Plastic waste is a growing global environmental problem, particularly in the marine ecosystems, in consideration of its persistence. The monitoring of the plastic waste has become a global issue, as ...reported by several surveillance guidelines proposed by Regional Sea Conventions (OSPAR, UNEP) and appointed by the EU Marine Strategy Framework Directive.
Policy responses to plastic waste vary at many levels, ranging from beach clean-up to bans on the commercialization of plastic bags and to Regional Plans for waste management and recycling. Moreover, in recent years, the production of plant-derived biodegradable plastic polymers has assumed increasing importance. This study reports the first preliminary characterization of carbon stable isotopes (δ13C) of different plastic polymers (petroleum- and plant-derived) in order to increase the dataset of isotopic values as a tool for further investigation in different fields of polymers research as well as in the marine environment surveillance. The δ13C values determined in different packaging for food uses reflect the plant origin of “BIO” materials, whereas the recycled plastic materials displayed a δ13C signatures between plant- and petroleum-derived polymers source. In a preliminary estimation, the different colours of plastic did not affect the variability of δ13C values, whereas the abiotic and biotic degradation processes that occurred in the plastic materials collected on beaches and in seawater, showed less negative δ13C values. A preliminary experimental field test confirmed these results. The advantages offered by isotope ratio mass spectrometry with respect to other analytical methods used to characterize the composition of plastic polymers are: high sensitivity, small amount of material required, rapidity of analysis, low cost and no limitation in black/dark samples compared with spectroscopic analysis.
•Carbon stable isotopes can characterize petroleum/plant derived polymers.•Different colours of plastic polymers did not affect the δ13C values.•Plastics degraded in the marine environment showed an increase of δ13C values.•EA/IRMS allowed analytical advantages with respect to other analytical methods.
Die-to-wafer hybrid bonding is a crucial technology in advanced chiplet integration systems. Temporary die bonding on wafers and subsequent debonding are key aspects of this process. However, ...conventional polymer-based temporary bonding techniques involve several challenges such as issues related to the accurate placement of the die. Although direct bonding is a promising technology, such processes normally involve permanent bonds. The present study demonstrates an innovative temporary bonding method based on plasma-activated direct bonding and examines the associated bonding/debonding mechanisms. In this work, a dielectric bonding film was deposited at a relatively low temperature by chemical vapor deposition. This method offers several advantages, including high alignment accuracy, limited risk of die shift, and cost reduction based on removal of the carrier wafer grinding process. Wafer bonding was performed with SiO2 films deposited at low temperatures, and voids were formed at the bonding interfaces during postbond annealing. The bonding energy was sufficiently low even after annealing to allow wafer pairs to be released as a consequence of voids serving as initiation points for debonding. Desorption gas analysis established that the SiO2 films absorbed significant moisture from ambient air, which was the root cause of void formation. Die-to-wafer bonding tests confirmed the formation of voids at the bonding interfaces. This dielectric is likely to have applications as a temporary bonding material in chiplet integration systems.
Aquatic ecosystems are globally contaminated with microplastics (MP). However, comparative data on MP levels in freshwater systems is still scarce. Therefore, the aim of this study is to quantify MP ...abundance in water and sediment of the German river Elbe using visual, spectroscopic (Fourier-transform infrared spectroscopy) and thermo analytical (pyrolysis gas chromatography mass spectrometry) methods. Samples from eleven German sites along the German part of the Elbe were collected, both in the water and sediment phase, in order to better understand MP sinks and transport mechanisms. MP concentrations differed between the water and sediment phase. Sediment concentrations (mean: 3,350,000 particles m−3, 125–5000 μm MP) were in average 600,000-fold higher than water concentrations (mean: 5.57 particles m−3, 150–5000 μm MP). The abundance varied between the sampling sites: In sediments, the abundance decreased in the course of the river while in water samples no such clear trend was observed. This may be explained by a barrage retaining sediments and limiting tidal influence in the upstream parts of the river. Particle shape differed site-specifically with one site having exceptionally high quantities of spheres, most probably due to industrial emissions of PS-DVB resin beads. Suspended MP consisted predominantly of polyethylene and polypropylene whereas sediments contained a higher diversity of polymer types. Determined MP concentrations correspond well to previous results from other European rivers. In a global context, MP levels in the Elbe relate to the lower (water) to middle section (sediment) of the global range of MP concentrations determined for rivers worldwide. This highlights that elevated MP levels are not only found in single countries or continents, but that MP pollution is an issue of global concern.
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•Low to medium microplastic (MP) levels in the river Elbe•Much higher MP abundance in sediments compared to the water phase•Decreasing levels of MP in sediments over the course of the river•Higher polymer diversity in sediments compared to the water phase•Industrial emissions possibly caused MP hotspots
Microplastics (MPs) have recently been documented as an emerging pollutant that poses a critical threat to environment. Wastewater treatment plants (WWTPs) are commonly regarded as significant ...contributors to the presence of MPs. This study aimed to assess the MPs load of three wastewater treatment facilities in Oman using various treatments, including MBR, SBR, and CAS. Wastewater samples from influent, effluent, and sludge were collected and analyzed to determine the concentration, morphology, size, color, and polymer type of the MPs. A set of sieves with a mesh size range of 1 mm–45 μm was used to for filtration. Oxidation treatment was applied for all samples using Fenton's reagent, followed by density separation by sodium chloride solution. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR- FTIR) method was utilized to test 10% from each sampling point to confirm the polymer types of the MPs. The pollution load index (PLI) and hazard index (HI) have been employed to assess the risk associated with the chemical toxicity and concentration of detected particles. The PROMETHEE method was used to rank the risk of sampling sites based on different criteria that posed potential ecological and human health risks. The results indicate that the average concentrations of 0.99 MP/L, 1.38 MP/L, and 0.93 MP/L were detected in the final treated effluent of WWTP A, WWTP B, and WWTP C, respectively. These concentrations correspond to overall removal efficiencies of 82.5%, 77.4%, and 79.2% for WWTP A, WWTP B, and WWTP C, respectively Most MPs found in tertiary effluent were smaller particles (425 μm) and fiber-shaped. The major types of MPs were polypropylene (PP), low-density polyethylene (LDPE), polyurethane (PU), polyethylene terephthalate (PET), and Polyvinyl chloride (PVC). This study showed that treated effluent and sludge release significant MPs into the environment.
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•MPs are a major threat to humans and ecosystems, with wastewater treatment plants as a key source.•In Oman, this study assessed different treatment methods' impact on MP removal rates and load.•Sampling and analysis examined MPs' concentration, size, shape, colour, and polymer type, focusing on tiny fibres.•Results showed removal efficiencies ranging from 77.4% to 82.5%, but significant MPs still entered the environment.•Major MP Types included PP, LDPE, PU, PET, and PVC.
Microplastic (MP), as a pollutant, is currently posing a biological hazard to the aquatic environment. The study aims to isolate, quantify, and characterize the MP pollutants in sediment samples from ...14 study sites at Kaveri River, Killa Chinthamani, Tiruchirappalli, South India. With Sediment-MP Isolation (SMI) unit, density separation was done with a hydrogen peroxide solution. Four forms of MPs namely, fragments, films, foams, and fibers with orange, white, green, and saffron red were observed. The plenitude and distribution of four forms of MPs and natural substrates were geometrically independent, with large amounts of microfragments within the research region accounting for 79.72% variation by Principal Component Analysis. FT-IR analyses of MPs showed the presence of polyamide, polyethylene, polyethylene glycol, polyethylene terephthalate, polypropylene, and polystyrene. Additionally, the scanning electron microscopic analysis revealed that the MPs have differential surface morphology with rough surfaces, porous structures, fissures, and severe damage. Most MPs comprised Si, Mg, Cu, and Al, according to energy dispersive X-ray analyses. The combined SMI, instrumental analyses and evaluation (heat map) of MPs in river sediments help assess contamination levels and types of MPs. The findings might provide an insight into the status of MPs in Kavery River sediments that could help in formulating regulations for MPs reduction and contamination in rivers eventually to protect the environment.
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•A mean concentration of 386.07 ± 84.5 items•kg−1 MPs was found in Kavery River sediments.•Microfragments were the predominant MPs with 39.76–70.64% proportion.•Color of MPs was orange (28%)>white (23%)>green (22%) >saffron red (18%)>others (9%).•Polyamides, polypropylene, PVC, polystyrene, and PET were the MPs in river sediments.•Si, Mg, Cu, and Al were also found in association with MPs as revealed by SEM-EDS.
Analysis of organic plastic additives (OPAs) associated to plastic polymers is growing. The current review outlines the characteristics and the development of (multi-step) pyrolysis coupled with a ...gas chromatography mass spectrometer (Py-GC/MS) for the identification and semi-quantification of OPAs. Compared to traditional methods, Py-GC/MS offers advantages like suppressing extensive steps of preparation, limiting contamination due to solvents and the possibility to analyse minute particles. Its key advantage is the successive analysis of OPAs and the polymeric matrix of the same sample. Based on the studied articles, numerous methods have been described allowing identification and, in some case, semi-quantification of OPAs. There is nevertheless no gold standard method, especially given the huge diversity of OPAs and the risks of interferences with polymers or other additives, but, among other parameters, a consensus temperature seems to arise from studies. More broadly, this review also explores many aspects on the sample preparation like weight and size of particles and calibration strategies. After studying the various works, some development prospects emerge and it appears that methodological developments should focus on better characterizing the limits of the methods in order to consider which OPAs can be quantified and in which polymers this is feasible.
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•The analysis of OPAs in polymers is an analytical challenge•Py-GC/MS allows an efficient thermal desorption to analyse OPAs•Py-GC/MS allows the simultaneous analysis of OPAs & polymer in the same sample•Pros and cons regarding the use of Py-GC/MS are thoroughly assessed•Standardized and reliable quantitative methods for the analysis of OPAs is required
Microplastic particles (MPs) contamination of aquatic environments has raised a growing concern in recent decades because of their numerous potential toxicological effects. Although fish are among ...the most studied aquatic organisms, reports on MPs ingestion in freshwater environments are still scarce. Thus, there is still much to study to understand the uptake mechanisms, their potential accumulation among the food webs and their ecotoxicological effects. Here, MPs presence in the digestive system of one of the most widespread and commercially exploited freshwater fish, the perch (Perca fluviatilis, Linnaeus 1758), was investigated in four different south-alpine lakes, to assess the extent of ingestion and evaluate its relation to the body health condition. A total of 80 perch specimen have been sampled from the Italian lakes Como, Garda, Maggiore and Orta. Microplastic particles occurred in 86% of the analysed specimens, with average values ranging from 1.24 ± 1.04 MPs fish−1 in L. Como to 5.59 ± 2.61 MPs fish−1 in L. Garda. The isolated particles were mainly fragments, except in L. Como where films were more abundant. The most common polymers were polyethylene, polyethylene terephthalate, polyamide, and polycarbonate, although a high degree of degradation was found in 43% of synthetic particles, not allowing their recognition up to a single polymer. Despite the high number of ingested MPs, fish health (evaluated by means of Fulton's body condition and hepatosomatic index) was not affected. Instead, fullness index showed an inverse linear relationship with the number of ingested particles, which suggests that also in perch MPs presence could interfere with feeding activity, as already described for other taxa.
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•Microplastics ingestion by perch occurred in all the studied environments.•Mean ingestion ranged from 1.24 in Lake Orta to 5.59 MPs fish−1 in Lake Garda.•A high degree of degradation was found among the isolated synthetic particles.•Particles ingestion did not affect fish health.•Microplastics occurrence was higher in empty stomachs.
Lignin extracted from black liquor was co-pyrolyzed with three kinds of plastic polymers (low density polyethylene (LDPE); polycarbonate (PC); polystyrene (PS)), in order to investigate the effect of ...plastic polymers on the distribution of pyrolysis products (especially monomeric aromatic compounds). TG-FTIR and Py-GC/MS were employed to understand the thermal behavior and identify the typical products from the pyrolysis of individual samples and their mixtures (mass ratio for the mixture: 1:1). For TG-FTIR analysis, the thermal decomposition behavior of lignin-PC mixture exhibits notable difference between the experimental and estimated results over that of lignin-PS mixture and lignin-LDPE mixture. The apparent activation energy for the main conversion zone of co-pyrolysis of lignin with PC (73.08 kJ/mol) is lowest among those of the lignin-plastic mixtures (180.17 kJ/mol for lignin with LDPE and 179.91 kJ/mol for lignin with PS mixtures), suggesting the strongest interaction between lignin and PC. The H2O produced by the decomposition of lignin at low temperature may promote the hydrolytic reaction of PC and the release of CO2. The production of several aromatic compounds assigned to lignin pyrolysis was suppressed by the addition of PC or LDPE, while the formation of monomer aromatic hydrocarbons was notably promoted during the co-pyrolysis of lignin with PS.
Pyrolysis is an important method for efficiently recovering plastic monomers, fuels and chemicals from plastic waste. The depolymerization of the backbone structure of plastic waste is a key step of ...the pyrolysis process. Currently, researches on the pyrolysis mechanism of plastics with C-O/C-N bonds in the backbone are still not sufficiently in-depth and also lack systematic and comprehensive investigation. Therefore, this study for the first time comprehensively investigated both macroscopic and microscopic pyrolysis processes of plastics with C-O/C-N bonds in the backbone, and evaluated the difficulty of breaking different backbone linkages via bond dissociation energy (BDE) obtained by density functional theory (DFT) calculations to deeply reveal the pyrolysis mechanism. The results indicated that polyethylene terephthalate (PET) had a higher initial pyrolysis temperature and its thermal stability was slightly stronger than nylon 6. The backbone of PET was mainly decomposed via the cleavage of Cα-O on the alkyl side, while the degradation of nylon 6 backbone began with NH2 groups at the end of the backbone. The pyrolysis products of PET were mainly derived from the small molecular fragments, which were generated by the degradation of the backbone through the cleavage of CO bonds or CC bonds, while the pyrolysis products of nylon 6 were always dominated by caprolactam. In addition, based on the results of DFT calculations, it could be inferred that the cleavage of CC bond in PET backbone and the cleavage of its adjacent Cα-O were most likely to occur, which followed a competitive reaction mechanism. However, in pyrolysis of nylon 6, the conversion to caprolactam was mainly via the concerted reaction of amide CN bonds. Compared with the concerted cleavage of amide CN bond, the cleavage of CC bond in the backbone of nylon 6 was not predominant.
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•Both macroscopic and microscopic pyrolysis processes of plastics with C-O/C-N bonds in the backbone were monitored.•The backbone of PET was mainly decomposed via the cleavage of Cα-O on the alkyl side.•The cleavage of C-C bond in PET and the cleavage of its adjacent Cα-O followed a competitive reaction mechanism.•The conversion of nylon 6 to caprolactam was mainly via the concerted reaction of amide C-N bonds.
Microplastics (MP) in the marine environment are widely reported. However, MP occurrence in some geographical areas such as from Small Island Developing States (SIDS) is missing. The main aim of this ...study was to assess MP levels in the urban coastal environment of Suva, the capital of the Republic of Fiji. Microplastics were measured from surface water, sediments and fish gastrointestinal tracts (GI) from three sites adjacent to Suva. In addition, an evaluation on the contribution from the local sewage treatment plant to MP levels was undertaken. In general, low levels of MP in water and sediments were detected, but significant differences were observed among sites. The sewage treatment plant was shown to contribute to MP levels in sediment but not in water. Species ingestion of MP was high and associated with MP in sediments. Fibres and fragments were the predominant type of MP, and fifteen different polymers were detected, with higher percentages of polyethylene, latex and polypropylene. In conclusion, MP were found in Suva coastal environment and these MP were associated to land based human activities.
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