Green Chemistry最新文献

Polyurethanes (PUs) are a versatile class of synthetic polymers, which are widely used in foams, coatings, and adhesives. The chemical composition of PUs makes them resistant to biodegradation and causes challenges in applications in which recycling is not an economically viable option, such as plant fixing clips, or tree shelters. A sustainable use in the latter applications requires PU-polymers designed for effective biodegradation with minimized ecological footprints. In this study, a proof of concept for accelerated degradation of biodegradable biocomposite PU materials has been achieved. The PU material was made from thermoplastic PUs (TPUs) and four thermostable cutinases, that were incorporated into industrially important TPUs via melt extrusion at standard TPU processing temperatures up to 200 °C. Embedded cutinases yielded a 37% enzymatic hydrolytic degradation in in vitro studies and biodegradation was accelerated up to ninefold at close to application conditions in activated sludge when compared to virgin TPU. Cutinase-accelerated TPU degradation is a step forward towards a responsible end-of-life waste management within a circular PU economy.

The rapid growth of biogas production and lithium-ion battery (LIB) deployment has led to two urgent challenges: the environmental burden of excess biogas residues and the sustainable recycling of spent LIB cathodes. In this work, a novel chemical looping phase separation (CLPS) process is proposed, using pretreated cathode materials as oxygen carriers, which react with the reducing gases produced by the pyrolysis of biogas residues, enabling simultaneous production of high-quality syngas and selective separation of valuable metals. Mechanistically, reduction proceeds through a cascade of cobalt valence changes coupled to oxygen-vacancy formation and outward migration of lattice oxygen, the resulting electronic-ionic reorganization destabilizes the layered Li–O–Co framework, drives Li⁺ efflux to the gas–solid interface, and promotes in situ stabilization of lithium as Li₂CO₃via reaction with CO₂. Kinetic studies using the Flynn–Wall–Ozawa model demonstrated distinct activation energy regimes, indicating transitions from surface adsorption to lattice oxygen participation. Optimal conditions (900 °C, 1.5 h) achieved recovery efficiencies of 94.3% for lithium and 98.5% for cobalt, and the regenerated lithium carbonate exhibited a high purity of 99.76%. An economic and environmental assessment based on the EverBatt model showed that CLPS reduces energy consumption to 29.5% of the hydrometallurgical route and lowers greenhouse gas emissions compared with both pyro- and hydrometallurgical processes. Moreover, CLPS exhibited the lowest overall cost and generated a projected profit of $20.5 per kilogram of recovered LCO batteries. This study shows that integrating biomass pyrolysis with oxygen-carrier phase separation enables sustainable, low-carbon, and cost-effective LIB recycling while valorizing agricultural residues.

The escalating environmental crisis and the pursuit of carbon neutrality have driven the development of bio-based polymers as sustainable alternatives to petroleum-derived materials. Flexible electronics require elastomers that integrate mechanical flexibility, processability, and environmental sustainability. Bio-based polyurethanes (BPUs) meet these requirements through strategic molecular designs integrating renewable feedstocks with functional modifications. This review summarizes modification strategies for BPUs, focusing on polyol and isocyanate tailoring, filler incorporation, polymer blending, and surface modification. Their applications in flexible sensors, wearable devices, energy storage, and electronic packaging are highlighted, demonstrating the multifunctional potential of BPUs in next-generation electronics. Challenges including limited electrical and thermal stability, narrow processing windows, and scalability issues are discussed. Future research directions emphasize advanced molecular design, hybrid modification systems, and innovative processing technologies to optimize BPU performance. This review provides theoretical and technological insights for developing sustainable, high-performance materials for flexible electronics.

Wilforic acid C is the key precursor in the biosynthesis of celastrol. The microbial production of triterpenoids, including wilforic acid C, is often hindered by limited availability of the necessary precursor due to the compartmentalization of acetyl-CoA metabolism. In this study, we designed a decompartmentalization strategy to enhance wilforic acid C biosynthesis in Saccharomyces cerevisiae by redirecting peroxisomal acetyl-CoA to the cytosol. It was achieved by manipulating the glyoxylate cycle and introducing Aspergillus nidulans ATP-citrate lyase (AnACL), which enabled an efficient supply of cytosolic acetyl-CoA. Optimization of the synthetic pathway and semi-rational design of ThCYP712K1 proteins further boosted production. Additionally, lipid droplet expansion and NADPH regeneration modules were integrated to improve overall metabolic flux. The resulting engineered strain LAC168 produced 263.55 mg L⁻¹ wilforic acid C in shake-flask culture, and reached 584.78 mg L⁻¹ in a 10 L bioreactor. This study offers a generalizable strategy for cytosolic acetyl-CoA supply and acetyl-CoA-derived chemicals production and represents the highest reported titer of wilforic acid C to date.

The depolymerization of plastics (e.g., PET and nylon) is of great significance to the polymer circular economy. Organic solvents (OSs) often play an important role in plastic recycling by swelling and dissolving polymers. In this study, we mimicked the swelling effect of OSs by redesigning the substrate access channel of nylonase to accelerate the depolymerization of nylon. In detail, eight OSs were evaluated and toluene showed the best swelling effect on nylon 6 (PA6). The key residues in the substrate access channel (loop88–93, loop219–222, and loop300–305) of nylonase were selected and substituted with aromatic amino acids. Multiplex PCR was used for smart library generation. After screening and rescreening, the final variant NylC-V3 (A91W/P220W/D304Y) with improved specific activity (18.7-fold) and thermostability (T_m value: increased by 3.9 °C) was obtained compared to the wild type (WT). Molecular dynamics simulations provided a mechanistic explanation for the enhanced performance of the NylC-V3 variant. The strategic incorporation of aromatic residues strengthened the interactions between adjacent subunits, increasing the structural rigidity of the enzyme. The D304Y substitution induced a steric rearrangement that widened the substrate access channel, thereby facilitating deeper substrate binding. Concurrently, the A91W substitution functioned as a molecular clasp utilizing hydrophobic forces and cation–π interactions from its indole ring to securely lock the substrate in a catalytically optimal conformation. This study provides proof of principle that mimicking the functional groups of OSs in nylon degrading enzymes accelerates depolymerization, providing a biocatalytic solution for developing environmentally friendly plastic recycling technology.

A natural deep eutectic solvent (DES), consisting of cysteine, lactic acid and 5 wt% water, is developed for the recovery of valuable metals from spent lithium-ion batteries. The DES integrates multiple functions of acidolysis, reduction and selective precipitation into one system. Under mild conditions, this DES completely dissolves LiCoO₂ (LCO), achieving direct cobalt recovery and complete lithium leaching. The leaching mechanism is revealed by a combination of experimental characterization and theoretical calculations. The LA first provides protons to drive the displacement of Li⁺ and the dissolution of Co from the LCO. Then Co³⁺ is reduced to Co²⁺ through the dimerization of the electron-donating group (–SH) in Cys, during which Cys itself is oxidized into cystine (CySSCy). Finally, the coordinated action of LA and CySSCy immobilize Co²⁺ as a pink precipitate. DFT calculations further clarify the micro-scale mechanism by analyzing the transition states and energy barriers for Li/Co removal during proton attack, tracing the pathway of DES-mediated Co reduction, and comparing the binding energies and band gaps among different metal-coordination complexes. Particularly, this Cys–LA DES exhibits broad adaptability, directly recovering Co (88%), Mn (98%), and Ni/Co/Mn (nearly 99%) from spent LCO (SLCO), spent lithium manganate (SLMO), and spent ternary cathode (SNCM) via precipitation, while retaining Li in the leachate. Without hazardous reagents and complex steps, the Cys–LA DES realizes the one-step selective recovery of Li and transition metals from waste batteries. This process presents low environmental burden in the life cycle assessment covering 18 indicators, successfully balancing economic and environmental objectives.

The construction of S-scheme heterojunctions can greatly improve the catalytic performance of photocatalysts. In this study, LZU-1 was carboxylated and then combined with Sb₂S₃ to construct an S-scheme Sb₂S₃@COF-LC(SSLC) heterojunction with excellent photocatalytic properties, in which the H atom on the carboxyl group is substituted by Sb to form a stable Sb–O–C bond. COF-LC contains a specific quantity of nucleophilic carboxyl groups that enhance the availability of effective active sites, and the enhanced interfacial contact stability between Sb₂S₃ and COF-LC greatly improves the charge transfer efficiency. Under the synergistic action of multiple free radicals, Sb₂S₃@COF-LC-2 showed photocatalytic degradation of different pollutants (MB and MO), and the degradation rates reached 93.15% and 94.52%, respectively. It is worth mentioning that the CO formation rate is as high as 831.74 μmol g⁻¹ h⁻¹, and the Sb₂S₃@COF-LC-2 heterojunction has good cycling stability. Additionally, density functional theory (DFT) analyses reveal the charge-transfer mechanism of the S-scheme heterojunction. In this study, the interfacial photocarrier transfer and space charge separation of antimony-based heterojunctions were promoted by post-treatment of COF LZU-1 and substitution of hydrogen atoms on carboxyl groups with metal elements, which has the potential to be extended to the construction of other heterojunction photocatalysts.

Supercapacitors are one of the most promising energy storage systems owing to their outstanding power density, reliable cycling life, ultra-fast charging rate, and wide range of operational conditions. Porous carbon materials demonstrate significant potential as electrode materials in supercapacitors because of their low cost, high surface area, excellent conductivity, and good electrochemical stability. This article systematically reviews the past five years of research progress regarding the application of food waste-derived porous carbon materials in supercapacitors, including carbonization processes, activation strategies, and heteroatom-doping methods. Specifically, this article examines the effect of different carbonization processes on material pore structure, surface area, and conductivity, with particular emphasis on the role of activation techniques and heteroatom doping in enhancing the quality and electrochemical performance of carbon materials during modification. In conclusion, this article outlines current technical challenges and suggests future research directions to advance the practical application and industrialization of food waste-derived porous carbon in supercapacitors.

C–H bond functionalization via (photoinduced) Hydrogen Atom Transfer (HAT) catalysis is emerging as a powerful eco-sustainable tool for sugar editing, albeit challenges in governing the reactivity patterns and site-selectivity remain. Quite surprisingly, no functionalization of the C-5 position in pyranoses via C–H activation has been described to date. We herein report the development of an efficient methodology for the site-selective and stereoselective alkylation of position 5 of β-fucosides by means of decatungstate photocatalyzed C(sp³)–C(sp³) bond formation. The experimental work is accompanied by spectroscopical studies based on laser flash photolysis and supplemented by computational simulations, offering insights into the reasons underlying the selectivity profile of the reported transformations.

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