Recycling

27 pages, 14111 KB

Open AccessArticle

End-of-Life Tire Geocells for Unpaved Road Reinforcement: A Comparative Performance Assessment Under Cyclic Loading

by María Paula Susunaga, Ennio Marques Palmeira, Ivonne Alejandra Gutiérrez Góngora, Karla Yolima Rodriguez Rodríguez and Juan Sebastián Perdomo Díaz

Recycling 2026, 11(7), 129; https://doi.org/10.3390/recycling11070129 - 20 Jul 2026

Abstract

The growing generation of end-of-life tires and the structural deficiencies of tertiary road networks in developing regions represent two interconnected challenges that call for integrated engineering solutions. Although recycled tire geocells have been explored as a reinforcement alternative for unpaved roads, their mechanical [...] Read more.

The growing generation of end-of-life tires and the structural deficiencies of tertiary road networks in developing regions represent two interconnected challenges that call for integrated engineering solutions. Although recycled tire geocells have been explored as a reinforcement alternative for unpaved roads, their mechanical performance has not been systematically compared against conventional high-density polyethylene (HDPE) geocells under controlled cyclic loading, nor has the material valorization potential been quantified in terms of waste diversion capacity. This study systematically evaluates and compares the deformation response, stress distribution, and aggregate degradation of both systems through large-scale laboratory testing. An instrumented steel chamber was used to apply up to 100,000 load cycles at 600 kPa contact pressure, across two cell heights (150 mm and 200 mm) and two granular infill qualities. The 200 mm recycled tire geocell reduced permanent surface deformation by up to 84% relative to the unreinforced condition, and Traffic Benefit Ratio values reached up to 1.6 times those recorded for HDPE geocells under lower-quality infill. The viscoelastic response of rubber promoted energy dissipation and limited aggregate particle breakage. Confinement performance was fully preserved after surface reconditioning, confirming the durability of the reinforcement system under maintenance cycles. The fabrication process requires no chemical transformation, valorizing approximately 16 end-of-life tires per square meter—equivalent to 56,000 tires per kilometer of reinforced road. These findings support the large-scale valorization of end-of-life tires as functional geotechnical materials, offering a circular economy pathway for solid waste diversion in regions where both road infrastructure deficits and tire disposal challenges coexist. Full article

(This article belongs to the Special Issue Advancing the Circular Economy: A Life Cycle Perspective on Waste Valorization)

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22 pages, 5417 KB

Open AccessArticle

Silver Purification from Waste for Bio–sonochemical Synthesis of Ag₂O Nanoparticles Using Cannabis sativa Flower Extract

by Sumita Chailoi, Napat Mahiwan, Chatisa Kansomket, Thanapon Chandakhiaw, Tapany Patcharawit, Tanakorn Uthaiphetra, Kiattisak Batsungnoen and Sakhob Khumkoa

Recycling 2026, 11(7), 128; https://doi.org/10.3390/recycling11070128 - 19 Jul 2026

Abstract

Rapidly increasing manufacturing waste intensifies the need for highly efficient and economically feasible waste-to-resource technologies. This research presented an upcycling strategy that transforms silver (Ag)-bearing waste into functional silver oxide nanoparticles (Ag₂O NPs) for potential use in biomedical applications. A two-step [...] Read more.

Rapidly increasing manufacturing waste intensifies the need for highly efficient and economically feasible waste-to-resource technologies. This research presented an upcycling strategy that transforms silver (Ag)-bearing waste into functional silver oxide nanoparticles (Ag₂O NPs) for potential use in biomedical applications. A two-step process of silver purification and the bio–sonochemical synthesis of Ag₂O NPs was employed. First, the sequential purification of Ag via melt-refining and electrorefining was utilized to efficiently achieve a silver purity of ≥99.90%. This purification encouraged the recycling of various forms of Ag-bearing waste. Subsequently, the purified Ag was prepared as the precursor for the bio–sonochemical synthesis of Ag₂O NPs, using Cannabis sativa SUT CBD12 flower extract as a natural reducing agent. The optimal conditions were adapted from a preliminary test using AgNO₃ as the precursor. At initial concentrations of 0.01 M Ag solution, 1 mM PVP solution, and 10 g dried weight of Cannabis sativa SUT CBD12 added to 100 mL DI water, the optimal condition was obtained at the capping agent:reducing agent:precursor volume ratio of 0.6:0.006:1, pH 10–12, under a short sonication time of 2 min. The purified Ag (waste-derived) and AgNO₃-derived Ag₂O NPs shared similar spherical shapes and sizes of ~100–130 nm. The Ag₂O NPs showed antibacterial effectiveness against S. aureus (ZOI of 26–29 mm) and E. coli (ZOI of 16–20 mm). Preliminary observations into the incorporation of Ag₂O NPs into polycaprolactone (PCL) to produce electrospun PCL/Ag₂O NPs nano fabrics shows a bead-free morphology, raising the possibility of a potential use in wound dressing. Following these preliminary explorations into potential uses and emission controls, a circular design maximizing the use of recycled resources is emphasized. Full article

21 pages, 1914 KB

Open AccessArticle

Reclaiming Gold from Integrated Circuits Waste via a Sustainable Physic-Hydrometallurgical Approach

by Márcia A. D. Silva, Liliana M. Martelo, Belmira Neto, Margarida M. S. M. Bastos and Helena M. V. M. Soares

Recycling 2026, 11(7), 127; https://doi.org/10.3390/recycling11070127 - 18 Jul 2026

Abstract

Integrated circuits (ICs), a major fraction of waste electrical and electronic equipment (WEEE), represent an important secondary source of gold (Au). However, recovering high-purity Au from ICs remains challenging due to the high silicon dioxide content that encapsulates Au within the IC core [...] Read more.

Integrated circuits (ICs), a major fraction of waste electrical and electronic equipment (WEEE), represent an important secondary source of gold (Au). However, recovering high-purity Au from ICs remains challenging due to the high silicon dioxide content that encapsulates Au within the IC core and the presence of complex base-metal mixtures that hinder selective purification. This study proposes a simplified end-to-end process that integrates mechanical liberation, magnetic separation, oxidative chlorination, ion-exchange purification and Au recovery from isolated ICs. Unlike conventional multi-stage comminution routes, the proposed pretreatment combines hydraulic pressing, milling/sieving and magnetic separation to maximize Au exposure while minimizing dust generation, metal losses and base-metal interference, which is subsequently subjected to oxidative leaching and purification. Optimal extraction conditions, determined through a Taguchi design (2.5 M HCl, 0.34 M NaClO, 40 °C, solid–liquid ratio 1 g/40 mL, 3 h), achieved a Au leaching efficiency of 89%. The resulting multi-metal leachate was treated with a strong anionic ion-exchange resin, increasing Au purity from 8% to 86% after thiourea elution in a sulfuric-acid medium. Final Au recovery was completed by reductive precipitation with sodium borohydride, yielding complete solidification (~100% efficiency). A comparative life-cycle assessment showed that this recycling route offers favourable environmental performance relative to primary mining. Beyond achieving efficient Au recovery, this work establishes an integrated recovery route for isolated ICs that combines process simplification with environmental positive impact, addressing an important gap in WEEE recycling. Full article

(This article belongs to the Special Issue Sustainable Management and Advanced Recycling of Waste Electrical and Electronic Equipment (WEEE))

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32 pages, 10088 KB

Open AccessArticle

Characterization and C25/30 Valorization of Construction and Demolition Waste Aggregates from Fez, Morocco: A Dreux-Gorisse Mix Design and PCA Approach

by Yasmine Boukhlouf, Mohammed Benabdelhadi, Hassan Tabyaoui, Abderrahim Lahrach, Abdallah Oulmekki, Maryame El-Yazidi, Zineb El Attar Soufi and Omar Kassou

Recycling 2026, 11(7), 126; https://doi.org/10.3390/recycling11070126 - 15 Jul 2026

Abstract

Construction and demolition waste valorization as recycled aggregates remains largely underdeveloped in North African urban contexts. This study presents the first normatively referenced characterization of recycled aggregates from ten sites in Fez, Morocco, combined with experimental C25/30 concrete formulation using the Dreux-Gorisse method. [...] Read more.

Construction and demolition waste valorization as recycled aggregates remains largely underdeveloped in North African urban contexts. This study presents the first normatively referenced characterization of recycled aggregates from ten sites in Fez, Morocco, combined with experimental C25/30 concrete formulation using the Dreux-Gorisse method. Physical, mechanical, and chemical analyses reveal high water absorption (9.98 ± 0.94%), low particle density (2197 kg/m³), sub-standard sand equivalent (39.4%), and elevated methylene blue (3.06 g/kg), all governed by attached cementitious mortar content. Principal component analysis identifies three groups: Cluster A (E2, E6, E8), directly valorizable for structural use; Cluster B (E3, E4, E7, E10), requiring fine-fraction removal (<80 µm) prior to concrete incorporation; and an intermediate group (E1, E5, E9), suitable for non-structural applications. Concrete mixes from a composite blend of all ten samples were experimentally validated on cylindrical specimens. At 25% substitution, the 28-day compressive strength reaches 22–28 MPa, achieving marginal C25/30 compliance when superplasticizer and pre-wetting correction (9.98 L/100 kg recycled aggregate) are applied; substitution at 50% and above does not meet structural requirements (18–24 MPa). Durability assessments confirm increasing carbonation depth (7–11 mm at 25%) and moderate-to-high chloride permeability, underscoring the need for source-selective sampling and pre-treatment in urban construction and demolition waste valorization programs, particularly in North African and Maghreb contexts where construction materials and building practices are broadly similar and demolition waste is typically processed without prior sorting. Full article

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21 pages, 3842 KB

Open AccessArticle

Sustainability Assessment of Green Concrete Using Building Material Sustainability Potential (BMSP) and Empathetic Added Sustainability Index (EASI)

by Rosalia Ruiz-Ruiz, Elia Mercedes Alonso-Guzman, Hugo L. Chavez-Garcia, Marco Antonio Navarrete-Seras, Mauricio Arreola-Sánchez, Judith Alejandra Velazquez-Perez and Wilfrido Martinez-Molina

Recycling 2026, 11(7), 125; https://doi.org/10.3390/recycling11070125 - 14 Jul 2026

Abstract

Concrete remains the most widely used construction material owing to its affordability, local availability, mechanical performance, durability, and versatility. However, its production has a significant environmental impact, and its service life may be reduced under aggressive exposure conditions, affecting both the functionality and [...] Read more.

Concrete remains the most widely used construction material owing to its affordability, local availability, mechanical performance, durability, and versatility. However, its production has a significant environmental impact, and its service life may be reduced under aggressive exposure conditions, affecting both the functionality and cost of structures. This study presents a sustainability assessment based on a harmonized database of previously developed concrete mixtures, rather than a new experimental campaign. Waste-containing mixtures and their corresponding conventional or reference controls were considered to anchor the comparison to reference concretes, rather than only to the minimum values within the analyzed dataset. The objective was to compare the consistency among sustainability index formulations: K_SB and K_SB,C, associated with the Building Material Sustainability Potential (BMSP), and the Empathetic Added Sustainability Index (EASI). These formulations integrate functional and environmental performance, although they differ in their aggregation approach and in the treatment of economic variables, such as cost and eco-cost. The indicators considered include 28-day compressive strength, carbonation rate, global warming potential (GWP), gross energy requirement (GER), natural raw material consumption (NRMC), eco-cost, and material cost. The results show that mixtures with higher replacement levels of natural aggregates by recycled concrete aggregate and partial replacement of cement by locally sourced ashes exhibited the best integrated performance. The 300/100RCAg mixture stood out, with index values close to 3.43, 3.52, and 3.99, up to approximately four times those of the control. Sensitivity and uncertainty analyses showed that the highest-ranked mixtures generally maintained favorable positions across assessment methods and under ±20% input variability, although some alternatives exhibited substantial method-dependent ranking changes. The results demonstrate that local waste materials can improve concrete sustainability; however, their benefits depend on waste type, conditioning requirements, functional performance, and the selected sustainability assessment method. Full article

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27 pages, 16720 KB

Open AccessArticle

Waste-on-Waste Roasting of Copper Slag with Flotation Tailings for Selective Recovery of Cu, Ni, and Co

by Bobur Gayratov, Bekhzod Gayratov, Labone L. Godirilwe, Gwiranai Danha and Atsushi Shibayama

Recycling 2026, 11(7), 124; https://doi.org/10.3390/recycling11070124 - 14 Jul 2026

Abstract

Copper smelter slag represents a significant secondary resource of critical metals, while flotation tailings serve as an abundant sulfur-bearing waste stream. This study investigated a waste-on-waste sulfation roasting approach for the selective recovery of Cu, Ni, and Co from fayalite copper smelter slag [...] Read more.

Copper smelter slag represents a significant secondary resource of critical metals, while flotation tailings serve as an abundant sulfur-bearing waste stream. This study investigated a waste-on-waste sulfation roasting approach for the selective recovery of Cu, Ni, and Co from fayalite copper smelter slag using flotation tailings as an in situ sulfur source and sodium metabisulfite (SMBS, Na₂S₂O₅) as a sulfation promoter. The effects of roasting temperature, roasting time, slag-to-tailings ratio, SMBS dosage, and water-leaching conditions were systematically evaluated. Under the optimum conditions of a slag-to-tailings ratio of 1:1, roasting at 600 °C for 4 h with 30 wt% SMBS addition, followed by water leaching at 25 °C for 2 h, extraction efficiencies of 85.5% Cu, 81.6% Ni, and 87.1% Co were achieved, while Fe dissolution remained below 5%, demonstrating high selectivity. Phase and microstructural analyses by XRD, FTIR, SEM, and TG–DTA revealed that pyrite oxidation generated sulfur oxides required for metal sulfation, whereas SMBS promoted sulfur release and sulfate stabilization, enhancing sulfation efficiency. Thermodynamic analysis further confirmed the feasibility of sulfide oxidation and sulfate formation within the investigated temperature range. The results demonstrate that the synergistic use of tailings and SMBS enables efficient low-temperature sulfation roasting of fayalite slag and provides a promising route for the selective recovery of valuable metals from metallurgical waste materials. Full article

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24 pages, 14302 KB

Open AccessArticle

Thermal Characterization of Expanded PLA Prototypes Incorporating Grape Stalks and Spruce Bark Residues for Bio-Based Packaging Applications

by Niccolò Rimbotti, Daniele Sarri, Jessica Scriva, Andrea Pagliai, Carolina Perna, Federico Rotini, Gianluca Bambi, Leonardo Conti and Giuseppe Rossi

Recycling 2026, 11(7), 123; https://doi.org/10.3390/recycling11070123 - 14 Jul 2026

Abstract

Bio-based packaging is receiving increasing attention due to the environmental impact of fossil-based plastics. However, its practical implementation requires further evidence on material processing and functional performance. This study evaluated the thermal properties of expanded polylactic acid (E-PLA) prototypes blended with raw, minimally [...] Read more.

Bio-based packaging is receiving increasing attention due to the environmental impact of fossil-based plastics. However, its practical implementation requires further evidence on material processing and functional performance. This study evaluated the thermal properties of expanded polylactic acid (E-PLA) prototypes blended with raw, minimally processed agroforestry residues. Specifically, spruce bark and grape stalks were used as waste wood fibers. This study focused primarily on the thermal characterization of the materials by measuring thermal conductivity and resistance. To evaluate the distribution of the two fractions (polymer and fibrous), samples were created with various volumetric ratios between the parts. Simultaneous pressure and microwave heating of the sample were used to stabilize the material. To characterize the raw materials used in this study, bulk density and moisture content were measured. To characterize the mixed materials samples, thermal conductivity and resistance, bulk density, and pressure were measured. To investigate the variables that influence thermal characteristics, statistical analyses such as regression models, ANCOVA, and Spearman correlation were applied. These analyses showed that increasing the biofiber content significantly reduced thermal resistance and increased thermal conductivity. However, negligible effects were observed for the type of fiber used and the duration of the heat treatment. These results describe the thermal properties of blends containing E-PLA and agroforestry residues. The results also show a marked effect of the biofiber content on thermal performance. This study does not provide a comprehensive characterization of the new materials, as it focuses on the prototyping methodology and the laboratory-scale production feasibility of E-PLA/agroforestry-residue prototypes. Full article

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29 pages, 11498 KB

Open AccessArticle

Valorization of Minimally Processed Blast Furnace Slag in Industrial Mortars: Early-Age Performance and Embodied Carbon Reduction

by Houssam Affan, Laurent Fehr, Ginan Al-Massri, Farjallah Alassaad, Amro Yaghi and Hassan Ghanem

Recycling 2026, 11(7), 122; https://doi.org/10.3390/recycling11070122 - 14 Jul 2026

Abstract

Conventional valorization of blast furnace slag commonly involves granulation, fine grinding, mechanical activation, or chemical activation, which increase energy demand and processing complexity. This study investigated a minimally processed blast furnace slag (MP-BFS), defined here as the fraction passing 64 µm obtained by [...] Read more.

Conventional valorization of blast furnace slag commonly involves granulation, fine grinding, mechanical activation, or chemical activation, which increase energy demand and processing complexity. This study investigated a minimally processed blast furnace slag (MP-BFS), defined here as the fraction passing 64 µm obtained by sieving a 0–8 mm industrial material without grinding, additional granulation, thermal treatment, or chemical activation. MP-BFS replaced 10–50% of the cement by mass to reduce clinker in industrial mortars formulated at a constant flow spread of 23–24 cm and tested from 8 h to 90 d. Bulk density, water-accessible porosity, total and capillary water absorption, and compressive and flexural strengths were evaluated. Replacing 10% of the cement with slag improved compressive strength from the earliest test age and increased the 28-day compressive and flexural strengths by 5.1% and 9.5%, respectively, relative to the control mortar; this response coincided with a reduction in measured porosity from 8.95% to 8.01%. This improvement is consistent with a physical filling effect and improved particle packing, although these mechanisms were not directly verified by microstructural analyses. At higher replacement levels, water-accessible porosity increased, reaching 24.45% at 50% slag replacement, alongside greater water ingress and delayed strength development. Exploratory empirical regression analyses described associations among slag content, porosity, water transfer, and compressive strength within the investigated formulations. A simplified screening-level constituent-production-and-transport comparison per cubic meter, based on generic ICE factors and an assumed 50 km transport distance, estimated a maximum embodied carbon reduction of 44% at 50% replacement. Curing energy, use, carbonation, maintenance, and end-of-life stages were excluded. Overall, 10% MP-BFS replacement provided the most favorable performance–carbon content balance, whereas 30–50% achieved larger carbon reductions but showed early-age strength losses that limit their suitability for rapid-demolding applications under the investigated conditions. Full article

(This article belongs to the Special Issue Celebrating 10 Years of Recycling: Shaping the Future of Waste Management)

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16 pages, 2450 KB

Open AccessArticle

Environmental Profile of Wood Waste Recycling and the Use of Recycled Wood in Furniture Manufacturing

by Caterina Barbiero and Anna Mazzi

Recycling 2026, 11(7), 121; https://doi.org/10.3390/recycling11070121 - 10 Jul 2026

Abstract

The wood furniture sector, heavily reliant on wood panels, faces supply risks and generates significant waste, which can be managed through recycling or energy recovery. This study investigates the environmental impacts of wood waste end-of-life management and the use of virgin versus recycled [...] Read more.

The wood furniture sector, heavily reliant on wood panels, faces supply risks and generates significant waste, which can be managed through recycling or energy recovery. This study investigates the environmental impacts of wood waste end-of-life management and the use of virgin versus recycled raw materials in the wood furniture sector, aiming to identify the most sustainable scenario in wood manufacturing between wood waste recycling as output and recycled wood as input. Environmental impacts of four scenarios were analyzed and compared through the life cycle assessment with the “grave-to-cradle” approach. Inventory was supported by information and data from an Italian furniture company, while the impact assessment was performed using the ReCiPe method and the SimaPro software. The results from the impact assessment and gravity analysis show the main contribution of different scenarios due to the incineration of wood waste and the manufacturing of wood panels; the sensitivity analysis highlights how increasing recycling allows for greater performance improvement than increasing recycled inputs. Although limited by the assumptions related to the case study, this research enriches the discussion on the environmental convenience of recycling manufacturing waste and using recycled materials and confirms the importance of life cycle assessment for implementing circular economy strategies in companies. Full article

(This article belongs to the Special Issue Advancing the Circular Economy: A Life Cycle Perspective on Waste Valorization)

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22 pages, 3403 KB

Open AccessArticle

Multi-Assay Characterization of an LED Recycler Feedstock for Economic and Environmental Valuation of Critical Metals

by Mehdi Golzar-Ahmadi and Maria Holuszko

Recycling 2026, 11(7), 120; https://doi.org/10.3390/recycling11070120 - 8 Jul 2026

Abstract

Urban mining is gaining importance as demand for critical metals continues to rise. Waste light-emitting diode (LED) lamps are a valuable secondary source of gallium, rare earth elements, precious metals, and base metals, yet accurately quantifying these metals remains challenging. In this work, [...] Read more.

Urban mining is gaining importance as demand for critical metals continues to rise. Waste light-emitting diode (LED) lamps are a valuable secondary source of gallium, rare earth elements, precious metals, and base metals, yet accurately quantifying these metals remains challenging. In this work, various LED waste streams from a lamp recycler were subjected to critical metal characterization. The strengths and weaknesses of established metal assay techniques were evaluated to advance the determination of gallium, rare earth elements (Ho, Lu, Tb, Y, Er, Nd, Ce), and precious metals (Au, Ag, Pt, Pd) in LED waste. Metal assays, including alkaline fusion, four-acid digestion, aqua regia, a fire assay, and energy-dispersive X-ray fluorescence, were compared, and precision was assessed using a newly created LED lamp reference material and OREAS465. A metal-analysis-driven approach was developed to quantify the reduction in mining through recycling LED lamps using the rock-to-metal ratio metric. The economic value of LED waste streams, together with their recyclability and grindability, was assessed. The results indicate that LED strips can contain up to 147,484 g/t Cu, 452 g/t Ga, 367 g/t Lu, 89 g/t Tb, and 95 g/t of precious metals. Recycling one tonne of waste LEDs can offset mining 75.5 tonnes of rock and primary ore. The estimated economic value of mixed LED waste was USD 3351 per tonne, increasing to USD 4089 per tonne after physical separation. The results demonstrate the importance of robust analytical methods for accurate metal accounting and provide a stronger foundation for assessing the recycling potential of LED waste. Full article

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19 pages, 13581 KB

Open AccessArticle

Enhancing the Efficiency of Anaerobic Digestion Treatment of Tetracycline-Containing Wastewater

by Huanjia Liu, Pengpeng Zhang, Zhaohan Zhang, Kuokai Sun, Weihua He and Yujie Feng

Recycling 2026, 11(7), 119; https://doi.org/10.3390/recycling11070119 - 8 Jul 2026

Abstract

To improve the efficiency of AD for tetracycline-containing wastewater, this study systematically investigated the effects of ZVI and PAC on pollutant removal, VFA metabolism, biogas production, and sludge physicochemical characteristics. RSM was employed to optimize the co-dosing conditions of ZVI and PAC. The [...] Read more.

To improve the efficiency of AD for tetracycline-containing wastewater, this study systematically investigated the effects of ZVI and PAC on pollutant removal, VFA metabolism, biogas production, and sludge physicochemical characteristics. RSM was employed to optimize the co-dosing conditions of ZVI and PAC. The results suggested that ZVI and PAC could significantly facilitate COD degradation, and the optimal dosages for COD removal were 1000 mg/L ZVI and 2000 mg/L PAC with a removal efficiency of 61.03% and 56.9%, respectively. Both additives effectively accelerated the catabolism of typical VFAs, thereby mitigating the accumulation of intermediate metabolites that may cause AD system instability. In terms of biogas production, 1000 mg/L ZVI and 2000 mg/L PAC enhanced methane yield by 55.9% and 35.0% compared to the control group, with ZVI exhibiting a more prominent enhancement effect. Mechanistic analysis suggested that ZVI and PAC reinforced the AD process through multiple pathways: enhancing the electrical conductivity of the AD system, possibly facilitating the electron transfer pathways, and stimulating the secretion of EPSs by anaerobic microbes. RSM optimization yielded the optimal co-dosing parameters: 1000 mg/L ZVI and 1200 mg/L PAC. Under these conditions, the methane yield was increased by 71.18% relative to the control group, and the model validation accuracy reached 97.94%. This study provides a viable technical strategy and theoretical basis for enhancing the efficiency of anaerobic treatment of tetracycline-containing wastewater. Full article

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31 pages, 2932 KB

Open AccessReview

Advancing the Circular Economy in the Indian Automotive Sector Through Materiality Assessment of Industry Practices and Policy Interventions

by Swapnil Gund, Sandeep G. Thorat, Sachin Pawar, Prashant Paraye and Anuj Prajapati

Recycling 2026, 11(7), 118; https://doi.org/10.3390/recycling11070118 - 3 Jul 2026

Abstract

The transition to a circular economy (CE) in the automotive sector is increasingly critical amid rising resource pressures and climate imperatives. In India, this shift is influenced by regulatory initiatives, corporate sustainability goals, and life-cycle-wide environmental challenges. However, current studies remain fragmented, often [...] Read more.

The transition to a circular economy (CE) in the automotive sector is increasingly critical amid rising resource pressures and climate imperatives. In India, this shift is influenced by regulatory initiatives, corporate sustainability goals, and life-cycle-wide environmental challenges. However, current studies remain fragmented, often neglecting the linkages between policy drivers, material issues, and firm-level responses. This study aims to evaluate how CE strategies are operationalized across the Indian automotive value chain using a Drivers–Materiality–Response (DMR) analytical framework. A multiple-case qualitative analysis was conducted involving six major automotive firms and associated ecosystem actors, with data sourced from corporate reports, national policies, and third-party assessments from 2018 to 2024. Semi-structured interviews with 11 industry experts were incorporated to strengthen triangulation, validate firm-level circular economy claims, and support the reliability of the DMR-based interpretation. Findings reveal strong alignment with national CE policies among leading firms, particularly Tata Motors and Mahindra, with comprehensive integration of electrification, battery reuse, zero-waste goals, and digital mobility solutions. However, challenges remain in end-of-life vehicle (ELV) formalization and circularity in downstream systems. The DMR model effectively bridges gaps in existing frameworks by offering a life-cycle-based lens that links Environmental, Social and Governance (ESG), Life Cycle Assessment (LCA), and policy–firm dynamics. The study contributes a scalable diagnostic tool for assessing CE maturity in emerging economies. While limited by reliance on secondary data, the triangulated approach enhances reliability and provides actionable insights for policymakers and industry leaders. Full article

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29 pages, 2850 KB

Open AccessArticle

Environmental Governance and Artificial Intelligence in Recreational Tourism Areas: Transformation in Waste Management

by Dalia Perkumienė, Ahmet Atalay, Giedrė Adomavičienė, Aidanas Perkumas and Marius Mažeika

Recycling 2026, 11(7), 117; https://doi.org/10.3390/recycling11070117 - 27 Jun 2026

Abstract

This study examines the transformation of environmental governance processes in recreational tourism in Turkey and Lithuania through artificial intelligence (AI)-supported waste management applications. The research focuses on the contributions of AI-based applications to sustainable destination management, environmental sustainability, and data-driven governance processes. A [...] Read more.

This study examines the transformation of environmental governance processes in recreational tourism in Turkey and Lithuania through artificial intelligence (AI)-supported waste management applications. The research focuses on the contributions of AI-based applications to sustainable destination management, environmental sustainability, and data-driven governance processes. A case study design was used within the framework of qualitative research methods. The dataset was obtained through semi-structured interviews with a total of 40 experts from Turkey and Lithuania. The data were analyzed using content analysis with the NVivo 14 program. The research findings reveal significant differences between the two countries in terms of digital infrastructure, institutional coordination, governance structures, and AI integration capacity. In Turkey, AI-supported waste management applications are still in their development phase; processes are largely shaped by managerial initiative, project-based approaches, financial constraints, and lack of institutional coordination. In contrast, Lithuania exhibits a more systematic and institutionalized digital governance structure thanks to EU-supported environmental and digitalization policies. However, data security, system sustainability, and high technology costs in small-scale recreation areas stand out as significant problem areas for Lithuania. This study addresses an underexplored intersection between artificial intelligence applications and environmental governance within recreational tourism contexts, contributing to the emerging literature on digital transformation in sustainable destination management. The findings reveal that AI-supported environmental management systems have significant potential to strengthen sustainable tourism management, increase operational efficiency, and support data-driven sustainable destination strategies. These findings offer practical implications for destination managers and policy makers by highlighting how AI-enabled environmental governance systems can enhance sustainability-oriented decision-making and improve operational efficiency in recreational tourism areas. Full article

(This article belongs to the Special Issue Celebrating 10 Years of Recycling: Shaping the Future of Waste Management)

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22 pages, 3665 KB

Open AccessReview

Transforming Beach-Accumulated Seaweed into High-Value Bioactive Products: A Recycling Perspective

by Dinusha Shiromala Dissanayake, Thilina U. Jayawardena and Dineth P. Nagahawatta

Recycling 2026, 11(7), 116; https://doi.org/10.3390/recycling11070116 - 26 Jun 2026

Abstract

Due to large-scale macroalgal blooms, nutrient enrichment, and changes in ocean circulation brought on by climate change, beach-accumulated seaweed (BAS) has quickly become a global environmental and waste-governance concern. Despite degradation and contamination during beach stranding, BAS retains valuable bioactive compounds, including sulfated [...] Read more.

Due to large-scale macroalgal blooms, nutrient enrichment, and changes in ocean circulation brought on by climate change, beach-accumulated seaweed (BAS) has quickly become a global environmental and waste-governance concern. Despite degradation and contamination during beach stranding, BAS retains valuable bioactive compounds, including sulfated polysaccharides, phlorotannins, pigments, proteins, peptides, and lipids, which exhibit anti-inflammatory, antioxidant, antimicrobial, antiviral, immunomodulatory, anticancer, and metabolic regulatory activities. This review critically evaluates BAS as a sustainable bioresource by integrating current knowledge on biomass composition, degradation-associated challenges, bioactive properties, valorization pathways, advanced extraction technologies, safety validation, regulatory considerations, and emerging commercialization opportunities. Attention is given to sustainable valorization pathways, ranging from composting and bioenergy production to the recovery of high-value bioactives through enzyme-assisted, green, and advanced extraction technologies. The review further discusses policy and regulatory gaps, contamination challenges, safety validation requirements, and life-cycle sustainability considerations that currently limit industrial adoption. Finally, emerging opportunities involving metabolomics, microbial bioprocessing, artificial intelligence, automation, and nanotechnology are explored as future directions for transforming BAS into a standardized and economically viable feedstock within the circular blue bioeconomy. Establishing harmonized regulatory frameworks and integrating BAS management with Sustainable Development Goals (SDGs) 12 and 14 will be critical for enabling sustainable resource recovery and long-term coastal resilience. Full article

(This article belongs to the Special Issue Coastal Waste Recycling: From Beach Collection to Circular Economy)

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21 pages, 27207 KB

Open AccessArticle

Spark Plasma Texturing in the Direct Recycling of Hot-Deformed Nd-Fe-B Scrap

by Monica Keszler, Martin Krengel, Felix Grosswendt, Doris Sebold, Olivier Guillon, Sebastian Weber and Martin Bram

Recycling 2026, 11(7), 115; https://doi.org/10.3390/recycling11070115 - 26 Jun 2026

Abstract

The particular microstructure of hot-deformed Nd-Fe-B magnets leads to difficulties in finding a direct recycling route. In this work, a combination of field-assisted sintering technology/spark plasma sintering (FAST/SPS) and spark plasma texturing (SPT) is used as pre-compaction and deformation techniques, respectively, for the [...] Read more.

The particular microstructure of hot-deformed Nd-Fe-B magnets leads to difficulties in finding a direct recycling route. In this work, a combination of field-assisted sintering technology/spark plasma sintering (FAST/SPS) and spark plasma texturing (SPT) is used as pre-compaction and deformation techniques, respectively, for the consolidation of crushed, hot-deformed Nd-Fe-B scrap. Field-assisted sintering has the unique advantage of maintaining fine microstructures during material densification, making it an ideal candidate for direct recycling of this material. Recycled magnets, made from 100 wt% crushed magnet scrap, were able to achieve energy products of over 200 kJ m⁻³ after FAST/SPS pre-compaction and SPT deformation. These recycled magnets could then be smoothed and cut to the size of industrial bar magnets for testing in the motor of a water pump. When tested, the recycled magnets could achieve 95% of the electromotive force compared to industrial standard magnets. Full article

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22 pages, 1869 KB

Open AccessArticle

Selective Lithium Recovery from Ni-Based Li-Ion Batteries via Sucrose-Assisted Reductive Roasting

by Martin Jantson, Rasmus Teppo and Kerli Liivand

Recycling 2026, 11(7), 114; https://doi.org/10.3390/recycling11070114 - 25 Jun 2026

Abstract

The increasing demand for lithium-ion batteries (LIBs) raises concerns about the security of critical raw material supply and the management of hazardous waste. Efficient recycling can alleviate these issues by transforming spent batteries into high-value secondary materials for the circular economy. Industrial recycling [...] Read more.

The increasing demand for lithium-ion batteries (LIBs) raises concerns about the security of critical raw material supply and the management of hazardous waste. Efficient recycling can alleviate these issues by transforming spent batteries into high-value secondary materials for the circular economy. Industrial recycling has traditionally focused on the recovery of nickel (Ni) and cobalt (Co), whereas lithium (Li) recovery has often been sidelined due to technical complexities and fluctuating economic incentives. To meet the European Union (EU) Batteries Regulation target of 80% lithium recovery by the end of 2031, technically effective and economically viable lithium recovery strategies are required. This study investigates the use of food-grade sucrose as an organic reductant for the targeted recovery of lithium from NMC622 and NCA battery materials. The process combines sucrose-assisted reductive roasting with selective water leaching. The effects of roasting temperature, holding time, sucrose dosage, and heating rate were systematically evaluated and optimised. Under the best conditions of 600 °C, 15 min, 15 wt% sucrose, and a heating rate of 20 °C/min, lithium leaching efficiencies of 93.2% and 87.6% were achieved for separated NMC622 cathode material and NMC622-derived black mass, respectively. The method was also applicable to NCA-based black mass, reaching 83.7% lithium recovery under the same conditions. Mechanistic analysis revealed that lithium release was strongly controlled by the extent of transition metal reduction. Cobalt was fully reduced to its metallic state under all tested conditions. However, maximum lithium recovery required nickel to be reduced to metallic Ni and manganese-containing phases to be converted to MnO. The sucrose-assisted roasting process was rapid and holding times longer than 15 min decreased lithium recovery. This decrease was caused by the formation of poorly soluble lithium-containing phases, such as LiF and Li₃PO₄. F composition analysis showed the black mass (1.06 wt%) and anode fractions (2.26 wt%) to contain significantly more F than the cathode fraction (0.46 wt%), hence leading to the 5% Li leaching efficiency difference between cathode and black mass fractions under most conditions tested. Overall, these results demonstrate that sucrose-assisted reductive roasting, followed by selective water leaching, provides a rapid and effective route for high-efficiency lithium recovery from NMC- and NCA-based battery materials. Full article

(This article belongs to the Special Issue Celebrating 10 Years of Recycling: Shaping the Future of Waste Management)

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31 pages, 12772 KB

Open AccessReview

A Review of Tailings Characterizations and Their Application as Aggregates in Concrete Materials

by Wenpeng Liu, Junbiao He, Qingyun Xu, Zhijie Pi, Nan Zhang and Di Wang

Recycling 2026, 11(7), 113; https://doi.org/10.3390/recycling11070113 - 25 Jun 2026

Abstract

Tailings are solid waste generated during mining and mineral processing. Their tremendous accumulation not only encroaches on arable land but also pollutes the environment. Currently, tailings are considered a viable alternative to natural fine aggregates in concrete because of their suitable physicochemical properties. [...] Read more.

Tailings are solid waste generated during mining and mineral processing. Their tremendous accumulation not only encroaches on arable land but also pollutes the environment. Currently, tailings are considered a viable alternative to natural fine aggregates in concrete because of their suitable physicochemical properties. However, existing studies remain highly fragmented and often report inconsistent conclusions owing to the considerable variability in tailings mineralogy, particle morphology, and physicochemical characteristics. To date, a comprehensive synthesis linking these intrinsic properties to the fresh, mechanical, durable, microstructural, environmental, and economic performance of tailings concrete remains lacking. Therefore, this review provides a systematic and critical assessment of tailings as aggregate in concrete and proposes an integrated framework connecting tailings characteristics, microstructural evolution, engineering performance, and sustainability outcomes. It systematically examines the physico-mechanical properties, durability, microstructure, hydration characteristics, environmental impact, and economic benefits of the resulting tailings concrete. The results showed that although tailings varied considerably in particle size, chemical composition, and mineralogy, they typically exhibited a rough surface texture and high water absorption. Furthermore, partial substitution of fine aggregates with tailings was found to improve the physical–mechanical properties and durability. However, to prevent performance decline, the substitution ratio should not exceed 50%. These benefits originated primarily from the filling effect and optimized particle packing, which increased matrix density. Microstructural analyses indicated that moderate tailings contents refined the pore structure, strengthened the interfacial transition zone (ITZ), and promoted hydration. In contrast, excessive substitution ratios weakened bonding and increased porosity. From an environmental perspective, the use of tailings generally reduced carbon emissions (by up to ~28%) and production costs (by up to ~50%) by lowering natural resource consumption and enabling large-scale waste valorization. Overall, tailings represent a sustainable aggregate alternative, provided that substitution levels are carefully controlled to balance workability, performance, and durability. Full article

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13 pages, 1430 KB

Open AccessArticle

Integration of Floating Constructed Wetlands and Microbial Fuel Cells for Sustainable Wastewater Treatment and Bioelectricity Generation

by Eduardo Guevara Hernández, Alba Jocelyne Aldabalde Hernández, Fernando Andrés Rojas Aguilar, Efraín Martínez Prior, Luis A. Godínez, Víctor A. Ramírez and Francisco J. Rodríguez-Valadez

Recycling 2026, 11(7), 112; https://doi.org/10.3390/recycling11070112 - 24 Jun 2026

Abstract

Floating wetlands have emerged as a sustainable alternative for improving water quality, and although some studies have investigated their performance, there is still much to be understood regarding their integration with energy-generating technologies. This study evaluated a combined system of floating wetlands and [...] Read more.

Floating wetlands have emerged as a sustainable alternative for improving water quality, and although some studies have investigated their performance, there is still much to be understood regarding their integration with energy-generating technologies. This study evaluated a combined system of floating wetlands and microbial fuel cells (MFCs) for treating real wastewater and generating bioelectricity. Experiments were conducted in batch mode to simulate application in natural water bodies, using real wastewater collected on different dates. As a result of the natural variability of the influent, initial chemical oxygen demand (COD) concentrations of 405 and 289 mg/L were observed. Performance was assessed in terms of organic matter and nitrogen removal, as well as voltage generation. COD removal efficiencies reached 50% and 69% for the higher and lower organic loads, respectively, indicating improved treatment at reduced concentrations. Maximum removals of 56% for ammoniacal nitrogen (NH₃-N) and 40% for total nitrogen (TN) were achieved, reflecting moderate nutrient removal capacity. Voltage generation was sustained for approximately 21 days, confirming stable bioelectrochemical activity, and power output was found to depend on the organic load serving as substrate for electrogenic microorganisms. Overall, the system represents a viable approach for wastewater treatment with the added benefit of energy recovery, although its performance is influenced by influent characteristics and operation conditions. Full article

(This article belongs to the Special Issue Advanced Wastewater Treatment and Resource Recovery: Pathways to Circular Valorization)

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22 pages, 18736 KB

Open AccessArticle

Waste Recycling of Scallop Shells in Concrete Production: Mechanical Behavior and Environmental Safety for End-of-Life Classification

by Farjallah Alassaad, Houssam Affan, Abdelrahman Mohamad, Amro Yaghi and Bechara Haddad

Recycling 2026, 11(6), 111; https://doi.org/10.3390/recycling11060111 - 22 Jun 2026

Abstract

This study investigates the feasibility of recycling scallop shells as a partial substitute for natural coarse aggregates in concrete at replacement rates of 20%, 30%, and 40% by mass. The originality of the work lies in combining conventional mechanical and durability tests with [...] Read more.

This study investigates the feasibility of recycling scallop shells as a partial substitute for natural coarse aggregates in concrete at replacement rates of 20%, 30%, and 40% by mass. The originality of the work lies in combining conventional mechanical and durability tests with a six-month environmental monitoring protocol under simulated rainfall and an end-of-life regulatory interpretation of chemical release. Processed shells were used as a 2/20 mm coarse fraction and characterized by a density of 2713 kg/m³, a water absorption of 2.93%, and a Los Angeles coefficient of 15.1. At 28 days, compressive strength decreased from 33.7 MPa for the reference concrete to 27.9 MPa, 28.1 MPa, and 26.7 MPa for SS20, SS30, and SS40, respectively. Water-accessible porosity increased from 7.8% to 9.9%, and carbonation depth after 70 days increased from 6.2 mm to 12.8 mm at 40% shell replacement. In contrast, chloride ion migration decreased from 19.0 × 10⁻¹² m²/s for the reference concrete to 17.4, 16.3, and 12.1 × 10⁻¹² m²/s at 90 days for SS20, SS30, and SS40, respectively. Environmental monitoring showed low runoff concentrations for anions and trace metals, all below the French regulatory thresholds considered in this work. Under the conditions of this study, shell replacement up to 30% appears technically feasible for non-structural or lightly loaded applications, while the environmental behavior remained compatible with an inert end-of-life classification. Full article

(This article belongs to the Special Issue Celebrating 10 Years of Recycling: Shaping the Future of Waste Management)

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