Search Results (569)

The increasing contamination of agricultural soils with microplastics (MPs) represents an emerging environmental challenge. While conventional plastics such as low-density polyethylene (LDPE) persist for decades, biodegradable alternatives like polybutylene adipate terephthalate (PBAT) are promoted as eco-friendly solutions. However, their environmental safety for crop plants and soil microbiota remains poorly understood. In this study, we evaluated the effects of LDPE and PBAT microplastics (1% w/w) on the growth and physiological state of winter wheat (Triticum aestivum L.) cultivated in soil, either alone or in combination with the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and the plant-beneficial fungus Trichoderma citrinoviride. Growth parameters (root and shoot length and mass), germination index, chlorophyll content, antioxidant enzyme activity, and lipidomic profiles of wheat were assessed. PBAT stimulated biomass accumulation but simultaneously triggered oxidative stress and remodeled membrane phospholipids, indicating physiological disturbance. T. citrinoviride enhanced wheat growth and mitigated oxidative stress under non-contaminated conditions; however, its beneficial effect was generally suppressed in the presence of PBAT and/or 2,4-D. The results suggest that, despite its biodegradability, PBAT may pose a higher phytotoxic potential than conventional LDPE, particularly by altering oxidative balance and membrane lipid composition in wheat. Full article

With the growing demand for eco-friendly food packaging, poly(butylene adipate-co-terephthalate) (PBAT)/polylactic acid (PLA) composite films have emerged as promising biodegradable alternatives, but their inherent limitations (e.g., poor antioxidant capacity, weak UV stability, and insufficient antimicrobial activity) hinder practical applications. This study aimed to address these drawbacks by incorporating Rosmarinus officinalis L. extract (RM) as a natural multifunctional additive. PBAT/PLA/RM blend films with RM concentrations of 0.1%, 0.3%, 0.5%, and 1% were fabricated via melt extrusion and blown film processing. Key characterizations were conducted to evaluate thermal stability, mechanical properties, morphology, antioxidant activity, UV-shielding performance, antimicrobial efficacy, and biodegradability. The results showed that RM significantly enhanced the antioxidant capacity of the films, with the highest DPPH radical scavenging activity achieved at 0.3% RM. UV-blocking performance improved incrementally with increasing RM concentration, and films containing ≥0.5% RM filtered over 90% of UVA and UVB radiation. All composite films met biodegradability standards, with over 90% degradation observed after 240 days of composting, though RM prolonged the initial degradation stage by inhibiting early microbial activity. However, the antimicrobial effect of RM was limited, and concentrations exceeding 1% caused film stickiness, impeding processing. This work demonstrates that RM is a viable natural additive for functionalizing PBAT/PLA films, offering enhanced antioxidant and UV-shielding properties while maintaining biodegradability, thus providing a promising solution for sustainable food packaging. Full article

This study assessed the effect of slicer-made interlocking joints on 3D printed sandwich panels manufactured through fused filament fabrication (FFF) in terms of flexural properties and energy absorption. Composites were prepared with thermoplastic polyurethane (TPU) as the core material and polyamide (PA), polylactic acid (PLA), polyethylene terephthalate (PET) as skin materials for each of the three composites, respectively. In order to assess the implications of internal geometry, 3D printing was done on five infill topologies (Cross-3D, Grid, Gyroid, Line and Honeycomb) at 20% density. All samples had 20% core density and underwent three point bending testing for flexural testing. It was noted that the Grid and Gyroid cores had the best performance in terms of maximum load capacity based on stretch-dominated behavior while Cross-3D and Honeycomb had lower strengths but stable moments during the bending process. Since Cross-3D topology offered the lowest deflection, it was selected for further experiments with slicer added interlocks at the face–core interface. This study revealed the most notable improvements as gains of up to 15% in peak load, 48% in maximum deflection, and 51% in energy absorption compared with the non-interlocked designs. The PET/TPU interlocked demonstrated the best performance in terms of the energy absorption (2.45 J/mm³) and peak load (272.6 N). In contrast, the PA/TPU interlocked exhibited the best flexibility and ductility with a mid-span deformation of 21.34 mm. These results confirm that slicer-generated interlocking interfaces lead to better load capacity and energy dissipation, providing a lightweight, damage-tolerant design approach for additively manufactured sandwich beams. Full article

The synthesis of two novel materials, aluminum-based MOF (Al-MOF) and cellulose-modified MOF (Al-MOF@C), as adsorbents is presented. Al-MOF was synthesized from aluminum sec-butoxide and terephthalic acid in a 1:1 molar ratio using a solvothermal method. Al-MOF@C was synthesized under similar solvothermal conditions by reacting environmentally friendly starting materials such as aluminum sec-butoxide, terephthalic acid, and cellulose in a 1:1:1 molar ratio. The synthesized materials’ structural, morphological, and surface properties were thoroughly characterized using XRD, SEM, EDS, BET (with specific surface areas calculated as 563.9 m²/g for Al-MOF and 487.1 m²/g for Al-MOF@C), and FTIR analyses. Then they were utilized in the water treatment process to remove the highly toxic anionic Congo red (CR) dye. Dye adsorption studies were carried out using UV-Vis spectroscopy. Batch adsorption experiments showed that Al-MOF and Al-MOF@C materials adsorbed CR dye with removal efficiencies of 95.06% and 91.79% in just 4 min, respectively. The equilibrium adsorption isotherm data for Al-MOF and Al-MOF@C were best fitted by the Langmuir model, and the calculated maximum adsorption capacities were 80.64 mg/g and 68.96 mg/g, respectively. The adsorption kinetics exhibited an excellent correlation with the pseudo-second-order model (R² = 0.9975 for Al-MOF and R² = 0.9936 for Al-MOF@C). Measurements taken after the adsorption process showed that Al-MOFs synthesized using environmentally friendly chemicals retained their stable chemical structure in aqueous environments and thus did not create secondary pollution in the environment, highlighting the importance of this study. Chemically stable, thermodynamically favorable, and highly reusable Al-MOF adsorbents offer a promising solution for the advanced environmental remediation of hazardous dye contaminants. Full article

Nanoplastics (NPs), emerging contaminants originating from the degradation of larger plastics, have raised significant environmental and health concerns due to their ability to penetrate biological barriers and disturb cellular homeostasis. Exposure to NPs has been shown to induce oxidative stress, mitochondrial dysfunction, and inflammatory responses in both mammalian and aquatic systems, ultimately leading to metabolic imbalance. Metabolomics, a comprehensive analytical approach focusing on small-molecule metabolites, provides a direct reflection of these biochemical alterations and offers critical insights into the mechanisms underlying NP-induced toxicity. This review summarizes recent metabolomic studies investigating nanoplastic toxicity across mammalian and aquatic organisms, highlighting commonly perturbed pathways such as lipid metabolism, arachidonic acid metabolism, the tricarboxylic acid (TCA) cycle, and amino acid metabolism. These disruptions indicate that NPs impair energy production, lipid regulation, and redox balance. In mammals, polystyrene and polyethylene terephthalate nanoplastics have been shown to alter hepatic and intestinal metabolism and induce oxidative and inflammatory stress, while in aquatic species, similar metabolic disturbances occur in the gills, liver, and brain. Collectively, the evidence emphasizes metabolomics as a powerful approach for elucidating the molecular basis of nanoplastic toxicity and suggests that integration with other omics techniques is essential for comprehensive risk assessment and mechanistic understanding. Full article

This study presents the synthesis and characterization of novel kaolinite niobium and kaolinite titanium niobium nanocomposites and their application as heterogeneous photocatalysts. Utilizing a hydrolytic sol–gel route, we combined kaolinite with isopropyl alcohol, acetic acid, titanium (IV) isopropoxide, and ammonium niobium oxalate, followed by heat treatment at 400, 700, and 1000 °C. X-ray diffraction confirmed the retention of kaolinite’s characteristic reflections, with basal spacings indicating the presence of semiconductors on the external surfaces and edges. Heating treatment not allowing the crystallization of anatase until 1000 °C reveals that Nb⁵⁺ could inhibit the transition to titanium crystalline phases (anatase and rutile). The bandgap energies decreased with clay mineral support, averaging 2.50 eV, and absorbing up to 650 nm. The model reaction of terephthalic acid hydroxylation accomplished by photoluminescence spectroscopy demonstrated that KaolTiNb400 presented a higher rate of *OH production, achieving 591 mmol L⁻¹ min⁻¹ compared to pure KaolNb400 173 mmol L⁻¹ min⁻¹. Photodegradation studies revealed significant photocatalytic activity, with the KaolTiNb400 nanocomposite achieving the highest efficiency, demonstrating 90% removal of methylene blue (combining adsorption and degradation) after 24 h of UV light irradiation. These materials also exhibited promising results for the degradation of the antibiotics Triaxon^® (40%) and Loratadine (8%), highlighting their potential for organic pollutants’ removal. In both cases the presence of byproducts is detected. Full article

Transparent conductive materials (TCMs) are essential for optoelectrical devices ranging from smart windows and defogging films to soft sensors, display technologies, and flexible electronics. Materials, such as indium tin oxide (ITO) and silver nanowires (AgNWs), are commonly used and offer high optical transmittance and electrical conductivity, but suffer from brittleness, oxidation susceptibility, and require high-cost materials, greatly limiting their use. Carbon nanotube (CNT) networks provide a promising alternative, featuring mechanical compliance, chemical robustness, and scalable processing. This study reports an aqueous ink formulation composed of ultra-long mix-walled carbon nanotubes (UL-CNTs), compatible with the flow coating process, yielding uniform transparent conductive films (TCFs) on polyethylene terephthalate (PET), glass, and polycarbonate (PC). The resulting films exhibit tunable transmittance (85%–88% for single layers; ~57% for three layers at 550 nm) and sheet resistance of 7.5 kΩ/□ to 1.5 kΩ/□ accordingly. These TCFs maintain stable sheet resistance for over 5000 bending cycles and show excellent mechanical durability with negligible effects on heating performance. Post-deposition treatments, including nitric acid vapor doping or flash photonic heating (FPH), further reduce sheet resistance by up to 80% (7.5 kΩ/□ to 1.2 kΩ/□). X-ray photoelectron spectroscopy (XPS) results in reduced surface oxygen content after FPH. The photonic-treated heaters attain ~100 °C within 20 s at 100 V. This scalable, water-based process provides a pathway toward low-cost, flexible, and stretchable devices in a variety of fields, including printed electronics, optoelectronics, and thermal actuators. Full article

The increasing use of biodegradable plastics derived from renewable sources (PLA, PHB, PBAT, and others) in the packaging industry raises controversies and risks related to potentially integrating these plastics into municipal waste streams, which may significantly hinder future recycling efforts. This publication addresses this issue by investigating a selected bio-based and biodegradable commercial mixture of poly(lactic acid) and poly(butylene adipate terephthalate) (PLA/PBAT), referred to as (BIO), in blends with polypropylene (PP) and polystyrene (PS). The blends were prepared with three different mass contents of 1, 5, and 10 wt.% using (PP) and (PS) as base materials. The effects of introducing biodegradable and bio-based plastics into municipal waste streams (PCR—Post-Consumer Recycling), which typically contain polypropylene, various grades of polyethylene, and polystyrene, remain unknown. The purpose of the study was to assess the consequences of contaminating municipal waste destined for recycling (using PP and PS as examples) with small amounts (between 1 and 10%) of BIO plastics. The designed experiment and the obtained results simulate the expected presence of BIO contamination in future PP and PS recyclates. The prepared mixtures were subjected to injection molding to produce test specimens, which were then analyzed for changes in their physical properties such as tensile strength, impact strength and hardness. Thermal properties were assessed using Differential Scanning Calorimetry (DSC), while dynamic properties were analyzed at variable temperatures using Dynamic Mechanical Thermal Analysis (DMTA). The tests provided insights into how the addition of selected, but insignificant ratios (of 1 to 10%) of biopolymers affects the properties of (PP) and (PS) compared to materials without content of biopolymers. The conducted tests of mechanical properties (static and dynamic) and thermomechanical properties have shown that the change in the properties of the mixture depends not only on the amount of biodegradable polymer but also on the nature of the load. It would be advisable to analyze mechanical properties in relation to the duration of the load; therefore, a long-term load analysis is necessary. For dynamic tests, a decrease in impact strength was demonstrated with increasing biodegradable polymer content in the produced mixtures. Similar behavior was recorded for hardness measurements. The results underscore the need for continued research, given the valuable findings for processors and the advancement of mechanical recycling technologies. Full article

Chemical recycling is one of the most prominent techniques that enables monomer recovery for plastics like polyethylene terephthalate (PET), which ultimately reduces the dependency on virgin material inputs. In this study, 40 deep eutectic solvents (DESs) were pre-screened using COSMO-RS to identify the best solvent for chemical recycling of PET. Quantitative evaluation was performed based on activity coefficients (γ) to assess solute–solvent interactions. Qualitatively, the sigma profile and sigma potential were analyzed to understand the polarity and affinity of each DES component. This study experimentally validated the two top-performing DESs based on COSMO-RS output. The DES formed by combining thymol with phenol (Thy/Phe (1:2)) achieved 100% PET degradation and 94.5% terephthalic acid (TPA) recovery from post-consumer PET in just 25 min. The rapid dissolution of PET into molten state accelerated the hydrolysis reaction, leading to efficient monomer recovery. The second DES, tetrabutylammonium bromide/sulfolane (TBABr/Sulf (1:7)), attained 93.7% PET degradation and 94% TPA recovery. The PET-to-solvent ratio used in this study was 0.75, while the PET-to-DES ratio in the mixture was only 0.15, the lowest reported for DES-assisted hydrolysis to date. Characterization of the recycled TPA confirmed a purity level comparable to its virgin grade, as verified by FT−IR analysis. This study presents two important outcomes. First, the use of COSMO-RS for DES selection provides a strong rationale for solvent choice in targeted reactions and processes. Second, the use of appropriate DES in this study helps reduce key parameters associated with depolymerisation process, including reaction time, temperature, and catalyst consumption. Full article

Esterases are ubiquitous enzymes found in all living organisms, including animals, plants, and microorganisms. They are involved in several biological processes, including the synthesis and breakdown of biomolecules, such as nucleic acids, lipids, and esters; phosphorus metabolism; detoxification of natural and artificial toxicants; polymer breakdown and synthesis; remodeling; and cell signaling. The present review focuses on the most industrially important esterases, namely lipases, phospholipases, cutinases, and polyethylene terephthalate hydrolases (PETases). Esterases are widely used in industrial and biotechnological applications. Notably, the biotechnological production of esters, including methyl acetate, ethyl acetate, vinyl acetate, polyvinyl acetate, and ethyl lactate, as an alternative to chemical production, represents a multi-billion-dollar industry. Currently, most enzymes (>75%) used in industrial processes are hydrolytic. Among them, lipases and phospholipases are primarily used for lipid modification. Lipases are the third most commercialized enzymes after proteases and carboxyhydrases, and their production is steadily increasing, currently representing over one-fifth of the global enzyme market. Esterases, particularly lipases, phospholipases, and cutinases, are employed in cosmetics, food, lubricants, pharmaceuticals, paints, detergents, paper, and biodiesel, among other industries. Overall, biotechnological production using enzymes is gaining global traction owing to its environmental benefits, high yields, and efficiency, aligning with green economy principles. Full article

Polyethylene terephthalate (PET) is widely used, yet the accumulation of its waste poses serious environmental challenges, making efficient recycling essential. PET glycolysis using EG as a solvent has emerged as a green recycling strategy. In this study, a cyclic alkylamino carbene copper (CAAC-Cu) complex was prepared as a catalyst for PET glycolysis. Under optimized conditions (160 °C, 90 min, catalyst amount 3 wt%, and PET/EG = 1:4.), PET conversion reached 98.2%, the selectivity toward BHET was 88.1%, and the yield was 86.5%. Kinetic analysis indicated that the glycolysis follows first-order kinetics with an activation energy of 98.7 kJ mol⁻¹. In addition, the catalyst can be recovered together with excess EG, and after multiple recycles, PET degradation remained above 95% and BHET yield remained above 80%. A possible mechanism has also been proposed: Cu acts as a Lewis acid coordinating to the carbonyl oxygen of PET, facilitating ester bond activation, while the amino-carbene forms hydrogen bonds with EG, assisting bond cleavage in a Brønsted-base manner. This catalytic system provides a novel and efficient approach for the green, high-performance glycolysis of PET. Full article

The technology of 3D printing has become one of the most effective methods of creating various parts, such as those used for fast prototyping. The most important aspect of 3D printing is the selection and application of the appropriate material, also known as filament. The current review concerns mainly the description of the mechanical and physical properties of the different filaments and the possibilities of improving those properties. The review begins with a short description of the development of 3D printing technology. Next, the basic characteristics of thermoplastics used in the fused filament fabrication (FFF) are discussed, namely polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate glycol (PETG). According to modern concepts, the printed parts can be reinforced with the use of different kinds of fibers, namely synthetic fibers (carbon, glass, aramid) or natural fibers (wood, flax, hemp, jute). Thus, the impact of such a reinforcement on the performance of FFF composites is also presented. The current review, unlike other works, primarily addresses the problem of the aging of parts made from the thermoplastics above. Environmental conditions, including UV radiation, can drastically reduce the physical and mechanical properties of printed elements. Moreover, the current review contains a detailed discussion about the influence of the different fibers on the final mechanical properties of the printed elements. Generally, the synthetic fibers improve the mechanical performance, with documented increases in tensile modulus reaching, for instance, 700% for carbon-fiber-reinforced ABS or over 15-fold for continuous aramid composites, enabling their use in functional, load-bearing components. In contrast, the natural ones could even decrease the stiffness and strength (e.g., wood–plastic composites), or, as in the case of flax, significantly increase stiffness (by 88–121%) while offering a sustainable, lightweight alternative for non-structural applications. Full article

The accumulation of polyethylene terephthalate (PET) in the environment demands efficient microbial strategies for its degradation. This study evaluates the biodegradation potential of Schizophyllum commune BNT39 toward bis(2-hydroxyethyl) terephthalate (BHET), a major PET intermediate, and PET itself. Clear halos on BHET-agar plates indicated extracellular hydrolytic activity. In liquid culture, thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analyses revealed a three-phase degradation profile characterized by rapid BHET hydrolysis, transient dimer accumulation, and subsequent conversion to terephthalic acid (TPA). BHET was reduced by approximately 96% within seven days, while TPA accumulation reached 0.8 mg/mL after 30 days of incubation. Although PET degradation was limited, TPA was consistently detected as the principal product, with no BHET or MHET intermediates. To explore strategies for enhancing enzymatic activity, apple-derived cutin, PET, BHET, and polycaprolactone (PCL) were tested as inducers. Cutin markedly stimulated extracellular enzyme production, suggesting activation of cutinase-like enzymes. Overall, S. commune BNT39 demonstrates the ability to transform PET-related substrates, with cutin emerging as a promising natural stimulant to enhance enzymatic depolymerization. Future studies should focus on enzyme purification, activity profiling, and reaction optimization near PET’s glass transition temperature, where the polymer becomes more accessible for enzymatic attack. Full article

This study addresses the critical issue of environmental pollution from plastic waste by investigating an effective chemical recycling method for polyethylene terephthalate (PET) via neutral catalytic hydrolysis. We utilized a recoverable and regenerable composite catalyst based on cracking zeolite and γ-Al₂O₃, which possesses both Brønsted and Lewis acidic sites that facilitate the depolymerization of PET into its constituent monomers, terephthalic acid (TPA) and ethylene glycol (EG). This investigation reveals that the catalytic performance is strongly dependent on the total acid site concentration and the specific nature of these sites. A key finding is that a balanced acidic profile with a high proportion of Brønsted acid sites is crucial for enhancing PET hydrolysis attributed to a significant decrease in the activation energy of the reaction. The experiments were conducted in a stirred stainless-steel autoclave reactor, where key parameters such as temperature (210–230 °C), the PET-to-water ratio (1:2 to 1:5), and reaction time were systematically varied. Under optimal conditions of 210 °C and a 6 h reaction time, the process achieved near-complete PET depolymerization (99.5%) and a high TPA yield (90.24%). The catalyst demonstrated remarkable recyclability, maintained its activity over multiple cycles and was easily regenerated. Furthermore, the recovered TPA was of high quality, with a purity of 98.74% as confirmed by HPLC, and exhibited a melt crystallization temperature 14 °C lower than that of the commercial standard. These results not only demonstrate the efficiency and sustainability of neutral catalytic hydrolysis using zeolite/alumina composites but also provide valuable insights for designing advanced catalysts with tunable acidic properties. By demonstrating the importance of tuning acidic properties, specifically the balance between Brønsted and Lewis sites, this work lays a foundation for developing more effective catalysts that can advance circular economy goals for PET recycling. Full article

Oxadiazoles, nitrogen-containing heterocycles, are attracting interest due to their promising biological activities. This study focuses on the synthesis of oxadiazole derivatives from functionalized intermediates derived from terephthalic acid, a versatile and readily available aromatic precursor widely used for the construction of nitrogen heterocycles and advanced organic structures. Different synthetic approaches were explored to evaluate the feasibility of these processes. Full article