Non-woven Fabric Filter Research Articles

Study on Preparation and Properties of CA/PLA Nonwoven Filter Materials Optimized by Response Surface Methodology

Study on Preparation and Properties of CA/PLA Nonwoven Filter Materials Optimized by Response Surface Methodology

Revolutionizing Airborne Virus Defense: Electromagnetic MXene-Coated Air Filtration for Superior Aerosol Viral Removal.

The COVID-19 pandemic sparked public health concerns about the transmission of airborne viruses. Current methods mainly capture pathogens without inactivation, leading to potential secondary pollution. Herein, we evaluated the inactivation performance of a model viral species (MS2) in simulated bioaerosol by an electromagnetically enhanced air filtration system under a 300 kHz electromagnetic induction field. A nonwoven fabric filter was coated with a 2D catalyst, MXene (Ti3C2Tx), at a coating density of 4.56 mg·cm-2 to absorb electromagnetic irradiation and produce local heating and electromagnetic field for microbial inactivation. The results showed that the MXene-coated air filter significantly enhanced the viral removal efficiency by achieving a log removal of 3.4 ± 0.15 under an electromagnetic power density of 369 W·cm-2. By contrast, the pristine filter without catalyst coating only garnered a log removal of 0.3 ± 0.04. Though the primary antimicrobial mechanism is the local heating as indicated by the elevated surface temperature of 72.2 ± 4 °C under the electromagnetic field, additional nonthermal effects (e.g., dielectrophoresis) on enhanced viral capture during electromagnetically enhanced filtration were investigated by COMSOL simulation to delineate the potential transmission trajectories of bioaerosol. The results provide unique insights into the mechanisms of pathogen control and thus promote alternative solutions for preventing the transmission of airborne pathogens.

Observationally constrained mass balance box model analysis of aerosol mitigation potential using fan powered filters

Indoor air pollution contributes significantly as a world-wide environmental issue, impacting health and livelihood. To quantify benefits of filtration on indoor air quality, it is essential to understand the relationships between the various factors impacting the concentrations of indoor air pollutants. This work uses a mass-conserving 2-box model, high-frequency observations of aerosol number concentration, and a home-made, low-cost, 3-layer non-woven fabric filter, powered by a standard ventilation fan to quantify the effectiveness aerosol reduction in multiple indoor environments. The data shows that aerosol loading is effectively reduced under both steady-state and extreme event conditions, although there are significant and important differences between simultaneous observations both indoor and outside. To obtain a proper accounting, the following must be considered: the usage or not of the fan filter, whether windows are opened or closed, the state of outdoor air is pollution, and the strength and duration of indoor emissions. The experiments are applied in residential indoor environments in four cities in eastern (Xuzhou), central (Zhoukou), and southern (Zhuhai and Shunde) China. Photographic evidence of the altered fan filter state under both conditions show that while usually dark/black aerosols dominate, there are conditions when yellow aerosols also dominate. The observations are based on multiple, independent, continuous low-cost sensors which have been calibrated against a GRIMM-180 over the number concentration range from 0.3 to 1.0 microns, and yield a removal rate due to the fan-filter of 46%, 80%, 81%, and 36% respectively across the four cities. A corresponding rate to return from an extreme event to steady-state, is computed outdoors and indoors respectively from: 14.−44. minutes, 6.6–21. minutes, 16.−33. minutes, and 24.−58. minutes. The most important factors contributing to the removal efficiency and decay gradient are observed as keeping windows closed and reducing leakiness, the apartment/classroom size, and the outdoor air pollution loading.

Anti-influenza Activity of Povidone-Iodine-Integrated Materials.

Personal protective equipment (PPE), including medical masks, should be worn for preventing the transmission of respiratory pathogens via infective droplets and aerosols. In medical masks, the key layer is the filter layer, and the melt-blown nonwoven fabric (NWF) is the most used fabric. However, the NWF filter layer cannot kill or inactivate the pathogens spread via droplets and aerosols. Povidone-iodine (PVP-I) has been used as an antiseptic solution given its potent broad-spectrum activity against pathogens. To develop PPE (e.g., medical masks) with anti-pathogenic activity, we integrated PVP-I into nylon-66 NWF. We then evaluated its antiviral activity against influenza A viruses by examining the viability of Madin-Darby canine kidney (MDCK) cells after inoculation with the virus strains exposed to the PVP-I-integrated nylon-66 NWF. The PVP-I nylon-66 NWF protected the MDCK cells from viral infection in a PVP-I concentration-dependent manner. Subsequently, we found to integrate PVP-I into nylon-66 and polyurethane materials among various materials. These PVP-I materials were also effective against influenza virus infection, and treatment with PVP-I nylon-66 NWF showed the highest cell survival among all the tested materials. PVP-I showed anti-influenza A virus activity when used in conjunction with PPE materials. Moreover, nylon-66 NWF integrated with PVP-I was found to be the best material to ensure anti-influenza activity. Therefore, PVP-I-integrated masks could have the potential to inhibit respiratory virus infection. Our results provide new information for developing multi-functional PPEs with anti-viral activity by integrating them with PVP-I to prevent the potential transmission of respiratory viruses.

Removal of Combustible volatile organic compounds (VOCs) using Polymetaphenylene isophthalamide Based Nonwoven Fabric (Nomex) Filters with Thin Layer of Activated Carbon

Removal of Combustible volatile organic compounds (VOCs) using Polymetaphenylene isophthalamide Based Nonwoven Fabric (Nomex) Filters with Thin Layer of Activated Carbon

Three-Dimensional Modeling of Spun-Bonded Nonwoven Meso-Structures.

As a type of fiber system, nonwoven fabric is ideal for solid-liquid separation and air filtration. With the wide application of nonwoven filter materials, it is crucial to explore the complex relationship between its meso structure and filtration performance. In this paper, we proposed a novel method for constructing the real meso-structure of spun-bonded nonwoven fabric using computer image processing technology based on the idea of a "point-line-body". Furthermore, the finite element method was adopted to predict filtration efficiencies based on the built 3D model. To verify the effectiveness of the constructed meso-structure and simulation model, filtration experiments were carried out on the fabric samples under different pollution particle sizes and inlet velocities. The experimental results show that the trends observed in the simulation results are consistent with those of the experimental results, with a relative error smaller than 10% for any individual datum.

Fabrication of a highly protective 3D-printed mask and evaluation of its viral filtration efficiency using a human head mannequin

Facemasks are one of the most effective and low-cost prophylactics for COVID-19. In the spring 2020, when a severe shortage of facemasks occurred worldwide, various types of 3D-printed masks were designed and proposed. However, the protective effects conferred by most of these masks were not experimentally evaluated. Here, we provide a new simple design of 3D-printed mask and evaluate its protective effect in a viral filtration test using a human head mannequin. The developed mask can be constructed with a low-cost 3D printer, with an approximate production cost of US $4. This mask has three parts: the main part, wearing parts, and a piece of non-woven fabric filter. The volume of the filter, which needs to be changed daily, was reduced to approximately 1/10 of that of commercially available surgical masks used in this study. The developed mask is fabricated from polylactic acid, a biodegradable plastic, and its surface contour contacting the face may be adjusted after softening the material with hot water at 60–80 °C. The viral filtration efficiency of the developed mask was found to be over 80%. This performance is better than that of commercially available facemasks, such as surgical masks and cloth masks, and equal to those of KN95 and KF94.

Surface Functionalization of Non-Woven Fabrics Using a Novel Silica-Resin Coating Technology: Antiviral Treatment of Non-Woven Fabric Filters in Surgical Masks.

Masks are effective for preventing the spread of COVID-19 and other respiratory infections. If antimicrobial properties can be applied to the non-woven fabric filters in masks, they can become a more effective countermeasure against human-to-human and environmental infections. We investigated the possibilities of carrying antimicrobial agents on the fiber surfaces of non-woven fabric filters by applying silica-resin coating technology, which can form silica-resin layers on such fabrics at normal temperature and pressure. Scanning electron microscopy and electron probe microanalysis showed that a silica-resin layer was formed on the fiber surface of non-woven fabric filters. Bioassays for coronavirus and quantitative reverse transcription-polymerase chain reactions (RT-PCR) revealed that all antimicrobial agents tested loaded successfully onto non-woven fabric filters without losing their inactivation effects against the human coronavirus (inhibition efficacy: >99.999%). These results indicate that this technology could be used to load a functional substance onto a non-woven fabric filter by vitrifying its surface. Silica-resin coating technology also has the potential of becoming an important breakthrough not only in the prevention of infection but also in various fields, such as prevention of building aging, protection of various cultural properties, the realization of a plastic-free society, and prevention of environmental pollution.

Analysis of microstructure and protective performance of melt-blown materials for medical protective masks

Since the end of 2019, the Corona Virus Disease 2019 (COVID-19) pandemic has led to a surge in the use of all kinds of medical supplies, especially surgical masks. Based on the microstructure and anti-virus mechanism of melt-blown materials used for medical masks, this paper introduces the research status of nonwoven filter materials used for protective masks. At the same time, the surface interface structure of four disposable medical protective masks from different manufacturers was analyzed by scanning electron microscope, and the difference of melt-blown materials of these masks was studied. The results show that the fiber diameter of melt-blown mask with better protective effect is fine and compact, and the aperture formed between fibers is smaller. This reasearch provides new ideas for further research and development of non-woven materials for medical masks.

Filtration performance of new reduced graphene oxide air filter material against bacteria in the atmosphere during the initial stage of heating

With the large-scale outbreak of the COVID-19, people have gradually realized the importance of bioaerosols in the environment, and how to efficiently filter out microbial aerosols in the air, so as to create a safe and healthy air environment is urgent. The non-bacteriostatic F6 non-woven filter material and the synthesized new reduced graphene oxide air filter were tested and analyzed in this paper, and the filtration performance of the material against bacterial aerosols in the atmosphere at the initial stage of heating. The results showed that during the initial stage of heating, the particle size distributions of aerosols in the atmosphere during working days were stageⅠ(>7.0μm)4.34%, stageⅡ(4.7~7.0μm)4.62%, stageⅢ(3.3~4.7μm)13.30%, stageⅣ(2.1~3.3μm)21.11%, stageⅤ(1.1~2.1μm)38.70%, stageⅥ(0.65~1.1μm)17.92%. The particle size distributions of aerosols in the atmosphere on non-working days were stageⅠ(>7.0μm)4.52%, stageⅡ(4.7~7.0μm)13.66%, stageⅢ(3.3~4.7μm)23.04%, stageⅣ(2.1~3.3μm)31.82%, stageⅤ(1.1~2.1μm)15.18%, stageⅥ (0.65~1.1μm)11.78%. The new reduced graphene oxide filter material had a 10% increase in the filtration efficiency of the total bacterial aerosol compared with the ordinary non-woven filter material. Among them, the filtration efficiency of the respirable bacterial aerosol (particle size <4.7μm) was significantly improved by 40%. The results of this study could provide a certain reference for building a safe interior in the post-epidemic era, and also provided reference value for the research and development of functional air filters.

Effects of Surface Finish of Nonwoven Fabric Bag Filters on Filter Efficiency

AbstractThe effects of the surface finish of the bag filter for industrial use on the spatial distributions of the fiber mass, air permeability, and thickness were examined using a nonwoven fabric filter made of polytetrafluoroethylene (PTFE) with no surface finish and two nonwoven fabric filters made of PTFE with different surface finishes, i.e., resin finish and membrane finish. The surface finish had no impact on the non‐uniformity in air permeability distribution. However, the air permeability of the filters was reduced with the use of a surface finish. In addition, the specific filtration resistance of the filter media increased by approximately 1.2 times in the case of the resin finish and 4.2 times for the membrane finish. Hence, the influence of the membrane finish on the filter efficiency is extremely strong.

Theoretical Prediction of The Pore Size of Woven, Knitted and Nonwoven Filter Fabrics.(Dept.T)

The present investigation deals with the study of pore size of filter fabrics. Theoretical expressions are derived for calculating the pore equivalent diameter of woven, knitted and nonwoven filter fabrics. Experimental results were obtained by using a new simplified apparatus. This apparatus has been designed by the author on the base of bubble-pressure method. The derived relations were found to be fairly close to those observed experimently.

Quality Assessment of Nonwoven Air Filters Used in Fertilizer Factories.(Dept.T)

Two experimental techniques used to evaluate fabric filtration efficiency. Gas filtration apparatus and another apparatus used optical techniques based on laser doppler velocimeter are constructed. The filtration efficiency have been measured for a wide varity of non-woven filter fabrics. Excellent agreement has been found between the two techniques. The necessary performance characteristics of air filter fabrics could be selected and arranged carefully in decreasing order of importance. In this paper several methods are used to assess the quality of some nonwoven fabrics as air filters similar to those filters used in the fertilizer factory. Complex evaluation of quality methods have been applied to determine the best filter which can be used in fertilizer factories. Quality assessment methods such as arithmetic mean, geometric mean, harmonic mean, exponential mean, polygon area, guality number and generalized desirability function can be used for assessing the quality ranking of air filter fabrics accurately.

Characterization of performance and disinfection resilience of nonwoven filter materials for use in 3D-printed N95 respirators

The COVID-19 pandemic has caused a high demand for respiratory protection among health care workers in hospitals, especially surgical N95 filtering facepiece respirators (FFRs). To aid in alleviating that demand, a survey of commercially available filter media was conducted to determine whether any could serve as a substitute for an N95 FFR while held in a 3D-printed mask (Stopgap Surgical Face Mask from the NIH 3D Print Exchange). Fourteen filter media types and eight combinations were evaluated for filtration efficiency, breathing resistance (pressure drop), and liquid penetration. Additional testing was conducted to evaluate two filter media disinfection methods in the event that the filters were reused in a hospital setting. Efficiency testing was conducted in accordance with the procedures established for approving an N95 FFR. One apparatus used a filter-holding device and another apparatus employed a manikin head to which the 3D-printed mask could be sealed. The filter media and combinations exhibited collection efficiencies varied between 3.9% and 98.8% when tested with a face velocity comparable to that of a standard N95 FFR at the 85 L min−1 used in the approval procedure. Breathing resistance varied between 10.8 to >637 Pa (1.1 to > 65 mm H2O). When applied to the 3D-printed mask efficiency decreased by an average of 13% and breathing resistance increased 4-fold as a result of the smaller surface area of the filter media when held in that mask compared to that of an N95 FFR. Disinfection by dry heat, even after 25 cycles, did not significantly affect filter efficiency and reduced viral infectivity by > 99.9%. However, 10 cycles of 59% vaporized H2O2 significantly (p < 0.001) reduced filter efficiency of the media tested. Several commercially available filter media were found to be potential replacements for the media used to construct the typical cup-like N95 FFR. However, their use in the 3D-printed mask demonstrated reduced efficiency and increased breathing resistance at 85 L min−1.

More Human BM-MSC With Similar Subpopulation Composition and Functional Characteristics Can Be Produced With a GMP-Compatible Fabric Filter System Compared to Density Gradient Technique.

BackgroundMesenchymal stromal cells (MSCs), multipotent progenitors that can be isolated from a variety of different tissues, are becoming increasingly important as cell therapeutics targeting immunopathologies and tissue regeneration. Current protocols for MSC isolation from bone marrow (BM) rely on density gradient centrifugation (DGC), and the production of sufficient MSC doses is a critical factor for conducting clinical MSC trials. Previously, a Good Manufacturing Practice (GMP)–compatible non-woven fabric filter device system to isolate MSCs was developed to increase the MSC yield from the BM. The aim of our study was to compare high-resolution phenotypic and functional characteristics of BM-MSCs isolated with this device and with standard DGC technology.MethodsHuman BM samples from 5 donors were analyzed. Each sample was divided equally, processing by DGC, and with the filter device. Stem cell content was assessed by quantification of colony-forming units fibroblasts (CFU-F). Immunophenotype was analyzed by multicolor flow cytometry. In vitro trilineage differentiation potential, trophic factors, and IDO-1 production were assessed. Functionally, immunomodulatory potential, wound healing, and angiogenesis were assayed in vitro.ResultsThe CFU-F yield was 15-fold higher in the MSC preparations isolated with the device compared to those isolated by DGC. Consequently, the MSC yield that could be manufactured at passage 3 per mL collected BM was more than 10 times higher in the device group compared to DGC (1.65 × 109 vs. 1.45 × 108). The immunomodulatory potential and IDO-1 production showed donor-to-donor variabilities without differences between fabric filter-isolated and DGC-isolated MSCs. The results from the wound closure assays, the tube formation assays, and the trilineage differentiation assays were similar between the groups with respect to the isolation method. Sixty-four MSC subpopulations could be quantified with CD140a+CD119+CD146+ as most common phenotype group, and CD140a+CD119+CD146+MSCA-1–CD106–CD271– and CD140a+CD119+CD146–MSCA-1–CD106–CD271– as most frequent MSC subpopulations. As trophic factors hepatocyte growth factor, epidermal growth factor, brain-derived neurotrophic factor, angiopoietin-1, and vascular endothelial growth factor A could be detected in both groups with considerable variability between donors, but independent of the respective MSC isolation technique.ConclusionThe isolation of MSCs using a GMP-compatible fabric filter system device resulted in higher yield of CFU-F, producing substantially more MSCs with similar subpopulation composition and functional characteristics as MSCs isolated by DGC.

Research of filter materials for dust fractioning

A special place in air pollution with dust emissions is occupied by the production of building materials, using large quantities of dispersed mineral substances as aggregates. The article is devoted to the study of hazardous dust fractions emission when assessing the dustiness of the working area for the production of concrete and reinforced concrete products, since the specific location and operation of the equipment complex is characterized by uneven dust formation in space and time. This reduces the efficiency of the aspiration systems. Based on the analysis of methods and means for assessing dustiness, the use of the gravimetric method is justified, however, to assess the content of the most dangerous dust particles for the human body with a size of 2.5 to 10 microns, a size separation of particles is required. Non-woven synthetic filter materials of various thick-nesses and densities are investigated. It is proposed to carry out sampling in blocks with three filters from different filter materials. The studies were carried out with the help of a specially made portable complex. The most effective filter materials were determined with the help of microscopic analysis. The conducted calibration of the blower performance with an assessment of the measurement accuracy showed relatively small errors in the air sampling, which confirms the feasibility of assessing the dustiness of the filter blocks.

Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter.

The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.

Investigation of air filter properties of nanofiber non-woven fabric manufactured by a modified melt-blowing method along with flash spinning method

Nanofibers are used in various fields and applications, such as medical care, environment protection, apparel, and agriculture; it is believed that they will continue to show substantial growth in the future. In this study, we focused on the filtration application of nanofibers. The filtration performances achieved polymeric nanofiber mass production by a melt-blowing method. First, the filtration performances of the fiber were experimentally tested with different thicknesses. Then, the computational fluid dynamics flow-analyzing software was used to simulate the pressure loss and flow resistivity of the trial-produced filter under the same conditions as those used in the experiment. Then, a three-directional physical model was proposed and used to calculate the fiber's gap size with different diameters under the same filling rate and the assumption that the fibers always exhibit uniform distribution. Consequently, it was confirmed that the trial-produced non-woven filter possessed excellent filtration abilities and that the investigated data can be used as a standard to manufacture non-woven fabric for producing high-performance filters and face masks. However, the manufacturing method of non-woven fabric filters must be investigated to satisfy both high particle filtration efficiency and low pressure loss in order to develop a high-performance filter.

Bursting behavior of polyester needle-punched filter fabrics

The effect of fabric weight, depth of needle penetration and needling density on bursting strength of needle-punched nonwoven filter fabrics prepared from virgin and recycled polyester fibres has been studied. The effect of fabric parameters on bursting behavior trend is found similar in both the virgin and the recycled polyester filter fabric samples. There is considerable fall in bursting strength of recycled polyester fabrics as compared to that in virgin one, under high fabric weight and needling density. Interestingly, it has been found that the recycled polyester filter fabric shows 3.584% lesser strength (average value of all samples) than the virgin polyester filter fabric, which signifies the use of recycled polyester filter wherever applicable, considering the recyclability and sustainability aspects.

Power Consumption Analysis of Pulse Jet Filtration System Assisted with Pre-charger using Polyester Conductive Media

Energy consumption is a vital aspect for any industry considering the cost-effective aspect. The current study embodies the power consumption during filtration of conductive filters at different dust pre-charging levels on laboratory-based pulse jet tubular set up assisted with pre-charger. Three types of polyester conductive non-woven filter materials, viz. PTFE-coated media, stainless steel fibre blended with PET media and stainless steel scrim media, have been characterized at three different charge levels, viz. 4 kV, 8 kV, 12 kV, and without charge. The outcome revealed that there has been a significant drop in power consumption with the rise in pre-charge level. Energy utilization results have further been compared with full-scale bag house condition by calculating the energy consumed for 50 bags. The results showed that among all the materials taken for investigation the performance of PTFE-coated media is the best and role of material is most significant towards the energy consumption by the filtration system. Overall energy consumption decreases with rise in pre-charging level. It is observed that percentage contribution of energy utilized for fan has been much higher for full-scale bag house as compared to tubular-based set-up. However, in case of energy consumed by the compressor, the difference in percentage contribution is relatively less and for energy utilized due to charge, not much variation in contribution can be noted.