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Search Results (262)

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Keywords = pyrolysis gas chromatography-mass spectrometry

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25 pages, 1160 KiB  
Review
MS and GC–MS Analytical Methods for On-Line Thermally Induced Evolved Gas Analysis (OLTI-EGA)
by Giuseppina Gullifa, Elena Papa, Giordano Putzolu, Gaia Rizzo, Marialuisa Ruocco, Chiara Albertini, Roberta Risoluti and Stefano Materazzi
Chemosensors 2025, 13(7), 258; https://doi.org/10.3390/chemosensors13070258 - 16 Jul 2025
Viewed by 452
Abstract
Mass spectrometry (MS) and coupled gas chromatography-mass spectrometry (GC-MS) are globally recognized as the primary techniques for the analysis of gases or vapors due to their selectivity, sensitivity, accuracy, and reproducibility. When thermal stress is applied, vapors or gases are released as a [...] Read more.
Mass spectrometry (MS) and coupled gas chromatography-mass spectrometry (GC-MS) are globally recognized as the primary techniques for the analysis of gases or vapors due to their selectivity, sensitivity, accuracy, and reproducibility. When thermal stress is applied, vapors or gases are released as a result of the reactions and changes that occur. The analysis of these gases during the thermally induced reaction is scientifically referred to as evolved gas analysis (EGA), which is essential for confirming the occurrence of the induced reactions. Pyrolyzers, thermobalances, or simple heaters can increase the temperature of the analyzed samples according to a programmed and software-managed ramp, allowing for control over both the heating rate and isothermal stages. The atmosphere can also be varied to simulate pyrolysis or thermo-oxidative processes. This way, each induced reaction generates a unique evolved gas, which can be linked to a theoretically hypothesized mechanism. Mass spectrometry (MS) and coupled gas chromatography–mass spectrometry (GC-MS) are fundamental analytical methods used for on-line thermally induced evolved gas analysis (OLTI-EGA). Full article
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17 pages, 2424 KiB  
Article
Advanced Spectroscopic Characterization of Synthetic Oil from Oil Sands via Pyrolysis: An FTIR, GC–MSD, and NMR Study
by Ainura Yermekova, Yerbol Tileuberdi, Ainur Seitkan, Anar Gabbassova, Yerlan Zhatkanbayev, Aisha Nurlybayeva, Nurzada Totenova and Stanislav Kotov
Molecules 2025, 30(14), 2927; https://doi.org/10.3390/molecules30142927 - 10 Jul 2025
Viewed by 620
Abstract
This paper presents a modern spectroscopic characterization of the synthetic oil from oil sands of Beke, Munaily-Mola, and Dongeleksor. The pyrolysis process was carried out at temperatures up to 580 °C with a controlled heating rate, and the products obtained were analyzed using [...] Read more.
This paper presents a modern spectroscopic characterization of the synthetic oil from oil sands of Beke, Munaily-Mola, and Dongeleksor. The pyrolysis process was carried out at temperatures up to 580 °C with a controlled heating rate, and the products obtained were analyzed using Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MSD), and nuclear magnetic resonance (NMR) spectroscopy. The FTIR spectra showed a predominance of aliphatic hydrocarbons in the sample from Munaily-Mola synthetic oil, while the content of aromatic compounds was higher in the sample from Beke. GC–MSD analysis revealed significant differences in the distribution of hydrocarbons between the samples, with the Munaily-Mola sample containing a higher proportion of heavy hydrocarbons. NMR spectroscopy provided additional information about the structural composition of the extracted oil. The results indicate the potential of pyrolysis as an effective method for processing oil sands, while the composition of the product varies depending on the geological origin of the raw materials. These findings provide valuable information for optimizing oil sands processing technologies and improving the efficiency of synthetic oil production. Full article
(This article belongs to the Special Issue Renewable Energy, Fuels and Chemicals from Biomass, 2nd Edition)
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46 pages, 5003 KiB  
Article
Optimization of Kerosene-like Fuels Produced via Catalytic Pyrolysis of Packaging Plastic Waste via Central Composite Design and Response Surface Methodology: Performance of Iron-Doped Dolomite and Activated Carbon
by Oratepin Arjharnwong, Tharapong Vitidsant, Aminta Permpoonwiwat, Naphat Phowan and Witchakorn Charusiri
Molecules 2025, 30(13), 2884; https://doi.org/10.3390/molecules30132884 - 7 Jul 2025
Viewed by 401
Abstract
Rapid economic growth has led to an increase in the use of multilayer plastic packaging, which involves complex polymer compositions and hinders recycling. This study investigated the catalytic pyrolysis of plastic packaging waste in a 3000 cm3 semibatch reactor, aiming to optimize [...] Read more.
Rapid economic growth has led to an increase in the use of multilayer plastic packaging, which involves complex polymer compositions and hinders recycling. This study investigated the catalytic pyrolysis of plastic packaging waste in a 3000 cm3 semibatch reactor, aiming to optimize kerosene-like hydrocarbon production. The temperature (420–500 °C), N2 flow rate (25–125 mL/min), and catalyst loading (5–20 wt.%) were examined individually and in combination with activated carbon and an Fe-doped dolomite (Fe/DM) catalyst. Central composite design (CCD) and response surface methodology (RSM) were used to identify the optimal conditions and synergistic effects. Pyrolysis product analysis involved simulation distillation gas chromatography (Sim-DGC), gas chromatography/mass spectrometry (GC/MS), and Fourier transform infrared (FT-IR) spectroscopy. The optimal conditions (440 °C, 50 mL/min N2 flow, catalyst loading of 10 wt.% using a 5 wt.% Fe-doped dolomite-activated carbon 0.6:0.4 mass/molar ratio) yielded the highest pyrolysis oil (79.6 ± 0.35 wt.%) and kerosene-like fraction (22.3 ± 0.22 wt.%). The positive synergistic effect of Fe/DM and activated carbon (0.6:0.4) enhanced the catalytic activity, promoting long-chain polymer degradation into mid-range hydrocarbons, with secondary cracking yielding smaller hydrocarbons. The pore structure and acid sites of the catalyst improved the conversion of intermediate hydrocarbons into aliphatic compounds (C5–C15), increasing kerosene-like hydrocarbon production. Full article
(This article belongs to the Special Issue Advances in Thermochemical Conversion of Solid Wastes)
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14 pages, 4406 KiB  
Article
Craftsmanship and Techniques of a Lacquered Ear Cup from the Ancient Nanyue Kingdom
by Lin Zheng, Xia Li, Zichen Zhao, Shuang’e Tian, Jianling Tang, Siming Li, Xiaocen Li, Na Wang and Tengfei Yu
Coatings 2025, 15(7), 752; https://doi.org/10.3390/coatings15070752 - 25 Jun 2025
Viewed by 408
Abstract
This study analyzes a lacquered ear cup excavated from the Luobowan tomb complex in Guigang, Guangxi, attributed to the Nanyue Kingdom of the early Han dynasty. A range of analytical techniques, including optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), [...] Read more.
This study analyzes a lacquered ear cup excavated from the Luobowan tomb complex in Guigang, Guangxi, attributed to the Nanyue Kingdom of the early Han dynasty. A range of analytical techniques, including optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), were employed to investigate the structural layers, material composition, and preservation state of the artifact. The lacquerware consists of four traditional layers: a wooden core, fabric reinforcement, lacquer ground, and lacquer film, reflecting Central Plains lacquerware techniques. The wooden core was identified as Phoebe sp., and the fabric layer is likely hemp, though fiber degradation limited exact identification. The lacquer ground layer contains natural lacquer mixed with SiO2 from brick or tile powder. The lacquer film is a blend of Chinese and Vietnamese lacquer, with no synthetic additives or plant oils detected. The red lacquer layer contains cinnabar (HgS) as a pigment, while the black lacquer uses carbon black. Differences in moisture content between the red and black lacquer films are attributed to variations in surface porosity and pigment characteristics. This research provides valuable insights into Nanyue lacquer technology and preservation challenges. Full article
(This article belongs to the Special Issue Research and Conservation of Ancient Lacquer)
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18 pages, 3348 KiB  
Article
Moderate-Temperature Pyrolysis Characteristics of Lump Coal Under Varying Coal Particle Sizes
by Yuanpei Luo, Luxuan Liu, Liangguo Lv, Shengping Zhang, Fei Dai, Hongguang Jin and Jun Sui
Energies 2025, 18(12), 3220; https://doi.org/10.3390/en18123220 - 19 Jun 2025
Viewed by 388
Abstract
Pyrolysis is an important methodology for achieving efficient and clean utilization of coal. Lump coal pyrolysis demonstrates distinct advantages over pulverized coal processing, particularly in enhanced gas yield and superior coke quality. As a critical parameter in lump coal pyrolysis, particle size significantly [...] Read more.
Pyrolysis is an important methodology for achieving efficient and clean utilization of coal. Lump coal pyrolysis demonstrates distinct advantages over pulverized coal processing, particularly in enhanced gas yield and superior coke quality. As a critical parameter in lump coal pyrolysis, particle size significantly influences heat transfer and mass transfer during pyrolysis, yet its governing mechanisms remain insufficiently explored. This research systematically investigates pyrolysis characteristics of the low-rank coal from Ordos, Inner Mongolia, across graded particle sizes (2–5 mm, 5–10 mm, 10–20 mm, and 20–30 mm) through pyrolysis experiments. Real-time central temperature monitoring of coal bed coupled with advanced characterization techniques—including X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM), gas chromatography (GC), and GC–mass spectrometry (GC-MS)—reveals particle-size-dependent pyrolysis mechanisms. Key findings demonstrate that the larger particles enhance bed-scale convective heat transfer, accelerating temperature propagation from reactor walls to the coal center. However, excessive sizes cause significant intra-particle thermal gradients, impeding core pyrolysis. The 10–20 mm group emerges as optimal—balancing these effects to achieve uniform thermal attainment, evidenced by 20.99 vol% peak hydrogen yield and maximum char graphitization. Tar yield first demonstrates a tendency to rise and then decline, peaking at 14.66 wt.% for 5–10 mm particles. This behavior reflects competing mechanisms: enlarging particle size can improve bed permeability (reducing tar residence time and secondary reactions), but it can also inhibit volatile release and intensify thermal cracking of tar in oversized coal blocks. The BET analysis result reveals elevated specific surface area and pore volume with increasing particle size, except for the 10–20 mm group, showing abrupt porosity reduction—attributed to pore collapse caused by intense polycondensation reactions. Contrasting previous studies predominantly focused on less than 2 mm pulverized coal, this research selects large-size (from 2 mm to 30 mm) lump coal to clarify the effect of particle size on coal pyrolysis, providing critical guidance for industrial-scale lump coal pyrolysis optimization. Full article
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19 pages, 1937 KiB  
Review
Current Approaches to Microplastics Detection and Plastic Biodegradation
by Paula Przygoda-Kuś, Katarzyna E. Kosiorowska, Aneta K. Urbanek and Aleksandra M. Mirończuk
Molecules 2025, 30(11), 2462; https://doi.org/10.3390/molecules30112462 - 4 Jun 2025
Viewed by 1140
Abstract
Environmental concerns about the widespread use of non-biodegradable plastic have generated interest in developing quick and effective methods to degrade synthetic polymers. With millions of tons of plastic waste generated annually, biodegradation by microorganisms presents a promising and eco-friendly solution. However, a bottleneck [...] Read more.
Environmental concerns about the widespread use of non-biodegradable plastic have generated interest in developing quick and effective methods to degrade synthetic polymers. With millions of tons of plastic waste generated annually, biodegradation by microorganisms presents a promising and eco-friendly solution. However, a bottleneck has arisen due to the lack of standardized methods for verification of the biodegradation process. Based on this literature review, he techniques most commonly employed for this purpose currently include measuring mass loss, examining the surface of plastic fragments by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and using analytical methods such as Fourier transform infrared spectroscopy (FTIR), pyrolysis–gas chromatography–mass spectrometry (Pyr-GC/MS) or high-performance liquid chromatography (HPLC). Each of these methods has its advantages and disadvantages. Nevertheless, currently, there is no universal approach to accurately assess the ability of individual microorganisms to degrade plastics. In this review, we summarize the latest advances in techniques for detecting biodegradation of synthetic polymers and future directions in the development of sustainable strategies for mitigating plastic pollution. Full article
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21 pages, 3889 KiB  
Article
Effects of Organic Acidic Products from Discharge-Induced Decomposition of the FRP Matrix on ECR Glass Fibers in Composite Insulators
by Dandan Zhang, Zhiyu Wan, Kexin Shi, Ming Lu and Chao Gao
Polymers 2025, 17(11), 1540; https://doi.org/10.3390/polym17111540 - 31 May 2025
Viewed by 594
Abstract
This study investigates the degradation mechanisms of fiber-reinforced polymer (FRP) matrices in composite insulators under partial discharge (PD) conditions. The degradation products may further cause deterioration of the electrical and chemical resistance (ECR) glass fibers. Using pyrolysis–gas chromatography-mass spectrometry (PY-GC-MS) and high-performance liquid [...] Read more.
This study investigates the degradation mechanisms of fiber-reinforced polymer (FRP) matrices in composite insulators under partial discharge (PD) conditions. The degradation products may further cause deterioration of the electrical and chemical resistance (ECR) glass fibers. Using pyrolysis–gas chromatography-mass spectrometry (PY-GC-MS) and high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS-MS), the thermal degradation gas and liquid products of the degraded FRP matrix were analyzed, revealing the presence of organic acids. These acids form when the epoxy resin’s cross-linked bonds break at high temperatures, generating anhydrides that hydrolyze into carboxylic acids in the presence of moisture. The hydrolyzation process is accelerated by hydroxyl radicals produced during PD. The resulting carboxylic acids deteriorate the glass fibers within the FRP matrix by degrading surface coupling agents and reacting with the alkali metal–silica network, leading to the substitution and precipitation of metal ions. Organic acids, particularly carboxylic acids, were found to have a more severe deteriorating effect on glass fibers compared to inorganic acids, with high temperatures exacerbating this process. These findings provide critical insights into the deterioration mechanisms of FRP under operational conditions, offering valuable guidance for optimizing manufacturing processes and enhancing the longevity of composite insulators. Full article
(This article belongs to the Special Issue New Insights into Fiber-Reinforced Polymer Composites)
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17 pages, 744 KiB  
Article
Quantitative Detection of Micro- and Nanoplastics (≥300 nm) in Human Urine Using Double-Shot Py-GC/MS with Internal Standard Calibration
by Shanshan Ji, Wei Wang, Yong Wang, Hexiang Bai, Zhuo Li, Zongli Huo and Kai Luo
Toxics 2025, 13(6), 452; https://doi.org/10.3390/toxics13060452 - 29 May 2025
Viewed by 1010
Abstract
The rapid increase in plastic production and consumption has intensified research into human exposure to micro- and nanoplastics (MNPs) and their health effects. This study quantitatively assessed MNP internal exposure levels in non-invasive human samples, focusing on the four most common types of [...] Read more.
The rapid increase in plastic production and consumption has intensified research into human exposure to micro- and nanoplastics (MNPs) and their health effects. This study quantitatively assessed MNP internal exposure levels in non-invasive human samples, focusing on the four most common types of MNPs (≥300 nm): polyethylene terephthalate (PET), polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS). Urine samples from 18 volunteers (4 males, 14 females) were analyzed using pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) with P(E-13C2) as an internal standard. The study developed a straightforward yet effective analytical approach for quantifying MNPs in biological fluids. MNPs were detected in all urine samples, with concentrations ranging from 0.098 to 0.986 μg/mL and an average concentration of 0.268 ± 0.235 μg/mL. LDPE, 0.074 μg/mL (interquartile range: 0.030–0.243 μg/mL), was the most abundant polymer, accounting for 67.72% of the total MNPs, followed by PS at 21.17%, while PP and PET accounted for 7.06% and 4.05%, respectively. The results also suggest that drinking water type may serve as a distinct source of MNPs in urine. This study provides novel evidence on MNP (≥300 nm) internal exposure in humans and the influence of drinking habits, highlighting the application prospects of this method in assessing the potential health risks of MNPs. Full article
(This article belongs to the Special Issue Biomonitoring of Toxic Elements and Emerging Pollutants)
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34 pages, 3535 KiB  
Article
Effect of Particle Size and Heating Rate on Formation of Polycyclic Aromatic Hydrocarbons During Corn Cob Biomass Pyrolysis
by Teka Tesfaye Mengesha, Venkata Ramayya Ancha, Abebe Nigussie, Million Merid Afessa and Ramchandra Bhandari
Sustainability 2025, 17(11), 4962; https://doi.org/10.3390/su17114962 - 28 May 2025
Viewed by 633
Abstract
Polycyclic aromatic hydrocarbons (PAHs) in biochar, as opposed to those in pyrolysis liquid products that exit the reactor without adhering to the solid product, are particularly undesirable due to their environmental persistence and potential toxicity. When applied as a soil amendment, biochar containing [...] Read more.
Polycyclic aromatic hydrocarbons (PAHs) in biochar, as opposed to those in pyrolysis liquid products that exit the reactor without adhering to the solid product, are particularly undesirable due to their environmental persistence and potential toxicity. When applied as a soil amendment, biochar containing PAHs poses risks to soil ecosystems and human health. Their formation during pyrolysis presents a significant challenge in biochar production, requiring the optimization of pyrolysis process parameters to minimize PAH content for safe soil amendment applications. This study explored the effects of particle size and heating rate on PAH formation during corn cob pyrolysis. Thermogravimetric analysis (TGA) was employed to heat corn cob powder of varying sample masses from ambient temperature to 550 °C at heating rates of 5, 10, and 20 °C/min. Simultaneously, the Chemical Reaction Engineering and Chemical Kinetics (CRECK) model simulated the pyrolysis of spherical corn cob biomass particles with a radius ranging from 1 to 40 mm, using feedstock chemical compositions as inputs. Tar species generated from the solid biomass model were introduced into a gas-phase batch reactor model to evaluate PAH formation. The results demonstrate that the particle size and heating rate significantly affect PAH formation, shedding light on the complex dynamics of biomass pyrolysis. A single spherical particle with a radius close to 1 mm approximates ideal TGA conditions by minimizing temperature and mass transfer limitations. The CRECK model suggested that a particle radius of 5–10 mm, combined with a low heating rate of 5 °C/min, optimally reduces PAH formation. Future research should focus on using thermogravimetric analysis coupled with gas chromatography–mass spectrometry (TGA-GC-MS) to comprehensively quantify PAH species formation. Full article
(This article belongs to the Special Issue Sustainable Waste Process Engineering and Biomass Valorization)
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19 pages, 1124 KiB  
Review
Endocrine Toxicity of Micro- and Nanoplastics, and Advances in Detection Techniques for Human Tissues: A Comprehensive Review
by Sabrina Bossio, Silvestro Antonio Ruffolo, Danilo Lofaro, Anna Perri and Mauro Francesco La Russa
Endocrines 2025, 6(2), 23; https://doi.org/10.3390/endocrines6020023 - 14 May 2025
Viewed by 1844
Abstract
Background: Plastic pollution driven by human activities has become a critical global issue for human health. A growing literature demonstrates that micro- and nanoplastics (MNPs) contain endocrine-disrupting chemicals (EDCs) and other harmful compounds that enter the body easily, acting as agonists or [...] Read more.
Background: Plastic pollution driven by human activities has become a critical global issue for human health. A growing literature demonstrates that micro- and nanoplastics (MNPs) contain endocrine-disrupting chemicals (EDCs) and other harmful compounds that enter the body easily, acting as agonists or antagonists for a wide range of hormonal receptors, and promoting endocrine toxicity. Endocrine disruption induced by MNPs occurs through the aberrant activation/inhibition of different signaling pathways that in addition to directly interfering with hormonal balances, trigger apoptosis, oxidative stress, and inflammation in endocrine cells. However, to date, the molecular mechanisms of these contaminants remain not completely elucidated. Furthermore, given the unanimous consensus on the negative impact of MNPs on human health, several methodologies have been developed to detect MNPs and contaminants not only in the environment but also in biological fluids and human tissues. Results: This review comprehensively summarizes the emerging experimental and clinical evidence explaining the mechanisms underlying the toxicity related to chronic plastic pollution in relation to the endocrine system. In addition, the review illustrates the new methodological approaches to detect MNPs in human biological samples, highlighting that employing complementary methods enables the precise characterization and quantification of MNPs. Conclusions: Future studies employing experimental, epidemiological, epigenetic, and multi-omics approaches are essential for understanding the short and long-term effects of MNPs on endocrine glands and developing effective strategies to mitigate their impact on human health. Full article
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21 pages, 3732 KiB  
Article
Pyrolysis Characterization of Simulated Radioactive Solid Waste: Pyrolysis Behavior, Kinetics, and Product Distribution
by Zhigang Wei, Lulu Dong, Wei Wang, Pan Ding, Wenqian Jiang, Chi Zuo, Lei Li and Minghui Tang
Energies 2025, 18(9), 2341; https://doi.org/10.3390/en18092341 - 3 May 2025
Viewed by 525
Abstract
The disposal of low-level and intermediate-level radioactive solid waste has aroused widespread concern. In this work, the pyrolysis characterizations of simulated radioactive solid waste, cotton gloves (CG), stain removal cloths (SRC), plastic bags (PB), shoe covers (SC), and ion exchange resins (IER), were [...] Read more.
The disposal of low-level and intermediate-level radioactive solid waste has aroused widespread concern. In this work, the pyrolysis characterizations of simulated radioactive solid waste, cotton gloves (CG), stain removal cloths (SRC), plastic bags (PB), shoe covers (SC), and ion exchange resins (IER), were analyzed using thermogravimetric analysis, Thermogravimetric–Fourier Transform Infrared Spectrometry–Mass Spectrometry (TG-FTIR-MS) and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). The main mass loss stages of CG, SRC, PB, SC, and IER were 240–500 °C, 210–500 °C, 400–550 °C, 180–610 °C, and 25–700 °C, respectively. The average activation energies calculated by three iso-conversional methods were 184.09–211.46 kJ/mol, 172.33–180.85 kJ/mol, 264.63–268.01 kJ/mol, 150.49–184.36 kJ/mol, and 150.72–151.66 kJ/mol, respectively. Pyrolysis of CG and SRC mainly produced CO2 and oxygenated compounds. SC generated large amounts of HCl during pyrolysis. Combined with rapid pyrolysis analysis, it was shown that CG and SRC mainly produced carbohydrates, aliphatic hydrocarbons, and aromatics. The pyrolysis products of SC mainly consisted of aliphatic hydrocarbons, aromatics, and acids. The pyrolysis products of PB were mainly olefins and alcohols. IER produced large amounts of aromatics during rapid pyrolysis. Specifically, the pyrolysis of IER generated some SO2. This work provides a theoretical basis and data support for the treatment of mixed combustible radioactive waste. Full article
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22 pages, 15367 KiB  
Article
Investigation of Liquid Oils Obtained by Thermo-Catalytic Degradation of Plastic Wastes in Energy Recovery
by Mihaela Vlassa, Miuța Filip, Simion Beldean-Galea, Didier Thiébaut, Jerôme Vial and Ioan Petean
Molecules 2025, 30(9), 1959; https://doi.org/10.3390/molecules30091959 - 28 Apr 2025
Cited by 1 | Viewed by 435
Abstract
The most efficient technique for resolving the issue of plastic waste disposal is by converting the wastes into high-quality liquid oils through thermal and catalytic pyrolysis. The objective of this work was to study the composition of liquid oils obtained by thermal and [...] Read more.
The most efficient technique for resolving the issue of plastic waste disposal is by converting the wastes into high-quality liquid oils through thermal and catalytic pyrolysis. The objective of this work was to study the composition of liquid oils obtained by thermal and catalytic degradation of plastic wastes containing polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). The clay catalysts were characterized by N2 adsorption–desorption isotherms (BET), Scanning Electron Microscopy (SEM) and Fourier transform Infrared Spectrometry (FTIR), Polarized Optical Microscopy (POM), Atomic Force Microscopy (AFM). The effect of temperature and clay catalyst type on the yields of the end-products resulting in thermo-catalytic degradation of PS has been evaluated. Degradation of PS showed the highest liquid oil production at 86.85% in comparison to other plastic types. The characterization of the liquid oils was performed by comprehensive two-dimensional gas chromatography coupled with single quadrupole mass spectrometry (GC × GC-qMS). In liquid oils of PS, eighteen principal compounds (of groups: linear hydrocarbons, mono-aromatics, and di-aromatics) were identified. In the liquid oils of the plastic waste mixture, twenty-four principal compounds (of groups: linear hydrocarbons, mono-aromatics, oxygen-containing aromatic, di-aromatics, and tri-aromatics) were identified. The liquid oils were investigated in order to reconvert them as styrene monomers or other chemicals in energy recovery. Full article
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28 pages, 10216 KiB  
Article
Stability and Degradation Issues of Manganese Violet Pigment in Polymeric Paints: Morphological and Chemical Changes Under SO2 and Humidity Exposure
by Laura Pagnin, Giulia Cardin, Valentina Pintus, Michele Back, Farkas Pintér, Katja Sterflinger and Francesca Caterina Izzo
Appl. Sci. 2025, 15(9), 4630; https://doi.org/10.3390/app15094630 - 22 Apr 2025
Viewed by 815
Abstract
This study focuses on investigating the stability of modern and contemporary paints based on manganese violet pigment PV16 (NH4MnP2O7) when exposed to atmospheric pollutants, specifically sulfur dioxide (SO2) in the presence of high relative humidity. [...] Read more.
This study focuses on investigating the stability of modern and contemporary paints based on manganese violet pigment PV16 (NH4MnP2O7) when exposed to atmospheric pollutants, specifically sulfur dioxide (SO2) in the presence of high relative humidity. In particular, this study aims to investigate the role of PV16 in increasing the degradation processes of various modern binders. Therefore, the objectives of this research can be divided into (i) evaluating the chemical modifications involving PV16, (ii) investigating the degradation processes that occur in different organic matrices (i.e., drying oil, alkyd resin, and acrylic and styrene–acrylic emulsions), and (iii) comparing the chemical stability of model and commercial paints. The paints were analyzed by 3D Optical Microscopy, Attenuated total Reflection–Fourier-Transform Infrared spectroscopy (ATR-FTIR) and μ-Raman Spectroscopy, Scanning Electron Microscope coupled with Energy Dispersive X-Ray spectroscopy (SEM-EDX), X-Ray Powder Diffraction (XRPD), Fiber Optic Reflectance Spectroscopy (FORS), Pyrolysis–Gas Chromatography–Mass Spectrometry (Py-GC/MS), and Thermally assisted Hydrolysis and Methylation (THM) of Py-GC/MS (THM-Py-GC/MS). The results show that when exposed to high relative humidity and SO2, PV16 presents a colorimetric change from violet to grey; several compounds crystallize on the surface; and, depending on the binder, various degradation reactions occur. This study highlights the susceptibility of manganese violet pigment PV16 under certain environmental conditions, which may be considered to define adequate conservation strategies for works of art containing this specific pigment. Additionally, the results obtained within this investigation point out the need to expand the chemical knowledge of this material for engineering, sensing, and industrial applications. Full article
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16 pages, 2992 KiB  
Article
Simultaneous Determination of Six Common Microplastics by a Domestic Py-GC/MS
by Yuanqiao Zhou, Bingyue Fu, Jinshui Che and Xingnan Ye
Atmosphere 2025, 16(4), 476; https://doi.org/10.3390/atmos16040476 - 19 Apr 2025
Cited by 1 | Viewed by 1109
Abstract
Pyrolysis coupled with gas chromatography–mass spectrometry (Py-GC/MS) is a novel technology capable of detecting micro- and nanoplastics without a size limit. However, the application of Py-GC/MS to airborne microplastic analysis remains inconsistent. This study explores optimal Py-GC/MS procedures using a domestic HenxiTM [...] Read more.
Pyrolysis coupled with gas chromatography–mass spectrometry (Py-GC/MS) is a novel technology capable of detecting micro- and nanoplastics without a size limit. However, the application of Py-GC/MS to airborne microplastic analysis remains inconsistent. This study explores optimal Py-GC/MS procedures using a domestic HenxiTM PY-1S pyrolyzer-based Py-GC/MS. The initial weight loss of PVC occurs at approximately 260 °C, indicating that the maximum thermal desorption temperature prior to pyrolysis should not exceed 250 °C. To avoid interference from semi-volatile organics present in the sample and injected air, it is essential to purge the sample with pure helium at elevated temperatures before pyrolysis. Microplastic standards can be prepared by ultrasonicating a water–microplastic dispersion system. Significant interactions between microplastic mixtures were observed during co-pyrolysis, indicating that the interactions of mixtures cannot be ignored during the optimization of quantitative references. The optimal procedure features good linearity (R2 > 0.98), low detection limit (0.06~0.0002 μg), and acceptable precisions (RSD < 10% in 8 days). Microplastics determined by the domestic PY-1S pyrolyzer coupled with a GC/MS system are comparable to those of the well-established PY-3030D-based Py-GC/MS, indicating that the domestic pyrolyzer coupled with GC/MS is a reliable and powerful tool for microplastic analysis. Full article
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21 pages, 9031 KiB  
Article
The Use and Deterioration of Intumescent Fire-Retardant Paint on Louise Nevelson’s Erol Beker Chapel of the Good Shepherd
by Lora V. Angelova, Aaron Shugar, Christopher A. Maines, Satoko Tanimoto, Martha Singer, Jean Dommermuth, Hannah Duggan, Teresa T. Duncan, Adam C. Finnefrock and Jennifer L. Mass
Heritage 2025, 8(4), 128; https://doi.org/10.3390/heritage8040128 - 3 Apr 2025
Cited by 1 | Viewed by 1204
Abstract
Louise Nevelson’s Erol Beker Chapel of the Good Shepherd (1977) is a sculptural environment consisting of wooden sculptures painted a monochromatic white color. The paints show signs of degradation including cracking, chipping, peeling, and the formation of blisters and powdery efflorescence. A significant [...] Read more.
Louise Nevelson’s Erol Beker Chapel of the Good Shepherd (1977) is a sculptural environment consisting of wooden sculptures painted a monochromatic white color. The paints show signs of degradation including cracking, chipping, peeling, and the formation of blisters and powdery efflorescence. A significant amount of pentaerythritol (PER) detected during a former analysis was concluded to originate from an alkyd paint. We show that the PER originates from the PVAc paint on the sculptures, which we have determined to be an intumescent, fire-retardant (IFR) coating. IFR paints and coatings are functional materials designed specifically to delay the combustion of their substrate. At least one other sculpture by Louise Nevelson is known to have been painted with an IFR coating. Our analyses by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), pyrolysis–gas chromatography/mass spectrometry (Py-GCMS), and cross-section microscopy show the presence and distribution of common IFR additives including PER, dicyandiamide, melamine, inositol, ethylenediamine, and phosphates. These are present throughout the PVAc paint and are enriched in the powdery efflorescence. In addition, the degradation behavior of the paint is typical for IFR coating systems that have been exposed to uncontrolled environmental conditions and especially high humidity events. Full article
(This article belongs to the Special Issue Molecular Spectroscopy in Art and Archaeology)
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