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1.
Pigment & Resin Technology ; 52(4):490-501, 2023.
Article in English | ProQuest Central | ID: covidwho-20242763

ABSTRACT

PurposeThis study aims to focus on the preparation and characterization of the silver nanowire (AgNWs), as well as their application as antimicrobial and antivirus activities either with incorporation on the waterborne coating formulation or on their own.Design/methodology/approachPrepared AgNWs are characterized by different analytical instruments, such as ultraviolet-visible spectroscope, scanning electron microscope and X-ray diffraction spectrometer. All the paint formulation's physical and mechanical qualities were tested using American Society for Testing and Materials, a worldwide standard test procedure. The biological activities of the prepared AgNWs and the waterborne coating based on AgNWs were investigated. And, their effects on pathogenic bacteria, antioxidants, antiviral activity and cytotoxicity were also investigated.FindingsThe obtained results of the physical and mechanical characteristics of the paint formulation demonstrated the formulations' greatest performance, as well as giving good scrub resistance and film durability. In the antimicrobial activity, the paint did not have any activity against bacterial pathogen, whereas the AgNWs and AgNWs with paint have similar activity against bacterial pathogen with inhibition zone range from 10 to 14 mm. The development of antioxidant and cytotoxicity activity of the paint incorporated with AgNWs were also observed. The cytopathic effects of herpes simplex virus type 1 (HSV-1) were reduced in all three investigated modes of action when compared to the positive control group (HSV-1-infected cells), suggesting that these compounds have promising antiviral activity against a wide range of viruses, including DNA and RNA viruses.Originality/valueThe new waterborne coating based on nanoparticles has the potential to be promising in the manufacturing and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time.

2.
Fresenius Environmental Bulletin ; 32(5):2146, 2023.
Article in English | ProQuest Central | ID: covidwho-20233781

ABSTRACT

Determination of the filtration efficiency (even to nanosize) of several textiles was carried out during emergency time at the beginning of the COVID-19 pandemic lockdown in order to perform a fast screening of materials candidate for facial masks. At this purpose, a double strategy was adopted in Milan: scanning electron microscopy investigation and a classical filtration test of ambient aerosol. The latter was used in order to mimic as much as possible the capability to filter ambient aerosol that might contain COVID-19. The two methods were compared to investigate their capability to identify only textiles characterized by a filtration efficiency higher than 90% (thus candidate for facial mask production). Results showed filtration efficiency above 90% for promising candidate textiles as well as poor filtration capabilities (below 60%) of other textiles, enabling a fast screening of the materials from different Italian factories.

3.
Journal of the Textile Institute ; 2023.
Article in English | Scopus | ID: covidwho-2320876

ABSTRACT

The global COVID-19 pandemic has triggered a huge demand for the protective nonwovens. However, the main raw material of nonwovens comes from petroleum, and the massive consumption of petroleum-based polymers brings great pressure to ecosystem. Therefore, it is significant to develop biodegradable protective barrier products. In this work, a polylactic-based composite (a tri-layer nonwovens composed of spunbond, meltblown and spunbond, SMS) was prepared and applied for protective apparel. The surface morphology and chemical changes of the fibers were characterized and analyzed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The liquid contact angle and permeability, breathability and moisture permeability, frictional charge and mechanical strength of the samples were evaluated and compared. The samples degradability was also recorded. The results demonstrate that the optimum formula for anti-fouling treatment on SMS is F-30. The treated fabric possesses superior liquid repellency and anti-permeability, with contact angles of water and alcohol at 128° and 115° respectively, while the alcohol repellent grade reaches level 7. The treated sample has less strength loss but exhibits favorable breathability, moisture permeability and anti-static properties, which can meet the requirements of protective apparels. After fluorine resin coating, the composite still provide excellent degradation performance, and the weight loss rate reaches more than 80% after 10 days water degradation. These results provide new insights for the application of PLA-based SMS in biodegradable protective apparel. © 2023 The Textile Institute.

4.
Journal of Physical Chemistry C ; 2023.
Article in English | Scopus | ID: covidwho-2318837

ABSTRACT

The integrative study of the pharmacokinetics and dynamics of a drug has been of great research interest due to its authentic description of the biomedical and clinical pros and cons. Acetaminophen (N-acetyl-4-aminophenol, AcAP) is a well-known analgesic having a high therapeutic value, including the Covid-19 treatment. However, an overdose of the drug (>200 mg/kg of men) can lead to liver toxicity. An intermediate, N-acetyl-p-benzoquinone imine (NAPQI), metabolite formation has been found to be responsible for the toxicity. For the detection of NAPQI, several ex situ techniques based on electrochemical methods followed by nuclear magnetic resonance, high-performance liquid chromatography, and LC-MS were stated. For the first time, we report an in situ electrochemical approach for AcAP oxidation and NAPQI intermediate (Mw = 149.1 g mol-1) trapping on a graphitic nanomaterial, carbon black (CB)-modified electrode in pH 7 phosphate buffer solution (CB@NAPQI). The NAPQI-trapped electrode exhibited a surface-confined redox peak at E°′ = 0.350 ± 0.05 V vs Ag/AgCl with a surface excess value of 3.52 n mol cm-2. Physicochemical characterizations by scanning electron microscopy, Raman, FTIR, and in situ electrochemical quartz crystal microbalance (EQCM) techniques supported the entrapment of the molecular species. Furthermore, the scanning electrochemical microscopy (SECM) technique has been adopted for surface-mapping the true active site of the NAPQI-trapped electrode. As a biomimetic study, the mediated oxidation reaction of NADH by CB@NAPQI was demonstrated, and the mechanistic and quantitative aspects were studied using cyclic voltammetry, rotating disc electrode, amperometry, and flow injection analysis techniques. © 2023 American Chemical Society.

5.
Journal of Building Engineering ; 72, 2023.
Article in English | Scopus | ID: covidwho-2290595

ABSTRACT

Stepping up the extraction of valuable resources from the oil palm agro-industry was fraught with palm kernel shell (PKS) disposal challenges. One mitigating measure was to recover these materials for use in fired brick production. So PKS and clay materials were characterized for their physical, mineral and thermal properties. These characterizations revealed the high content of SiO2 and Al2O3 in the clay resources and the 95.60% organic content of PKS along with its estimated 21, 774.94 (kJ/kg) higher heating value (HHV). Indexed minerals from X-ray diffraction (XRD) studies of the clay material were kaolinite, quartz, calcite and goethite. Bricks prepared with the inclusion of up to 16 wt% PKS were fired at 900 and 1000 °C. For bricks fired at 1000 °C, bulk densities decreased from 2.07 to 1.54 g/cm3, apparent porosity increased up to 89.14%, water absorption increased from 100% in reference bricks to 203.54% with the addition of 16 wt% PKS. While compressive strengths decreases were in the range of 21.67–6.07 MPa, thermal insulation improved by 22%. Similar trends were established for bricks fired at 900 °C. The analyses showed that PKS addition was more effective in tailoring the technical properties of the bricks than changes in firing temperature. The marginal differences in technical properties of bricks fired at 1000 °C relative to the 900 °C fired brick units were understood from scanning electron microscopy (SEM) studies. Therefore, this research has provided compelling evidences for use of PKS in fired brick production. © 2023 Elsevier Ltd

6.
Production Planning and Control ; 2023.
Article in English | Scopus | ID: covidwho-2303385

ABSTRACT

The challenges imposed by the business environment increasingly obligate supply chains to seek lower costs while maintaining high service levels. Healthcare supply chains face additional challenges since their main indicator is to save lives and provide care, nonetheless, keeping the revenue flow to support the activities. The covid-19 pandemic evidenced that a severe rupture in healthcare chains generates rupture in all other supply chains. In this sense, our paper has the objective of presenting a conceptual healthcare supply chain performance framework empirically validated by structural equation modelling. Our survey data were processed through the covariance-based structural equation modelling method, adopted for assessing the causal connection among the constructs. The paper revealed a relationship of supply chain integration, supply chain risk management, and supply chain 4.0 (antecedents) with healthcare supply chain performance (consequent). The literature contributions of this paper are (i) developing and validating a new scale for each construct;(ii) finding evidence of the causal relationships between the factors;(iii) measuring how the constructs influence the healthcare supply chain performance in both public and private healthcare sectors and providing discussion and tools to improve these results;(iv) this work empirically tested a theoretical framework;(v) the study reveals that the sector (public or private) has a moderating effect on all the constructs. Furthermore, the results of this study help to address some literature gaps identified by scholars having the potential to serve as a guide to organisations that are willing to implement these practices. Lastly, we recommend that HC supply chain managers consider the implementation of robust initiatives regarding SCRM, SCI, and SC40. © 2023 Informa UK Limited, trading as Taylor & Francis Group.

7.
Antibiotics (Basel) ; 12(4)2023 Apr 14.
Article in English | MEDLINE | ID: covidwho-2303204

ABSTRACT

Resistant bacteria may kill more people than COVID-19, so the development of new antibacterials is essential, especially against microbial biofilms that are reservoirs of resistant cells. Silver nanoparticles (bioAgNP), biogenically synthesized using Fusarium oxysporum, combined with oregano derivatives, present a strategic antibacterial mechanism and prevent the emergence of resistance against planktonic microorganisms. Antibiofilm activity of four binary combinations was tested against enteroaggregative Escherichia coli (EAEC) and Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC): oregano essential oil (OEO) plus bioAgNP, carvacrol (Car) plus bioAgNP, thymol (Thy) plus bioAgNP, and Car plus Thy. The antibiofilm effect was accessed using crystal violet, MTT, scanning electron microscopy, and Chromobacterium violaceum anti-quorum-sensing assays. All binary combinations acted against preformed biofilm and prevented its formation; they showed improved antibiofilm activity compared to antimicrobials individually by reducing sessile minimal inhibitory concentration up to 87.5% or further decreasing biofilm metabolic activity and total biomass. Thy plus bioAgNP extensively inhibited the growth of biofilm in polystyrene and glass surfaces, disrupted three-dimensional biofilm structure, and quorum-sensing inhibition may be involved in its antibiofilm activity. For the first time, it is shown that bioAgNP combined with oregano has antibiofilm effect against bacteria for which antimicrobials are urgently needed, such as KPC.

8.
Current Traditional Medicine ; 9(3):28-43, 2023.
Article in English | EMBASE | ID: covidwho-2267482

ABSTRACT

The mass casualties caused by the delta variant and the wave of the newer "Omicron" variant of SARS-COV-2 in India have brought about great concern among healthcare officials. The government and healthcare agencies are seeking effective strategies to counter the pandemic. The application of nanotechnology and repurposing of drugs are reported as promising approaches in the management of COVID-19 disease. It has also immensely boomed the search for productive, re-liable, cost-effective, and bio-assimilable alternative solutions. Since ancient times, the traditional-ly employed Ayurvedic bhasmas have been used for diverse infectious diseases, which are now employed as nanomedicine that could be applied for managing COVID-19-related health anomalies. Like currently engineered metal nanoparticles (NPs), the bhasma nanoparticles (BNPs) are also packed with unique physicochemical properties, including multi-elemental nanocrystalline compo-sition, size, shape, dissolution, surface charge, hydrophobicity, and multi-pathway regulatory as well as modulatory effects. Because of these conformational and configurational-based physico-chemical advantages, Bhasma NPs may have promising potential to manage the COVID-19 pandemic and reduce the incidence of pneumonia-like common lung infections in children as well as age-related inflammatory diseases via immunomodulatory, anti-inflammatory, antiviral, and adju-vant-related properties.Copyright © 2023 Bentham Science Publishers.

9.
Aerosol and Air Quality Research ; 23(3), 2023.
Article in English | Scopus | ID: covidwho-2253705

ABSTRACT

Wearing respirators and face masks is effective for protecting the public from COVID-19 infection. Thus, there is a need to evaluate the performance of the commonly used respirators and face masks. Two experimental systems were developed to investigate seven different mask materials, which have a fiber size range from 0.1 µm (100 nm) to 20 µm (20,000 nm). One of the systems is a computer-controlled setup for measuring the filtration performance, including size-dependent filtration efficiency and pressure drop, while the other system is for testing the fiber shedding behavior of the materials. The technique of scanning electron microscope (SEM) was applied to observe the dimensions and structures of those materials, which are made of nonwoven-fabrics electret-treated media, cotton woven fabrics, or nanofiber media. The study indicated that the 3M N95 respirator has the best overall filtration performance with over 95% efficiency and low pressure drop of 74.1 Pa. The two commercial cotton face masks have the worst filtration performance in general, with a filtration efficiency of around 25%. No broken fibers from by the seven tested respirator and face mask materials were discovered;however, dendrite structures likely shed by the SHEMA97 face mask with a size comparable to its nanoscale fibers were identified. The reason for this phenomena is presented. © 2023, AAGR Aerosol and Air Quality Research. All rights reserved.

10.
ACS Applied Polymer Materials ; 2023.
Article in English | Scopus | ID: covidwho-2286853

ABSTRACT

The Covid-19 crisis has led to a massive surge in the use of surgical masks worldwide, causing risks of shortages and high pollution. Various decontamination techniques are currently being studied to reduce these risks by allowing the reuse of masks. In this study, surgical masks were washed up to 10 times, each cycle under the same conditions. The consequences of the washing cycles on the structure, fiber morphology, and surface chemistry have been studied through several characterization techniques: scanning electron microscopy, wetting angle measurements, infrared spectroscopy, X-ray diffraction, and X-ray photoelectrons spectroscopy. The washing process did not induce large changes in the hydrophobicity of the surface, the contact angle remaining constant throughout the cycles. The composition observed in the IR spectrum also remained unchanged for washed masks up to 10 cycles. Some slight variations were observed during X-ray analysis: the crystallinity of the fibers as well as the size of the crystals increases with the number of wash cycles. The XPS analysis shows that after 10 cycles, the surface of the masks underwent a slight oxidation. In the SEM images, changes were observed in the arrangement of the fibers, which are more visible the more times the mask has been washed: they align themselves in bundles, form areas with holes in the mask layer, and are crushed in some areas. © 2023 American Chemical Society

11.
ACS Applied Polymer Materials ; 2022.
Article in English | Scopus | ID: covidwho-2285232

ABSTRACT

The current global health crisis caused by the SARS-CoV-2 virus (COVID-19) has increased the use of personal protective equipment, especially face masks, leading to the disposal of a large amount of plastic waste causing an environmental crisis due to the use of non-biodegradable and non-recyclable polymers, such as polypropylene and polyester. In this work, an eco-friendly biopolymer, polylactic acid (PLA), was used to manufacture hierarchical nanoporous microfiber biofilters via a single-step rotary jet spinning (RJS) technique. The process parameters that aid the formation of nanoporosity within the microfibers were discussed. The microstructure of the fibers was analyzed by scanning electron microscopy (SEM) and a noninvasive X-ray microtomography (XRM) technique was employed to study the three-dimensional (3D) morphology and the porous architecture. Particulate matter (PM) and aerosol filtration efficiency were tested by OSHA standards with a broad range (10-1000 nm) of aerosolized saline droplets. The viral penetration efficiency was tested using the ΦX174 bacteriophage (∼25 nm) with an envelope, mimicking the spike protein structure of SARS-CoV-2. Although these fibers have a similar size used in N95 filters, the developed biofilters present superior filtration efficiency (∼99%) while retaining better breathability (<4% pressure drop) than N95 respirator filters. © 2023 American Chemical Society

12.
Biomedical Signal Processing and Control ; 83 (no pagination), 2023.
Article in English | EMBASE | ID: covidwho-2282952

ABSTRACT

Pandemics such as COVID-19 have exposed global inequalities in essential health care. Here, we proposed a novel analytics of nucleic acid amplification tests (NAATs) by combining paper microfluidics with deep learning and cloud computing. Real-time amplifications of synthesized SARS-CoV-2 RNA templates were performed in paper devices. Information pertained to on-chip reactions in time-series format were transmitted to cloud server on which deep learning (DL) models were preloaded for data analysis. DL models enable prediction of NAAT results using partly gathered real-time fluorescence data. Using information provided by the G-channel, accurate prediction can be made as early as 9 min, a 78% reduction from the conventional 40 min mark. Reaction dynamics hidden in amplification curves were effectively leveraged. Positive and negative samples can be unbiasedly and automatically distinguished. Practical utility of the approach was validated by cross-platform study using clinical datasets. Predicted clinical accuracy, sensitivity and specificity were 98.6%, 97.6% and 99.1%. Not only the approach reduced the need for the use of bulky apparatus, but also provided intelligent, distributable and robotic insights for NAAT analysis. It set a novel paradigm for analyzing NAATs, and can be combined with the most cutting-edge technologies in fields of biosensor, artificial intelligence and cloud computing to facilitate fundamental and clinical research.Copyright © 2023 Elsevier Ltd

13.
Chemosphere ; 312, 2023.
Article in English | Scopus | ID: covidwho-2246618

ABSTRACT

Environmental-friendly and efficient strategies for triclosan (TCS) removal have received more attention. Influenced by COVID-19, a large amount of TCS contaminants were accumulated in medical and domestic wastewater discharges. In this study, a unique g-C3N4/Bi2MoO6 heterostructure was fabricated and optimized by a novel and simple method for superb photocatalytic dechlorination of TCS into 2-phenoxyphenol (2-PP) under visible light irradiation. The as-prepared samples were characterized and analyzed by XRD, BET, SEM, XPS, etc. The rationally designed g-C3N4/Bi2MoO6 (4:6) catalyst exhibited notably photocatalytic activity in that more than 95.5% of TCS was transformed at 180 min, which was 3.6 times higher than that of pure g-C3N4 powder. This catalyst promotes efficient photocatalytic electron-hole separation for efficient dechlorination by photocatalytic reduction. The samples exhibited high recyclable ability and the dechlorination pathway was clear. The results of Density Functional Theory calculations displayed the TCS dechlorination selectivity has different mechanisms and hydrogen substitution may be more favorable than hydrogen ion in the TCS dechlorination hydrogen transfer process. This work will provide an experimental and theoretical basis for designing high-performance photocatalysts to construct the systems of efficient and safe visible photocatalytic reduction of aromatic chlorinated pollutants, such as TCS in dechlorinated waters. © 2022 Elsevier Ltd

14.
Electrochimica Acta ; 438, 2023.
Article in English | Scopus | ID: covidwho-2246238

ABSTRACT

As a common antioxidant and antimicrobial agent in plants, luteolin has a variety of pharmacological activities and biological effects, the ability to specifically bind proteins and thus inhibit novel coronaviruses and treat asthma. Here, Co doped nitrogen-containing carbon frameworks/MoS2−MWCNTs (Co@NCF/MoS2−MWCNTs) nanocomposites have been synthesized and successfully applied to electrochemical sensors. X-ray photoelectron spectroscopy, scanning electron microscopy and X-ray diffraction were used to examine the morphology and structure of the samples. Meanwhile, the electrochemical behavior of Co@NCF/MoS2−MWCNTs was investigated. Due to its excellent electrical conductivity, electrocatalytic activity and adsorption, it is used for the detection of luteolin. The Co@NCF/MoS2−MWCNTs/GCE sensor can detect luteolin in a linear range from 0.1 nM to 1.3 μM with a limit of detection of 0.071 nM. Satisfactory results were obtained for the detection of luteolin in natural samples. In addition, the redox mechanism and electrochemical reaction sites of luteolin were investigated by the scan rate of CV curves and density functional theory. This work demonstrates for the first time the combination of ZIF-67-derived Co@NCF and MoS2−MWCNTs as electrochemical sensors for the detection of luteolin, which opens a new window for the sensitive detection of luteolin. © 2022 Elsevier Ltd

15.
Journal of Pharmaceutical and Biomedical Analysis ; 223, 2023.
Article in English | Scopus | ID: covidwho-2245767

ABSTRACT

A fast procedure obtained by the combination of fabric phase extraction (FPSE) with high performance liquid chromatography (HPLC) has been developed and validated for the quantification of favipiravir (FVP) in human plasma and breast milk. A sol-gel polycaprolactone-block-polydimethylsiloxane-block-polycaprolactone (sol-gel PCAP-PDMS-PCAP) coated on 100% cellose cotton fabric was selected as the most efficient membrane for FPSE in human plasma and breast milk samples. HPLC-UV analysis were performed using a RP C18 column under isocratic conditions. Under these optimezed settings, the overall chromatographic analysis time was limited to only 5 min without encountering any observable matrix interferences. Following the method validation procedure, the herein assay shows a linear calibration curve over the range of 0.2–50 µg/mL and 0.5–25 µg/mL for plasma and breast milk, respectively. The method sensitivities in terms of limit of detection (LOD) and limit of quantification (LOQ), validated in both the matrices, have been found to be 0.06 and 0.2 µg/mL for plasma and 0.15 and 0.5 µg/mL for milk, respectively. Intraday and interday precision and trueness, accordingly to the International Guidelines, were validated and were below 3.61% for both the matrices. The herein method was further tested on real samples in order to highlight the applicability and the advantage for therapeutic drug monitoring (TDM) applications. To the best of our knowledge, this is the first validated FPSE-HPLC-UV method in human plasma and breast milk for TDM purposes applied on real samples. The validated method provides fast, simple, cost reduced, and sensitive assay for the direct quantification of favipiravir in real biological matrices, also appliyng a well-known rugged and cheap instrument configuration. © 2022 Elsevier B.V.

16.
OpenNano ; 9, 2023.
Article in English | EMBASE | ID: covidwho-2244461

ABSTRACT

Biomimetic strategies can be adopted to improve biopharmaceutical aspects. Subsequently, Biomimetic reconstitutable pegylated amphiphilic lipid nanocarriers have high translational potential for systemic controlled drug delivery;however, such an improvised system for systemic aspirin delivery exploring nanotechnology is not available. Systemic administration of aspirin and its controlled delivery can significantly control blood clotting events, leading to stroke, which has immediate applications in cardiovascular diseases and Covid-19. In this work, we are developing aspirin sustained release pegylated amphiphilic self-assembling nanoparticles to develop reconstitutable aspirin injections by solvent-based co-precipitation method with phase inversion technique that leads to novel "biomimetic niosomal nanoparticles (BNNs).” DOE led optimization is done to develop Design of space for optimized particles. Upon reconstitution of solid powder, the particle size was 144.8 ± 12.90 nm with a surface charge of -29.2 ± 2.24 mV. The entrapment efficiency was found to be 49 ± 0.15%, wherein 96.99 ± 1.57% of the drug was released in 24hr showing super case II transport-based drug release mechanism. The formulation has the least hemolysis while showing significant suppression of platelet aggregation. MTT assay does not show any significant cytotoxicity. This is a potential nanoparticle that can be explored for developing aspirin injection, which is not available.

17.
Journal of Hazardous Materials ; 443, 2023.
Article in English | Scopus | ID: covidwho-2242953

ABSTRACT

This study focuses on characterizing microplastics and non-microplastics released from surgical masks (SMs), N95 masks (N95), KN95 masks (KN95), and children's masks (CMs) after simulating sunlight aging. Based on micro-Raman spectrum analysis, it was found that the dominant particles released from masks were non-microplastics (66.76–98.85%). Unfortunately, CMs released the most microplastics, which is 8.92 times more than SMs. The predominant size range of microplastics was 30–500 µm, and the main polymer types were PP and PET. Compared with the whole SMs, the microplastic particles released from the cutting-SMs increased conspicuously, which is 12.15 times that of the whole SMs. The main components of non-microplastics include β-carotene, microcrystalline cellulose 102, and eight types of minerals. Furthermore, non-microplastics were mainly fibrous and fragmented in appearance, similar to the morphology of microplastics. After 15 days of UVA-aging, the fibers of the face layers had cracks to varying degrees. It was estimated that these four types of masks can release at least 31.5 trillion microplastics annually in China. Overall, this study demonstrated that the masks could release a large quantity of microplastics and non-microplastics to the environment after sunlight aging, deserving urgent attention in the future study. © 2022 Elsevier B.V.

18.
Journal of the Textile Institute ; 114(1):55-65, 2023.
Article in English | Scopus | ID: covidwho-2241397

ABSTRACT

With the emergence of the COVID-19, masks and protective clothing have been used in huge quantities. A large number of non-degradable materials have severely damaged the ecological environment. Now, people are increasingly pursuing the use of environmentally friendly materials to replace traditional chemical materials. Silk fibroin (SF) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) have received increasing attention because of their unique biodegradability and biocompatibility. In this paper, a series of biodegradable SF/PHBV nanofiber membranes with different PHBV content were fabricated by using electrospinning technology. The morphology of the electrospun SF/PHBV composite nanofiber was observed by scanning electron microscopy (SEM). The average diameters of the pure SF, SF/PHBV (4/1), SF/PHBV (3/1), and SF/PHBV (2/1) nanofibers were 55.16 ± 12.38 nm, 75.93 ± 21.83 nm, 69.35 ± 21.55 nm, and 61.40 ± 12.31 nm, respectively. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to explore the microstructure of the electrospun SF/PHBV composite nanofiber. The crystallization ability of the composite nanofiber was greatly improved with the addition of PHBV. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the thermal stability of SF was better than PHBV obviously, so SF could improve the thermal stability of the composite materials within a certain range. The mechanical properties of the electrospun nanofiber membranes were evaluated by using a universal testing machine. In general, the elongation of the composite nanofiber membranes decreased, and the breaking strength increased with the addition of PHBV. The small pore size of the nanofiber membranes ensured that they had good application prospects in the field of filtration and protection. When the spinning time was 1 h, the filtration efficiency of SF/PHBV/PLA composite materials remained above 95%. © 2021 The Textile Institute.

19.
Journal of Hazardous Materials ; 441, 2023.
Article in English | Scopus | ID: covidwho-2239696

ABSTRACT

This study explored the degradation behavior of three types of disposable face masks in simulated seawater via the accelerated aging experiments. Microplastics (MPs) and dissolved organic carbon (DOC) were monitored in UV- and thermal-treated mask suspensions and their concentrations increased slowly in the early stage at 50 ℃ and 58 ℃. Owing to the high energy supply, the release rates of MPs and DOC at 76 ℃ were much faster than the above two temperatures. The time-temperature superposition principle (TTSP) was used to superpose the MPs/DOC release kinetics from other tested temperatures to the reference temperature and its applicability was verified by the similar activation energy. Then, a release kinetics model was established and fitted well with the superposed MP data (R2 ≥ 0.96). Since less than 0.1 % of carbon was leached, the superposed DOC data was roughly modelled by the exponential function (R2 ≥ 0.90). According to the TTSP and the established kinetics models, about 15 years were estimated to decompose half of a certain marine mask waste, together with leaching 0.21 ± 0.02 mg∙g-mask−1 of DOC. If mask consumption remains the same before 2025, they would contribute 40000–230000 tonnes of MPs and 13–97 tonnes of DOC to the ocean by 2040. © 2022

20.
Chemosphere ; 311, 2023.
Article in English | Scopus | ID: covidwho-2238550

ABSTRACT

The CO2 emission is enhancing drastically because of the continuous emission from industries and transport sector. Although the CO2 emission had decreased in the first half of 2020 by 8.8% due to COVID-19 restrictions however, it is again on the rise and it might exceed the estimated level in 2030. The current methods used for CO2 separation have serious operational and environmental constraints. To overcome these problems we have devised a supported ionic liquid membrane (SILM) incorporated with the blend of bimetallic metal-organic framework (MOF) of copper and magnesium ions (CuxMgx) and Trihexyltetradecylphosphonium chloride [P66614] [Cl] ionic liquid (IL). CuxMgx MOF were synthesized and characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and energy dispersive X-ray analysis (EDX). CuxMgx MOF with [P66614] [Cl] IL were immobilized on a flat sheet of polytetrafluoroethylene (PTFE) membrane. Single gas permeation tests of membranes loaded with 0.2/0.8 wt/wt% MOF/IL solution showed the highest CO2 permeability of 2937 Barrer and CO2/N2 selectivity of 33.26. The performance of SILM was also investigated with different water loadings of (30 wt % and 50 wt %) in addition to MOF/IL solution and at different feed pressure varying from 0.5 to 2 bars. Membranes showed enhancement in CO2 permeability to 3738 and 4628 Barrer whereas CO2/N2 selectivity decreased to 23.53 and 21.8 with membranes loaded with 30 and 50 wt % water, respectively, at a feed pressure of 2 bar. The gas permeation results show that the incorporation of CuxMgx MOF with IL in polymeric membrane enhances the CO2/N2 separation under humid conditions but slightly decreases CO2/N2 selectivity with an increase in feed pressure. The SILM synthesized in this research is highly viable for industrial flue gases because of the incorporation of phosphonium-based ILs that have high thermal stability. © 2022

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