Search Results (523)

The recycling of polyethylene terephthalate (PET) is gaining increasing importance, as it enables the conversion of plastic waste into valuable raw materials and contributes to a circular economy. Recent research has primarily focused on optimizing the depolymerization step of PET glycolysis, while downstream processes often overlook what are at least equally critical downstream steps in recovering the monomer bis(2-hydroxyethyl) terephthalate (BHET). The implementation of a water-free PET glycolysis process eliminates challenges related to internal solvent and homogeneous catalyst recycling that commonly occur in conventional processes. This study, therefore, focuses on BHET crystallization and filtration as key downstream unit operations. Two nucleation strategies, gassing and seeding, were investigated and compared with experiments without a nucleation strategy. The aim was to achieve reproducible process control during crystallization and to obtain crystals with good filterability, which can be critical for subsequent steps in the product purification process. Experiments without a nucleation strategy showed poor reproducibility. In contrast, gassing and seeding improved crystallization control, particularly regarding nucleation temperature and relative crystallization yield. However, these strategies also resulted in significantly prolonged filtration times due to differences in filter cake properties. The anisotropic crystals exhibited a broad particle size distribution with a high fraction of fine particles, leading to small and heterogeneous pores in the filter cake. Limited crystal growth was identified as the main cause of the unfavorable filtration behavior. Full article

The emerging demand for water pollution control has driven a significant interest in advanced porous materials for sustainable and effective wastewater treatment technologies. Metal–organic frameworks (MOFs) have been employed as promising substrates due to their versatile properties, especially their high surface area, tunable properties, and chemical functionality. However, their practical applications are often limited by poor aqueous stability, instability during recovery, and high production costs. Lignocellulosic biomass (LCB) is an abundant, low-cost, and renewable resource, primarily composed of cellulose, hemicellulose, and lignin, offering a sustainable solution for these challenges. This review critically examines the recent advances in design and applications of LCB-MOF materials for wastewater remediation. Several synthesis strategies, including in situ growth, ex situ impregnation, and post-synthetic modification, are systematically discussed in relation to their significance in enhancing stability, recyclability, and dispersibility of MOFs. The key, structural, morphological, and physicochemical properties of these LCB-MOFs were analyzed, along with their performance in removing organic dyes and heavy metal ions. Current drawbacks in long-term stability, scalability, and real-world wastewater performance are highlighted. Overall, LCB-MOFs demonstrate a promising class of sustainable materials that align with the principles of the circular economy and green chemistry, making them ideal for next-generation wastewater remediation technologies. Full article

While aluminum (Al) continues to be a cornerstone for microelectronic interconnect technologies, its chronic tendency toward hillock growth and thermal instability necessitates a transition toward high-performance nanostructured material architectures. This research tackles these reliability bottlenecks by achieving a molecular-level integration of graphene nanoplatelets (GNPs) within Al matrices, a strategy designed to fortify structural resilience. Adopting a green chemistry approach, we synthesized Al-GNP (0.25 vol.%) composite thin films through Pulsed Laser Deposition (PLD) using precursors derived from recycled aluminum. A major obstacle—the formation of the deleterious Al₄C₃ intermetallic phase—was effectively suppressed by ensuring a homogeneous supramolecular dispersion via a specialized dual protocol (ultrasonication and magnetic stirring) during the powder metallurgy stage. Comprehensive physicochemical characterization, utilizing HR-TEM and XRD, verified the structural integrity of the multilayer GNPs (d-spacing = 4.6 Å). Furthermore, surface metrology analysis uncovered a radical shift in growth kinetics: whereas pure Al grew via a “spiky” Volmer-Weber mechanism (Sku = 31.17), the carbon-based inclusion stabilized the film evolution, tempering the kurtosis to Sku = 7.74. Analytical cross-sectional EDS confirmed both stoichiometric fidelity and the achievement of void-free Si/Pt/Al-GNP interfaces. These outcomes prove that a precise nanoscale tailoring of surface morphology via carbonaceous reinforcements significantly bolsters microstructural stamina. Consequently, these PLD-deposited composites emerge as sustainable, cutting-edge candidates for the next generation of microelectronic packaging and interfacial chemistry applications. Full article

Rising environmental concerns have intensified interest in waste valorisation and the development of sustainable, bio-based materials through green chemistry approaches. In this study, proteins extracted from waste lentil and chickpea seeds were used to develop protein-based films using a range of carboxylic acids as cross-linkers. The acids facilitated protein unfolding and promoted intermolecular interactions, allowing tunable control over mechanical strength, barrier performance, and water resistance. In addition to their structural role, the inherent bioactivity of selected carboxylic acids imparted added functionality to the resulting materials. Physical characterisation and FTIR secondary structure analysis revealed that the acid-type, plasticiser, and, in some cases, protein fraction composition influenced the final material performance. Liquid monocarboxylic acids produced cohesive and flexible films, with tensile strength ranging from ~1 to 23 MPa, with formic acid yielding the strongest films. Lactic acid and its blends improved flexibility and reduced permeability, achieving water vapour permeability (WVP) of 5.76 ± 0.7 × 10⁻¹² g m m⁻² s⁻¹ Pa⁻¹ and oxygen permeability (OP) of 5.8 ± 0.0 × 10⁻¹³ mL m m⁻² s⁻¹ Pa⁻¹ at low acid loadings. In contrast, solid di- and polycarboxylic acids tended to crystallise at higher concentrations. Citric acid was an exception, exhibiting behaviour distinct from the other solid acids and producing clear, crystal-free films with excellent flexibility, showing elongation at break (EAB) up to ~326%. Preliminary proof-of-concept application testing demonstrated the suitability of selected films for vegetable shelf-life extension for up to 17 days and for gradual lactic acid release, supporting their potential use as biodegradable cosmetic mask/patch platforms. Full article

This study investigates the hydrothermal modification of commercial titanium dioxide (TiO₂) in the presence of a natural licorice root extract (Glycyrrhiza glabra L.), serving as a stabilizing and growth-modulating agent. The experimental framework combines hydrothermal treatment in a Teflon-lined autoclave with subsequent thermal calcination to elucidate the structural, morphological, and chemical evolution of the material. The plant-based extract significantly influences particle assembly during synthesis, fostering the formation of an initial organic–inorganic hybrid system that results in enhanced morphological homogeneity compared to pristine TiO₂. Thermal analyses (TGA and DSC) demonstrated the progressive decomposition of the organic components with increasing temperature, yielding a thermally stable, predominantly inorganic material at 600 °C. Scanning Electron Microscopy (SEM) observations confirmed a more uniform particle distribution in the modified samples. X-ray diffraction (XRD) patterns corroborated that the primary crystalline phase of TiO₂ remains intact across all conditions, with structural variations limited to peak definition and long-range organization. Furthermore, FTIR spectroscopy supported the preservation of characteristic TiO₂ vibrational features while indicating a gradual depletion of weakly bound surface species following thermal treatment. In conclusion, these findings demonstrate that natural extracts can effectively function as growth-modulating agents, steering material organization without altering its intrinsic chemical properties. This approach aligns with the principles of Green Chemistry and the circular economy, highlighting the potential of renewable plant-based resources as functional additives for the sustainable processing of inorganic materials. Rather than seeking to outperform commercial benchmarks, this work establishes a viable and low-environmental-impact strategy for morphological and structural modulation. Full article

Efficient solubilization of nonpolar substances in polar solvents represents a fundamental challenge in environmental remediation, green chemistry, and separation processes. This limitation stems from the hydrophobic effect, which creates thermodynamic barriers, resulting in low intrinsic solubility and strong phase separation. This review examines the thermodynamic basis of solubilization, focusing on free-energy changes and molecular interaction mechanisms. It discusses various strategies, including surface and interface engineering, host–guest inclusion, solvent engineering, and nanostructure encapsulation, along with their practical applications. Future research directions include smart responsive materials, green solvent design theories, and precise construction of solubilization systems through multi-scale simulations. Full article

To promote green chemistry and improve the utilization of plant resources, flavonoids from Dalbergia pinnata (Lour.) Prain were extracted in this study by combining NADES (natural deep eutectic solvents) with UAE (ultrasound-assisted extraction). Among the 13 synthesized NADES, choline chloride (ChCl)–urea (NADES-13) exhibited the highest extraction rate, outperforming traditional organic solvents. The optimal conditions determined by response surface methodology (RSM) were as follows: ChCl–urea molar ratio of 1:3, moisture content of 60%, liquid-to-material ratio of 28.5 mL/g, ultrasonic extraction time of 49 min, and temperature of 62 °C. Under these conditions, the extraction rate reached 117.95 ± 5.97 mg/g, a 73.5% improvement compared with 80% EtOH extraction. The comparison of the two algorithms showed that RSM (R = 0.9981, RMSE = 0.6570) had better fitting accuracy and prediction stability under small sample conditions than MLP (R = 0.9427, RMSE = 5.261) and RF (R = 0.9431, RMSE = 5.2442). DFT (density functional theory) analysis demonstrated that hydrogen bonds, Van der Waals forces, and cation–π interactions mediate the interaction between NADES-13 and flavonoids. Ultrasonic cavitation-induced cell wall damage and the hydrogen-bond network of NADES-13 were confirmed separately by SEM (scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy). In vitro experiments showed that the extract possessed concentration-dependent antioxidant activity and strong antibacterial activity, with an inhibition rate of 96.87 ± 5.09% against Escherichia coli at a concentration of 0.04 mg/mL. In this study, a “Smart Optimization–Molecular Mechanism–Activity Verification” green extraction system was developed, which offers an efficient and environmentally friendly strategy for extracting plant bioactive components and contributes to the progress of green chemistry. Full article

Fuel cells are regarded as highly promising energy devices due to their clean and efficient energy conversion characteristics. However, their core material, platinum-based catalysts face challenges such as high cost, resource scarcity, and the high energy consumption and pollution associated with traditional synthesis methods, which contradict the green development principles of fuel cell technology. The rise of green chemistry provides a new research direction for developing environmentally friendly and cost-effective catalyst preparation routes. This review systematically summarizes recent research progress in the green synthesis of platinum-based catalysts for fuel cells, focusing on four core strategies: green solvent systems, biological reduction systems, renewable resource templates, and green energy-saving methods. It provides a detailed analysis of the principles of each method and their regulatory mechanisms on the microstructure. More importantly, this review elucidates the effects of size, morphology, and surface state on catalytic performance and establishes a structure–activity relationship linking green synthesis methods, microstructure, and catalytic performance and further discusses the regulatory mechanisms of catalyst structure, operating temperature, and electrolyte environment on electrochemical kinetic behavior. Furthermore, this article critically evaluates the advantages, limitations, and industrialization challenges of various green technologies. This review provides an important reference for the preparation and industrial application of high-performance, low-platinum, and environmentally friendly fuel cell catalysts. Full article

The concepts of “circular economy” and “sustainable chemistry” cover a range of related topics, including resource efficiency, the transition to renewable resources, as well as the choice of recycling, reusing, or recovering materials. At the middle school level, the “green message” of chemistry and the circular economy can be conveyed during regular classes or optional subjects. This paper presents an experimental study conducted with middle school students, aiming to develop ecological competencies by comparing traditional educational methods of teaching–learning–assessment with modern methods. The study was conducted on a sample of 58 lower secondary students (N = 30 in class 8A—traditional methods; N = 28 in class 8B—modern/STEM-based methods), using a quasi-experimental pre-test/post-test design using a questionnaire. The results indicated a significant improvement in students’ performance, with correct response rates increasing from 17–33% in the pre-test to over 80–100% in the post-test across most items. While both traditional and modern teaching methods improved students’ theoretical understanding of green chemistry and circular economy concepts, the modern STEM-based approach facilitated higher performance in application-oriented items, critical thinking, and real-life problem-solving tasks. The study emphasizes the importance of fostering an environmentally friendly attitude among students, encouraging a commitment to sustainability, as well as their active involvement in pollution prevention. Thus, the effectiveness of the applied educational strategies in increasing ecological awareness is underlined. Full article

The growing demand for food production has increased the pressure on soil and fertilizer use, often leading to nutrient losses, soil degradation, and environmental pollution. Green chemistry offers practical solutions to these challenges by encouraging cleaner, safer, and more efficient ways of producing and using fertilizers. This review summarizes recent advances in multi-nutrient sustainable fertilizers developed through green chemistry principles, including renewable raw materials, low-toxicity synthesis methods, and environmentally friendly delivery systems. Different approaches, such as controlled-release carriers, nano-enabled formulations, chelated nutrients, and bio-based coatings, are discussed with a focus on how they reduce nutrient losses and improve soil and plant health. The review also highlights the benefits and limitations of these technologies, gaps in current research, and the need for long-term field studies to assess their safety and effectiveness. Overall, green chemistry-guided fertilizer development shows strong potential to support sustainable agriculture by improving nutrient efficiency while reducing environmental impacts. Full article

Microwave technology is being used increasingly in polymer processing, where significant time and energy savings have been demonstrated across many systems. In this work, we first provide an overview of microwave-assisted processes involving agro-based materials, with emphasis on microwave-assisted modification reactions and extractions. A more detailed review then highlights several examples from the authors’ laboratories. For example, microwave heating has been shown to greatly accelerate the synthesis of cellulosic derivatives from cellulose and the formation of a polyurethane from a carbohydrate and a diisocyanate, while still producing polymers comparable in structure to those obtained by conventional heating. Likewise, microwave treatment can speed up pericyclic reactions involving triglycerides and cardanol, leading to products with enhanced viscosity. In extraction applications, such as recovering phenolic compounds from common beans, microwave methods can sometimes yield higher extraction efficiencies. Beyond time and energy savings, the reduced processing duration also decreases workers’ exposure to chemicals and solvents, thereby improving safety and lowering chemical hazards. Thus, microwave treatment can be considered a “green”, energy-efficient tool for many polymer reactions and processes. Full article

Formic acid (FA) has emerged as a promising liquid hydrogen storage material, yet efficient photothermal dehydrogenation catalysts with high activity and H₂ selectivity remain challenging. Herein, a polymetallic synergistic PdCu/M-ZNC (where M represents the co-doped In, Sn and Mo species) is fabricated by molten-salt-assisted pyrolysis of ZIF-8 precursors followed by metal incorporation. The unique molten salt environment effectively preserves the porous architecture of ZIF-8, enabling the secure anchoring of PdCu alloy nanoparticles onto the carbonaceous matrix enriched with M-N_x coordination sites. Under light irradiation, the PdCu alloy sites kinetically accelerated the overall adsorption and activation of FA molecules. Based on empirical observations and corroborated by the established literature, this alloying effect was inferred to facilitate the C-H bond cleavage and HCOO* desorption processes. Concurrently, the M-N_x sites act as efficient electron transfer channels, facilitating the rapid coupling of photogenerated electrons with protons (H⁺) to evolve H₂. Consequently, the optimal catalyst exhibits an enhancement in gaseous product yield (404.46 mmol/g/h) and H₂ selectivity (67.49%) at 75 °C. This work offers a catalyst design that aligns with several principles of green chemistry: it maximizes the atom utilization of precious Pd, incorporates synergistic non-precious metals within MOF-derived frameworks to enhance stability, and leverages solar energy to drive hydrogen production under mild conditions, presenting a more sustainable pathway for hydrogen release from liquid carriers. Full article

The development of efficient, sustainable, and low-cost catalysts for wastewater treatment remains a major environmental challenge. In this work, Zn-doped CuO nanostructures were successfully synthesized via a green route using Aloysia citrodora leaf extract as a natural reducing and stabilizing agent. The structural and morphological properties of the prepared catalysts were systematically characterized by XRD, Raman spectroscopy, FTIR, SEM, and EDX analyses. The results revealed the formation of highly crystalline monoclinic CuO nanoparticles, whose defect density and surface properties were significantly modified by Zn incorporation. The catalytic performance of the synthesized materials was evaluated through the heterogeneous Fenton-like degradation of Rhodamine B in aqueous solution under dark conditions. The Zn-doped CuO catalyst exhibited outstanding degradation efficiency (~99.97%) within only 30 min, using a low catalyst dosage of 15 mg and a minimal H₂O₂ amount of 25 μL. The enhanced catalytic activity is attributed to the synergistic interaction between Zn-induced lattice defects and the Cu²⁺/Cu⁺ redox cycle, which promotes efficient H₂O₂ activation and •OH radical generation. Radical scavenging experiments confirmed the dominant role of hydroxyl radicals in the degradation process. Compared with previously reported CuO-based catalysts, the present system demonstrates superior performance in terms of reaction rate, oxidant consumption, and energy efficiency. These findings highlight the potential of Zn-doped CuO synthesized via green chemistry as a promising and sustainable catalyst for advanced wastewater treatment applications. Full article

Transition towards sustainable and environmentally friendly practices within the field of chemistry and materials science has become essential in light of current environmental challenges. This review provides a comprehensive overview of the challenges and opportunities in the various steps involved in producing chitosan derivatives, with particular emphasis on eco-friendly strategies. Key methodologies for chitin isolation from diverse natural sources, chitin deacetylation, and the chemical modification of chitosan are discussed, integrating green chemistry principles and eco-efficient processes. Advances in sustainable technologies that prioritize cost-effectiveness, safety, and performance are highlighted. The importance of interdisciplinary collaboration, innovative isolation and purification strategies, the adoption of continuous-flow processes, and greener synthetic approaches, such as click chemistry, are also explored. Overall, this work supports the adoption of a holistic approach for the development of chitosan derivatives, contributing to more sustainable and environmentally responsible materials and production processes. Full article