Search Results (1,231)

Driven by environmental concerns and aligned with the principles of the circular economy, urban plastic waste—including packaging materials, disposable items, non-functional objects, and industrial scrap—is increasingly being collected, recycled, and marketed as a potential substitute for virgin polymers. However, the use of recycled polymers introduces uncertainties that can significantly affect both the durability and the further recyclability of the resulting products. This paper demonstrates how spectroscopic analysis in the mid-infrared (MIR) and near-infrared (NIR) regions can be applied well beyond the basic identification of the main polymeric component, typically performed during the sorting stage of recycling processes. A detailed interpretation of spectral data, based on well-established correlations between spectroscopic response and material structure, enables the classification of recycled polymers according to specific physicochemical properties, such as chemical composition, molecular architecture, and morphology. In this context, infrared spectroscopy not only provides a reliable comparison with the corresponding virgin polymer references but also proves particularly effective in assessing the homogeneity of recycled materials and the reproducibility of their properties—factors not inherently guaranteed due to the variability of input sources. As a case study, we present a robust protocol for determining the polypropylene content in recycled polyethylene samples. Full article

The Textiles and Clothing sector is increasingly focused on transitioning towards circular production, with industrial companies striving to integrate sustainable practices. Achieving this goal can involve the rapid adoption of innovative raw fibers (e.g., biodegradable and biobased materials) and maximizing the use of recycled and recyclable fibers. This implicitly demands acting on the total transparency of information along the complex supply chains in this sector to guarantee the correct adoption of these innovative fibers. It is precisely this complexity that hinders efforts to track and accurately disclose material usage. To address this issue, this paper presents a systematic literature review to explore the main challenges in adopting technologies like digital product passports, which can help track materials information along supply chains to support sustainable transitions. The analyzed articles were selected by excluding student thesis works, non-retrievable articles, papers that had a different focus, and literature published before 2020 or in non-institutional journals. The 53 resulting contributions are analyzed through a thematic analysis and discussed, focusing on identifying key material-related data that should be monitored to ensure responsible material use and strengthen sustainable production practices in the Textiles and Clothing sector, thereby guaranteeing control over material use and preventing premature disposal. Full article

The growing demand for sustainable waste management practices has prompted interest in the land application of paper sludge as an alternative to landfilling and incineration. This study evaluates the environmental potential of paper sludge derived from recycled hygienic paper production by investigating its effects on soil respiration, seed germination, and seedling development. A comprehensive set of respirometric tests using the OxiTop^® system assessed microbial activity in soil amended with various concentrations of paper sludge (1–100%). Concurrently, bioassays using Lepidium sativum L. and Pisum sativum L. seeds examined the phytotoxicity and physiological response during germination. The results show that low to moderate sludge concentrations (1–20%) stimulated microbial activity and enhanced germination parameters, with a germination index (GI) up to 150% at 1%. However, higher concentrations (>40%) led to oxygen depletion, microbial stress, and decreased plant growth, indicating potential phytotoxicity and the need for application thresholds. For certain intermediate concentrations (e.g., 30–40%), a delay of approximately 21 days before sowing is recommended to allow microbial communities to stabilize and avoid initial stress conditions for plants. This study demonstrates that controlled application of paper sludge in soil systems can serve as a viable and sustainable disposal method, supporting circular economy principles and reducing the environmental burden of paper industry by-products. Full article

Advancements in material science have allowed us to exploit the potential of new era for aircraft production. High-performance composites and alloys have allowed us to improve the performance and durability of aircraft, but they have become more and more precious with time. These materials can provide significant advantages in use but are costly, energy-intensive to produce, and their recovery and reuse has become a critical step to be addressed. Accordingly, a new approach in which end-of-life aircrafts represent unconventional mines rather than a disposal challenge is becoming increasingly relevant, providing access to high-value strategic raw materials and aligning with circular economy principles including European Green Deal and the United Nations Sustainable Development Goals. The complexity of dismantling and processing hybrid structures composed of metal alloys, ceramics, and advanced composites requires multiple approaches able to integrate chemical, mechanical, and thermal recovery routes. Accordingly, this review critically discusses the state of the art of the routes of end-of-life aircraft treatments, evaluating the connections between technology and regulation, and positions material recycling and reuse as central pillars for advancing sustainability in aerospace. Furthermore, this review provides a comprehensive reference for addressing the technical, economic, and policy challenges of waste management in aviation, contributing to broader goals of resource circularity and environmental preservation set forth by international sustainability agendas. Full article

Soil stabilization is a key process in geotechnical engineering, particularly for expansive clay soils that exhibit low strength and high volume-change potential. This study examines the use of waste tire powder (WTP) and autoclaved aerated concrete powder (ACP) as sustainable soil additives to improve mechanical performance while promoting sustainable waste recycling. Clayey soils from the Çorlu/Tekirdağ region were blended with varying proportions of WTP and ACP, and their properties were evaluated through Standard Proctor compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests. The results showed that UCS increased from 3.7 MPa to 4.5 MPa with 5% ACP, while CBR values rose from 21.3% to 29.8% with 17% ACP addition. Incorporating 2% WTP enhanced elasticity and reduced brittleness, although higher WTP contents (4%) lowered cohesion and strength. The optimum formulation, 2% WTP + 5% ACP, produced balanced improvements in strength, stiffness, and deformation resistance. The novelty of this research lies in establishing a hybrid stabilization mechanism that combines the elastic contribution of WTP with the pozzolanic bonding of ACP. Beyond technical improvements, recycling these industrial by-products mitigates environmental pollution, reduces disposal costs, and provides economic benefits. Thus, this study advances both the scientific understanding and practical application of sustainable soil stabilization. Full article

An integrated approach to waste management is based on efficient and safe methods for waste prevention, recycling, and safe waste treatment. In accordance with these principles, in this study, non-hazardous aluminosilicate waste (dust and sand) was used in the solidification/stabilization (S/S) treatment of hazardous waste (coating, emulsion, and sludge) from the automotive industry. Also, the oily component of the waste was valorized and investigated for energy recovery through co-incineration. The two S/S processes were proposed and their sustainability was assessed by utilizing all types of waste generated in the same plant, obtaining stabilized material suitable for safe disposal and oil phases for further valorization, and by techno-economic analysis. The efficiency of the S/S processes was evaluated by measuring unconfined compressive strength, hydraulic conductivity, density, and the EN 12457-4 standard leaching test of S/S products, along with XRD, SEM-EDS, and TG-DTG analyses. The possibility of using the oil phase was assessed based on its calorific value. The techno-economic assessment compared the investments, operating costs, and potential savings of both treatment scenarios. The results show that an integrated approach enables safe waste immobilization and resource recovery, contributing to environmental protection and economic benefits. Full article

In order to study the generation, management, and disposal status of waste mineral oil in China’s railway transport industry, this article takes the Beijing Railway Bureau and its subordinate Tangshan Locomotive Depot as the research objects and comprehensively applies the survey, case study, and statistical analysis methods to analyze the source of the generation of railway waste mineral oil, the distribution of the disposal enterprises and locomotive depots, the management mode, and the economic and environmental benefits of recycling waste engine oil. The results show that waste oil mainly originates from locomotive overhaul and maintenance. There is significant regional imbalance in the generation and disposal capacity of railway waste oil. The Beijing Railway Bureau can achieve the timely disposal of waste mineral oil and reduce transport risks. Waste mineral oil management integrates generation, storage, transfer, and disposal. If cooperation is initiated with waste oil disposal enterprises, the use of recycled oil can save up to RMB 178,600/year and reduce carbon emission by 76.42 tCO₂/year for this locomotive depot. In view of the current situation, the railway industry should improve the management and disposal deficiencies and explore the new model of waste oil reduction, reuse, and recycling. Full article

Research has often overlooked examination of circular consumption practices from the consumer’s perspective by primarily focusing on specific consumption activities, hindering researchers from obtaining comprehensive insights into consumers’ upstream and downstream roles. Addressing this gap would highlight their role as simultaneous product users and resource suppliers. The framework draws from the concepts of the circular economy, attitude–behavior–context theory, and practice theory to develop a model that explores circular consumption behavior based on 8R-strategies for addressing and reducing product demand and disposal. These strategies comprise refuse, rethink, reduce, reuse, repair, refurbish, repurpose, and recycle. The proposed model was empirically tested using partial least squares structural equation modeling with data collected from 528 consumers. The results show that the antecedents positively impacted circular consumption behavior, with environmental concern and consumer social responsibility acting as partial mediators. Habits moderated the relationship between these variables, though they showed insignificant moderation between circular economy knowledge and circular consumption behavior. The findings underscore the importance of consumers’ role as both product users and resource suppliers in circular consumption practices. Full article

Mattresses represent one of the most widespread and problematic bulky waste streams worldwide, due to their unavoidable daily use, their high presence in municipal solid waste flows, and the complexity of their end-of-life management. Their heterogeneous composition—combining polyurethane foams, textiles, metal springs, and adhesives—makes separation and recovery difficult, leading many discarded mattresses to end up in landfills or incinerators, with associated greenhouse gas emissions and the loss of valuable secondary resources. Within this context, recycling emerges as a priority alternative under the circular economy framework, enabling material recovery and reducing reliance on traditional disposal methods. Among current options, mechanical recycling is especially promising, as it provides energy savings and lower emissions compared to thermal treatments. However, its large-scale implementation requires improvements in product design, collection logistics, and regulatory frameworks to address existing challenges. This article provides a critical review of the current state of mattress recycling and valorization, examining technological advances, environmental impacts, and systemic barriers. It also highlights successful initiatives in the hospitality and healthcare sectors, which illustrate the potential of circular strategies to transform bulky waste management and promote sustainable material flows. Full article

Electronic waste is becoming a growing global pollution issue due to short device lifespans and insufficient safe disposal methods. Hazardous metals like arsenic and mercury from electronic waste harm both the environment and human health. Recycling processes remain underdeveloped, requiring new eco-friendly solutions. This paper reports on the synthesis and properties of the cationic surfactants ammonium terthiophene (CTT) and 3,4-propylene-dioxythiophene (C-ProDOT), which may have potential use in organic electronics. Ecotoxicological tests showed no significant long-term toxicity and medium-to-high biodegradability, which are keys for environmental protection. These surfactants also displayed selective bacterial adhesion, making them candidates for bionic devices. Life cycle assessment revealed higher energy use and ecotoxicity for C-ProDOT than CTT, underscoring the need for sustainable chemical design. Full article

This study evaluates the viability of water jig for removing the impurities from CDW and the concentration of concrete aggregates from mixtures containing 10%, 20%, and 30% impurities (brick and gypsum), simulating the materials commonly found in CDW. Laboratory-scale jigging tests were conducted in single-stage jigging, and the products were characterized based on density > 2.6 g/cm³, water absorption, shape factor, and bulk density to evaluate the separation performance. It was noted that dense fractions consistently achieved high purity with less than 1% impurities and a concrete content of more than 99% and that more than 80% of dense material was recovered. These results demonstrate that water jigging is a technically viable method for producing recycled aggregates of sufficient quality for reuse in concrete while also reducing CDW disposal by more than 40% and contributing to the sector’s carbon footprint reduction. The findings confirm that even a single-stage jigging process can provide high-quality recycled aggregates, offering a simple and effective route for CDW beneficiation. Full article

Current food packaging, primarily made of non-biodegradable plastics, significantly contributes to environmental pollution. New packaging systems for food applications from biopolymers and/or with multifunctional properties are being developed as substitutes for synthetic polymers. The increasing concern over the environmental effects of packaging waste is driving a transition toward renewable packaging materials. Edible films and coatings play a vital role in maintaining food quality by preventing the loss of aroma, flavour, and important components, while also extending shelf life. Biopolymers, including polysaccharides, proteins, and lipids, are gaining attention as the future of packaging due to the environmental issues linked to petrochemical-based plastics. Modern packaging should not only protect products but also be biodegradable, recyclable, and have a minimal ecological impact. This review comprehensively summarises edible packaging in the form of single-use, fast-dissolving pouches for food applications as a circular approach and a sustainable solution in food technology. Innovations have resulted in the development of a unique packaging solution made from renewable sources. This packaging utilises plant and animal by-products to create edible films and pouches that are easy to seal. Edible packaging is emerging as a sustainable alternative, designed to simplify food packaging while minimising waste. Fast-dissolving scalable packaging, particularly edible films that dissolve in water, is used for individual servings of dry foods and instant beverages. This includes items like breakfast cereals, instant coffee or tea, and various powdered products. Additionally, there is an innovative approach to single-use packaging for oils and powders, leveraging the convenience and efficiency of these fast-dissolving films. Edible pouch packaging, made from safe and edible materials, provides a biodegradable option that decomposes naturally, thereby reducing pollution and the need for disposal. Full article

The global outbreak and prolonged presence of Coronavirus Disease 2019 (COVID-19) have resulted in a substantial accumulation of discarded masks, posing serious environmental challenges. This study proposes an eco-friendly and low-carbon strategy to repurpose discarded DMFM fibers as a key component in fiber-reinforced self-compacting recycled aggregate concrete (FRSCRAC). The mechanical and environmental performance of FRSCRAC was systematically evaluated by investigating the effects of recycled coarse aggregate (RCA) replacement ratios (0%, 50%, 100%), discarded DMFM fiber material (DMFM) contents (0%, 0.1%, 0.2%, 0.3%), and fiber lengths (2 cm, 3 cm, 4 cm) on axial compression failure mode and stress–strain behavior. The results demonstrated that DMFM fibers significantly enhanced concrete ductility and peak stress via the fiber-bridging effect. Based on fiber influence, modified stress–strain and shrinkage models for SCRAC were established. To further understand the fiber fixation mechanism, X-ray computed tomography (X-CT) and scanning electron microscopy (SEM) analyses were conducted. The findings revealed a stable random distribution of fibers and strong interfacial bonding between fibers. These improvements contributed to enhanced mechanical performance and the effective immobilization of polypropylene microfibers, preventing further microplastics release into the air. This innovative approach provides a sustainable solution for recycling and effectively immobilizing discarded DMFM fibers in concrete over long curing periods, while also enhancing its properties. Full article

This study evaluates the environmental impact of swimming goggles through a Life Cycle Assessment (LCA), comparing virgin and recycled polycarbonate models. It identifies key hotspots, assesses circular economy benefits, and examines barriers to sustainable disposal, aligning with European Union’s (EU) 2050 sustainability objectives. The LCA was modeled using SimaPro, with the Environmental Footprint (EF) 3.1 method to analyze 16 impact categories (e.g., climate change, human toxicity, resource depletion). Two scenarios were assessed: (1) virgin polycarbonate production and (2) a closed-loop system (80% recycled content, 30% reintegration). Primary data from a survey of 150 competitive swimmers quantified disposal behaviors. The lens production phase (bisphenol A processing) dominated impacts, contributing to 62% of climate change and 75% of human toxicity. The recycling scenario reduced total impact by 23.1% (119 → 91.5 mPt), with significant declines in freshwater ecotoxicity (−28.6%) and marine eutrophication (−25.1%). Survey data highlighted critical gaps: low consumer participation in recycling due to lack of awareness and inadequate disposal infrastructure. Recycled polycarbonate can substantially mitigate environmental impacts, but systemic barriers (consumer behavior, collection gaps) limit progress. Future work should explore bio-based polymers and policy incentives to accelerate circularity. Full article

Currently, many foundries successfully reuse sand multiple times within their production cycle. However, when the sand can no longer be reused, it is disposed of, resulting in environmental damage and high disposal costs for the company. The present research aims to explore the potential reuse of foundry sands as fine aggregate in concrete. Since this by-product is classified as non-hazardous waste, it can offer interesting opportunities for the recycling of a material that is currently one of the most widely used in the construction industry. This paper studies the potential reuse of green sand (GS) and chemically bonded sand (CBS) as a partial replacement for natural sand (NS) in concrete. Concrete specimens made with 10%, 20%, and 30% of foundry sand were tested, and a comparative analysis was carried out with the standard mixture in terms of chemical–physical properties, workability, and mechanical properties. The results showed a reduction in the performance of concrete specimens prepared with foundry sands. The lowest reductions in the strength, which were always below 10%, were observed for a 10% inclusion rate of both GS and CBS, with slightly better performance for CBS. Performance reductions tend to increase with higher replacement rates. However, these performance reductions turn out to be acceptable for concrete used in non-structural applications. Full article