Unlocking the in vitro neuroprotection of sloe residues phenolic extracts by bioanalytical and chemometric strategies.

Wild fruits, particularly the underutilized sloe (Prunus spinosa), are gaining interest as natural antioxidants, with residues from liqueur production being a source of bioactive compounds. This study proposes a sustainable approach for valorizing sloe residues, seeds and skins, by employing an innovative green extraction method. HPLC-ESI-QTOF and spectrophotometric techniques were used to explore the phenolic profile, highlighting the predominance of quercetin, 2,3-dihydroxybenzoic and ferulic acids (9.7-57 µg·g-1). In addition, the presence of Cu, Zn and Ca was confirmed by atomic absorption spectroscopy. Simultaneously, their neuroprotective potential against Alzheimer's disease (AD) was studied by exploring the inhibition of beta-amyloid aggregation and oxidative stress cytoprotection in SH-SY5Y cell line, standing out 1 µg·g-1 and 10 µg·g-1 extracts of sloe skin. Phenolic composition was correlated with bioactivities by means of multivariate analysis. These results contributed to highlight the potential of this bio-residue as a neuroprotective agent against AD in pharmaceutical and nutraceutical industries.

Decarbonizing the global steel industry in a resource-constrained future-a systems perspective.

Decarbonizing the global steel industry hinges on three key limited resources: geological carbon storage, zero-emission electricity and end-of-life scrap. Existing system analysis calls for an accelerated expansion of the supply of these resources to meet the assumed ever-increasing steel demand. In this study, we propose a different view on how to decarbonize the global steel industry, based on the principle that resource supply can only expand in line with historical trends and actual construction plans. Our analysis shows that global steel production cannot grow any further within a Paris-compatible carbon budget, resulting in a shortfall of approximately 30% against 2050 demand. This trajectory involves the phasing out of blast furnaces, along with strong growth in scrap recycling and hydrogen-based production. These findings highlight critical yet often overlooked challenges: (i) reducing excess demand while providing essential services, (ii) producing high-grade steel through upcycling scrap, and (iii) ensuring an equitable distribution of limited production across the globe. These perspectives contrast with those of the current agenda, which largely emphasizes the need to invest in new production technologies. Grounded in a physical basis, this analysis offers a complementary perspective for a more balanced debate in policymaking and industrial strategy. This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Sustainable extraction and recycling of non-ferrous metals: a review from a European perspective.

This review article provides a comprehensive examination of sustainable extraction and recycling methods for non-ferrous metals, which are critical to a wide range of industries including electronics, construction and renewable energy. Focusing on metals such as aluminium, copper and silicon, the study highlights the importance of recycling in conserving resources and minimizing environmental impact. It discusses the challenges posed by material diversity in recycling processes and the advances in recycling technologies that have emerged in response. Special emphasis is placed on the importance of a circular economy in maintaining a sustainable balance between consumption and conservation of metal resources. Through detailed analysis, it advocates innovative recycling practices and improved design for recyclability and highlights the role of policy, industry and consumer behaviour in achieving sustainability goals. The findings contribute to the discourse on strategic self-sufficiency in Europe through recycling, providing insights into how to improve efficiency and manage the complexity of the global material cycle. This work calls for a collaborative effort towards sustainable metallurgy and underlines the critical need for advances in recycling infrastructure and technology to ensure the long-term availability and environmental stewardship of non-ferrous metals.This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

What influences the on-site recycling behaviour of C&D plastic waste in Australia? An action determination model approach.

While the recycling of construction waste has received widespread attention, plastic waste generated at construction sites has been overlooked. At the same time, existing studies on pro-environmental behaviour have only considered practical knowledge of implementing recycling, while ignoring the possible impact of circular economy knowledge on recycling behaviour. This study investigates on-site personnel's behaviour regarding C&D plastic waste recycling through the lens of the comprehensive action determination model (CADM), which uniquely incorporates behaviour as a key variable and extends with moderating effect of knowledge of the circular economy. Utilizing Partial Least Squares Structural Equation Modelling (PLS-SEM), results indicate that perceived behavioural control is the most substantial factor influencing recycling behaviour of plastic waste on construction sites rather than intention. This is in stark contrast to existing pro-environmental behaviours research and reflects the importance of providing resources and encouragement to increase personnel's confidence in performing recycling behaviours on site, contributing more to actual behaviours than intention. Key areas for improvement were identified, including management encouragement, resource allocation (site area, timeline, budget), and recycling training. Contrary to expectations, awareness of the circular economy did not statistically significantly moderate the predictors of recycling behaviour and intentions, perhaps because participants had limited knowledge of plastic consumption and recycling rates in the construction industry. As construction personnel become more familiar with the circular economy, future research should re-evaluate these moderating effects and consider conducting categorical moderation analyses with larger sample sizes, incorporating variables such as work experience, project type, and project phase.

A Planetary Boundary for Mineral, Metal, and Fossil Resource Extraction Rates: How Much Primary Materials Can a Circular Economy Extract?

Resource consumption is expected to further increase in the next decades. A circular economy could decrease the environmental impact of this resource consumption by minimizing the primary raw materials consumption and minimizing emissions that render materials inaccessible for further use. However, such a circular economy will still have primary raw material inflows, due to population growth, stock expansion, energy transition, and inevitable dissipation. The potential magnitude of such primary raw material inflows in a circular economy remains unclear. To address this uncertainty, the planetary boundary framework, which defines absolute limits on resource and emission flows, could be utilized. Although this framework incorporates aspects of biomass, water, and land use, mineral, metal, and fossil resources are not included. This study provides a principle for a planetary boundary for these three resources, based on the net accessibility rate and an allocated share of the accessible resource stock in the ecosphere. Inter- and intragenerational equality are crucial for determining this allocated share and for quantifying a sustainable rate of resource extraction in (an economy transitioning toward) a circular economy. Next steps to operationalize this principle provide further guidance to determine the safe operating space for mineral, metal, and fossil resource extraction.

Mining of primary raw materials as the critical foundation of 'sustainable' metals: a wicked problem for technology innovation clusters.

A transition to a more sustainable human-nature system is inextricably linked to raw materials production, if economic growth is to be maintained or increased by the emergence of new, energy- and metal-hungry technology innovation clusters. The dependence on mined raw materials is a wicked problem for societies vulnerable to negative ecological impacts and for global power bases wanting to secure access to an increasing array of feedstocks. We interrogate the issue of what constitutes a sustainable metal from a triple perspective: (i) the characteristics of ore deposits and the primary extractive operations that supply critical raw materials; (ii) the impediments for complex and interacting supply chains to maintain critical (and other) metals in use; and (iii) the lack of transparency in supply chains that makes it challenging for customers to avoid resources that have been produced by unsustainable and poor practices. We examine existing and emerging structures for resource management to explain the limits to the circular economy and what constitutes a meaningful systemic structure for primary production by responsible mining. We call for the inclusion of a standardized statement of the 'natural capital' embodied in R&D for technological materials as a means to create transparency about what constitutes a sustainable metal.This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Current recycling innovations to utilize e-waste in sustainable green metal manufacturing.

The ever-increasing market demand and the rapid uptake of the technologies of electronics create an unavoidable generation of high-volume electronic waste (e-waste). E-waste is embedded with valuable metals, alloys, precious metals and rare earth elements. A substantial portion of e-waste ends up in landfills and is incinerated due to its complex multi-material structure, creating loss of resources and often leading to environmental contamination from the release of landfill leachates and combustion gases. Conversely, due to the ongoing demand for valuable metals, global industrial and manufacturing supply chains are experiencing enormous pressure. To address this issue, researchers have put multifaceted efforts into developing viable technologies and emphasized right-scaling for e-waste reclamation. Several conventional and emerging recycling technologies have been recognized to be efficient in recovering metal alloys, precious and rare earth metals from e-waste. The recovery of valuable metals from e-waste will create an alternative source of value-added raw materials, which could become part of supply chains for manufacturing. This review discusses the urgency of metal recycling from e-waste for sustainability and economic benefit, up-to-date recycling technologies with an emphasis on their potential role in creating a circular economy in e-waste management.This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Examining the synergy of green supply chain practices, circular economy, and economic growth in mitigating carbon emissions: Evidence from EU countries.

Integrating green supply chain strategies and circular economy (CE) practices holds substantial potential for promoting environmental sustainability and reducing CO2 emissions. This study investigates the synergy between green supply chain practices, circular economy, and economic growth (RGDP) impacts on carbon emissions in 13 selected European Union (EU) countries, using a comprehensive panel dataset from 2000 to 2022. We employ both linear and nonlinear panel ARDL models, along with causality tests, to examine how CO2 emissions respond to changes in green supply chain management (GSCM), real GDP (RGDP), and various recycling practices, including bio-waste, municipal waste, and packaging waste. Our findings reveal that GSCM practices significantly reduce carbon emissions in the long run, while economic growth (RGDP) and municipal waste generation correlate positively with increased CO2 emissions. Interestingly, the nonlinear ARDL model highlights that only recycling packaging waste (RWP) exhibits a positive long-run effect on reducing emissions. Additionally, the method of moments quantile regression (MMQR) analysis indicates that the impact of GSCM is more pronounced at higher quantiles of CO2 emissions, whereas the effect of RGDP on emissions remains inconsistent. These results underscore the crucial need to adopt and enhance green supply chain practices within a circular economy framework to achieve substantial carbon emission reductions, holding significant implications for carbon emissions policies in the selected EU countries.

Achieving sustainable performance: synergistic effects of nano-silica and recycled expanded polystyrene in lightweight structural concrete.

Lightweight concrete, particularly polystyrene concrete, has been extensively utilized in civil engineering for decades. The incorporation of waste expanded polystyrene (EPS) as a filler material in the production of lightweight concrete presents significant advantages from a circular economy perspective. Prior research indicates that increasing the proportion of lightweight aggregates, such as EPS, typically results in reductions in strength and bulk density. The utilization of substantial amounts of EPS waste in the formulation of structural polystyrene concrete is crucial for advancing sustainable construction practices. This study investigates the effects of varying nano-silica content on the bulk density, compressive strength, flexural strength, splitting tensile strength, and water penetration depth of structural polystyrene concrete. Concrete specimens were prepared by substituting 25%, 50%, 75%, and 100% of sand with EPS waste, while evaluating nano-silica contents of 0.75%, 1%, and 1.25%. The findings reveal that increasing the volume fraction of EPS corresponds to a decrease in the concrete's bulk density. This research provides critical insights into optimizing structural lightweight concrete, thereby promoting advancements in sustainable construction applications.

Closing the Loop: A comprehensive exploration of Taiwan's e-waste to resource conversion journey.

Taiwan stands as a significant player in the global electronics market, capitalizing on its technological prowess and manufacturing capacities. Projected to achieve a notable compound annual growth rate (CAGR) of 13.2%, reaching an impressive USD 145.11 billion by 2030, the island nation profoundly influences the industry's trajectory. By 2022, consumer electronics are forecasted to attain a valuation of USD 1,056.6 billion, with exports surging to USD 15 billion in 2019 and expected to further grow by USD 3.8 billion within the subsequent five years. However, amidst this surge in electronic consumption, a formidable challenge looms-the accumulation of obsolete electronic waste (e-waste)-a menace to human health, ecological equilibrium, soil vitality, and aquatic ecosystems. The inclusion of heavy and rare metals in e-waste complicates recycling efforts but simultaneously presents economic opportunities through extraction. Taiwan responded to global calls for sustainable waste management in 1998 by instituting a regulated Waste Electrical and Electronic Equipment (WEEE) recycling scheme. Despite its technological acumen, Taiwan grapples with managing a burgeoning volume of outdated electronics. As the WEEE recycling market nears saturation, recent innovative regulatory endeavors aim to confront these challenges. This review delves into Taiwan's e-waste management landscape, scrutinizing regulatory intricacies, prevailing challenges, and future trajectories. By highlighting Taiwan's pivotal role, this initiative aligns with the UN agenda 2030 for sustainable development, envisioning a triumphant WEEE recycling system and nurturing a comprehensive circular economy.

Deep learning approaches for classification of copper-containing metal scrap in recycling processes.

Separating copper from iron scrap is a critical operation in metal recycling and achieving this with low cost sensoric equipment like RGB cameras instead of XRF/XRT is becoming increasingly attractive. In this article, the groundwork for creating an image classification model to separate copper from iron scrap has been performed. Twenty of the most common and most easily available CNN architectures were trained on 2200 metal scrap specimens and evaluated inline on a sensor-based sorting rig for their prediction accuracy and their inference latency to mimic real circumstances in an industrial setting. Out of these evaluated architectures, DenseNet-201 with 98% accuracy in inline tests is recommended if potent hardware is available. Otherwise AlexNet with 92% accuracy or MobileNet-V2 with 90% accuracy are recommended for further investigation and model creation if hardware restrictions apply. Based on the presented results in this article, the initial cumbersome surveyance of the most suitable network architecture can be substantially reduced and the creation of a sorting model can be streamlined. This article thus provides the basis for creating an inline applicable sorting method for scrap metal that uses low cost sensorics equipment and can provide reasonably high accuracy in its prediction.

Prediction of municipal waste generation using multi-expression programming for circular economy: a data-driven approach.

The existing surge in municipal waste generation (MWG), characterized by swiftly changing and uncontrollable factors, poses a significant challenge to sustainable development. This prompted the need for improved predictive models to guide strategic waste management within the circular economy framework. This study aims to develop a predictive model using multi-expression programming (MEP) to assess MWG. The model was developed using historical data on socioeconomic and environmental factors and validated via comparative analyses with artificial neural network (ANN), random forest (RF), and multiple linear regression (MLR) using various evaluation metrics. The parametric and sensitivity analyses of the MEP model were also conducted. The MEP, ANN, RF, and MLR models have a coefficient of determination (R2) (for testing datasets) of 0.977, 0.974, 0.957, and 0.964, respectively. The MEP model is superior in terms of accuracy and performance for the prediction of MWG when compared to the other three models. The sensitivity analysis revealed the relative importance of each input variable in the established MEP model. The novelty of this research lies in the application of MEP to predict MWG and the formulation of a new mathematical model that links socioeconomic and environmental factors with MWG. The model can be used by waste management authorities to optimize waste collection, transportation, and disposal infrastructure for an effective circular economy and sustainable development. This model also aids in the development of effective waste management policies.

Valorization of diverse waste-derived nanocellulose for multifaceted applications: A review.

The study underscores the urgent need for sustainable waste management by focusing on circular economy principles, government regulations, and public awareness to combat ecological threats, pollution, and climate change effects. It explores extracting nanocellulose from waste streams such as textile, paper, agricultural matter, wood, animal, and food waste, providing a detailed process framework. The emphasis is on waste-derived nanocellulose as a promising material for eco-friendly products. The research evaluates the primary mechanical and thermal properties of nanocellulose from various waste sources. For instance, cotton-derived nanocellulose has a modulus of 2.04-2.71 GPa, making it flexible for lightweight applications. Most waste-derived nanocelluloses have densities between 1550 and 1650 kg/m3, offering strong, lightweight packaging support while enhancing biodegradability and moisture control. Crystallinity influences material usage: high crystallinity is ideal for packaging (e.g., softwood, hardwood), while low crystallinity suits textiles (e.g., cotton, bamboo). Nanocelluloses exhibit excellent thermal stability above 200 °C, useful for flame-retardant coatings, insulation, and polymer reinforcement. The research provides a comprehensive guide for selecting nanocellulose materials, highlighting their potential across industries like packaging, biomedical, textiles, apparel, and electronics, promoting sustainable innovation and a more eco-conscious future.

Optimizing phosphorus precipitation from acidic sewage sludge ash leachate: Use of Mg-rich mining by-products for enhanced nutrient recovery.

Phosphorus recovery from Sewage Sludge Ashes (SSA) by wet chemical extraction followed by selective precipitation has gained great attention in recent years, attempting to reduce the anthropic pressure on natural reserves. This study investigates the selective precipitation process at lab- and small pilot-scales by means of two conventional and one innovative precipitating agents, the latter derived from a low-grade magnesium oxide mining by-product (LG-MgO named PC8), assessing the role of the most relevant operating parameters. Lab-scale experiments were performed on leachates obtained from bottom and fly ashes, in which several operating conditions were tested, differing in the type of precipitating agent, target pH and nutrient molar ratio. Based on experimental results, small pilot-scale experiments were conducted with Ca(OH)2 and PC8 at pH 7. Effective phosphorus precipitation was obtained at lab-scale at pH equal to 4 for high Al/P molar ratio, while SSA leachate with low Al/P molar ratio promoted improved phosphorus precipitation (>90%) only at pH higher than 8 with PC8. Small pilot-scale findings confirmed the effectiveness of PC8 in increasing simultaneously the pH and the nutrient content of the solid precipitate. The comprehensive assessment of the samples denoted compliance with the European Regulation (EU 2019/1009), which allows the formulation of different fertilizers with agronomic relevance. This is the first time that experiments from small pilot-scale tests in the field of phosphorus recovery from SSA were investigated using an innovative precipitant providing key information for the process scale-up.

Investigation of the agricultural reuse potential of urban wastewater and other resources derived by using membrane bioreactor technology within the circular economy framework.

The European Union, as delineated in Regulation (EU) 2020/741, sets forth minimum criteria for the reuse of wastewater. Directive 86/278/CEE sets the regulations for the reuse of sewage sludge in agriculture. This study aimed to investigate the treated water derived from a pilot plant situated in Granada, Spain, that utilizes membrane bioreactor technology to process real urban wastewater with the quality standards necessary for agricultural reuse. Additionally, the study evaluated the utilization potential of other resources generated during wastewater treatment, including biogas and biostabilized sludge. The pilot plant incorporated a membrane bioreactor featuring four ultrafiltration membranes operating continuously alongside a sludge treatment line operating in batch mode. The pilot plant operated during four cycles, each with distinct hydraulic retention times (6 h and 12 h) and variable mixed liquor-suspended solids concentrations (ranging from 2688 mg L-1 to 7542 mg L-1). During these cycles, the plant was doped with increasing concentrations of emerging contamination compounds (diclofenac, ibuprofen, and erythromycin) to test their effect on the resources derived from the treatment. Subsequently, a tertiary treatment involving an advanced oxidation process was applied to the different water lines, which left the wastewater treatment plant for a period of 30 min and utilized varying concentrations of oxidant. The results indicate that the effluent obtained meets the required quality standards for agricultural use. Therefore, there is potential to use this waste as a resource, which is in line with the principles of the circular economy. Furthermore, the other resources generated during the treatment process, such as the biogas produced during the digestion process and the biostabilized sludge, have the potential to be used as resources according to the circular economy indicators.

Greening the city: A holistic assessment of waste management alternatives in India.

Waste is one of the major urban challenges faced globally today, and the severity of the challenge is further exacerbated by rapid urbanisation, growing populations and increasing per capita waste generation. As one of the largest urban agglomerations in the world, Delhi collects 11,352 t of waste every day. Without adequate segregation, most of this waste is sent to dumpsites and waste-to-energy plants, often associated with significant capital costs and environmental externalities. This paper conducts a life cycle assessment of the current waste management system and a comparative analysis with a suggested alternative scenario, where the share of recyclables and compostables going to landfills and waste-to-energy plants is reduced through adequate segregation. Our results revealed that landfills and waste-to-energy plants are associated with significant adverse environmental impacts such as climate change, soil and water acidification, freshwater eutrophication, human toxicity, and respiratory health. In comparison, compost plants showed negligible emissions per tonne of waste. The alternative scenario (i.e. reduce waste to landfill through adequate segregation) can help reduce the negative impact on all environmental indicators by an average of 23 %. We posit that the prevailing narrative of addressing the waste issue through waste-to-energy plants in Delhi goes against the country's climate neutrality targets. Instead, the circular economy approach offers simpler, faster, and more cost-effective solutions that policymakers should consider to reduce the financial and environmental load of the current and future waste management issue.

Increasing the Recycling of PVC Flooring Requires Phthalate Removal for Ensuring Consumers' Safety: A Cross-Checked Substance Flow Analysis of Plasticizers for Switzerland.

As our planet grapples with the severe repercussions of plastic pollution, mechanical recycling has been proposed as a potential remedy. However, increasing mechanical recycling may have unintended negative consequences. For example, recycling of PVC flooring containing hazardous plasticizers that were used in the past may lead to continued exposure. Here we propose measures to increase recycling while circumventing adverse health impacts caused by legacy additives. For this, we conduct a dynamic substance flow analysis for Switzerland and the time period from 1950 to 2100, focusing on three plasticizers: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), and di(2-ethylhexyl) terephthalate (DEHT). We quantify the uncertainty of results, check their plausibility against measured concentrations in samples representative for the Swiss market, and compare them with modeled substance flows in Germany. Based on the cross-checked model, future average concentrations of DEHP in PVC flooring on the Swiss market are expected to be above the legal limit of 0.1 wt % for several decades if increased recycling rates are implemented without additional measures. Phasing out the potentially concerning DiNP, too, and preventing phthalates from entering recycling would lower their average market concentrations to values below 0.1 wt % and enable increasing recycling rates without compromising product safety. Analogous measures could help achieve this goal across other European countries and product groups.

Comparing the end-of-life circularity potential of commercial fishing gear deployed in Norway by applying multi-criteria decision analysis (MCDA).

Abandoned, lost, or otherwise discarded fishing gear is one of the most harmful types of marine litter globally, causing irreversible damage to ocean life and ecosystems. Therefore, global and regional policies are currently being designed and implemented to limit the influx of fishing gear into the marine environment, emphasizing the importance of circular end-of-life management of fishing gear. This study compares the end-of-life circularity potential of the six most used commercial fishing gears in Norway to identify how the heterogeneity of gears impacts their management alternatives. The main findings of the multi-criteria decision analysis (MCDA) applied in this study are that considering the economic and environmental sustainability, as well as technological feasibility of the gears' end-of-life management, purse seines have the most significant circularity potential, followed by trawls and Danish seines, while gillnets, longlines, and traps and pots are most challenging to manage according to circularity principles. Finally, some policy implications of these findings are discussed, considering especially the role of the Extended Producer Responsibility policy in the accommodation for fishing gears' circularity.

Brazil Nut Semi-Defatted Flour Oil: Impact of Extraction Using Pressurized Solvents on Lipid Profile, Bioactive Compounds Composition, and Oxidative Stability.

Brazilian nuts are native to the Amazon rainforest and are considered a non-timber forest-product of extreme economic importance to local populations. This study evaluated the lipid profile, bioactive compounds, and oxidative stability of semi-defatted Brazilian nut flour oil (BNSDFO) obtained using pressurized fluids (n-propane at 40 °C and 2, 4, and 8 MPa or a CO2/n-propane mixture at 40 °C and 12 MPa). A Brazilian nut kernel oil (BNKO) processed by conventional cold pressing was also obtained. The BNKO showed a higher concentration of total phenolic compounds and saturated fatty acids, higher antioxidant activity, and the presence of gallic acid derivatives. The oils extracted using pressurized fluids showed a higher concentration of linoleic acid, ß-sitosterol, and polyunsaturated fatty acids. The utilization of pressurized n-propane resulted in higher yields (13.7 wt%), and at intermediate pressures (4 MPa), the product showed myricetin 3-O-rhamnoside and higher oxidative stability (OSI, 12 h) than at lower pressures (2 MPa). The CO2/n-propane mixture of pressurized solvents resulted in higher concentrations of squalene (4.5 times), the presence of different phenolic compounds, and a high OSI (12 h) but lower yield (2.2 wt%). In conclusion, oils with better fatty acid profiles (oleic e linoleic acids), phytosterol composition, and suitable radical scavenging activity may be obtained using pressurized fluids and Brazilian nut flour, a byproduct of oil extraction. The mixture of solvents may improve the concentration of squalene, whereas using only n-propane may increase oil yield.

New Polymer Biocomposites Based on Biopoly(Ethylene Terephthalate) and Waste Mollusc Shells.

Currently, scientific studies have are focusing on environmentally friendly solutions, such as the effective use of waste in new green polymeric materials according to circular economy. Waste valorization is the main driving force for upcoming academic research. In this study, the impact of mussel particle size on reinforced biopoly(terphtalate ethylene) (bPET) is investigated. The waste filler was modified using NaOH. The filler content was 10 wt% and the same for all samples. The strength properties of the materials were determined in static tensile, bending and impact tests. The wetting angle was also analyzed for the obtained biocomposites. A low-cycle dynamic test was carried out to determine changes in dissipation energy and to observe the development of relaxation processes. This present study proves that preparation of new biocomposites based on waste mussels is an effective option in waste management.