Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Res ; 245: 118016, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38154563

RESUMO

Recovery of carbon fibres and resin from wind turbine blade waste (WTB) composed of carbon fibres (CF)-reinforced unsaturated polyester resin (UPR) has been environmentally challenging due to its complex structure that is not biodegradable and that is rich in highly toxic styrene (main component of UPR). Within this framework, this paper aims to liberate CF and UPR from WTB using a pyrolysis process. The treatment was performed on commercial WTB (CF/UPR) up to 600 °C using a 250 g reactor. The UPR fraction was decomposed into liquid and gaseous phases, while CF remained as a residue. The composition of gaseous phase was monitored during the entire treatment using a digital gas analyser, while gas chromatography-mass spectrometry (GC-MS) was used to characterize the collected liquid phase. CF fraction was collected and exposed to additional oxidation process after treatment at 450 °C for purification propose, then it was analysed using FTIR and SEM-EDX. Finally, the life cycle assessment (LCA) of the CF/UPR pyrolysis was studied using SimaPro software and the results were compared with landfill disposal practices. The pyrolysis results manifested that 500 °C was sufficient for UPR decomposition into styrene-rich oil and gaseous products with yields of 15.23 wt% and 6.83 wt%, respectively, accompanied by 77.93 wt% solid residue including CF. The LCA results showed that pyrolysis with oxidation process has high environmental potential in WTB recycling with significant reduction in several impact categories compared to landfill. However, the pyrolysis scenario revealed several additional environmental burdens related to ecosystems, acidification, Ozone formation, and fine particulate matter formation that must be overcome before upscaling.


Assuntos
Ecossistema , Pirólise , Fibra de Carbono , Poliésteres , Estireno , Carbono
2.
Materials (Basel) ; 16(18)2023 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-37763357

RESUMO

This research aims to maximize polyethylene terephthalate (PET) nonwoven fabric waste and make it as a new source for benzoic acid extraction using a pyrolysis process. The treatment was performed using a thermogravimetric analyzer (TGA) and released products were characterized using FTIR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The pyrolysis kinetic and thermodynamic behavior of PET fabric was also studied and simulated using different linear and nonlinear models. The results show that the PET fabric is very rich in volatile matter (80 wt.%) and can completely degrade under 490 °C with a weight loss of 84%. Meanwhile, the generated vapor was rich in the carbonylic C=O functional group (FTIR), and the GC-MS analysis concluded that benzoic acid was the major compound with an abundance of 75% that was achieved at the lowest heating rate (5 °C/min). The linear kinetic results showed that PET samples had an activation energy in the ranges of 193-256 kJ/mol (linear models) and ~161 kJ/mol (nonlinear models). The thermodynamic parameters, including enthalpy, Gibbs free energy, and entropy, were estimated in the ranges of 149-250 kJ/mol, 153-232 kJ/mol, and 256-356 J/mol K, respectively. Accordingly, pyrolysis treatment can be used to extract benzoic acid from PET fabric waste with a 134% increase in the benzoic acid abundance that can be recovered from PET bottle plastic waste.

3.
Polymers (Basel) ; 14(21)2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36365523

RESUMO

Modern day industries are highly focused on the development of bio-inspired hybrid natural fiber composites for lightweight biosensor chips, automobile, and microfluidic applications. In the present research, the mechanical properties and morphological characteristics of alkaline (NaOH)-treated hemp, flax, noil hemp, and noil flax fiber-reinforced ecopoxy biocomposites were investigated. The samples were fabricated by employing the hand layup technique followed by the compression molding process. A total of two sets of composites with various weight fractions were fabricated. The samples were tested for mechanical properties such as flexural strength, interlaminar shear strength, moisture absorption, and contact angle measurement. The treated fibers were analyzed by using an optical microscope and Fourier transform infrared spectrometer (FTIR). The morphological characteristics, such as porosity and fracture mechanisms, were investigated by using scanning electron microscopy and SEM-EDX spectroscopy. The results revealed that the flexural properties of hybrid composites vary from 22.62 MPa to 30.04 MPa for hemp and flax fibers and 21.86 MPa to 24.70 MPa for noil fibers, whereas in individual fiber composites, the strength varies from 17.11 MPa to 21.54 MPa for hemp and flax fibers and 15.83 MPa to 18.79 MPa for noil fibers. A similar trend was observed in interlaminar shear properties in both cases. From moisture analysis, the rate of absorption is increased with time up to 144 h and remains constant in both cases. The moisture gain was observed more in individual composites than hybrid composites in both cases. Hence, the impact of hybridization was observed clearly in both cases. Also, hybrid composites showed improved properties compared to individual fiber composites.

4.
Sci Total Environ ; 844: 157150, 2022 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-35803432

RESUMO

This research aims to study the effect of aluminum (Al) leaching pre-treatment on the catalytic pyrolysis of metallised food packaging plastics waste (MFPW). The experiments started with removal of Al from MFPW using leaching process to prepare Al-free mixed plastic waste (MPW). The catalytic pyrolysis of MPW over ZSM-5 zeolite catalyst was carried out using thermogravimetric (TG) analysis coupled with FTIR, while GC-MS was used to observe the compounds of the volatile products. The catalytic pyrolysis kinetic behaviour of MPW was studied using the linear and nonlinear isoconversional approaches. The elemental and proximate results showed that MPW is very rich in carbon elements (79 %) and volatile content (99 %). The TG results showed that MPW and ZSM/MPW were fully decomposed in the range of 376-496 °C without any presence of char. Based on TG-FTIR analysis, methane and carboxylic acid residue were the main groups of the synthesized volatile products, whereas nitrous oxide, 1-Butanol, 1-Propene, acetic acid, and formic acid were the major GC compounds. In case of ZSM/MPW, carbon dioxide and acetic acid were the major GC compounds at 5-25 °C/min, triphenylphosphine oxide and Phosphine oxide at 30 °C/min. The kinetic analysis showed that when the activation energies are located in the range 287-297 kJ/mol (MPW) and 153-187 kJ/mol (ZSM/MPW) and KAS, Vyazovkin, and Cai methods are the most suitable models to study pyrolysis kinetic of MPW with R2 > 89. Based on that, leaching and catalytic pyrolysis processes are a highly suggested technology that can be used to convert MFPW into high-added energy and chemical products.


Assuntos
Plásticos , Pirólise , Alumínio , Catálise , Embalagem de Alimentos , Cinética , Plásticos/química
5.
Environ Technol ; 43(18): 2755-2770, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33678146

RESUMO

Marine biomass is a promising renewable energy source, especially as this waste contains a large amount of cellulose and hemicellulose, which can contribute to convert it into energy products using anaerobic digestion (AD) and pyrolysis processes. This work was focused on a synergetic view of marine coastal waste treatment (seaweed) using two different technologies, anaerobic microbiological co-digestion, and pyrolysis. The experiments were performed with two merged technologies to assess the captured energy from the digestate in case it is contaminated. Anaerobic co-digestion was conducted using a periodic load laboratory bench with a vertical biogas digester. An evaluation of possible product yields and composition during pyrolysis at a laboratory-scale bench has been performed. The products obtained after the thermal treatment analyzed using an online gas measurement system and gas chromatographs Agilent 7890A with TCD detector (for gases) and Agilent 7890A with MS detector (for liquids).The results demonstrated that biogas yield was 174.1 l/kg (DM). Seaweed washed by seawater yields a higher amount of biogas (202.5 l/kg). Meanwhile, seaweed, sewage sludge, and digestate samples subjected to thermal treatment produced 17%, 30%, and 15% of liquids products, respectively. The economic performance assessment showed that the application of the developed merged approach on an industrial scale could provide an economic return of up to 8.3 $/100 kg of waste. Based on that, merged AD and pyrolysis technologies could be adapted as a promising technology to valorize seaweed wastes and utilize them as a new sustainable source for renewable energy.


Assuntos
Biocombustíveis , Metano , Anaerobiose , Biocombustíveis/análise , Reatores Biológicos , Esgotos
6.
Polymers (Basel) ; 13(10)2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064980

RESUMO

Due to the increasing demand for glass fibre-reinforced epoxy resin composites (GFRC), huge amounts of GFRC waste are produced annually in different sizes and shapes, which may affect its thermal and chemical decomposition using pyrolysis technology. In this context, this research aims to study the effect of mechanical pre-treatment on the pyrolysis behaviour of GFRC and its pyrolysis kinetic. The experiments were started with the fabrication of GFRC panels using the vacuum-assisted resin transfer method followed by crushing the prepared panels using ball milling, thus preparing the milled GFRC with uniform shape and size. The elemental, proximate, and morphology properties of the panels and milled GFRC were studied. The thermal and chemical decomposition of the milled GFRC was studied using thermogravimetric coupled with Fourier-transform infrared spectroscopy (TG-FTIR) at different heating rates. Meanwhile, the volatile products were examined using TG coupled with gas chromatography-mass spectrometry (GC-MS). The TG-FTIR and TG-GC-MS experiments were performed separately. Linear (Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman) and nonlinear (Vyazovkin and Cai) isoconversional methods were used to determine the pyrolysis kinetic of the milled GFRC based on thermogravimetry and differential thermal gravimetry (TG/DTG). In addition, the TG/DTG data of the milled GFRC were fitting using the distributed activation energy model and the independent parallel reactions kinetic model. The TG results showed that GFRC can decompose in three stages, and the main decomposition is located in the range 256-500 °C. On the other hand, aromatic benzene and a C-H bond were the major functional groups in the released volatile components in FTIR spectra, while phenol (27%), phenol,4-(1-methylethyl) (40%), and p-isopropenylphenol (34%) were the major compounds in GC-MS analysis. Whereas, the kinetic results showed that both isoconversional methods can be used to determine activation energies, which were estimated 165 KJ/mol (KAS), 193 KJ/mol (FWO), 180 KJ/mol (Friedman), 177 KJ/mol (Vyazovkin), and 174 KJ/mol (Cai).

7.
J Anal Appl Pyrolysis ; 156: 105118, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33875899

RESUMO

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.

8.
Polymers (Basel) ; 13(5)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652610

RESUMO

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.

9.
Sci Total Environ ; 762: 143107, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33129549

RESUMO

Lint-microfibers (LMs) generated during clothes drying are classified as primary microplastics and consist mainly of cotton, polyester and lignin. This research aims to convert LMFs into energy products using a pyrolysis treatment. The pyrolysis experiments were performed using a pilot pyrolysis plant. SEM-EDS was used to observe the morphology and elemental composition of the feedstock and the obtained biochar, while a digital unit of Instantaneous Gas analyzer and Gas chromatography (GC) were used to observe the concentration of O2, N2, CO2, CO, H2, CH4 gases during the whole conversion process. Finally, a simple mathematical model was developed to evaluate the economic and environmental performance of the suggested strategy based on the LMFs generated by one million persons. Based on the results of the developed model and yield of pyrolysis process, around 45 tons of LMFs are generated by one million persons annually and this amount is enough to produce 13.8 tons of oil (~31%), 21.5 tons of gas (47.7%), and 9.7 ton of char (21.6%) with estimated profitability of 120,400$ and reduction in carbon footprint estimated at -42,039,000kg CO2-eq/t of LMFs.

10.
Polymers (Basel) ; 12(8)2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32781759

RESUMO

Recently, a pyrolysis process has been adapted as an emerging technology to convert metalized food packaging plastics waste (MFPWs) into energy products with a high economic benefit. In order to upscale this technology, the knowledge of the pyrolysis kinetic of MFPWs is needed and studying these parameters using free methods is not sufficient to describe the last stages of pyrolysis. For a better understanding of MFPWs pyrolysis kinetics, independent parallel reactions (IPR) kinetic model and its modification model (MIPR) were used in the present research to describe the kinetic parameters of MFPWs pyrolysis at different heating rates (5-30 °C min-1). The IPR and MIPR models were built according to thermogravimetric (TG)-Fourier-transform infrared spectroscopy (FTIR)-gas chromatography-mass spectrometry (GC-MS) results of three different types of MFPWs (coffee, chips, and chocolate) and their mixture. The accuracy of the developed kinetic models was evaluated by comparing the conformity of the DTG experimental results to the data calculated using IPR and MIPR models. The results showed that the dependence of the pre-exponential factor on the heating rate (as in the case of MIPR model) led to better conformity results with high predictability of kinetic parameters with an average deviation of 2.35% (with an improvement of 73%, when compared to the IPR model). Additionally, the values of activation energy and pre-exponential factor were calculated using the MIPR model and estimated at 294 kJ mol-1 and 5.77 × 1017 kJ mol-1 (for the mixed MFPW sample), respectively. Finally, GC-MS results illustrated that pentane (13.8%) and 2,4-dimethyl-1-heptene isopropylcyclobutane (44.31%) represent the main compounds in the released volatile products at the maximum decomposition temperature.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...