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The development of an efficient and environmentally sustainable chemical hydrolysis process for recycling waste plastics, based on green chemistry principles, is a key challenge. In this work, we investigated the role of subcritical CO2 on the hydrolysis of polyethylene terephthalate (PET) into terephthalic acid (TPA) at 180–200 °C for 10–100 min. The addition of CO2 into the reaction mixture led to the in situ formation of carbonic acid that helps to catalyze PET hydrolysis relative to hot compressed H2O (i.e. N2– H2O). The highest TPA yield of 85.0 ± 1.3% was obtained at 200 °C, PET loading of 2.5 g PET in 20 mL H2O for 100 min, and 208 psi of initial CO2 pressure. In addition, the subcritical CO2–H2O system demonstrated high selectivity toward hydrolyzing PET in a mixture with polyethylene (PE) at 200 °C for 100 min, thus providing “molecular sorting” capabilities to the recycling process. The robustness of the process was also demonstrated by the ability to hydrolyze both colored Canada Dry and transparent Pure Life® waste PET bottles into high yields of TPA (>86%) at 200 °C. In addition, subcritical CO2–H2O hydrolysis of colored PET bottles resulted in a white TPA product similar to that generated from transparent PET bottles. Overall, this work shows that, under optimized reaction conditions, subcritical CO2 can provide acid tunability to the reaction medium to favor waste PET hydrolysis for subsequent recycling. [ABSTRACT FROM AUTHOR]

In this study, hydrothermal co-liquefaction of restaurant waste for biocrude production was conducted. The feedstock was resembled using the organic fraction of restaurant waste and low-density polyethylene, polypropylene, polystyrene, and polyethylene terephthalate, four plastic types commonly present in municipal solid waste. Using design of experiment and a face-centered central composite design, three factors (feedstock plastic fraction, temperature, time) were varied at three levels each: feedstock plastic fraction (0, 0.25, 0.5), temperature (290 °C, 330 °C, 370 °C), and reaction time (0 min, 30 min, 60 min). The literature reports positive synergistic interactions in hydrothermal co-liquefaction of biomass and plastics; however, in this work, only negative synergistic interactions could be observed. A reason could be the high thermal stability of produced fatty acids that give little room for interactions with plastics. At the same time, mass might transfer to other product phases. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET), the most abundantly produced polyester plastic, can be depolymerized by the Ideonella sakaiensis PETase enzyme. Based on multiple PETase crystal structures, the reaction has been proposed to proceed via a two-step serine hydrolase mechanism mediated by a serine-histidine-aspartate catalytic triad. To elucidate the multi-step PETase catalytic mechanism, we use transition path sampling and likelihood maximization to identify optimal reaction coordinates for the PETase enzyme. We predict that deacylation is likely rate-limiting, and the reaction coordinates for both steps include elements describing nucleophilic attack, ester bond cleavage, and the "moving-histidine" mechanism. We find that the flexibility of Trp185 promotes the reaction, providing an explanation for decreased activity observed in mutations that restrict Trp185 motion. Overall, this study uses unbiased computational approaches to reveal the detailed reaction mechanism necessary for further engineering of an important class of enzymes for plastics bioconversion. Polyethylene terephthalate (PET) can be depolymerized by the Ideonella sakaiensis PETase enzyme, however, questions remain about the precise catalytic mechanism. Here, the authors use unbiased QM/MM MD simulations to determine optimal mechanistic descriptions of the acylation and deacylation reactions, revealing the rate-limiting step and key interactions within the catalytic triad and Trp185 conformation. [ABSTRACT FROM AUTHOR]

Micro- and nanoplastics are widespread throughout the world. In particular, polyethylene (PE) and polyethylene terephthalate or polyester (PET) are two of the most common polymers, used as plastic bags and textiles. To analyze the toxicity of these two polymers, oligomers with different numbers of units were used as models. The use of oligomers as polymeric templates has been used previously with success. We started with the monomer and continued with different oligomers until the chain length was greater than two nm. According to the results of quantum chemistry, PET is a better oxidant than PE, since it is a better electron acceptor. Additionally, PET has negatively charged oxygen atoms and can promote stronger interactions than PE with other molecules. We found that PET forms stable complexes and can dissociate the guanine-cytosine nucleobase pair. This could affect DNA replication. These preliminary theoretical results may help elucidate the potential harm of micro- and nanoplastics. [ABSTRACT FROM AUTHOR]

The design and study of active microbial consortia able to degrade plastics represent an exciting area of research toward the development of bio-based alternatives to efficiently transform plastic waste. This forum article discusses concepts and mechanisms to inform emerging strategies for engineering microbiomes to transform plastics under controlled settings. [ABSTRACT FROM AUTHOR]

Plastic waste is being manufactured for the production of hydrogen. The amount of plastic waste collected annually is 189,953 tonnes from adjacent nations like Indonesia and Malaysia. Polyethylene (PE), Polypropylene (PP), Polyethylene Terephthalate (PET), Polyvinyl chloride (PVC), and Polystyrene (PS) are the five most prevalent forms of plastic found in most waste. Pyrolysis, water gas shift and steam reforming reaction, and pressure swing adsorption are the three main phases utilized and studied. In this research, authors examines the energy consumption on every stage. The plastic waste can be utilized to manufacture many hydrocarbons using the pyrolysis reaction. For this process, fast pyrolysis is being used at a temperature of 500 °C. A neutralization process is also needed due to the presence of Hydrochloric acid from the pyrolysis reaction, with the addition of sodium hydroxide. This is being carried to prevent any damage to the reactor during the process. Secondly, the steam reforming process continues after the water gas shift reaction has produced steam and carbon monoxide, followed by carbon dioxide and hydrogen formation. Lastly, pressure swing adsorption is designed to extract H2S and CO2 from the water gas shift and steam reforming reaction for greater purity of hydrogen. From the simulation study, it is observed that using various types of plastic waste procured (total input of 20,000 kg per hour of plastics) from, Brunei Darussalam, Malaysia and Indonesia, can produce about 340,000 tons of Hydrogen per year. Additionally, the annual profit of the Hydrogen production is estimated to be between $ 271,158,100 and $ 358,480,200. As per the economic analysis, it can be said that its a good to start hydrogen production plant in these regions. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) is a widely used plastic, but its short service life and non‐degradable features make it a major source of white pollution. In this context, the efficient recycling and rational reuse of PET have become a global research priority. In this paper, a deep eutectic solvent（DES）is prepared using methylurea and zinc chloride to catalyze the efficient PET glycolysis, which produces a high purity product bis(2‐hydroxyethyl) terephthalate (BHET), in 83.75% of yield. The product is condensed with diethyl adipate to produce Poly (ethyleneadipate‐co‐terephthalate) (PEAT). The relationships between the structural, thermal, mechanical, and degradation properties of PEAT with different intrinsic viscosities and composition ratios are studied. The addition of benzene ring improves the thermal properties and tensile strength of PEAT, but also makes them stiffer and less degradable. An increase in intrinsic viscosity can improve the thermal and mechanical properties to some extent but has little effect on the degradation. In general, the PEAT produced by the above process has good thermal properties, controllable degradation properties, and better mechanical properties than Poly (butyleneadipate‐co‐terephthalate) (PBAT). This work achieves the conversion of waste PET to high value‐added PEAT and has potential development prospects in recycling of PET. [ABSTRACT FROM AUTHOR]

A biodegradable polymer packaging system for 'Benitaka' table grapes (Vitis vinifera L.) was developed to inhibit the development of gray mold during refrigerated storage. The system consisted of packages and sachets containing Na2S2O5 to release sulfur dioxide (SO2), both produced with biodegradable films of starch, glycerol, and poly (adipate co-butylene terephthalate) (PBAT) produced via blown extrusion. The films were characterized in terms of thickness, density, mass loss in water, water vapor permeability, sorption isotherms, and mechanical properties. The table grapes were packed with biodegradable plastic bags containing SO2-releasing sachets inside. The experimental design was completely randomized, with four repetitions and five treatments: (a) control, without sachet containing Na2S2O5 and SiO2; (b) 2 g of Na2S2O5 + 2 g of SiO2; (c) 4 g of Na2S2O5 + 1 g of SiO2; (d) 4 g of Na2S2O5 + 2 g of SiO2; and (e) 4 g of Na2S2O5 + 4 g of SiO2. The bunches were stored in a refrigerated chamber at 1 ± 1 °C and relative humidity above 90%. The treatments were evaluated 30 and 45 days after the beginning of refrigerated storage and 3 days at room temperature. The grapes were evaluated based on the incidence of gray mold, mass loss, stem browning, shattered berries, and berry bleaching. The data were subjected to the analysis of variance, and the means were compared using Tukey's test at 5%. The biodegradable films had good processability during the production via blown extrusion, with good physical properties to be used in the packaging of grapes and the production of SO2-releasing sachets. The biodegradable polymer packaging system (biodegradable plastic bags + SO2-releasing sachets) inhibited the development of gray mold on 'Benitaka' table grapes for 45 days at 1 °C, preserving their quality, with low mass loss, few shattered berries, and rachis freshness. [ABSTRACT FROM AUTHOR]

Huge amounts of plastic products are produced, utilized, and discarded each year, contributing to the increasingly serious ecological problem. Photoreforming, a solar-driven technology, provides an uncomplicated route to simultaneously recycle plastics and facilitate hydrogen (H 2) production. Herein, we proposed innovative CdS/NiS composites which used visible light to drive H 2 evolution from plastic wastes. Results confirmed that the loading of NiS on CdS could facilitate the transmission of photoexcited electrons, which greatly improved the photocatalytic performance. The H 2 production capability of CdS/NiS was more than 6 times higher than that of pure CdS, and the highest H 2 yield reached 62.9 mmol g−1 h−1 under optimized conditions when polylactic acid (PLA) was treated. Typical polyester plastics, including polyethylene terephthalate (PET), polybutylene adipate (PBA), polybutylene terephthalate (PBT), and poly (butyleneadipate-co-terephthalate) (PBAT), as well as raw PLA drink straws, were also successfully employed as the hole scavenger to enhance H 2 generation. This system utilized abundant resources (solar energy and waste plastics) and worked under mild conditions, proffering a sustainable approach for H 2 synthesis together with waste plastic pollutant reduction for a carbon-neutral future. [Display omitted] • CdS/NiS composite photocatalyst was used for visible-light-driven H 2 generation. • Various polyester plastics were employed as feedstocks to produce H 2 and organics. • The highest H 2 yield reached 62.9 mmol g−1 h−1 when polylactic acid was used. • The hydroxyl-containing monomers worked as hole scavengers in the reaction process. • The reaction mechanism of waste plastics photo-reforming over CdS/NiS was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF-based extraction and depolymerization of PET nanoplastics. • Accurate detection of PET nanoplastics via depolymerization products. • Fast magnetic extraction in 60 sec. • Efficient PET nanoplastics depolymerization in 0.5 h. The detection and quantification of nanoplastics in aqueous medium is largely untapped because of an absence of appropriate sample processing methods. In this work, magnetic ZIF-8 nanoparticles (Nano-Fe@ZIF-8) have been applied for the magnetic extraction and depolymerization of polyethylene terephthalate (PET) nanoplastics. Nano-Fe@ZIF-8 enabled the fast aggregation and magnetic retrieval of PET nanoplastics from water. The Zn(II) present in Nano-Fe@ZIF-8 subsequently acted as a catalyst for the depolymerization of the extracted PET nanoplastics using ethylene glycol at 180 °C. PET nanoplastics were depolymerized in just 30 min, producing the depolymerization product bis(2-hydroxyethyl) terephthalate. The selective quantification of the depolymerization product using reversed-phase liquid chromatography enabled the measurement of the original PET nanoplastics present in water at parts-per-million level, and with a high reproducibility (RSD, 2.8–5.9 %). This is the first example of an integrated magnetic-catalytic nanomaterial enabling the isolation, depolymerization, and detection of nanoplastics from aqueous medium. [ABSTRACT FROM AUTHOR]

[Display omitted] Microplastics (MPs) are an everyday part of life, and are now ubiquitous in the environment. Crucially, MPs have not just been found within the environment, but also within human bodies, including the blood. We aimed to provide novel information on the range of MP polymer types present, as well as their size and shape characteristics, in human whole blood from 20 healthy volunteers. Twenty-four polymer types were identified from 18 out of 20 (90 %) donors and quantified in blood, with the majority observed for the first time. Using an LOQ approach, five polymer types met the threshold with a lower mean ± SD of 2466 ± 4174 MP/L. The concentrations of plastics analysed in blood samples ranged from 1.84 − 4.65 μg/mL. Polyethylene (32 %), ethylene propylene diene (14 %), and ethylene–vinyl-acetate/alcohol (12 %) fragments were the most abundant. MP particles that were identified within the blood samples had a mean particle length of 127.99 ± 293.26 µm (7–3000 µm), and a mean particle width of 57.88 ± 88.89 µm (5–800 µm). The MPs were predominantly categorised as fragments (88 %) and were white/clear (79 %). A variety of plastic additive chemicals were identified including endocrine disrupting-classed phthalates. The procedural blank samples comprised 7 polymer types, that were distinct from those identified in blood, mainly resin (25 %), polyethylene terephthalate (17 %), and polystyrene (17 %) with a mean ± SD of 4.80 ± 5.59 MP/L. This study adds to the growing evidence that MPs are taken up into the human body and are transported via the bloodstream. The shape and sizes of the particles raise important questions with respect to their presence and associated hazards in terms of potential detrimental impacts such as vascular inflammation, build up within major organs, and changes to either immune cell response, or haemostasis and thrombosis. [ABSTRACT FROM AUTHOR]

• MPs were mainly fibrous, blue and in 20–500 μm in industrial mariculture. • Long operating time led to higher MP concentration in RAS. • Occurrence and distribution of MPs was analyzed in long & short operated RAS. • Microfilter removed MP in film, granule, fragment and those > 1000 μm efficiently. • PMF model was used to analyze the source of MP based on the polymer type. Industrial mariculture, a vital means of providing high quality protein to humans, is a potential source of microplastics (MPs) which have recently received increasing attention. This study investigated the occurrence and distribution of microplastics in feed, source water and recirculating aquaculture system (RAS) with long & short operating times as well as in fish from typical industrial mariculture farms in China. Results showed that microplastics occurred in all samples with the average concentration of 3.53 ± 1.39 particles/g, 0.70 ± 0.17 particles/L, 1.53 ± 0.21 particles/L and 2.21 ± 0.62 particles/individual for feed, source water, RAS and fish, respectively. Microplastics were mainly fiber in shape, blue in color and 20–500 μm in size. Compared with short operated RAS, long operating time led to higher microplastic concentration in RAS, especially that of microplastic in 20–500 μm, granular and blue. Regardless of short or long operating time, microplastics in RAS mainly gathered in culture tank, tank before microfilter and fixed-bed biological filter, and the microfilter removed efficiently the microplastic with the shape of film, granule, fragment as well as those with size > 1000 μm. As for the polymer types, polyamide (PA, 71.9 %) and polyethylene terephthalate (PET, 65.7 %) dominated in feed and source water, respectively, which may be the reason for the high proportion of PA (38.8 % and 26.4 %) and PET (31.8 % and 30.2 %) in RAS and fish. In addition, polypropylene (PP) was also detected in RAS (18.7 %) and fish (22.6 %), indicating that other plastic facilities such as PP brush carrier also made a contribution. Positive matrix factorization (PMF) model revealed three sources of MP in RAS, namely plastic facilities, industrial sewage and plastic packaging products. Our results provided a theoretical basis for the management of MP in RAS. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Microwave pyrolysis treated polyethylene terephthalate and low-density polypropylene simultaneously. • Coconut husk carbon showed favorable process features and product features as microwave absorbent. • This process enhances the synergistic production of monocyclic aromatics. • High yields of oil (42.50 wt%) were obtained with a high content of monocyclic aromatics (77.11 %). The application of biochar as microwave absorbers in microwave-assisted catalytic fast pyrolysis (MACFP) has been widely studied. It has been reported that coconut husk carbon (CHC) showed good process characteristics and product distribution as microwave absorbers. However, the existing studies did not pay much attention to the reusability of CHC absorbers. In this study, the CHC absorbers prepared from agricultural and forestry wastes were reused in multiple cycles in the MACFP of polyethylene terephthalate (PET) and low-density polyethylene (LDPE). Compared with typical microwave absorbers such as spherical silicon carbide (SiC) and granular activated carbon (GAC), CHC demonstrated favorable process characteristics with relatively high heating rate (29 °C/min) and short heating time (within 12 min). In terms of product properties, the highest liquid yield of 51.67 wt% and the highest content of monocyclic aromatic hydrocarbons (MAHs) of 82.82 % were obtained at the appropriate pyrolysis temperature (550 °C). After five consecutive uses, the CHC bed still produced comparable heating profiles and product distributions, compared to that of SiC. At the same time, a positive synergistic effect between PET and LDPE was observed. The co-feeding of PET and LDPE (50L50P) appropriately increased the liquid yield (42.50 wt% vs 38.75 wt%) and the relative content of MAHs (77.11 % vs 72.96 %) in comparison to their theoretical value. Finally, this study supplies a new strategy for utilizing recycled CHC as a microwave absorber for the treatment of hydrogen-rich and hydrogen-deficient mixed plastic wastes to produce MAHs products, which also reduces waste and realizes energy conversion. [ABSTRACT FROM AUTHOR]

Continuous exposure to plastic pollutants may have serious consequences on human health. However, most toxicity assessments focus on non-environmentally relevant particles and rarely investigate long-term effects such as cancer induction. The present study assessed the carcinogenic potential of two secondary nanoplastics: polyethylene terephthalate (PET) particles generated from plastic bottles, and a biodegradable polylactic acid material, as respective examples of environmentally existing particles and new bioplastics. Pristine polystyrene nanoplastics were also included for comparison. A broad concentration range (6.25–200 μg/mL) of each nanoplastic was tested in both the initiation and promotion conditions of the regulatory assessment-accepted in vitro Bhas 42 cell transformation assay. Parallel cultures allowed confirmation of the efficient cellular internalisation of the three nanoplastics. Cell growth was enhanced by polystyrene in the initiation assay, and by PET in both conditions. Moreover, the number of transformed foci was significantly increased only by the highest PET concentration in the promotion assay, which also showed dose-dependency, indicating that nano PET can act as a non-genotoxic tumour promotor. Together, these findings support the carcinogenic risk assessment of nanoplastics and raise concerns regarding whether real-life co-exposure of PET nanoplastics and other environmental pollutants may result in synergistic transformation capacities. [Display omitted] • Polyethylene terephthalate, polylactic acid, and polystyrene nanoplastics were used. • Carcinogenicity was assessed using the in vitro Bhas 42 cell transformation assay. • Only polyethylene terephthalate (PET) nanoplastics induced cell transformation. • PET nanoplastics acted through a tumour promotion mode of action. • The three types of nanoplastics were efficiently internalised into cells. [ABSTRACT FROM AUTHOR]

Pyrolysis-gas chromatography coupled to Orbitrap-mass spectrometry is a novel technique that allows the low level and precise determination of microplastics in environmental samples. In this paper, we develop and assess the target and untargeted performance of Pyr-GC-Orbitrap-MS. The method was optimized for 10 plastic polymers: polymethyl methacrylate, nylon-6,6, polypropylene, nitrile butadiene rubber, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, polyethylene, polycarbonate, and polystyrene. Standards were home-made using a diamond driller to attain mean sizes within the range of 45–382 µm. A step-by-step optimization of the analytical procedure was carried out. First, accurate mass measurement of each polymer at 60,000 resolution was studied to select the 3 most intense and selective quantification and confirmation ions. Second, internal standard quantification was optimized, and good linearity, repeatability, and reproducibility were obtained. Blank contribution and instrumental detection limit were evaluated for each polymer. Finally, the combined and expanded uncertainty of the Pyr-GC-Orbitrap-MS method was calculated to determine the sources of variation, considering that home-made standards were used. To evaluate method performance, targeted and non-targeted analysis of indoor air samples collected from gyms and department stores were carried out. The Pyr-GC-Orbitrap-MS methodology herein described can be applied for the quantitative assessment of MPs and other substances in different matrices. [Display omitted] • Pyrolysis with orbitrap mass spectrometry allows detection of microplastics in air. • Microplastic standards allow calibration and calculation of quality parameters. • Exact mass measurements allows target and non-target analysis of microplastics. • The uncertainty of the method allows validating the method for trace concentrations. • Microplastics and other contaminants have been detected in air from stores and gyms. [ABSTRACT FROM AUTHOR]

The processing of residual fractions after the distillation of oil and waste plastics into fuels is an important aspect from environmental, energetic and economic points of view. However, current methods of their processing are not effective enough for widespread implementation. In this work the effect of the addition of polyethylene terephthalate (PET), low-density polyethylene (LDPE) and polypropylene (PP) to the atmospheric residue on the composition of final products of subsequent cracking is investigated. It has been established that addition of PET to the atmospheric residue has a positive effect on the yield of light fractions and the destruction of resin-asphaltene substances (RAS) in comparison with cracking of atmospheric residue (AR) only. After cracking with the PET additive, the additional yield of light fractions is 4.8 wt%. It has been shown that PET affects the amount and structure of coke resulted from the cracking of atmospheric residue. A positive effect of the PP additive on the destruction of RAS is also revealed. In particular, the content of asphaltenes is lowered by a factor equal to 9.8 compared to that in the liquid products after fuel oil cracking. It has been also found out that polypropylene 1.7 times more than PET and 1.5 times more than PE enhances additional coke formation. It is shown that LDPE has the least positive effect from co-cracking with AR compared to the case with PET and PP. A hypothetical mechanism is presented for the interaction of PET, LDPE, and PP with AR during co-cracking. • The cracking of AR and PP produced liquid products with low levels of asphaltenes. • The process of cracking AR with LDPE, PET, and PP primarily yields gasoline fractions. • PET in AR cracking impacts both the quantity and quality of the resulting coke. • LDPE, PET and PP decrease the molecular weight of asphaltenes. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) is one of the most produced plastics globally and its accumulation in the environment causes harm to the ecosystem. Polyethylene terephthalate hydrolyse (PETase) is an enzyme that can degrade PET into its monomers. However, free PETase lacks operational stabilities and is not reusable. In this study, development of cross-linked enzyme aggregate (CLEA) of PETase using amylopectin (Amy) as cross-linker was introduced to solve the limitations of free PETase. PETase-Amy-CLEA exhibited activity recovery of 81.9 % at its best immobilization condition. Furthermore, PETase-Amy-CLEA exhibited 1.37-, 2.75-, 2.28- and 1.36-fold higher half-lives than free PETase at 50 °C, 45 °C, 40 °C and 35 °C respectively. Moreover, PETase-Amy-CLEA showed broader pH stability from pH 5 to 10 and could be reused up to 5 cycles. PETase-Amy-CLEA retained >70 % of initial activity after 40 days of storage at 4 °C. In addition, lower K m of PETase-Amy-CLEA indicated better substrate affinity than free enzyme. PETase-Amy-CLEA corroded PET better and products yielded was 66.7 % higher than free PETase after 32 h of treatment. Hence, the enhanced operational stabilities, storage stability, reusability and plastic degradation ability are believed to make PETase-Amy-CLEA a promising biocatalyst in plastic degradation. • PETase-Amy-CLEA gave high activity recovery. • PETase-Amy-CLEA showed better thermal, pH and storage stabilities than free PETase. • PETase-Amy-CLEA showed better PET degradation than free PETase. • Molecular docking validated the precipitation results in CLEAs' preparation. • Molecular dynamic validated the results of thermal stability. [ABSTRACT FROM AUTHOR]

Considering the significant demands for construction products and the increasing disposals of plastic and agroforestry residues, this research evaluated the influence of recycled particles of polyethylene terephthalate (PET) inserted in the manufacture of five particleboard prototypes based on Pinus elliottii wood and castor-oil-based polyurethane resin (CPUR). The following panel traits were obtained: 100% pine wood, 0% PET and 10% CPUR (M100P-0PET-10C); 70% pine, 30% PET, and 10% CPUR (M70P-30PET-10C); 50% pine, 50% PET, and 10% CPUR (M50P-50PET-10C); 70% pine, 30% PET, and 5% CPUR (M70P-30PET-5C); and, 50% pine, 50% PET, and 5% CPUR (M50P-50PET-5C). Panels were evaluated according to physical (density, moisture content, thickness swelling, and water absorption), mechanical (modulus of rupture, modulus of elasticity, perpendicular tensile), and morphological tests (scanning electron microscope). M50P-50PET-10C particleboards revealed the best performance in the physical and mechanical tests, as well as M70P-30PET-10C and M50P-50PET-5C panels showed equivalent results. The findings suggested a notable environmental contribution and a great economic feasibility. Thus, it is possible to obtain wood-based particleboards manufactured from recycled PET, reusing this highly discarded non-biodegradable plastic and using a smaller volume of adhesive, with physical-mechanical properties that meet the expected performance for this bioresource-based product. [ABSTRACT FROM AUTHOR]

Discarding PET plastic (dPET) causes serious environmental pollution and enormous fossil resources waste. Processing techniques have mainly focused on the conversion of dPET into monomers, with minimal reports highlighting their transformation into high–value materials. This work intends to transform dPET into a high–performance material with potential alternative value in harsh production environments. The soft and hard segments of the thermoplastic polyester elastomeric (TPEE) molecular structure are reacted and cross–linked with dPET using a facile one–pot process, and two main polymers, (C 8 H 4 O 4) n and ((C 16 H 18 O 4) 0.76 ·(C 4 H 8 O) 0.24) n are generated after the reaction. Through chemical reactions between TPEE and dPET, new characteristic products and chemical bond–crossing structures are formed, while the resulting product particles or multiple TPEE particles are anchored by the high viscosity of dPET, which endows the material with superior tensile strength (34.21 MPa) and impact resistance. The glass transition temperature (T g) of the material implies that neither the molecular chain nor the chain segments can move, while only the atoms or groups composing the molecule vibrate at their equilibrium positions. The development of this new treatment method may contribute to the reduction of environmental pollution and the improvement of the high–value conversion and utilization of dPET. [Display omitted] • An innovative strategy to convert dPET into functional materials was developed. • The fabricated material showed excellent tensile strength and impact resistance. • (C 8 H 4 O 4) n and (C 16 H 18 O 4) 0.76 ·(C 4 H 8 O) 0.24) n were generated after polymerization. • Newly formed long–chain polymer is responsible for superior tensile strength. • This study gives a new alternative approach to high-value utilization of dPET. [ABSTRACT FROM AUTHOR]

[Display omitted] • Both floating and suspended MPs could be the carbon sources for microorganisms. • UV exposure could stimulate the release of dissolved organic matter (DOM) from MPs. • PET leachates had the highest chromophoric DOM concentration and aromaticity. • Protein-like substances were the main fluorescent DOM from UV- and dark-treated MPs. • Monomers to hexamers with new functional groups were identified in MP suspensions. This study investigated the impacts of light irradiation and polymer types on the leaching behavior of dissolved organic matter (DOM) from microplastics (MPs) in freshwater. Polypropylene had the highest leaching capacity of DOM after photoaging, followed by polystyrene (PS), polyamide (PA) and polyethylene terephthalate (PET). While similarly low levels of DOM were observed in the remaining 5 MP suspensions under UV irradiation and in almost all MP suspensions (except PA) under darkness. These suggest that the photooxidation of some buoyant plastics may influence the carbon cycling of nature waters. Among 9 MP-derived leachates, PET leachates had the highest chromophoric DOM concentration and aromaticity, probably owing to the special benzene rings and carbonyl groups in PET structures and its fast degradation rate. Protein-like substances were the primary fluorescent DOM in MP suspensions (except PS), especially in darkness no other fluorescent substances were found. Considering the bio-labile properties of proteins together, MPs regardless of floating or suspended in an aquatic environment may have prevalent long-term effects on microbial activities. Besides, from monomers to hexamers with newly formed chemical bonds were identified in UV-irradiated MP suspensions. These results will contribute to a deep insight into the potential ecological effects related to MP degradation. [ABSTRACT FROM AUTHOR]

Nanoplastics are emerging environmental contaminants, but their presence in environmental and potable water remains largely understudied due to the absence of quantitative analytical methods. In this study, we developed and validated a pretreatment method that combines hydrogen peroxide digestion and Amicon® Stirred Cell ultrafiltration (at 100 kDa, approximately 10 nm) with subsequent detection by pyrolysis gas chromatography–mass spectrometry (Pyr-GC/MS). This method allows for the simultaneous identification and quantification of nine selected nanoplastic types, including poly(ethylene terephthalate) (PET), polyethylene (PE), polycarbonate (PC), polypropylene (PP), poly(methyl methacrylate) (PMMA), polystyrene (PS), polyvinylchloride (PVC), nylon 6, and nylon 66, in environmental and potable water samples based on polymer-specific mass concentration. Limits of quantification ranged from 0.01 to 0.44 µg/L, demonstrating the method's ability to quantitatively detect nanoplastics in environmental and potable water samples. Most of the selected nanoplastics were detected at concentrations of between 0.04 and 1.17 µg/L, except for PC, which was consistently below the limit of detection (<0.44 µg/L). The prevalent polymer components in the samples were PE (0.10 – 1.17 µg/L), PET (0.06 – 0.91 µg/L), PP (0.04 – 0.79 µg/L), and PS (0.06 – 0.53 µg/L) nanoplastics. The presented analytical method offers an accurate means to identify, quantify, and monitor nanoplastics in complex environmental and potable water samples. It fills gaps in our understanding of nanoplastic pollution levels, providing a valuable methodology and crucial reference data for future studies. [Display omitted] • Presentation of a methodology for the quantification of nanoplastics in water. • Mass concentrations of nanoplastics across water samples were assessed by Pyr-GC/MS. • Eight nanoplastics (PMMA, Nylon 6, Nylon 66, PC, PS, PET, PP, PE) quantified. • PE, PET, PP and PS were the predominant nanoplastics. • Total nanoplastics concentrations of between 0.04 and 1.17 µg/L in water samples. [ABSTRACT FROM AUTHOR]

Nanoplastics (NPLs) persist in aquatic habitats, leading to incremental research on their interaction mechanisms with metalloids in the environment. In this regard, it is known that plastic debris can reduce the number of water-soluble arsenicals in contaminated environments. Here, the arsenic interaction mechanism with pure NPLs, such as polyethylene terephthalate (PET), aliphatic polyamide (PA), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), and polystyrene (PS) is evaluated using computational chemistry tools. Our results show that arsenic forms stable monolayers on NPLs through surface adsorption, with adsorption energies of 9–24 kcal/mol comparable to those on minerals and composite materials. NPLs exhibit varying affinity towards arsenic based on their composition, with As(V) adsorption showing higher stability than As(III). The adsorption mechanism results from a balance between electrostatics and dispersion forces (physisorption), with an average combined contribution of 87%. PA, PET, PVC, and PS maximize the electrostatic effects over dispersion forces, while PE and PP maximize the dispersion forces over electrostatic effects. The electrostatic contribution is attributed to hydrogen bonding and the activation of terminal O–C, C–H, and C–Cl groups of NPLs, resulting in several pairwise interactions with arsenic. Moreover, NPLs polarity enables high mobility in aqueous environments and fast mass transfer. Upon adsorption, As(III) keeps the NPLs polarity, while As(V) limits subsequent uptake but ensures high mobility in water. The solvation process is destabilizing, and the higher the NPL polarity, the higher the solvation energy penalty. Finally, the mechanistic understanding explains how temperature, pressure, pH, salinity, and aging affect arsenic adsorption. This study provides reliable quantitative data for sorption and kinetic experiments on plastic pollution and enhances our understanding of interactions between water contaminants. [Display omitted] • The As(V) adsorption is stronger than that of As(III) on all polymers. • PET/PVC and PA are the strongest As(III) and As(V) adsorbents, respectively. • The mechanism arises from combined electrostatics and dispersion forces (80%). • Changes in the polymer polarity increase the mobility and faster mass transfer. • The adsorption process is exothermic, with a high degree of orderliness. [ABSTRACT FROM AUTHOR]

Supercritical water (SCW) treatment of plastics is a clean technology in the 'waste-to-energy' path. In this work, PP and PET plastics were processed by sub-/supercritical water. The results showed that temperature was the most important factor of the PP and PET degradation. The influence of factors on the degradation of plastics follows the following order: temperature > residence time > plastic/water ratio. These factors influenced the yield of gas products by promoting or inhibiting various reactions (such as reverse water gas shift reaction, methylation reaction, and Fischer-Tropsch synthesis reaction). Besides, the composition of liquid oil was also analyzed. The main composition of the liquid oil produced by PET was benzoic acid and acetaldehyde, which were generated from the decarboxylation of terephthalic acid (TPA) and dehydration reaction of ethylene glycol (EG). The liquid oil from PP was mainly long-chain olefins, long-chain alkanes, cycloalkanes, etc., which were formed by the interaction of various methyl, alkyl, hydroxyl, and other free radicals. This study could build fundamental theories of plastic mixture treatment. [Display omitted] • PET and PP waste recycling was performed by thermal treatment in sub-/supercritical water. • Influence of key operating parameters on PET and PP degradation was identified. • Gas yield could be manipulated by controlling WGS, methylation and F-T synthesis. • Hydrolysis, polyol gasification and reforming proceeded in PET decomposition. • Bond breaking and recombination were the dominating mechanism in PP decomposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • PET hydrolase (WCCG) delayed the humification of composting. • WCCG altered the microbial community and decreased the relative abundance of thermophilic genus. • Plastic-degrading microbiota are enriched in plastisphere. • WCCG and plastic-degrading microbiota explain the degradation of PET-MPs during high-temperature composting. This research aims to explore the degradation properties of polyethylene terephthalate (PET) by PET hydrolase (WCCG) in high-temperature composting and its impact on microbial communities. PET degradation, composting parameters and microbial communities were assessed in 220 L sludge composters with PET and WCCG using high-throughput sequencing. Results showed that WCCG addition led to a deceleration of the humification process and a reduction in the relative abundance of thermophilic genera. Potential PET degrading microbiota, e.g. Acinetobacter , Bacillus , were enriched in the plastisphere in the composters where PET reduced by 26 % without WCCG addition. The external introduction of the WCCG enzyme to compost predominantly instigates a chemical reaction with PET, concurently curtailing the proliferation of plastic-degrading bacteria, leading to a 35 % degradation of PET. Both the WCCG enzyme and the microbiota associated with plastic-degradation showed the potential for reducing PET, offering a novel method for mitigating pollution caused by environmental microplastics. [ABSTRACT FROM AUTHOR]

Microplastics and microfibres are found ubiquitously in global oceans as well as marine organisms from different trophic levels. However, little is known about the presence of microplastics and microfibres in marine megafauna, such as sharks. This study provided the first investigation of the presence of microplastics and other anthropogenic fibres (i.e., cellulose based fibres) in intestine and muscle samples of four large apex shark species in Australian coastal waters. Microplastics and other anthropogenic fibres were found in 82% of the analysed intestine samples. The mean abundance in intestine samples was 3.1 ± 2.6 particles/individual, which corresponded to 0.03 ± 0.02 particles/g of intestine, across all shark species. The size of particles ranged from 190 to 4860 μm in length with 92% being fibrous in shape and the rest fragments. FTIR spectroscopy identified that 70% of fibres were cellulose-based followed by polyethylene terephthalate (PET), while the fragments were polyethylene and polypropylene. In shark muscles, 60% of samples contained microplastics and other anthropogenic fibres, again with the majority being cellulose-based fibres followed by PET fibres. Methodological differences hinder a more comprehensive assessment of microplastic contamination across studies. Additionally, we identified some challenges which should be factored in for future studies looking at the presence of microplastics as well as other anthropogenic fibres in these large marine organisms. Overall, the findings provide first evidence of microplastics and other anthropogenic fibres not only in the intestines, but also in muscle tissues of large apex shark species. [Display omitted] • Microplastics and other anthropogenic fibres were found in four apex shark species. • Fibres were predominantly found in both intestine and muscle samples. • Cellulose-based fibres accounted for 61–82% of all fibres detected. • PET plastic fibres accounted for the majority of plastic fibres. • Challenges in methodologies and cross-study comparison were identified. [ABSTRACT FROM AUTHOR]

Biodegradable plastics have been regarded as promising candidates in the struggle against plastic pollution. However, the aging and dynamic leaching process of biodegradable and conventional plastics under photooxidation is still unclear. Herein, three types of non-biodegradable plastics (polypropylene, polyethylene, and polyethylene terephthalate), and two types of biodegradable plastics (polylactic acid and cornstarch-based plastics) were treated with 21 days of photooxidation followed by 13 days of dark conditions. Scanning electron microscopy was applied to display the morphological changes. Also, the carbonyl index, oxygen-to-carbon ratio, and contact angle were utilized to characterize the aging degree of the plastic surface. Unexpectedly, biodegradable plastics did not always display a greater aging degree than non-biodegradable plastics. Moreover, the dissolved organic carbon during the leaching process was identified using excitation-emission matrix fluorescence spectroscopy. The findings suggested that biodegradable plastics showed the potential to release more dissolved organic carbon. Particularly, the polylactic acid plastic displayed higher concentrations and more types of dissolved organic carbon release than that of conventional plastics in our experiment. This research highlights the necessity for monitoring the aging process of both biodegradable and non-biodegradable plastics and the non-negligible ecological risk of leached organic pollutants due to plastic degradation. • Aging process of biodegradable and conventional plastics under photooxidation were studied. • Biodegradable plastics did not always display greater aging degree over non-biodegradable plastics. • PLA displayed higher concentrations and more types of dissolved organic carbon. • Monitoring the aging process of both biodegradable plastics and non-biodegradable plastics is necessary. • Leached dissolved organic carbon could bring ecological risks to the already complicated plastic issues. [ABSTRACT FROM AUTHOR]