RSC sustainability最新文献

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Recent trends in papermaking have led to an increase in the use of alternative resources. Alginate fibres, derived from marine sourced brown seaweed (blue carbon), offer a potential alternative to wood pulp in paper production. The process of obtaining alginate involves pre-treatment, alkaline extraction, precipitation, and purification. Through successful extraction, alginates were obtained from Laminaria japonica (L. japonica) and Sargassum polycystum (S. polycystum) with yields ranging from 17.4% to 28.9% and 14.7% to 26.8%, respectively. The molecular mass of the alginates ranged from 0.68 × 10⁵ to 2.74 × 10⁵ g mol⁻¹ for L. japonica and from 0.39 × 10⁵ to 0.994 × 10⁵ g mol⁻¹ for S. polycystum. Calcium alginate fibres and wood pulp fibres were combined to create composites. The results from this study suggest that the composites achieved an optimum tensile index when the samples contained 50% calcium alginate fibres. Although the results were promising, the tensile index of the paper made exclusively from pulp fibres remained superior. Furthermore, thermal degradation tests demonstrated improved thermal stability for the composite papers compared to hardwood bleached kraft pulp (HBKP) sheets. In conclusion, a composite prepared from a mixture of calcium alginate and wood pulp fibres was successfully produced and overall 50% inclusion of calcium alginate fibres provided an optimum composite.

Nitric oxide and nitrogen dioxide (combined, known as NO_x) and their contribution to ozone and photochemical smog generation are persistent issues in urban environments. Many technologies have been developed to alleviate this issue, including photochemical transformation. While previous experiments have focused on incorporating photocatalysts into paving and building materials, we report coating glass substrates for the eventual application to solar panels that are inherently positioned to optimize the amount of solar exposure they receive, creating a surface compatible with photocatalytic coatings. As most photocatalyst materials absorb the ultraviolet spectrum outside the light range used for energy production, this approach could enable dual-functionalized solar panels for energy generation and air remediation. Proof of concept testing was conducted to determine the effectiveness of TiO₂-based photocatalytic products to oxidize NO_x to NO₃⁻/HNO₃. It was found that the tested TiO₂-based photocatalytic products can successfully reduce NO_x concentrations by up to 36%. With the success of laboratory proof of concept experiments, field testing was conducted to determine if glass panels coated with TiO₂ products can reduce NO_x concentrations in environmental conditions. Deionized water washes of the coated glass panels were analyzed through ion chromatography to determine the concentration of NO₃⁻ formed on the surface of the coated glass panels. Field testing resulted in flux values up to 33 mg of NO₃⁻ per m² per day and an average flux up to 8.8 mg of NO₃⁻ per m² per day, representing an order of magnitude value to evaluate possible large-scale implementation. Utilizing field testing results, scale-up estimations suggest widespread application would have a limited impact on total NO_x concentrations. Still, at the local scale, deployment at sites with elevated NO_x concentrations could meaningfully improve local air quality.

Micro- and meso-porous solid materials based on metal–organic frameworks (MOFs) have been gaining significant attention for the last three decades as they offer diverse applications in a large number of areas. An advantage of these materials is that they can be rationally designed with desired characteristics using several metal ions belonging either to the s-, p-, d-, or f-block elements of the periodic table, in combination with suitable polytopic organic linkers (multidentate ligands), resulting in various structural and application aspects. Among the MOFs, those composed of lanthanide ions {Ln(III)}, commonly referred to as Ln-MOF systems, have attracted enormous attention because they display favorable characteristics, like large structural diversity, tailorable structural designs, tunable porosity, large surface area, high thermal stability, and immense chemical stability. All these characteristics are very useful for their widespread applications in diverse areas. Since Ln(III) ions possess higher coordination numbers compared to transition metal (TM) ions, Ln-MOF materials are generally more porous, offering better applications. Further, hybrid MOF systems consisting of both Ln(III) and TM ions (Ln–TM-MOF systems) can introduce additional features to these mixed metal porous materials for their much wider applications. Luminescence and magnetic properties of Ln(III) ions make these materials ideal for various display and sensing applications, in addition to their porosity-related applications. In this review article, our aim is to discuss the basic aspects, preparation methodologies, important properties, and utilizations of MOF materials with a special emphasis on Ln(III)-based MOF systems. Initially, a short introduction is provided on MOF systems, which is followed by other aspects of these materials as mentioned above. Subsequently, we sequentially highlight the interesting characteristics of these materials, including their structural aspects, porosity, magnetic properties, and luminescence behavior. Finally, some of the potential uses of these systems have been presented with special emphasis on their gas storage, catalysis and luminescence-based chemical sensing applications.

This work presents a multiscale Computational Fluid Dynamics (CFD) analysis of direct DME synthesis in a packed bed reactor with physically mixed Cu/ZnO/Al₂O₃ and γ-Al₂O₃ catalysts. The model accounts for hierarchical transport behavior by coupling a one-dimensional intraparticle subgrid model to a two-dimensional (axial and radial) model for heat and mass transport along the catalyst bed, with fully integrated chemical reaction kinetics. To enhance the predictive accuracy, the model incorporates directly measured critical bed properties. X-ray computed tomography was performed at the scale of the packed bed reactor and the scale of individual catalyst particles to obtain bed properties such as bed porosity, particle diameter and permeability, as well as catalyst characteristics including intraparticle porosity and pore size. Experiments were conducted in a lab-scale reactor to validate the model, and the model predictions show good agreement with experimental data for the investigated process conditions. The validated model is further exercised to study the influence of process variables such as feed temperature, feed rate, and wall temperature. The results indicate that the pattern of hot spot formation and magnitude of hot spot temperature are sensitive to processing conditions, mainly the feed rate and reactor wall temperature. It has also been found that internal mass transport limitations exist even in smaller particles (∼215 μm), particularly in the hot spot region.

This study employs Life Cycle Assessment (LCA) to evaluate the environmental impacts of wastewater treatment systems in industrial zones of Vietnam. Focusing on two treatment technologies—Anoxic–Oxic (OA) and Sequencing Batch Reactor (SBR)—as well as different electricity production methods and sludge management strategies, the research aims to identify opportunities for enhancing sustainability and reducing environmental footprints. Utilizing the ReCiPe v1.13 method and SimaPro 9.6.0.1 software, the study assesses key impact categories: climate change, freshwater eutrophication, human toxicity and freshwater ecotoxicity. The results showed that the OA system resulted in 30% lower climate change impacts than the SBR system (0.61 vs. 0.87 kg_{CO2 eq}) but 24% higher freshwater eutrophication (6.17 × 10⁻⁴vs. 4.69 × 10⁻⁴ kg_{P eq}). Utilizing electricity produced from natural gas resulted in an 8.4% reduction in climate change impacts compared to using electricity from the local grid (0.6 vs. 0.66 kg_{CO2 eq}) and an 81% reduction in freshwater ecotoxicity (1.29 × 10⁻³vs. 2.18 × 10⁻⁵ kg_{1,4-DB eq}). Additionally, endpoint analysis of Scenario 0 highlights that the AAO biological and coagulation tanks are the main contributors to Human Health and Resource impacts, with respective scores of 13.8 mPt and 11.5 mPt, demonstrating areas for targeted improvement. The utilization of sewage sludge as fertilizer reduces the impact on climate change by 80% (0.036 vs. 0.3 kg_{CO2 eq}) and nearly eliminates freshwater eutrophication (5.01 × 10⁻⁶vs. 1.77 × 10⁻⁴ kg_{P eq}) compared to landfill. These findings provide detailed insights into different treatment processes and resource utilization strategies, offering a robust framework for enhancing sustainability in developing countries.

This study describes a microwave-assisted hydrothermal method to synthesise carbon-supported Cu-based electrocatalysts for CO₂ conversion using citrus peels as both the carbon precursor and the reducing agent for Cu cations. XPS, TEM, and XRD analyses reveal the structural heterogeneity of the samples, resulting from a complex chemistry influenced by both the type of citrus peel used and the Cu salt precursor. As a result, mixed Cu/Cu₂O nanoparticles form, which are immobilized on the surface or embedded within the carbon matrix. Orange peel-derived systems exhibit an optimal graphitic-to-defective carbon ratio, resulting in an optimal porosity, electron conduction, and Cu stabilisation, leading to superior CO₂ reduction performance. A Cu sulphate-derived catalyst supported on orange peel-derived carbon yields the best performance for CO and methane production, shedding light on specific structural characteristics of the catalysts precursor state able to generate in situ an active phase with improved performance. This work demonstrates the potential of orange peel waste as a sustainable feedstock for the production of CO₂ reduction electrocatalysts, offering a green strategy for waste valorisation and clean energy technologies.

Correction for ‘Shape selective cracking of polypropylene on an H-MFI type zeolite catalyst with recovery of cyclooctane solvent’ by Tomohiro Fukumasa et al., RSC Sustainability, 2025, https://doi.org/10.1039/d4su00484a.

The increasing global demand for energy has led to a rise in the usage of lithium-ion batteries (LIBs), which ultimately has resulted in an ever-increasing volume of related end-of-life batteries. Consequently, recycling has become indispensable to salvage the valuable resources contained within these energy storage devices. While various methods have been developed for the recovery of valuable cathode metals from spent LIBs, the anode's active material, graphite, is mostly lost from circulation. This study introduces an innovative method to valorize black mass leach residue, a waste product from industrial hydrometallurgical LIB recycling processes. Predominantly composed of graphite and minor metal residues, this material can be converted into a valuable bifunctional oxygen electrocatalyst. This transformation is achieved by doping the leach residue with nitrogen and through the incorporation of carbon nanotubes into the modified matrix, to enhance the surface area and conductivity of the produced electrocatalyst. These novel catalyst materials can enhance the oxygen reduction reaction and oxygen evolution reaction in zinc–air batteries (ZAB). The best catalyst material exhibited a commendable power density of 97 mW cm⁻² in ZAB, demonstrating stable performance over 70 hours of continuous charge–discharge cycling. This research represents a significant advancement in the shrewd utilization of LIB recycling waste, which further enhances the goal of closed-loop materials circularity.

Concerns regarding single-use petroleum-based plastic have led to a push toward bioplastic packaging. Poly(lactic acid) (PLA), one of the most utilized bioplastics, suffers from poor oxygen barrier that limits its application as a packaging material. In this work, layer-by-layer nanocoatings consisting of chitosan, deoxyribonucleic acid (DNA), and cellulose nanocrystals are applied to PLA to improve its barrier performance. These coatings decrease the oxygen transmission rate of PLA by up to 30× at just 120 nm of thickness, placing them among the best-performing fully biobased barriers ever reported. Combinations of coating materials are investigated to provide the best performance in both dry and humid conditions. The effect of humidity on the barrier performance is found to depend heavily on the presence of cellulose nanocrystals in the film. Additionally, the biobased coatings do not impede the biodegradability of the PLA substrate. The barrier technology and deposition process fulfill the principles of green chemistry and represent a significant improvement in sustainable gas barrier films.