 2.22% to 8.89% as the zeolite concentration increased from 0% to 0.75%. In addition, the PZ-0.75 membrane effectively removed RR dye at a concentration of 1 mg/L, with an optimal contact time of approximately 60 min. The adsorption mechanism of the PZ-0.75 membrane aligns with the Freundlich model, with an R2 value of 0.983. Overall, this study demonstrates the efficiency of zeolite in the fabric substrates to improve the filtration and adsorption properties for wastewater treatment, particularly in textile industries. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are a pollutant that increasingly threatens freshwater ecosystems and requires effective solutions for their removal. The aim of this study is to review current filtration methods used to remove MPs from freshwater environments. This study uses a systematic review method of existing literature regarding filtration techniques for removing MPs. Data were collected from various scientific sources published between 2015 and 2023. The filtration techniques analyzed include traditional filtration and advanced filtration technology. The study results show that advanced filtration technologies such as nanofiltration and biofiltration have a high potential in removing MPs from freshwater. However, each technique has its own challenges, including removal efficiency and implementation cost. The conclusion is that filtration is an effective method for dealing with MP pollution in freshwater ecosystems; however, further study is needed to address the existing challenges. This study provides in‐depth insights that can help develop more efficient policies and technologies for managing MP pollution in the future. [ABSTRACT FROM AUTHOR]

Efficient reduction of Cr(VI) to Cr(III) was performed over the modified cellulose filter paper via a simple filtration set-up. A plain cellulose filter paper was covalently functionalized by silane groups followed by Pd/C NPs. The adsorption-reduction took place completely for 30 min under neutral pH, at 25 °C, for 500 mg/L of Cr(VI) in the presence of formic acid. The best conditions for the reduction were achieved by an experimental design on Design-Expert 13.0.5.0 × 64 software. According to the kinetics studies, the reduction follows a pseudo-second-order kinetics. The positive value of ΔH indicates that the adsorption process of Cr(VI) by the adsorbent was endothermic. Also, negative ΔG indicates that the reaction is spontaneous. The obtained positive ΔS value also indicates an increase in disorder in the reduction and an increase in adsorption in the expected phase of solid and liquid during the adsorption process. Also, a deep study was conducted over the mechanism of the reduction, wherein a consecutive adsorption-reduction was suggested and the Pd sites and formic acid play a crucial role in the electron transfer and reduction of Cr(VI) to Cr(III) ions. The recyclability studies revealed that the filter paper could be reactivated and recycled several times without loss of catalytic activity, as well as physical quality of the filter paper in terms of swellability and shrinkage. Applicability of the filter was also studied on a real industrial wastewater, wherein Cr(VI) reduction/adsorption was carried out without the interference of other anions and cations. The results suggest that the catalytic filter paper can be effectively used in purification systems to reliably remove Cr(VI). A new approach has been developed for the efficient reduction of Cr(VI) based on an adsorption-reduction on a modified cellulose filter paper via fast filtration [ABSTRACT FROM AUTHOR]

Sand media filters are especially recommended to prevent emitter clogging with loaded irrigation waters, but their performances rely on backwashing. Despite backwashing being a basic procedure needed to restore the initial filtration capacity, there is a lack of information about the solid removal efficiency along the media bed depth. An experimental filter with a 200 mm silica sand bed height was used to assess the effect of two operation velocities (30/45 and 60/75 (filtration/backwashing) m h−1) and two clogging particles (inorganic sand dust and organic from a reclaimed effluent) on the efficiency of backwashing for removing the total suspended solids retained in different media bed slices. The average solid removal backwashing efficiency was greater with organic particles (78%) than with inorganic ones (64%), reaching its maximum at a 5–15 mm bed depth. A higher operation velocity increased the solid removal efficiency by 16%, using organic particles, but no significant differences were observed with inorganic particles. The removal efficiencies across the media bed were more uniform with organic particles (63–89%) than with inorganic (40–85%), which makes it not advisable to reduce the media height when reclaimed effluents are used. This study may contribute to future improvements in sand media filter design and management. [ABSTRACT FROM AUTHOR]

Abstract Background An October, 2021 review of Public Health Ontario's COVID-19 guidance for congregate settings such as shelters and long-term care homes demonstrated that this guidance did not include references to ventilation or filtration. In April 2022, an interdisciplinary team with expertise in indoor air quality (IAQ), engineering, epidemiology, community programming and knowledge translation launched a virtual ventilation and filtration consultation program for community spaces in Toronto, Ontario. The program gives people working in community spaces direct access to IAQ experts through 25-min online appointments. The program aims to help reduce the risk of COVID-19 transmission in community spaces, and was designed to help compensate for gaps in public health guidance and action. Methods Representatives from participating organizations (n. 27) received a link to an online survey via email in April 2023. Survey questions explored the impacts of the program on topics such as: purchase and use of portable air filters; maintenance and use of bathroom fans; and, maintenance and modification of HVAC systems. Survey participation was anonymous, and no demographic information was collected from participants. Results Representatives from 11 organizations completed the survey (40%). Of those who responded, nine (82%) made changes as a result of the program, with eight (73%) making two or more changes such as purchasing portable air filters and increasing routine maintenance of HVAC systems. Conclusions When presented with brief access to expert support and tailored plain language guidance, people working in community spaces increased their use of ventilation and filtration strategies for COVID-19 infection prevention and control.

A bench-scale study of river water treatment using composite polyethersulfone (PES) membrane was carried out. Polyethylene glycol-silver nanoparticles (PEG-AgNPs) additive was designed to support the simultaneous filtration and disinfection performance of PES membranes via in situ incorporation. Significant improvements in the PES membranes after modification with PEG-AgNPs were observed. The experimental results showed that the PEG-AgNPs increased the PES membrane water flux from 2.87 to 172.84 L/m2·h. The anti-fouling test of the PES membrane toward humic acid molecules after the addition of PES/PEG-AgNPs increased the reversible fouling and decreased the irreversible fouling. In terms of filtration performance, the PES/PEG-AgNP membranes showed high filtration performance, with a water disinfection ability of 99.99 %. Moreover, the leach of silver particles from the PES membrane forced by ultrasonication was

Open-cell ceramic foams are widely used as filters for the purification of molten metals due to their high permeability and high efficiency for capturing non-metallic inclusions. With the consideration of manufacture and filtration behaviour, most filters are produced by replica methods. The intrinsic multiscale porous structure requires the ceramic foams to have sufficient strength. As a consequence, different processing approaches, material compositions and characterizations are investigated. Meanwhile, to further enhance the filtration performance, the functionalization of ceramic foam filters is often conducted with surface coating. This review summarizes the processing and characteristics of ceramic foam filters (CFFs), the nature and formation of non-metallic inclusions (NMIs), the filtration mechanism and applications of CFFs. The characterization of mechanical and filtration performance, as well as the corresponding strengthening and functionalization methods are also presented.

For the marine industry biofouling has a negative reputation. On ship hulls, the accumulation of these unwanted plants and animals can lead to increased drag, fuel consumption, and greenhouse gas emissions. Offshore platforms are also subject to biofouling which can result in corrosion and hydrodynamic loading, thus shortening their lifespan. While the harmful impacts of biofouling are commonly reported throughout the literature, biofouling can also benefit both aquatic and human populations. Common biofouling organisms act as natural filtration systems, thus improving water quality. Many of the same flora and fauna serve as a food source, and structures could be designed to lessen the impacts of fouling on hydrodynamic forces. In addition, microfouling species commonly found in biofilms have the potential to be harnessed as biofuel sources and can be a component of the carbon cycle. The following review discusses the benefits of biofouling and why ecological engineering initiatives may aid in ecosystem restoration versus the use of antifouling techniques for preventative growth.

Purpose: quantitative assessment of the filtration coefficient of coherent soils of the existing irrigation canal base. Materials and methods. The initial materials for the research were pre-design, operational and other technical documentation on the Chernozemelskaya environmental protection system, as well as field survey data of the system technical condition in the Yashkul district of Kalmykia. When performing measurements, the following equipment was used: a measuring container, metal rulers, a digital thermometer with a needle probe, a two-ring infiltrometer, a time clock. Results. The value of the filtration coefficient (at steady flow) varied within 0.24–0.27 m/day (or 0.17–0.19 mm/min). The average value for the filtration coefficient according to field measurements was 0.18 mm/min, which corresponds to 0.255 m/day. According to the N. A. Kachinsky classification, the soils of the studied area are characterized as medium loamy (with a predominance of sand fraction). The range of values of the filtration coefficient for these soils is from 0.005 to 0.4 m/day. According to the calculation results, the filtration coefficient was 0.238 m/day or 0.165 mm/min. Conclusions. Comparison of the calculated and experimental values shows that the calculated filtration coefficient coincides with the experimental one (obtained in the field) well. The discrepancy between the values was 7.1 %. Nevertheless, the estimated estimation of the filtration coefficient according to empirical dependencies is approximate, therefore, in further filtration calculations of the bulk section of the Yashkul distribution canal, data from field measurements of the soil filtration coefficient of the channel base under consideration will be taken into account.

This research aims to evaluate the effect of porous filter configuration on flow characteristics within filter using CFD simulation. This simulation model was chosen for comprehensive analysis that considers different variables affecting the filter performances. Dynamics of the flow and pressure drop under different flow conditions and filter geometry were studied. The Euler-Lagrangian approach was used to model multiphase flow, and the standard K-ε model was used for turbulence characterisation. Particle size distribution was characterized using Rosin-Rammler distribution. The initial status of these properties was obtained by previous experimental references and their evolution over time was simulated at the cell level of the model using User-Defined Functions (UDF). The main conclusions of the study are: i) The pressure drop increased with flow rate and thickness of the filter but decreased with increasing filter length and diameter. ii) There is no significant change in velocity ratio with the distance from the filter inlet at the filter centre line except the first 5% from the inlet and last 5% close to the end. iii) it was identified that higher radial velocity ratios imply a less particle deposition within the filter media. The results also shows that the particle loading on 290 mm filter is 50% - 60% lower than the other filters but evenly distributed across the filter. However, the pressure drop decreased with the filter length. 55mm filter that has the highest radial velocity ratio performs poorly in particle trapping.

Abstract The purification of water is not only essential for human consumption but is becoming a necessity considering the limited freshwater reserves of the planet. Over the last few decades advancements in material sciences and technology have paved the way for the development of novel purification techniques. Amongst these techniques membrane-based filtration is considered as the least expensive and most effective. These membrane-based filtration techniques can be broadly categorized into reverse osmosis (RO), ultrafiltration, microfiltration and activated carbon filters (ACF). The mode of operation, research evolution and practical applications of each technique are compared in this holistic analysis. Although RO is the oldest and most established membrane-based filtration technique in the literature, it is ACF that is ranked as the most promising new technique with much simplicity and effectiveness.

The process of nanofiltration purification of water from various organic pollutants was examined. Cellophane film made from cheap natural raw materials was used as a membrane. The model substances targeted for removal were dyes (Safranin O, Orange II, and Remazol Brilliant Blue R, each differing in molecular weight, chemical composition, and charge) and ceftriaxone. The obtained cellophane permeability to water was 0.145 kg/(m2∙h∙atm). Cellophane membranes were found to be effective in retaining dissolved anionic substances containing acid groups. When Orange II and Remazol Brilliant Blue R were removed from the water, the retention coefficients were 97 ± 2 and 99 ± 1%, respectively. For the cationic dye Safranin O, the retention coefficient values were negative, –7 ± 3%. At the same time, ceftriaxone had the retention coefficient of only 41 ± 5%, which can be attributed to a combination of factors, such as its high affinity for cellophane and steric restrictions.

Abstract Background Particulate contamination due to infusion therapy (administration of parenteral nutrition and medications) carries a potential health risk for infants in neonatal intensive care units (NICUs). This particulate consists of metals, drug crystals, glass fragments, or cotton fibers and can be generated by drug packaging, incomplete reconstitution, and chemical incompatibilities. In-line filters have been shown to remove micro-organisms, endotoxin, air, and particles in critically ill adults and older infants, but its benefits in newborn remain to be demonstrated. Moreover, 50% of inflammatory episodes in the setting of NICUs are blood culture-negative. These episodes could be partly related to the presence of particles in the infusion lines. Methods A multicenter randomized single-blind controlled trial was designed. All infants admitted to NICUs for which prolonged infusion therapy is expected will be enrolled in the study and randomized to the Filter or Control arm. All patients will be monitored until discharge, and data will be analyzed according to a “full analysis set.” The primary outcome is the frequency of patients with at least one sepsis-like event, defined by any association of suspected sepsis symptoms with a level of c-reactive protein (CRP) > 5 mg/L in a negative-culture contest. The frequency of sepsis, phlebitis, luminal obstruction, and the duration of mechanical ventilation and of catheter days will be evaluated as secondary outcomes. The sample size was calculated at 368 patients per arm. Discussion This is the first multicenter randomized control trial that compares in-line filtration of parenteral nutrition and other intravenous drugs to infusion without filters. Sepsis-like events are commonly diagnosed in clinical practice and are more frequent than sepsis in a positive culture contest. The risk of these episodes in the target population is estimated at 30–35%, but this data is not confirmed in the literature. If the use of in-line filters results in a significant decrease in sepsis-like events and/or in any other complications, the use of in-line filters in all intravenous administration systems may be recommended in NICUs. Trial registration ClinicalTrials.gov, NCT05537389, registered on 12 September 2022 ( https://classic.clinicaltrials.gov/ct2/show/results/NCT05537389?view=results ).

The widespread use of unmanned aerial vehicles (UAVs) of various classes in both the military and civilian spheres requires the development and production of high-precision on-board navigation systems of low cost, weight and dimensions. An important characteristic that determines the ability and quality of the UAV's flight task performance is the accuracy of its positioning. The basis of management of existing UAVs is the use of satellite navigation systems (SNS). In SNS of UAVs, increasing the accuracy of positioning is achieved by using various algorithms for processing received navigation data. A generalized analysis of the most common approaches to solving the problem of filtering navigation measurements showed that the task of synthesizing effective filtering algorithms remains relevant. A possible way to increase the accuracy of determining the navigation parameters is the joint processing of the results of measurements of the distance to the satellite and the radial velocity. The work describes the methodology of synthesis of complex filtering algorithms for range measurements in UAV satellite navigation systems. The methodology is based on a polynomial model of the filtering algorithm and input data. The described approach is based on the presentation of smoothing filters as dynamic systems described by discrete transfer functions. The theoretical basis for determining the transfer functions is the third form of the invariance conditions of the filter error with respect to the input influence model. The proposed approach allows: synthesizing effective complex filtering algorithms that have minimal computational complexity for their implementation; at the stage of synthesis, forming the properties of filters in relation to noise smoothing and exclusion of dynamic errors; in the synthesis process, determining the conditions under which the digital filter will be stable. The workability and efficiency of the synthesized algorithm was investigated by means of computer simulation. It is shown that the application of the synthesized filter allows reducing the dynamic range estimation error in the conditions of changing the mathematical model of the input data without deteriorating the quality of filtering of measurement errors.

Water contamination in rural Malaysian areas, mainly caused by logging activities leading to soil erosion and river pollution, presents a significant threat to water supplies. In response, a specialized activated carbon water filtering device was developed to target the absorption of organic molecules. The impact of compaction of activated carbon on water filtering efficiency was evaluated. Testing both compacted and uncompacted activated carbon filters with contaminated river water, the study utilized the Malaysia Department of Environment's (DOE) water quality index (WQI) to assess filter effectiveness. The results revealed that water filtered through compacted activated carbon was clearer and less yellowish compared to the uncompacted counterpart. Moreover, the compacted filter showed higher dissolved oxygen levels, lower ammoniacal nitrogen levels, and a lower pH, resulting in a significantly higher WQI score of 80.4 compared to 78.8 for the uncompacted filter. Further analysis via an adsorption isotherm test demonstrated the superior ability of compacted activated carbon to absorb acetic acid, as evidenced by higher lines in the Freundlich isotherm model graphs. These findings emphasize the efficacy of compacted activated carbon in water filtration, advocating for its integration into filter construction to enhance water quality in rural regions.

Introduction: Protection of the respiratory system has been a vital, and for this purpose, various solutions have been proposed, including the use of masks. One of the most important parameters to measure the effectiveness of the mask against the penetration of microbial agents. The present study was conducted with the aim of evaluating the bacterial and particle filtration of medical masks. Material and Methods: To assess bacterial performance, the national standard 6138, compliant with EN14683, and Type I medical masks were utilized. Staphylococcus aureus bacterial suspension was prepared and passed through the mask using a nebulizer and through an impactor with a flow rate of 28.3 l/min. Plates containing soy agar were placed in the impactor. Subsequently, all plates were incubated, and the bacterial filtration efficiency (BFE) of the masks was determined by counting the bacterial colonies that passed through the mask’s media as a percentage of the total bacteria. It is worth noting that the pressure drop and particle filtration efficiency were also determined for all masks Results: Based on the results of the particle removal performance for the particle size of 3 µ, the masks were categorized into three groups with efficiency above 99%, above 95% and 90%. According to the standard, all masks had an acceptable pressure drop below 40 Pa. The acceptable bacterial filtration rate for type I masks should be above 95%. The results showed that type A and B masks have an acceptable bacterial filtration rate and there is a significant correlation between the types of masks examined in terms of bacterial and particle efficiency. Conclusion: The results showed that different types of masks under investigation have significant differences in terms of particle capture efficiency and bacterial filtration performance. In addition, there is a significant correlation between bacterial and particle filtration efficiency.

Let F be a field of characteristic different from 2, and let L = F(b + 2ca) be a tower of two quadratic field extensions. We construct a filtration on the relative Brauer group Br(L/F) and compute its factors in terms of certain norm groups. The answer depends on whether the extension L/F is biquadratic or not. As a consequence we obtain a description of the group F∗2N E/FE∗ for a Galois field extension E/F with dihedral Galois group. Also, we prove that for any 2-torsion abelian group G and any biquadratic extension L/F there exists a field extension K/F linearly disjoint with L/F such that Br(LK/K)/2Br(LK/K) ≃ G. [ABSTRACT FROM AUTHOR]

Wetlands are critical ecological infrastructures that improve water quality, serve as habitat for fish and other aquatic life, accumulate floodwaters, and maintain surface water flow during dry periods. However, the health of wetlands has been compromised by anthropogenic activities that affect the constant supply of ecosystem services. This study assessed the impact of anthropogenically modified land use on wetland health in the Witbank Dam Catchment in South Africa, whose land use has been severely modified for agriculture and mining purposes. The study developed a model linking surface runoff generated in the catchment with land use and wetland typology to comprehend diffuse pollution from pollution-source land uses. Runoff data and related wetland spatial information were processed and analysed in a Geographic Information System (GIS) to estimate pollutants (agricultural nutrients and acid mine drainage) from runoff detained and released by wetlands. The analysis facilitated the assessment of the value of wetlands in enhancing water quality, as well as human and environmental health. The runoff volume from pollution-source land uses (urban areas, farmlands, and mining) was used to evaluate annual pollution levels. Wetland types are ranked according to their efficiency levels to filter pollutants. The assumption is that the difference between filtered and unfiltered runoff is the quantity of polluted runoff water discharged into the river system. The analysis has shown that 85% of polluted runoff generated in the catchment ends up in the river system. An important observation is that although wetlands have a substantial ability to absorb excess pollutants, they have finite boundaries. Once they reach their full holding capacity, they can no longer absorb any further pollutants. The excess is discharged into the river system, risking human and environmental health. This explains why the Limpopo River is heavily polluted resulting in the death of fish, crocodiles and other aquatic life. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate and design masks against viruses, especially SARS-CoV-2 associated with COVID-19. A continuum filtration model was developed where the rate of particle deposition and "sticking" on the filter fibers is a critical term in the mass transfer, together with permeation velocity, filter porosity, tortuosity, and Brownian diffusion. CFD simulations of the airflow during respiration lead to the recommendation that the filter permeability should be above 4 × 10−11 m2 to direct the airflow for effectiveness against virus particles; otherwise, low filter permeabilities cause the unfiltered air to flow preferentially through the leak gaps between the mask and the headform. Different mask filters with microstructural and geometry data from the literature are assessed via filtration simulations for breathability and filtration efficiency. The results demonstrate that a surgical mask of 25% porosity, pore size of 150 µm and permeability of 4.4 × 10−11 m2 can achieve 100% minimum efficiency while demonstrating high breathability, complying with the criteria of FFP3, N95, and surgical Class II and IIR masks. Selected cotton and synthetic cloths as well as electrospun fiber layers are predicted to comply with FFP2, N95, and surgical mask Class II and IIR standards. [ABSTRACT FROM AUTHOR]

In [11] , we established the theory of twisted D-modules over general base schemes. In this short note, we construct a K -invariant positive exhaustive filtration on the globalization of the twisted D-module on a smooth quasi-compact K -scheme over a Dedekind scheme S obtained by the direct image of a K -equivariant twisted integrable connection along a K -equivariant closed immersion from a smooth proper K -scheme Y with K a smooth S -affine group scheme, whose p th associated graded O S -module is locally free of finite rank for every integer p. In particular, the k -module of its global sections is projective if S is affine with coordinate ring k. [ABSTRACT FROM AUTHOR]

Classical filtration equations incorporate microscopic parameters, which pose challenges when applied in industrial settings. Previous extensive research has established the impact of filter cake thickness and variations in filtration pressure on the filtration rate. Moreover, the thickness of the filter cake is influenced by various factors, such as the filtration chamber's design dimensions and the coal slurry's properties. Thus, by expressing the properties of the coal slurry at a macroscopic level, it becomes possible to achieve a macroscopic representation of the filtration rate. This study presents the derivation of a macroscopic filtration equation that relies on the viscosity of the filtrate. The derivation process is mainly based on Darcy's law, analyzing the relationship between the permeability of each layer and the permeability of cake under constant pressure and explaining and analyzing the method of determining the equation parameters. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are being increasingly measured in water and wastewater due to emerging toxicity concerns and strict regulatory limits. Previous studies have filtered water samples to remove suspended solids before PFAS analysis. However, filtration may introduce negative bias to measured PFAS concentrations. Using a well-controlled syringe pump assembly, we evaluated retention of six perfluoroalkyl carboxylates, three perfluoroalkyl sulfonates, one fluorotelomer sulfonate, and two perfluorooctane sulfonamides by glass-fiber, glass-fiber cellulose acetate, nylon, polyethersulfone, polypropylene, polyvinylidene fluoride/ difluoride, and surfactant-free cellulose acetate filters. The impacts of water quality and operational parameters were also investigated for select filter types. We found that PFAS were retained on all filters, with the glass-fiber cellulose acetate filters demonstrating the lowest retention. For all filters, PFAS retention was linearly related to chain length and hydrophobicity above certain thresholds (i.e., log D higher than 1.5). Importantly, more PFAS were retained at low filtrate volumes, and ~ 30 mL filtrate was required before the retention efficiencies stabilized. Solution pH only affected the retention of perfluorooctane sulfonamides. Pore size (i.e., 0.20, 0.45, 0.70 µm), filtration rate (i.e., 0.5, 1.0 mL min−1), and PFAS concentration (i.e., 10, 100 µg L−1), did not exert major influences on PFAS retention. The presence of dissolved organic matter improved PFAS permeation. Based on the reported results, filtration introduces bias and is not recommended for sample pretreatment. [ABSTRACT FROM AUTHOR]

Microplastic pollution poses an increasing environmental and human health risk and additional techniques are needed to facilitate nondestructive, quantitative particle recovery and analysis. Using a mini-extruder filtration (MEF) device, the efficiency of pristine particle capture from solution and digested biological tissue (blood clots) was assessed. Polystyrene particles in both the submicron (100, 300, and 500 nm) and micron range (2, 5, 7, and 10 µm) with aminated, carboxylated, or unmodified surface modifications were explored. The MEF-isolated-particle recovery was analyzed pre- and postseparation isolation and quantified via a Nanosight LM10 particle tracking system (submicron particles) or hemacytometer (micron particles). Particles' surface chemistry and concentration did not impact recovery compared to unfiltered samples with smaller particle sizes reducing recovery efficiency. Micron particle size recovery averaged 86.8 ± 4.3% across all surface chemistries at the same concentration; however, submicron particle recoveries varied by size and charge with 500 nm exhibiting recoveries of 80.6 ± 16.6%, 300 nm 73.0 ± 10.4%, and 100 nm particles 17.0 ± 10.3%. The mini-extruder device, used as a filtration recovery system, efficiently captures 10 to 0.5 µm particles from environmental and tissue samples making it an effective and low-cost platform facilitating the nondestructive capture of diverse microplastics for subsequent analysis. [ABSTRACT FROM AUTHOR]

The purification of water is not only essential for human consumption but is becoming a necessity considering the limited freshwater reserves of the planet. Over the last few decades advancements in material sciences and technology have paved the way for the development of novel purification techniques. Amongst these techniques membrane-based filtration is considered as the least expensive and most effective. These membrane-based filtration techniques can be broadly categorized into reverse osmosis (RO), ultrafiltration, microfiltration and activated carbon filters (ACF). The mode of operation, research evolution and practical applications of each technique are compared in this holistic analysis. Although RO is the oldest and most established membrane-based filtration technique in the literature, it is ACF that is ranked as the most promising new technique with much simplicity and effectiveness. [ABSTRACT FROM AUTHOR]