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Pyrolysis kinetic behaviour and TG-FTIR-GC-MS analysis of Coronavirus Face Masks.

ABSTRACT: In the times of Covid-19, face masks are considered to be the main source of protection against the virus that reduces its spread. These masks are classified as single-use medical products with a very short service life, estimated at few days, hence millions of contaminated masks are generated daily in the form of hazardous materials, what requires to develop a safe method to dispose of them, especially since some of them are loaded with viruses. 3-ply face masks (3PFM) represent the major fraction of this waste and are composed mainly from polypropylene and melt blown filter with high content of volatile substances (96.6 wt.%), what makes pyrolysis treatment an emerging technology that could be used to dispose of face masks and convert them into energy products. In this context, this work aims to study pyrolysis kinetic behaviour and TG-FTIR-GC-MS analysis of 3PFM. The research started with analysis of 3PFM using elemental analysis, proximate analysis, and compositional analyses. Afterwards, TG-FTIR system was used to study the thermal and chemical decomposition of 3PFM analyzed at different heating rates: 5, 10, 15, 20, 25, and 30 °C/min. The GC/MS system was used to observe the synthesized volatile products at the maximum decomposition temperatures. After that, isoconversional methods, the advanced nonlinear integral isoconversional method, and the iterative linear integral isoconversional method were used to determine the activation energies of mask pyrolysis, while the distributed activation energy model and the independent parallel reactions kinetic model were used to fit TGA and DTG curves with deviations below <1. The TGA-DTG results showed that 3PFM can decompose in three different periods with a total weight loss of 95 % and maximum decomposition in the range 405-510 °C, while the FTIR spectra and GC-MS analysis exhibited that - C-H (aromatic and aliphatic) and 2,4-Dimethyl-1-heptene (28-43 % based on heating rate) represented the major compounds in the released volatile components. Finally, Vyazovkin and the iterative linear integral isoconversional methods gave activation energies almost similar to that obtained by the KAS isoconversional method.

SUBMITTER: Yousef S

PROVIDER: S-EPMC8045431 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Recently, the pyrolysis process has been adapted as a sustainable strategy to convert metallized food packaging plastics waste (MFPW) into energy products (paraffin wax, biogas, and carbon black particles) and to recover aluminum. Usually, catalysts are used in pyrolysis treatment to refine pyrolysis products and to increase their yield. In order to study the effect of a catalyst on the formulated volatile products, this work aims to study the pyrolysis behavior of MFPW in presence of catalyst, using TG-FTIR-GC-MS system. The pyrolysis experiments were conducted with ZSM-5 Zeolite catalyst with different concentrations (10, 30, and 50 wt.%) at different heating rates (5, 10, 15, 20, 25, and 30 °C/min). In addition, TG-FTIR system and GC-MS unit were used to observe and analyze the thermal and chemical degradation of the obtained volatile compounds at maximum decomposition peaks. In addition, the kinetic results of catalytic pyrolysis of ZSM-5/MFPW samples matched when model-free methods, a distributed activation energy model (DAEM), and an independent parallel reaction kinetic model (IPR) were used. The TGA-DTG results showed that addition of a catalyst did not have a significant effect on the features of the TGA-DTG curves with similar weight loss of 87-90 wt.% (without taking the weight of the catalyst into account). Meanwhile, FTIR results manifested strong presence of methane and high-intensity functional group of carboxylic acid residues, especially at high concentration of ZSM-5 and high heating rates. Likewise, GC-MS measurements showed that Benzene, Toluene, Hexane, p-Xylene, etc. compounds (main flammable liquid compounds in petroleum oil) generated catalysts exceeding 50%. Finally, pyrolysis kinetics showed that the whole activation energies of catalytic pyrolysis process of MFPW were estimated at 289 kJ/mol and 110, 350, and 174 kJ/mol for ZSM-5/MFPW samples (10, 30, and 50 wt.%, respectively), whereas DAEM and IPR approaches succeeded to simulate TGA and DTG profiles with deviations below <1.

Project description:In general, the greater the number of directly linked nitrogen atoms in a molecule, the better its energetic performance, while the stability will be accordingly lower. But 1,1'-azobis-1,2,3-triazole (1) and 4,4'-azobis-1,2,4-triazole (2) show remarkable properties, such as high enthalpies of formation, high melting points, and relatively high stabilities. In order to rationalize this unexpected behavior of the two compounds, it is necessary to study their thermal decompositions and pyrolyses. Although a great deal of research has been focused on the synthesis and characterization of energetic materials with 1 and 2 as the backbone, a complete report on their fundamental thermodynamic parameters and thermal decomposition properties has not been published.Thermogravimetric-differential scanning calorimetry were used to obtain the thermal decomposition data of the title compounds. Kissinger and Ozawa-Doyle methods, the two selected non-isothermal methods, are presented for analysis of the solid-state kinetic data. Pyrolysis-gas chromatography/mass spectrometry was used to study the pyrolysis process of the title compounds.The DSC curves show that the thermal decompositions of 1 and 2 are at different heating rates involved a single exothermic process. The TG curves provide insight into the total weight losses from the compounds associated with this process. At different pyrolysis temperatures, the compositions and types of the pyrolysis products differ greatly and the pyrolysis reaction at 500 °C is more thorough than 400 °C.Apparent activation energies (E) and pre-exponential factors (lnA/s-1) are 291.4 kJ mol-1 and 75.53 for 1; 396.2 kJ mol-1 and 80.98 for 2 (Kissinger). The values of E are 284.5 kJ mol-1 for 1 and 386.1 kJ mol-1 for 2 (Ozawa-Doyle). The critical temperature of thermal explosion (T b ) is evaluated as 187.01 °C for 1 and 282.78 °C for 2. The title compounds were broken into small fragment ions under the pyrolysis conditions, which then might undergo a multitude of collisions and numerous other reactions, resulting in the formation of C2N2 (m/z 52), etc., before being analyzed by the GC/MS system.

Project description:BackgroundUniversal face mask use was recommended owing to the growing pandemic of the coronavirus disease (COVID-19). However, little is known about the public's compliance with mask-wearing behaviours.ObjectiveTo evaluate the public's mask-wearing behaviours in the context of COVID-19.DesignCross-sectional study.SettingOnline survey from 6 April 2020 to 5 May 2020 in China.ParticipantsThis study included 10,165 persons who lived in China, understood Chinese, and were not health care providers.MethodsDescriptive statistics were used to assess the public's mask-wearing behaviours. A binary logistic regression analysis was performed to identify the risk factors affecting the mask-wearing behaviours.ResultsNearly all (99%) people wore a mask during the covid-19 pandemic, with most (73.3%) demonstrating good compliance with face mask use. However, 41.8% of the participants seldom cleaned their hands before putting on a face mask, and more than half (55.3%, 62.1%) of those who touched (n=8108, 79.8%) or adjusted (n=9356, 92.0%) their mask while using it failed to consistently wash their hands afterward. When removing a used mask, 7.6% of the participants discarded it into a garbage bin without a lid and 22.5% discarded it into a garbage bin in their reach regardless of presence of a lid. Participants reported wearing disposable medical masks (93.8%), followed by N95 respirators (26.2%), and cloth face masks (8.5%). Some participants wore multiple masks simultaneously (occasionally 26.5%, often 2.1%, always 1.5%). A total of 5,981 (58.8%) participants reported reusing disposable masks, with nearly two thirds (n=3923, 65.6%) indicating they would hang the used masks in well-ventilated places. More than one-third (37.6%) of the respondents did not replace mask when it had been used for more than 8 hours. Exposure to instructions on face mask use was the strongest predictor of good compliance (odds ratio=4.13, 95% confidential interval= 3.60-4.75, p=0.000). Other factors included specific situations, location, and gender. The influence of age needs further investigation. Most participants (76.4%) accessed information mainly via social media platforms.ConclusionsNearly all people wore face mask and most of them used it properly during the COVID-19 pandemic. Hand hygiene before and during mask-wearing, choosing an appropriate type of face mask, reusing disposal face mask, and disposing of used face masks should be particularly emphasized in future evidence dissemination or behaviour-change interventions. Information on social media platforms for evidence dissemination and behaviour change may benefit the public the most, but this initiative requires further research to investigate its effectiveness.

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Pyrolysis kinetic behaviour and TG-FTIR-GC-MS analysis of Coronavirus Face Masks.

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