Search Results (1,184)

Marine oil spills remain a recurring environmental concern, particularly in coastal and estuarine areas. Among the available strategies for managing spilled oil, sorbents derived from natural fibers have attracted considerable interest as viable alternatives to synthetic materials due to their biodegradability, low cost, and alignment with circular economy principles. This review synthesizes recent advances by connecting technical and environmental aspects with operational applications. It emphasizes structural and surface modifications of lignocellulosic fibers to enhance petroleum sorption capacity, selectivity, buoyancy, and reusability. Physical, chemical, and biological approaches are discussed, focusing on how these modifications influence sorption dynamics under realistic conditions. The review also highlights the incorporation of agricultural and industrial residues as raw materials, along with regeneration and reuse strategies that support waste valorization. However, significant gaps remain, such as the lack of studies with weathered crude oils, the limitation of larger-scale testing, and the need for standardized methods and evaluation of the final fate of exhausted biosorbents. Through the integration of technical, environmental, and operational criteria, this review provides a critical foundation for developing more efficient and circular marine oil spill response technologies. Full article

Rapid urbanisation and population growth call for more Industrialised Construction (IC) as a swifter, safer, higher-quality and affordable means of delivering housing and infrastructure. Meanwhile, rising global temperatures and extreme weather patterns call for immediate action to combat environmental degradation. The Building Construction Industry (BCI) is a leading contributor to global resource extraction and waste generation, posing a significant threat to our environment and planet. Design for Circular Manufacturing and Assembly (DfCMA) is an overarching design framework that synergises circularity (Design for Circularity (DfC)) and modularity (Design for Manufacturing and Assembly (DfMA)) by enhancing their shared values. This study explores the functional apparatus of DfCMA by identifying 21 DfMA constructs and 20 DfC constructs in the BCI through a rigorous literature review, first analysed descriptively, followed by Exploratory Factor Analysis (EFA) and Fuzzy Synthetic Evaluation (FSE) of the initial findings from a suitably focused questionnaire survey. The study findings confirm the significance of applying the 41 constructs above in advancing the concept of DfCMA in the BCI. This study thus adds value to research and practice, exploring the underlying mechanism of this novel DfCMA concept, which synergises two imperatives, promoting a Circular Economy (CE) and DfMA principles and practices in IC. Full article

This study investigates the potential of Pinus pinaster subsp. atlantica bark, a forestry by-product from northern Portugal, as a source of phenolic compounds with strong antioxidant properties. Microwave-assisted extraction (MAE) was used to optimize recovery, assessing the effects of solvent composition (water, ethanol, and 50:50 water–ethanol), extraction time (15 or 30 min), and temperature (90, 110, or 130 °C) using a one-variable-at-a-time approach. High-Performance Liquid Chromatography (HPLC) profiling characterized the polyphenol composition. The results showed that solvent choice strongly influenced extract composition and bioactivity, with hydroethanolic and ethanolic extracts exhibiting the highest antioxidant activities in DPPH, ABTS, and ORAC assays. Optimal conditions—50:50 water–ethanol, 130 °C, 15 min—yielded 11.13% (w/w) extract, 3.10 mg GAE/mL total phenolics, and 2.01 mg CE/mL condensed tannins, comparable to commercial extracts such as Pycnogenol^®. MAE proved effective, rapid, and solvent-efficient, enhancing phenolic recovery without degrading extract quality. These findings highlight the potential of P. pinaster bark extracts for biomedical, nutraceutical, and cosmetic applications, supporting the sustainable valorization of forestry residues and aligning with circular economy principles. Full article

The escalating global water crisis, coupled with the unsustainable accumulation of industrial and urban waste, demands innovative solutions that align with circular economy principles. This review explores the transformative potential of waste-derived ceramic membranes as a sustainable strategy for water purification, simultaneously addressing waste valorization and clean water scarcity. Ceramic membranes, traditionally fabricated from high-purity inorganic materials, are renowned for their superior chemical resistance, thermal stability, and durability. Recent advances demonstrate that industrial byproducts, such as red mud, coal fly ash, blast furnace slag, coal gangue, and kiln roller waste, can be effectively repurposed into cost-effective, high-performance filtration materials. This paper critically examines fabrication techniques, material properties, and performance metrics of waste-derived ceramic membranes. By transforming industrial waste into functional filtration materials, this approach not only mitigates environmental pollution but also contributes to sustainable water security. Full article

The transformation of organic by-products derived from waste into value-added resources represents a promising strategy to advance circular economy principles and bolster environmental and agricultural sustainability, especially in soilless cultivation. This study evaluates the viability of three organic by-products—wood fiber (WF), coffee silverskin (CS), and brewer’s spent grains (BSGs)—as partial peat replacements in horticultural substrates. Ten growing media formulations were assessed, incorporating increased doses (0–40% v/v as peat replacement-PR) of each alternative by-product. The effects on physical and hydraulic substrate properties, along with plant growth traits, were examined using two ornamental Salvia genotypes, ‘Victoria’ and ‘Amistad’. To synthesize the multivariate growth data into a single, biologically meaningful metric, based on the first principal component, a Growth Index (GI), a PC1-derived index, was calculated, providing a powerful, unified metric to rank substrate efficacy. WF-based substrates exhibited increased porosity and diminished water retention, whereas media enriched with CS and BSG enhanced moisture availability, particularly at 20–40 PR. The bulk density was highest at PR40 for both WF and BSG treatments, and at PR20 in CS-based substrates. Electrical conductivity increased in CS and BSG treatments with rising PR levels. The results on the vegetative growth of ornamental sages have highlighted that differential PR rates are required depending on the specific organic by-product and plant genotype. In ‘Victoria’, GI indicates that a 20% replacement of peat with BSG provided the optimal conditions for holistic plant development; the lowest GI for WF substrates across nearly all peat replacement levels indicated that it was the most detrimental alternative for this cultivar. In ‘Amistad’, the analysis of the GI scores revealed that the CS20 and BSG20 of peat replacement yielded the highest overall growth, with GI scores significantly greater than those of the peat control. CS10 and BSG40 also showed high GI scores in ‘Amistad’. WF10 had GI scores similar to those of the peat control. In general, the GI-based approach confirms that moderate inclusion of brewer’s spent grain (BSG20) is a highly effective peat replacement for both genotypes. At the same time, coffee silverskin (CS) is particularly effective for the ‘Amistad’ genotype. This analysis underscores that optimal substrate formulation is not only dependent on the amendment type and rate but also critically on the plant genotype. Full article

The processing of freshly cut fruits and vegetables represents an important niche for implementing circular economy principles, particularly through the reuse of washing water. This is especially relevant as post-wash water is often treated as wastewater and discarded without reuse. One promising research avenue is the use of plant-derived extracts in water sanitation processes. Their antimicrobial properties offer a natural alternative to conventional disinfectants while reducing the formation of harmful disinfection by-products. The aim of this study was to evaluate the effectiveness of different filter bed configurations in removing pathogens from water. These configurations included a hydrogel saturated with natural plant extracts, an ion exchange resin layer, and an activated carbon layer. The most effective composite was also tested using real process water from a fruit washing line. The test materials included concentrated extracts from oak bark (Quercus robur), willow (Salix alba), birch (Betula pendula), raspberry shoots (Rubus idaeus), tea leaves (Camellia sinensis), and linden flowers (Tilia cordata), all immobilized in hydrogel, along with activated carbon and ion-exchange resin. Water samples were artificially inoculated with six opportunistic pathogens and collected process water was also used. Samples were analyzed microbiologically at six time intervals. The composite filter (hydrogel–resin–carbon) achieved a reduction of over 2 log₁₀ in heavily inoculated water (~10⁸ CFU mL⁻¹) and maintained at least a 1 log₁₀ reduction in real process effluents. The proposed solution supports blue water footprint reduction strategies (as the system aims to decrease the demand for freshwater resources through the reuse of treated wastewater) and aligns with the principles of green processing. Full article

Winter and Spring variations of the fat and fatty acid compositions of discards from six species of the Aegean Sea were investigated to assess the potential suitability for human or aquaculture consumption. European pilchard (Sardina pilchardus), anchovy (Engraulis encrasicolus), curled picarel (Centracanthus cirrus), gilt sardine (Saridenella aurita), horse mackerel (Trachurus mediterraneus) and bogue (Boops boops) were collected from the local fishing wharf during winter and spring. In most species, the specimens caught in spring exhibited elevated fat and n-3 long-chain polyunsaturated fatty acid content, with Sardina pilchardus showing an increase in DHA from 13.59% to 16.06% and Engraulis encrasicolus from 20.36% to 23.41% of the total identified fatty acids. Despite their lower commercial value, the high n-3 LC-PUFA content renders them nutritionally valuable and eligible for use by the aquafeed industry as an alternative to the increasingly costly fish oil. Moreover, in accordance with EU legislation banning discards and mandating the landing of unwanted catches, the valorisation of these species, in line with circular economy principles, could enhance fishers’ income, reduce waste and contribute to the long-term sustainability of marine ecosystems. Full article

The specificity of the business of agro-food companies is that their products have little or no impact on the environment. However, environmental pollution of these products is caused by the use of packaging. Therefore, it is necessary to apply the principles of the circular economy in the business of companies. Applying green packaging that has little or no impact on the environment helps in preserving the environment. Companies usually purchase packaging from suppliers and therefore, it is necessary to choose the right supplier from which to purchase green packaging to support the implementation of the circular economy. The aim of this research is to select a green packaging supplier for company X in order to influence the development of a circular economy in the company’s business. Based on this, the following research question is considered in this paper: how can the selection of a green packaging supplier influence the implementation of a circular economy at company X? The research covers ten criteria used in this selection, with which eight suppliers were observed. Because every decision-making process in the economy is characterized by risk and insecurity that affects the uncertainty in decision-making, an intuitionistic fuzzy set (IFS) was used. Determining the importance of weights was performed directly based on the ratings of the decision-maker (DM) and the steps of the SiWeC (Simple Weight Calculation) method, as well as using the Entropy method. The compromise results of these methods showed that the most important criteria for assessing the life cycle of packaging are transparency and ethics in business. The ranking of suppliers was carried out using the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method and its results showed that supplier 5 is the first choice for establishing long-term cooperation in the procurement of green packaging. Full article

The article focuses on verifying the potential of using cellulose obtained from waste cardboard to improve the soil’s water retention capacity, depending on its texture and type, in accordance with the principles of the circular economy. The study compares reference cellulose (RFC) and waste carton-extracted cellulose (WCC) in terms of their structure and water-holding capacity (WHC), using FTIR spectroscopy and experiments across various soil types. Results showed that WCC has a significantly higher WHC (12.6 g/g) than RFC (0.75 g/g) due to its greater proportion of amorphous sections and the presence of lignin and hemicellulose. In contrast, the high crystalline content of RFC limits its water sorption capabilities. Soil texture and soil organic matter (SOM) play a crucial role in water retention. The highest WHC values were observed in fine-grained soils classified as silt loam. The study confirms that SOM has a stronger influence on WHC than texture alone. Applying WCC led to a linear increase in WHC across different soil types. Even soils with initially low WHC showed notable improvement with low doses of WCC (1%). The findings highlight the potential of waste carton-extracted cellulose as a soil amendment to enhance water retention in agricultural soils, especially in adapting to climate variability and drought conditions. Full article

Hydrogen is key to achieving a net-zero carbon future, yet current production remains predominantly fossil-based. Biohydrogen derived from agricultural residues represents a sustainable alternative aligned with circular economy principles. While several studies have assessed the bioenergy potential from agricultural residues in various African countries, their potential in Togo remains largely unexplored. This study employed an exploratory mixed-methods approach to quantify residue availability, evaluate production pathways, and estimate potential biohydrogen yields. Secondary data on crop production from the Food and Agriculture Organization (FAO) and theoretical conversion factors were used to assess the availability of agricultural residues from the eight major crops in Togo, resulting in a residue potential of 7.95 million tons per year. Considering ecological and competing aspects of residue utilization, a sustainable share of 3.1 to 6.6 million tons was estimated to be available for biohydrogen production, depending on the residue recoverability assumptions. A multi-criteria decision analysis (MCDA) was used to evaluate different biohydrogen production processes, identifying dark fermentation as the most suitable due to its low energy requirements and decentralized applicability. The theoretical biohydrogen potential was estimated at 20,991–42,293 tons per year (2.5–5.1 PJ per year) based on biochemical residue composition data and stoichiometric calculations. This study established a baseline assessment of biohydrogen potential from agricultural residues in Togo, offering a methodological framework for assessing biohydrogen potential in other regions. The results also underscore the need for site-specific data to reduce uncertainty and support evidence-based energy planning. Full article

This review paper explores the transformative potential of polymer composites and adhesives in reducing the weight of aircraft landing gear, thereby improving fuel efficiency and lowering emissions. The replacement of conventional metallic materials and mechanical fastenings with advanced thermoset/thermoplastic composites and adhesives can significantly enhance durability and performance in demanding operational environments. Unlike traditional fastening methods, the structural adhesives eliminate the weight penalties associated with mechanical fasteners, offering a lighter and more reliable solution that meets the rigorous demands of modern aerospace engineering. Furthermore, the review highlights a variety of manufacturing techniques and innovative materials, including bio-based polymers, self-healing materials, noobed composites, helicoid composites, and hybrid composites. The use of thermosets and vitrimers in adhesive bonding are presented, illustrating their ability to create robust and durable joints that enhance the structural integrity of landing gear systems. The paper also addresses current challenges, including recycling limitations and high material costs. Sustainability considerations, including the integration of self-healing materials, structural health monitoring systems, and circular economy principles, are discussed as essential for aligning the aerospace sector with global climate goals. Full article

Since the 1970s, the understanding of cultural heritage (CH) has expanded from a focus on monumental conservation to a systemic, socially constructed concept shaped by communities and dynamic values. While recognized as a resource for sustainable development, CH remains marginal in global policy agendas, notably in the UN’s 2030 Agenda. This paper explores how the Historic Urban Landscape (HUL) approach and broader heritage systems can function as enablers of sustainable urban development, moving beyond heritage-as-object to heritage-as-process. It synthesizes conceptual advances, policy frameworks, and empirical cases—such as Capitals of Culture programs, adaptive reuse initiatives, and circular economy models—to analyze how heritage systems contribute to environmental, social, and economic sustainability. Drawing on a value-based and people-centered framework, the paper identifies key principles, models, and success factors for integrating CH into urban planning. Case studies from Europe and Asia illustrate the potential of heritage to foster inclusive governance, community resilience, and innovation, while also exposing challenges such as institutional fragmentation, gentrification, and policy–practice gaps. The findings highlight the need for holistic, cross-sectoral, and participatory strategies to embed CH meaningfully in urban transformation processes, offering concrete insights for advancing heritage-led sustainable development through the lens of systems thinking. Full article

The exponential increase in global solid waste generation poses significant environmental, economic, and social challenges, particularly in rapidly urbanizing regions. Traditional waste management methods that focus on handling and disposal have proven unsustainable because of their negative impacts on air, soil, and water quality, and their contribution to greenhouse gas emissions. In response, the concept of zero-waste cities, rooted in circular economy principles, has gained increasing attention in recent years. This study proposes a comprehensive and integrated waste management system designed to optimize resource recovery across four distinct waste streams: household, healthcare, green/organic, and inert. The system integrates four specialized facilities: a Secondary Sorting Facility, Energy Recovery Facility, Composting Facility, and Inert Processing Facility, coordinated through a central Primary Sorting Hub. By enabling interconnectivity between these processing units, the system facilitates material cascading, maximizes the reuse and recycling of secondary raw materials, and supports energy recovery and circular nutrient flow. The anticipated benefits include enhanced operational efficiency, reduced environmental degradation, and generation of multiple revenue streams. However, the implementation of such a system faces challenges related to high capital investment, technological complexity, regulatory fragmentation, and low public acceptance. Overcoming these limitations will require strategic planning, stakeholder engagement, and adaptive governance. Full article

The COVID-19 pandemic has caused a surge in the use of disposable surgical masks, primarily composed of polypropylene (>86% carbon), whose improper disposal contributes to persistent microplastic pollution. In alignment with circular economy principles, this study explores the valorization of surgical masks into carbonaceous adsorbent materials (ACMs) for dye removal from water. The masks were chemically treated with concentrated H₂SO₄ at 85 °C for 2 h and subsequently activated with air (400 °C), CO₂, or steam (800 °C, 1 h). The resulting ACMs were characterized by SEM, FT-IR, nitrogen adsorption at −196 °C, and pH of the aqueous carbon suspension (pH_Sus, 1.96–9.25). CO₂ and steam activation yielded the highest surface areas (525 and 632 m²·g⁻¹, respectively). FT-IR confirmed the introduction of sulfonic groups, enhancing dye interactions. Adsorption tests using methylene blue (MB), methyl orange (MO), and orange G (OG) in ultrapure and river water showed removal efficiencies up to 100% for MB with ACM-WV and ~94% with ACM. All dyes followed pseudo-second-order kinetics. These findings demonstrate that surgical mask waste can be effectively transformed into high-value adsorbents for water treatment applications. Full article