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1.
ACS Appl Mater Interfaces ; 16(33): 44261-44269, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39134960

RESUMO

As the potential adverse health and environmental effects of nanoscale pollutants have garnered significant attention, the demand for monitoring and capturing ultrafine particulate matter has been growing. With the rise in ultrafine dust emissions, this issue has become increasingly important. However, submicron particles require advanced strategies to be captured because of their limited inertial effect. For example, electrostatic air filters have been investigated for their improved performance in the fine particle regime. On the other hand, Raman spectroscopy was proposed as a promising analytical strategy for aerosol particles because it can be used to conveniently detect analytes in a label-free manner. Thus, the synergistic integration of these strategies can open new applications for addressing environment-related challenges. This study presents a multifunctional approach for achieving both air filtration and surface-enhanced Raman scattering (SERS) for analyte identification. We propose a nanoporous membrane composed of a thin gold layer, copper, and copper oxide to provide the desired functions. The structures are produced by performing scalable electrodeposition and subsequent electron-beam evaporation, attaining an excellent filtration efficiency of 95.9% with an applied voltage of 5 kV for 300 nm KCl particles and a pressure drop of 121 Pa. Raman intensity measurements confirm that the nanodendritic surface of the membrane intensifies the Raman signals and allows for the detection of 10 µL of nanoplastic particle dispersion with a concentration of 50 µg/mL. Rhodamine 6G aerosol stream with an approximate particle deposition rate of 0.040 × 106 mm-2·min-1 is also identified in a minimum detectable time of 50 s. The membrane is shown to be recyclable owing to its structural robustness in organic solvents. In addition, the fatigue resistance of the structure is evaluated through 22,000 iterative loading cycles at a pressure of 177 kPa. No performance degradation is observed after the fatigue loading.

2.
Environ Int ; 190: 108939, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39116555

RESUMO

To protect occupants in vehicle cabin environments from the health risks of high concentrations of particulate matter (PM), it is important to install vehicle cabin air filter (VCAF) to eliminate PM. In this study, we investigated the filtration performance of 22 VCAFs. Results showed that the minimum average filtration efficiency was 56.1 % for particles with a diameter of 0.1-0.3 µm, a pressure drop of 33.2-250 Pa at air velocity of 2.5 m/s, and the dust-holding capacity ranged from 5.8 to 19.4 g. In addition, as the filter area increased from 0.23 m2 to 0.50 m2, the filtration efficiency for particles with a diameter of 0.1-0.3 µm increased from 56.7 % to 77.5 %, the pressure drop decreased from 96.1 to 62.5 Pa, and the dust holding capacity increased 2.7 times. Furthermore, we compared the service life of VCAF from 31 major Chinese cities and found that the service life varied greatly from maximum of 1730 h for Haikou to minimum of 352 h for Shijiazhuang. Considering occupant health risks, Beijing requires that VCAFs have PM2.5 filtration efficiency at least 88.1 %, and Liaoning requires minimum of 97.5 %. Hence, choosing the appropriate VCAF based on the atmospheric environment of different cities deserves our attention.


Assuntos
Filtros de Ar , Filtração , Material Particulado , China , Material Particulado/análise , Poluentes Atmosféricos/análise , Tamanho da Partícula , Poluição do Ar em Ambientes Fechados/análise , Poluição do Ar em Ambientes Fechados/prevenção & controle , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Monitoramento Ambiental , Poeira/análise , Humanos , Cidades , Poluição do Ar/prevenção & controle , Poluição do Ar/estatística & dados numéricos , Emissões de Veículos/análise , Automóveis
3.
Materials (Basel) ; 17(13)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38998329

RESUMO

The purpose of this study was to empirically evaluate the performance of fibrous materials that meet the criteria for inlet air filtration in internal combustion engines. The characteristics of filtration efficiency and accuracy, as well as the characteristics of flow resistance, were determined based on the mass of dust accumulated in the filter bed during the filtration process. Single-layer filter materials tested included cellulose, polyester, and glass microfiber. Multilayer filter media such as cellulose-polyester-nanofibers and cellulose-polyester were also examined. A new composite filter bed-consisting of polyester, glass microfiber, and cellulose-and its filtration characteristics were evaluated. Utilizing specific air filtration quality factors, it was demonstrated that the composite is characterized by high pre-filtration efficiency (99.98%), a short pre-filtration period (qs = 4.21%), high accuracy (dpmax = 1.5-3 µm) for the entire lifespan of the filter, and a 60-250% higher dust absorption coefficient compared to the other tested materials. A filtration composite bed constructed from a group of materials with different filtration parameters can be, due to its high filtration efficiency, accuracy, and dust absorption, an excellent filter material for engine intake air. The composite's filtration parameters will depend on the type of filter layers and their order relative to the aerosol flow. This paper presents a methodology for the selection and testing of various filter materials.

4.
Nanomaterials (Basel) ; 14(13)2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38998757

RESUMO

The exposure of workers to propylene glycol monomethyl ether acetate (PGMEA) in manufacturing environments can result in potential health risks. Therefore, systems for PGMEA removal are required for indoor air quality control. In this study, core-shell zeolite socony mobil-5 (ZSM-5)/polyvinylpyrrolidone-polyvinylidene fluoride nanofibers were directly electrospun and partially wet-etched on a mesh substrate to develop a cover-free compact PGMEA air filter. The electrospinning behaviors of the core-shell nanofibers were investigated to optimize the electrospinning time and humidity and to enable the manufacture of thin and light air-filter layers. The partial wet etching of the nanofibers was undertaken using different etching solvents and times to ensure the exposure of the active sites of ZSM-5. The performances of the ZSM-5/PVDF nanofiber air filters were assessed by measuring five consecutive PGMEA adsorption-desorption cycles at different desorption temperatures. The synthesized material remained stable upon repeated adsorption-desorption cycles and could be regenerated at a low desorption temperature (80 °C), demonstrating a consistent adsorption performance upon prolonged adsorption-desorption cycling and low energy consumption during regeneration. The results of this study provide new insights into the design of industrial air filters using functional ceramic/polymer nanofibers and the application of these filters.

5.
Polymers (Basel) ; 16(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38732709

RESUMO

This paper reports the successful fabrication of a new nanofibrous membrane, F-PI/PAN, through electrospinning of polyacrylonitrile (PAN) and fluorinated polyimide (F-PI). The nanofibrous membrane exhibits comprehensive properties for high-temperature filtration and robust PM2.5 (particulate matter with an aerodynamic equivalent diameter of 2.5 microns or less) removal. The introduction of F enhances the hydrophobicity of the PI. The relationship between the hydrophobic performance and the filtration performance of particles is investigated. The chemical group of the composite membrane was demonstrated using FITR, while the surface morphology was investigated using field emission scanning electron microscopy. The TGA results indicated good thermal stability at 300 °C. Various ratios of F-PI membranes were prepared to characterize the change in properties, with the optimal mass ratio of F-PI being 20 wt%. As the proportion of F-PI increases, its mechanical and filtration efficiency properties and hydrophobicity become stronger. The contact angle reaches its maximum of 128 ± 5.2° when PAN:F-PI = 6:4. Meanwhile, when PAN:F-PI = 8:2, the filtration efficiency reaches 99.4 ± 0.3%, and the elongation at break can reach 76%. The fracture strength can also reach 7.1 MPa, 1.63 times that of the pure PAN membrane.

6.
J Multidiscip Healthc ; 17: 2613-2622, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38813091

RESUMO

Background: Asthma affects the quality of life (QoL) of millions of people worldwide. Effective control is paramount to a decline in prevalence and severity. To address this, we aimed to investigate the effectiveness of an asthma home management manual and low-cost air filter in improving resource-limited settings. Patients and Methods: This randomized controlled trial was conducted between March to July 2022. The participants were 18-55 years old outpatient with asthmatic patients. A total of 114 participants were recruited and randomly assigned to three groups: home management only, home management and air filtering, and control. Validated measurement tools were applied, and the Wilcoxon test was used to evaluate changes in QoL. Results: Asthma burden was found in at least one-third of participants in each group. At baseline, there was no difference in mAQLQ scores among participants in all group allocations (p-value > 0.05), and the air filter group had an increase in the total mAQLQ score (p-value = 0.044) and post-intervention activity quality of life (p-value = 0.002). The environmental quality of life increased post-intervention (p-value = 0.004) and remained higher after four weeks of follow-up compared to baseline (p-value = 0.041) in the home management group participants. Conclusion: The findings indicate that the enforcement of a home management manual and the application of low-cost filters in air circulation systems offer advantages in improving the quality of life of patients with moderate and mild asthma.

7.
MethodsX ; 12: 102693, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38633417

RESUMO

Dust is a sink for many semi-volatile compounds including flame retardants of the organophosphate ester (OPE) and brominated flame-retardant (BFR) classes. Given the large amount of time that we spend indoors, our exposure to these compounds via dust is of significant interest. Here, we present a novel microextraction approach to determine quantitative levels of selected OPEs and BFRs sampled from residential air filters from HVAC systems using a small volume of solvent. Dust samples (25 mg) is extracted with 1 mL of hexane/acetone (50/50, v/v). Upon solvent extraction of these HVAC dust samples, the analytes (TCPP, TDCPP, TPHP, T24DtBPP, TBBPA, and TriBBPA) were quantified via gas chromatography-mass spectrometry (GC/MS) or liquid chromatography-mass spectrometry (LC/MS). The methods for extracting these compounds from HVAC dust samples are detailed here with extensive method validation data to demonstrate accuracy and precision of these methods. •Dust is a sink for many semi-volatile compounds, including novel or emerging indoor pollutants like the organophosphate ester flame retardant T24DtBPP.•Here, a small amount of dust (25 mg) is extracted with a small volume of solvent (1 mL hexane and acetone) prior to analysis via chromatographic separation and mass spectrometric detection.

8.
J Hazard Mater ; 469: 134064, 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38513444

RESUMO

Water vapor from respiration can severely accelerate the charge dissipation of the face mask, reducing filtration efficiency. Moreover, the foul odor from prolonged mask wear tends to make people remove their masks, leading to the risk of infection. In this study, an electro-blown spinning electroactive nanofibrous membrane (Zn/CB@PAN) with antibacterial and deodorization properties was prepared by adding zinc (Zn) and carbon black (CB) nanoparticles to the polyacrylonitrile (PAN) nanofibers, respectively. The filtration efficiency of Zn/CB@PAN for PM0.3 was > 99% and could still maintain excellent durability within 4 h in a high-humidity environment (25 â„ƒ and RH = 95%). Moreover, the bacterial interception rate of the Zn/CB@PAN could reach 99.99%, and it can kill intercepted bacteria. In addition, the deodorization rate of Zn/CB@PAN in the moist state for acetic acid was 93.75% and ammonia was 95.23%, respectively. The excellent filtering, antibacterial, and deodorizing performance of Zn/CB@PAN can be attributed to the synergistic effect of breath-induced Zn/CB galvanic couples' electroactivity, released metal ions, and generated reactive oxygen species. The developed Zn/CB@PAN could capture and kill airborne environmental pathogens under humid environments and deodorize odors from prolonged wear, holding promise for broad applications as personal protective masks.


Assuntos
Nanofibras , Humanos , Antibacterianos , Ácido Acético , Zinco , Amônia , Filtração
9.
Environ Res ; 248: 118223, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38286254

RESUMO

Dust is a sink for flame retardants, which are added to a myriad of consumer products in residential spaces. Organophosphate esters (OPEs) and brominated flame retardants (BFRs) are two classes of flame retardants that are frequently used in consumer products and consequently found in dust. In this present work, a novel solvent-limited microextraction technique, which we detailed in a companion study, was applied for the determination of four OPEs and two BFRs with limits of quantitation at the ng/g level by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry from n = 47 air filter dust samples collected from forced air HVAC systems. Levels of the BFRs, including tetrabromobisphenol-A and its derivative tribromobisphenol-A, were found at levels <4 µg/g and not frequently detected. Conversely, all four OPEs were detected in all air filter dust samples. Total OPE load was dominated by tris(2,4-di-tert-butylphenyl) phosphate, T24DtBPP, a novel OPE not widely examined in the literature. Comparison of individual and total OPE concentrations to residential characteristics revealed statistically significant relationships to location of the home and dominant flooring type. Overall, this study motivates future work in examining the whole house exposome using air filter dust as a passive sampling regime with more examination of T24DtBPP loads within other indoor spaces.


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados , Expossoma , Retardadores de Chama , Retardadores de Chama/análise , Poeira/análise , Organofosfatos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , Ésteres/análise
10.
Int J Biol Macromol ; 254(Pt 2): 127862, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37939775

RESUMO

Functionalization of bio-based nanofibers is the development tendency of high-performance air filter. However, the conventional structural optimization strategy based on high solution conductivity greatly hinders the development of fully bio-based air filter, and not conducive to sustainable development. This work fabricated fully bio-based nanofibrous membrane with formaldehyde-adsorbable and antibacterial capabilities by electrospinning low-conductivity solution for high-performance air filtration and applied to lightweight mask. The "water-like" ethyl cellulose (EC) was selected as the base polymer to "nourish" functional materials of gelatin (GE), ß-cyclodextrin (ßCD), and curcumin (Cur), thus forming a solution system with high binding energy differences and electrospinning into ultrafine bimodal nanofibers. The filtration efficiency for 0.3 µm NaCl particles, pressure drop, and quality factor were 99.25 %, 53 Pa, and 0.092 Pa-1, respectively; the bacteriostatic rates against Escherichia coli and Staphylococcus aureus were 99.9 % and 99.4 %, respectively; the formaldehyde adsorption capacity was 442 µg/g. This is the first report on antibacterial and formaldehyde-adsorbable high-performance air filter entirely made from bio-based materials. This simple strategy will greatly broaden the selection of materials for preparing high-performance multifunctional air filter, and promote the development of bio-based air filter.


Assuntos
Curcumina , Nanofibras , Nanofibras/química , Curcumina/farmacologia , Gelatina , Filtração , Antibacterianos/farmacologia
11.
Nanomaterials (Basel) ; 13(14)2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37513082

RESUMO

Air purification devices, such as air purifiers, provide fresh air by filtering out airborne pollutants, dust, and other harmful substances using various filter systems. While air filters are generally effective in filtering pollutants such as dust, they encounter a challenge when filtering harmful microorganisms such as mites, bacteria, mold, and viruses. These microorganisms, which are present in public transport and public indoor spaces, tend to proliferate on the surface of the filter media, eventually reintroducing themselves into the air or causing unpleasant odors. To address this issue, herein, copper particles were prepared as one masterbatch and deposited on polypropylene (PP) pellets through plasma vacuum deposition to effectively filter dust and microorganisms and prevent their growth on the surface of the filter media. After adding 3-10 wt.% of the masterbatch to conventional PP pellets to fabricate a filter media, the distribution of copper on the surface of the filter media was observed through a scanning electron microscope. To verify the safety and effectiveness of the antimicrobial material, the filter media containing antimicrobial particles was tested using Escherichia coli (E. coli) and Staphylococcus aureus through a filter emission test.

12.
Int J Biol Macromol ; 246: 125721, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37419257

RESUMO

Today, one of the world's critical environmental issues is air pollution, which is the most important parameter threatening human health and the environment. Synthetic polymers are widely used in industrial air filter production; however, they are incompatible with the environment due to their secondary pollution. Using renewable materials to manufacture air filters is not only environmentally friendly but also essential. Recently, a new generation of biopolymers called cellulose nanofiber (CNF)-based hydrogels have been proposed, with three dimensional (3D) nanofiber networks and unique physical and mechanical properties. CNFs have become a hot research topic for application as air filter materials because they can compete with synthetic nanofibers due to their advantages, such as abundant, renewable, nontoxic, high specific surface area, high reactivity, flexibility, low cost, low density, and network structure formation. The main focus of the current review is the recent progress in the preparation and employment of nanocellulose materials, especially CNF-based hydrogels, to absorb PM and CO2. This study summarizes the preparation methods, modification strategies, fabrications, and further applications of CNF-based aerogels as air filters. Lastly, challenges in the fabrication of CNFs, and trends for future developments are presented.


Assuntos
Filtros de Ar , Nanofibras , Humanos , Hidrogéis/química , Nanofibras/química , Celulose/química , Polímeros
13.
Nanomaterials (Basel) ; 13(11)2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37299623

RESUMO

Multifunctional nanofibers for particulate matter (PM) and volatile organic compounds (VOCs) removal from the indoor atmospheric environment were manufactured from eco-friendly natural cellulose materials via electrospinning using an optimized solvent system containing 1-ethyl-3-methylimidazolium acetate (EmimAC) and dimethylformide (DMF) in a 3:7 volume ratio. EmimAC improved the cellulose stability, whereas DMF improved the electrospinnability of the material. Various cellulose nanofibers were manufactured using this mixed solvent system and characterized according to the cellulose type, such as hardwood pulp, softwood pulp, and cellulose powder, and cellulose content ranging from 6.0-6.5 wt%. The correlation between the precursor solution alignment and electrospinning properties indicated an optimal cellulose content of 6.3 wt% for all cellulose types. The hardwood pulp-based nanofibers possessed the highest specific surface area and exhibited high efficiency for eliminating both PM and VOCs, with a PM2.5 adsorption efficiency of 97.38%, PM2.5 quality factor of 0.28, and toluene adsorption of 18.4 mg/g. This study will contribute to the development of next-generation eco-friendly multifunctional air filters for indoor clean-air environments.

14.
Membranes (Basel) ; 13(4)2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37103807

RESUMO

State-of-art face masks and respirators are fabricated as single-use devices using microfibrous polypropylene fabrics, which are challenging to be collected and recycled at a community scale. Compostable face masks and respirators can offer a viable alternative to reducing their environmental impact. In this work, we have developed a compostable air filter produced by electrospinning a plant-derived protein, zein, on a craft paper-based substrate. The electrospun material is tailored to be humidity tolerant and mechanically durable by crosslinking zein with citric acid. The electrospun material demonstrated a high particle filtration efficiency (PFE) of 91.15% and a high pressure drop (PD) of 191.2 Pa using an aerosol particle diameter of 75 ± 2 nm at a face velocity of 10 cm/s. We deployed a pleated structure to reduce the PD or improve the breathability of the electrospun material without compromising the PFE over short- and long-duration tests. Over a 1 h salt loading test, the PD of a single-layer pleated filter increased from 28.9 to 39.1 Pa, while that of the flat sample increased from 169.3 to 327 Pa. The stacking of pleated layers enhanced the PFE while retaining a low PD; a two-layer stack with a pleat width of 5 mm offers a PFE of 95.4 ± 0.34% and a low PD of 75.2 ± 6.1 Pa.

15.
ACS Appl Mater Interfaces ; 15(17): 20977-20986, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37070411

RESUMO

According to clinical case reports, bacterial co-infection with COVID-19 can significantly increase mortality, with Staphylococcus aureus (S. aureus) being one of the most common pathogens causing complications such as pneumonia. Thus, during the pandemic, research on imparting air filters with antibacterial properties was actively initiated, and several antibacterial agents were investigated. However, air filters with inorganic nanostructures on organic nanofibers (NFs) have not been investigated extensively. This study aimed to demonstrate the efficiency of electropolarized poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) NFs decorated with Li-doped ZnO nanorods (NRs) to improve the filtering ability and antibacterial activity of the ultrathin air filter. The surfactant was loaded onto the ZnO─known for its biocompatibility and low toxicity─nanoparticles (NPs) and transferred to the outer surface of the NFs, where Li-doped ZnO NRs were grown. The Li-doped ZnO NR-decorated NF effectively enhanced the physical filtration efficiency and antibacterial properties. Additionally, by exploiting the ferroelectric properties of Li-doped ZnO NRs and PVDF-TrFE NFs, the filter was electropolarized to increase its Coulombic interaction with PMs and S. aureus. As a result, the filter exhibited a 90% PM1.0 removal efficiency and a 99.5% sterilization rate against S. aureus. The method proposed in this study provides an effective route for simultaneously improving the air filter performance and antibacterial activity.


Assuntos
Filtros de Ar , Nanofibras , Óxido de Zinco/química , Lítio/química , Antibacterianos/química , Antibacterianos/farmacologia , Nanofibras/química , Nanofibras/ultraestrutura , Staphylococcus aureus/efeitos dos fármacos
16.
J Hazard Mater ; 452: 131241, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36958166

RESUMO

Exploring pore structures that are optically transparent and have high filtration efficiency for ultrafine dust is very important for realizing passive window filters for indoor air purification. Herein, a polyester track-etched (PETE) membrane with vertically perforated micropores is investigated as a cost-effective candidate for transparent window filters. The pore size, which governs transparency and filtration efficiency, can be precisely tuned by conformally depositing an ultrathin oxide layer on the PETE membrane via atomic layer deposition. The maximum visible light transmittance (∼81.2 %) was achieved with an alumina layer of approximately 55 nm, and the resulting composite membrane exhibited competitive filtration efficiency compared to commercial products. The chemically inert alumina layer also increased resistance to various external stimuli and enabled simple cleaning of the contaminated membrane surface with a solvent. The membrane installed on an insect screen effectively maintained its filtration performance (∼85 % for PM2.5) even after 10 reuse cycles under extremely harsh conditions (PM2.5 concentration: ∼5000 µg cm-3). The proposed through-hole composite membrane can expand the choice of aesthetic window filters to situations that require high outside visibility and daylighting.

17.
Artigo em Inglês | MEDLINE | ID: mdl-36776477

RESUMO

Background: Exposure to particulate air pollution is one of the greatest environmental risk factors for adverse human health outcomes. However, the constituents that may be responsible for such adverse health effects have not been fully studied. Methods: Total suspended particulates filters collected every 6 days in 2011 from three South Carolina locations were used in this case study. An inductively coupled plasma mass spectrometer interfaced with a laser ablation system (LA-ICP-MS) was used to directly analyze 41 inorganic elemental species on air pollution filters. Then, machine learning and multivariate statistical methods was employed to identify combinatorial patterns in the data and classify sites based on their elemental composition. Results: Forty-one elements were assessed and 33 were used in subsequent analysis. Correlations between United States Environmental Protection Agency (US EPA)'s chemical analysis dataset and data from the current study revealed significant associations between 7/15 elements with enough variation for comparison (r between 0.28 to 0.66, p<0.05). Subsequent multivariate analyses revealed four distinct patterns in the distribution of elements by sample location throughout the year. Conclusion: The different airborne elements may need to be assessed to understand combinations of elements which occur together over space and/or time. Such information can be helpful in planning effective counter measures and strategies to control particulate air pollution.

18.
Polymers (Basel) ; 15(3)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36772022

RESUMO

In this work, PLLA and CD/PLLA nanofibers were fabricated using electrospinning and utilized as a particulate matter (PM) and volatile organic compounds (VOCs) filter. The electrospun PLLA and CD/PLLA were characterized with various techniques, including SEM, BET, FTIR, XRD, XPS, WCA, DSC, tensile strength testing, PM and VOCs removal efficiency, and triboelectric performance. The results demonstrated that the best air filter was 2.5 wt%CD/PLLA, which performed the highest filtration efficiencies of 96.84 ± 1.51% and 99.38 ± 0.43% for capturing PM2.5 and PM10, respectively. Its PM2.5 removal efficiency was 16% higher than that of pure PLLA, which were contributed by their higher surface area and porosity. These 2.5 wt%CD/PLLA nanofibers also exhibited the highest and the fastest VOC entrapment. For triboelectric outputs, the 2.5 wt%CD/PLLA-based triboelectric nanogenerator provided the highest electrical outputs as 245 V and 84.70 µA. These give rise to a three-fold enhancement of electrical outputs. These results indicated that the 2.5 wt%CD/PLLA can improve surface charge density that could capture more PM via electrostatic interaction under surrounding vibration. Therefore, this study suggested that 2.5 wt%CD/PLLA is a good candidate for a multifunction nanofibrous air filter that offers efficient PM and VOC removal.

19.
Intensive Crit Care Nurs ; 74: 103335, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36651655

RESUMO

BACKGROUND: The application of Continuous Positive Airway Pressure (CPAP) with a helmet is increasing around the world, both inside and outside of the intensive care unit. Current published literature focus's on indications, contraindications and efficiency of Helmet CPAP in differing clinical scenarios. Few reports, summarising the available knowledge concerning technical characteristics and nursing interventions to improve patient's comfort, are available. AIM: To identify the crucial technical aspects in managing patients undergoing Helmet-CPAP, and what nursing interventions may increase comfort. METHODS: A narrative literature review of primary research published 2002 onwards. The search strategy comprised an electronic search of three bibliographic databases (Pubmed, Embase, CINAHL). RESULTS: Twenty-three studies met the inclusion criteria and were included in the review. Research primarily originated from Italy. Nine key themes emerged from the review: gas flow management, noise reduction, impact of gas flow and HME filters on delivered FiO2, filtration of exhaled gas / environmental protection, PEEP monitoring, airway pressure monitoring, active humidification of gas flow, helmet fixation and tips to implement awake prone position during Helmet-CPAP. CONCLUSIONS: A Helmet-CPAP check-list has been made of nine key interventions based on the available evidence regarding system set up, monitoring and management. Implementation of this check-list may help nurses and physicians to increase the comfort of patients treated with Helmet CPAP and enhance their compliance with long-term treatment.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas , Unidades de Terapia Intensiva , Humanos , Itália , Monitorização Fisiológica , Ruído
20.
Carbohydr Polym ; 302: 120322, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36604039

RESUMO

In this work, we present novel, sustainable filters based on bacterial cellulose (BC) functionalized with low-pressure argon plasma (LPP-Ar). The "green" production process involved BC biosynthesis by Komagataeibacter xylinus, followed by simple purification, homogenization, lyophilization, and finally LPP-Ar treatment. The obtained LPP-Ar-functionalized BC-based material (LPP-Ar-BC-bM) showed excellent antimicrobial and antiviral properties against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, and an enveloped bacteriophage phage Φ6, with no cytotoxicity versus murine fibroblasts in vitro. Further, filters consisting of three layers of LPP-Ar-BC-bM had >99 % bacterial and viral filtration efficiency, while maintaining sufficiently low airflow resistance (6 mbar at an airflow of 95 L/min). Finally, as a proof-of-concept, we were able to prepare 80 masks with LPP-Ar-BC-bM filter and ~85 % of volunteer medical staff assessed them as "good" or "very good" in terms of comfort. We conclude that our novel sustainable, biobased, biodegradable filters are suitable for respiratory personal protective equipment (PPE), such as surgical masks and respirators.


Assuntos
Gases em Plasma , Humanos , Animais , Camundongos , Gases em Plasma/farmacologia , Staphylococcus aureus , Escherichia coli , Celulose/farmacologia , Bactérias
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