Sustainable Materials and Technologies最新文献

Globally, vast amount of food-derived waste is generated including residues from fruit processing, which requires innovative strategies to avoid problematic disposal of useful resources. Orange peels contain a variety of valuable compounds such as limonene, enzymes, and carbohydrates that exhibit interesting properties for various applications. In this work, a biorefinery concept is presented to generate versatile bioproducts from orange peel waste. First, limonene and peroxidase enzymes were extracted from orange peels by solvent extraction and three phase partitioning, respectively. The remaining solids, containing mainly cellulose, were enzymatically hydrolyzed, and soluble monosaccharides converted into lactic acid (LA) by Weizmannia coagulans and the biopolyester polyhydroxybutyrate (P(3HB)) by Priestia megaterium. 8 g L⁻¹ limonene and peroxidases with remarkable specific activity of 426 U mg⁻¹ were extracted. Utilization of the sugars in batch fermentations resulted in a LA concentration of 17 g L⁻¹ as well as a P(3HB) content up to 43 % in cell dry weight without the need for further medium components. By combining these bioproducts, fully biobased polymer blend films of P(3HB) with PLA and limonene as plasticizer were successfully fabricated by thermoplastic processing, i.e., extrusion. In conclusion, the tested concept has shown very promising results and thereby emphasize the potential of the presented valorization strategies for orange peel waste.

Aqueous zinc-ion batteries (AZIBs) are gaining rising popularity as potential energy storage solutions for large-scale renewable energy, attributed to their affordable pricing and inherent safety features. The reversible capacity of AZIBs, which is crucial for their cycle performance, is significantly influenced by the choice of cathode material, with Na₃V₂(PO₄)₃ standing out as promising candidates for their large 3D transport channels and rapid kinetics. However, they suffer from rapid degradation caused by low structural stability during the charge-discharge process. In this work, we researched the electrochemical performance of cathode materials by employing a sol-gel preparation for Mn-doped Na_3-xV_2-xMn_x(PO₄)₃/rGO (x = 0, 0.05, 0.1), in which graphene oxides (rGO) were introduced as carbon sources. It is identified that the Mn doping exerts a beneficial influence to enhance stability of the structure. The Mn0.05-NVP/rGO material, optimized for performance, exhibits a specific capacity of 106.3 mAh·g⁻¹ with a discharge plateau at 1.3 V at a current density of 100 mA·g⁻¹, which corresponds to an energy density of 134.7 Wh·kg⁻¹. Particularly, the addition of Mn enhances cycling performance, leading to a remarkable capacity retention rate of 75.3 % even after 100 cycles. This work confirms the feasibility using NASICON-type cathodes and offers valuable perceptions into the advancement of cathode materials in AZIBs.

The traditional Fenton process has two issues that hinder its further application and promotion. One is the generation of large amounts of iron sludge. The other is the safe storage and transport of explosive H₂O₂. The problems could be solved by accelerating to regenerate Fe(II) and realizing to self-generate H₂O₂. The key to the solution lies in the use of reducing active hydrogen [H] to supply electrons. The effect of different loading methods of Pd⁰ nanoparticles (NPs), active centres for [H] generation, on the catalytic performance is unknown. Herein, the Pd/UiO-66(Zr) (Pd⁰ NPs loaded on the surface of UiO-66(Zr)) and Pd@UiO-66(Zr) (Pd⁰ NPs confined into the pores of UiO-66(Zr)) were synthesized. It confirmed that the [H] could be used to promote to regenerate Fe(II) and self-generate H₂O₂. Using only a trace amount of ferrous (25 μM) and without H₂O₂, the trimethoprim (20 mg·L⁻¹) could be thoroughly removed within 90 min. Moreover, the stability of Pd@UiO-66(Zr) was slightly superior to that of Pd/UiO-66(Zr) because of the confinement effect of pore wall on Pd⁰ NPs, as well as the interception effect on the intermediate products that can be complexed with Pd⁰ NPs.

Harvesting energy from vibrations using piezoelectric mechanism has attracted much attention for powering wireless sensors over the past decade. This paper proposes a tunable pendulum-like piezoelectric energy harvester for multidirectional vibration (TP-PVEH) to enhance the power generation characteristic, durability, and environmental adaptability of energy harvester. Unlike traditional cantilevered piezoelectric vibration energy harvesters (PVEHs), which typically lowered working frequencies by adding the weight of proof mass at the end of beam or reshaping beam, TP-PVEH employed a pendulum to harness low-frequency vibrations. Moreover, in contrast to typical pendulum-like PVEHs, the pendulum in this design was not mounted at the end of beam but was attached to a radial spherical plain bearing (RSPB) structure, which avoided the irreversible beam damage caused by gravitational force. TP-PVEH utilized simple-pendulum-induced RSPB motion to smoothly pluck piezoelectric beams, subjecting the piezoelectric beams to unidirectional compressive stress only. Meanwhile, the RSPB structure's capability to facilitate multidirectional rotation enabled TP-PVEH to efficiently capture energy from various directions. Theoretical analysis, numerical analysis and experiment tests were conducted to validate the design and examine how excitation and structural parameters influenced on the output performance of TP-PVEH. The results demonstrated that the excitation amplitude, excitation angle, proof mass, and mass distance brought significant effects on the output characteristic of TP-PVEH. The working frequency, output voltage and power could be efficiently tuned by the abovementioned parameters. With an excitation amplitude of 3 mm, TP-PVEH achieved an optimal output power of 9.81 mW and an output power density of 11.37 μW/mm³, operating with a load resistance of 200 kΩ at a frequency of 12.5 Hz.TP-PVEH could power 100 blue LEDs and a calculator. Additionally, the ability of TP-PVEH to charge capacitors further demonstrated its practical power supply capabilities.

Graphene oxide (GO) exhibits great potential in various fields such as catalysis, wastewater treatment, and energy storage. However, traditional top-down GO preparation methods based on graphite exfoliation often suffer from high energy consumption and inevitably environmental pollution. In this work, an environmentally benign and low-voltage electrochemical exfoliation approach to fabricate nanoscale GO employing carbon fiber-based materials as the precursor using phosphate was proposed. Under neutral phosphate electrolyte, bilayer graphene oxide with a lateral size of ∼500 nm, thickness of ∼1.5 nm, and C/O ratio of 2.96 could be obtained via a constant potential process. By adjusting the pH to 12 to intensify the exfoliation reaction, the lateral size of the graphene oxide was controllable, decreasing to ∼50 nm, while the C/O ratio decreased to 0.9. Due to the further decrease in C/O ratio, the thickness increased slightly to 2–3 nm. The exfoliation potential (1.6–2.5 V vs. Ag/AgCl) and electrolyte concentration (50–500 mM) had an obvious impact on the yield of graphene oxide. Through electrochemical analysis such as linear sweep voltammetry, as well as density functional theory calculations, the exfoliation mechanism of phosphate is elucidated in detail, demonstrating that the stepwise ionized phosphate anions possess more robust intercalation capability than sulfate, thus enabling efficient exfoliation to the intertwined nanocrystalline graphite structure of carbon fibers. The DFT results revealed the bilayer-favored intercalation of phosphate, which accords well with experiments. This work provides a new controllable and green approach for GO synthesis, demonstrated by life cycle assessment. It could assist subsequent studies exploring the size effects of GO and its applications in environmental remediation and energy storage.

The production of aerospace-grade aluminum alloy sheet is characterized by stringent demands, resulting in a low yield rate. The processing of this material generates considerable amounts of highly alloyed scrap, complicating its recycling due to the challenge of maintaining melt cleanliness. This study employed an aerospace-grade melt refining system to purify the recycled 7075 alloy melt obtained from comprehensive scrap remelting. The melt's cleanliness was assessed using Porous Disc Filtration Analysis (PoDFA) and Liquid Metal Cleanliness Analyzer (LiMCA) and Alscan. The microstructure of the ingots and sheets was examined through Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction (EBSD), whereas the mechanical properties of recycled sheets were evaluated and benchmarked against those of primary sheet at an aerospace-certified testing facility. The findings indicate that the recycled 7075 sheet meets aviation standards, with no significant differences in microstructure or performance when compared to primary sheet. Furthermore, the study highlights the economic benefits of recycling scrap, revealing a potential cost saving of $4210.8 per ton of recycled sheet. The findings presented herein offer a theoretical framework and empirical evidence supporting the development of a recycling system for aerospace scraps and the certification of airworthiness for recycled aerospace aluminum alloy.

Poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends provide sustainable packaging solutions renowned for their robustness and biodegradability. Herein, we used a commercial PLA/PBAT blend (Ecovio® - E) to develop films by thermo-pressing, incorporating polylimonene (PLM) and comparing them with limonene (LIM) at 5% and 10% additive concentrations. Remarkably, E/PLM10% film exhibited an 84.9% reduction in Staphylococcus aureus count and a 62% decrease in Aspergillus niger count, surpassing LIM and PLA/PBAT. Additionally, PLM substantially improved the antioxidant activity of the films, achieving more than 40% DPPH scavenging and providing light-blocking capability, with E/PLM5% virtually halting UV-A transmission. Mechanical assessments showed that, although higher PLM levels reduced tensile strength, E/PLM5% matched control performance. FT-IR analysis confirmed PLM presence without chemical alterations, and minimal changes in crystallinity were observed via DSC and XRD, while TGA confirmed the attractive thermal stability of the films. Expanding on these findings, we evaluated film efficacy in cherry tomato preservation, including unpackaged controls. E/PLM5%-packaged tomatoes exhibited superior visual quality and fungal inhibition, proving a promising option for active food packaging due to their antimicrobial effectiveness, antioxidant activity, and UV-light protection. Therefore, this study represents significant progress in advanced packaging development, providing prolonged food preservation, sustainability, and retained performance even when prepared in simulated industrial conditions.

The present global energy shortage and climate crisis can be addressed by embracing recycling, reuse, and recovery; for example, this can be achieved by methodically utilizing the problematic wastes for energy harvesting. This research describes a novel approach for recovery and reutilization of waste material by incorporating dog fur waste into a triboelectric energy harvester; this was accomplished via a simple, inexpensive, and eco-friendly chemical processing to turn this problematic waste into a high-performance tribolayer. Due to the complications of operating practical devices with dog fur in its natural form, the dog fur waste was transformed for the first time into a uniform thin-film-based high-performance positive tribolayer. The optimization of the fabrication of the dog fur film featured hexagonal pyramid nanostructures, and a novel tribopair was selected and consisted of the dog fur-based film and a Teflon film; these films have very large differences in electron affinities. Based on this optimization and selection, we achieved an outstanding output voltage, current, and power density of 2021.46 V, 109.84 μA and 24,669.957 μWcm⁻², respectively, along with appreciable mechanical stability during continuous operation up to 10,000 cycles. Our research demonstrates the potential for integration of green electronics and self-powered human-pet interaction systems while providing a sustainable approach to a circular bioeconomy.

Developing sustainable energy storage devices is challenging for the progress of energy storage applications. Here, nanotechnology represents a strategic route to reduce the amount of used critical materials, while continuing to take advantage of their properties, thanks to the high surface to volume ratio which characterizes nanostructures. WO₃ nanostructures represent a promising active material for energy storage applications, thanks to their wide capability of small positive ions (H⁺ and Li⁺) intercalation and their high stability in acidic conditions. The coupling between WO₃ nanorods and carbon black powder is studied to realize a highly efficient coin cell supercapacitor. The morphology of WO₃ nanorods and carbon black is investigated by using a scanning electron microscope, and the energy storage performances were evaluated by performing cycling voltammetry and galvanostatic charge and discharge analysis, thus obtaining promising specific capacitance results (79 and 70 F/g at 5 mV/s and 0.5 A/g respectively). Moreover, the stability of the obtained coin cell was investigated, thus getting good capacity retention over 250 charge-discharge cycles. Energy and power densities were also calculated, obtaining the highest energy density of 39 Wh/kg at a power density of 500 W/kg. The WO₃‑carbon black coin cells are used to power a red LED, so demonstrating the viability for practical applications.

The demand for eco-friendly and natural food packaging materials has sparked considerable interest in the research and development of sustainable active packaging materials. In this study, a chitosan-based film was developed using glycerol as a plasticiser, chitooligosaccharide (COS) as an additive, and gallic acid as a cross-linking agent. The physical, barrier, mechanical, morphological, thermal, and functional properties of fabricated films were measured. The bio-composite film showed significantly lower moisture content (from 24.28 to 17.01%), water solubility (from 41.56% to 31.03%), water vapour permeability (14.63 to 9.79 × 10⁻⁹ gm⁻¹s⁻¹Pa⁻¹), and light transmittance (from 63.67% to 21.71%) compared to neat chitosan film. Furthermore, the bio-composite film exhibited higher tensile strength (57.66 MPa) and elongation at break (88.76%), smooth microstructure, strong DPPH and ABTS radicals scavenging capacity, and good antimicrobial activity towards E. coli, L. innocua, and S. cerevisiae, and non-toxic to HaCaT cells indicating promising potential for use in sustainable active food packaging.