Search Results (267)

In this research, thermoplastic waste (polyethylene and propylene) from waste electrical and electronic equipment (WEEE) was used to manufacture polymer composite materials that included talc, fly ash, and elastomers, with tailored electromagnetic interference shielding properties, for the potential use for electric car components. A distribution of inorganic components within the polymer structures without particle clustering were observed, illustrating an effective melt compounding process. The gradual replacement of talc with fly ash lowered both the fluidity index and the softening temperature values. The increase in fly ash content resulted in higher values of both permittivity and dielectric loss factor. The novelty was related to a significant increase in both dielectric characteristics at increased quantities of fly ash at higher temperatures, an aspect more relevant at higher frequencies where they approached a steady value. The permittivity values surpassed five, and the dielectric loss factor values exceeded 0.04, fulfilling the requirements for their application in electrical equipment. The recipes containing 10% fly ash may guarantee an electromagnetic shielding effectiveness of at least 99% within the frequency domain of 0.1–4 GHz. Composites with greater amounts of fly ash can conduct heat more efficiently, leading to improved diffusivity and thermal conductivity values, with significant thermal conductivity values surpassing 0.2 W/(m*K). Finally, it was concluded that the composites with 10% talc, 10% fly ash, and elastomer using recycled high-density polyethylene might be the best choice for electric vehicle parts, in line with all required standards for these uses. Full article

The circular economy (CE) encourages sustainability by shifting towards business models that prolong resource use. The quantity of waste generated by electric and electronic equipment (WEEE or e-waste) is rapidly rising and is one of the fastest-growing waste streams. Our paper explores the awareness, benefits, barriers, incentives, and implementation of CE in the electric and electronic equipment (EEE) industry in Slovenia and Croatia. In the theoretical section, we review the existing literature on CE, the EEE industry in both countries, and their policy frameworks for developing CE. Based on primary research through a survey and inferential statistical analysis in the empirical section, we investigate the implementation of CE in the EEE industry in both countries. This paper identifies which CE practices companies in the EEE industry implement, how company size affects CE implementation, how companies evaluate institutional support to CE, and their plans regarding CE. The results highlight some differences between the two countries. Drawing on the empirical findings, we determine key challenges and opportunities for increasing CE adoption in this sector and formulate some European suggestions for policymakers, industry practitioners, and researchers. Full article

In the context of the Carbon Generalized System of Preferences (CGSP), this paper develops a three-tier reverse supply chain model comprising the government, recyclers, and consumers. Differential game analysis is employed to investigate the evolutionary dynamics of consumers’ perceived recycling value and to examine how government recycling efforts and recyclers’ point rewards levels influence this perception. Furthermore, the study explores the dynamic trajectory of consumers’ perceived recycling value across three decision-making models—collaborative-driven, government-driven, and market-driven—and evaluates its impact on supply chain efficiency. The research shows that (1) enhanced recycling efforts by both the government and recyclers significantly improve consumers’ perceived recycling value, thereby promoting the recycling of waste electrical and electronic equipment, with the most pronounced improvement observed under the collaborative-driven strategy; (2) in the government-driven model, the government’s subsidy rate affects recyclers’ decisions regarding point-based incentives but does not influence the government’s own recycling effort; (3) the evolutionary trajectories of consumers’ perceived recycling value and system efficiency differ among the models, with the highest levels achieved under the collaborative-driven model, followed by the government-driven model, and the lowest under the market-driven model. This study fully accounts for the dynamic nature of consumers’ perceived recycling value, offering theoretical and practical guidelines for effective WEEE recycling. Full article

This study investigates the use of waste glass powder derived from fluorescent lamps as a partial replacement for cement in mortar production, aiming to valorize this Waste from Electrical and Electronic Equipment (WEEE) and enhance sustainability in the construction sector. Mortars were formulated by substituting 25% of cement by volume with glass powders from fluorescent lamp glass and green bottle glass. The experimental program evaluated mechanical strength, durability parameters and ecotoxicological performance. Results revealed that clean fluorescent lamp mortars showed the most promising mechanical behavior, exceeding the reference in long-term compressive (54.8 MPa) and flexural strength (10.0 MPa). All glass mortars exhibited significantly reduced chloride diffusion coefficients (85–89%) and increased electrical resistivity (almost 4 times higher), indicating improved durability. Leaching tests confirmed that the incorporation of fluorescent lamp waste did not lead to hazardous levels of heavy metals in the cured mortars, suggesting effective encapsulation. By addressing both technical (mechanical and durability) and ecotoxic performance, this research contributes in an original and relevant way to the development of more sustainable building materials. Full article

Plastics make up a significant proportion of the stream of the European Waste of Electric and Electronic Equipment (WEEE), yet the use of recycled plastic materials is very low in new manufactured products. A description of the WEEE waste stream in Europe is given, with a focus on the plastic materials commonly found in WEEE that include four principal polymers: polypropylene (PP), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS). Furthermore, the legislative aspects related to WEEE and plastics recycling in Europe are complex, and numerous norms have been dictated by the European Commission. These norms are crucial to the sector of polymer recycling and production in Europe. Moreover, an overview of the entire treatment chain is presented. More specifically, each step of a typical recycling chain is introduced, with a focus on the sorting of plastics and the separation of polymers. Lastly, the influence of contaminants in the plastic fraction is discussed, both in terms of polymer particles and unwanted additives. By showing the impact of the purity rate on the mechanical properties of recycled plastics, the consequences of inadequate end-of-life treatment for WEEE-plastics is highlighted, hence linking the quality of recycled plastics to the separation step and the re-compounding of recycled granulates. Full article

The exponential increase in electronic waste (e-waste) from end-of-life electrical and electronic equipment presents a growing environmental challenge. E-waste contains high concentrations of rare earth elements (REEs), which are classified as critical raw materials (CRMs). Their removal and recovery from contaminated systems not only mitigate pollution but also support resource sustainability within a circular economy framework. The present study proposed the use of hazelnut shells as a biosorbent to reduce water contamination and recover REEs. The sorption capabilities of this lignocellulosic material were assessed and optimized using the response surface methodology (RSM) combined with a Box–Behnken Design (three factors, three levels). Factors such as pH (4 to 8), salinity (0 to 30), and biosorbent dose (0.25 to 0.75 g/L) were evaluated in a complex mixture containing 9 REEs (Y, La, Ce, Pr, Nd, Eu, Gd, Tb and Dy; equimolar concentration of 1 µmol/L). Salinity was found to be the factor with greater significance for REEs sorption efficiency, followed by water pH and biosorbent dose. At a pH of 7, salinity of 0, biosorbent dose of 0.75 g/L, and a contact time of 48 h, optimal conditions were observed, achieving removals of 100% for Gd and Eu and between 81 and 99% for other REEs. Optimized conditions were also predicted to maximize the REEs concentration in the biosorbent, which allowed us to obtain values (total REEs content of 2.69 mg/g) higher than those in some ores. These results underscore the high potential of this agricultural waste with no relevant commercial value to improve water quality while providing an alternative source of elements of interest for reuse (circular economy). Full article

The rapid advancement of technology has led to a substantial increase in Waste Electrical and Electronic Equipment (WEEE), which poses significant environmental threats and increases pressure on the planet’s limited natural resources. In response, Artificial Intelligence (AI) has emerged as a key enabler of the Circular Economy (CE), particularly in improving the speed and precision of waste sorting through machine learning and computer vision techniques. Despite this progress, to our knowledge, no comprehensive, systematic review has focused specifically on the role of AI in disassembling and recycling Waste-Printed Circuit Boards (WPCBs). This paper addresses this gap by systematically reviewing recent advancements in AI-driven disassembly and sorting approaches with a focus on machine learning and vision-based methodologies. The review is structured around three areas: (1) the availability and use of datasets for AI-based WPCB recycling; (2) state-of-the-art techniques for selective disassembly and component recognition to enable fast WPCB recycling; and (3) key challenges and possible solutions aimed at enhancing the recovery of critical raw materials (CRMs) from WPCBs. Full article

Global resource consumption continues to grow each year, exerting increasing pressure on their availability. This trend could lead to a shortage of raw materials in the coming years. Aware of the risks associated with this situation, the European Union has implemented policies and strategies aimed at diversifying its supply sources, including waste recycling. In this context, the present study was conducted with the objective of developing innovative processes to concentrate valuable metals present in the non-recovered fractions of waste electrical and electronic equipment (WEEE). Three types of samples were studied: washing table residues (WTRs), printed circuit boards (PCBs), and powders from cathode-ray tube screens (CRT powders). Several separation techniques, based on the physical properties of the elements, were implemented, including electrostatic separation, magnetic separation, and density and gravity-based separations. The results obtained are promising. For WTRs and PCBs, the recovery rates of targeted metals (Cu, Al, Pb, Zn, Sn) reached approximately 91% and 80%, respectively. In addition to these metals, other valuable metals, present in significant quantities, deserve further exploration. Regarding CRT powders, the performances are also encouraging, with recovery rates of 54.7% for zinc, 57.1% for yttrium, and approximately 71% for europium. Although these results are satisfactory, optimizations are possible to maximize the recovery of these critical elements. The techniques implemented have demonstrated their effectiveness in concentrating target metals in the treated fractions. These results confirm that recycling constitutes a viable alternative to address resource shortages and secure part of the supplies needed for the European Union’s industry. Full article

The rapid increase in waste electrical and electronic equipment (WEEE) creates major environmental and governance issues in developing countries like Ecuador struggle because they with minimal formal collection and recycling rates. This research presents a potential sustainable management approach that tracks products through their life cycles while following circular economy principles that include product extension and material extraction and waste minimization. A systematic literature review (SLR) using the PRISMA methodology combined with a bibliometric analysis found essential global strategies and technological frameworks and regulatory frameworks. The analysis of articles demonstrates that information management systems (IMSs) together with digital technologies and consistent regulations serve as essential elements for enhancing traceability and material recovery and formal recycling processes. A WEEE management IMS model was developed for the Ecuadorian market through an analysis of the findings; it follows a five-stage development process, starting from the technological infrastructure setup to complete data visualization integration. The proposed model is designed to enable public–private–community partnerships using digital tools that promote sustainable practices. The combination of circular strategies with traceability technologies and strong regulatory frameworks leads to improved WEEE governance, which supports sustainable system transitions in emerging economies. Full article

Rare earth elements (REEs), particularly neodymium (Nd), dysprosium (Dy), and praseodymium (Pr), are critical in the production of neodymium–iron–boron (NdFeB) magnets used in electronic devices, wind turbines, and electric vehicles. Due to the limited availability of these metals, their recovery from waste electronic equipment such as hard disk drives (HDDs) offers a promising solution. The aim of this study was to develop a method to grind NdFeB magnets obtained from the physical recycling of HDD. The recycled magnets were ground using a planetary mill. A review of the literature highlights the limitations of the currently used grinding methods, which require energy-intensive pretreatment processes, specialised conditions, or expensive equipment. This study employed a Fritsch planetary mill, tungsten carbide grinding balls, and ethanol as a grinding medium. NdFeB magnet samples (120 g) were ground for different durations (0.5 h–15 h) at a speed of 300 rpm, using a cyclic operating mode to minimise material heating. The resulting powders were analysed using a laser particle analyser, an optical microscope, and an X-ray diffractometer. The results enable the determination of optimal grinding parameters, achieving an average particle size (d₅₀) below 5 μm, which is essential for further processing and new magnet production. Finally, the economic and environmental aspects of producing the neodymium alloy were analysed. Full article

This article examines urban mining in Brazil, highlighting its unique context compared to other regions. While European Union focuses on critical metal supply and advanced Waste Electrical and Electronic Equipment (WEEE) legislation and circular economy, Brazil’s urban mining is primarily driven by waste management and social inclusion. The current investigation was underpinned by the PRISMA extension for Scoping Reviews (PRISMA-ScR framework), using targeted searches on the Web of Science platform for technological processes and the Brazilian scenario, complemented by an analysis of legislative evolution and a Critical Discourse Analysis of national policies. The results indicate that, despite advanced legislation, significant gaps exist between discourse and practice, highlighting the need for technological appropriation, specific public policies that incentivize reverse logistics and the integration of the informal sector, and overcoming infrastructural challenges. It concludes that Brazil has a unique opportunity to develop an urban mining model that pioneeringly integrates environmental sustainability, technological innovation, and social inclusion, demanding coordinated efforts to overcome existing barriers. Full article

The recovery of lithium from extracts obtained from a black mass of spent lithium-ion batteries treated with a ternary solvent system at acidic pH was investigated using flat-sheet nanofiltration (NF) membranes operated according to a dead-end configuration. Specifically, four samples obtained at different pH values (2.5 and 5) and extraction times (48, 96 and 168 h) were treated in selected operating conditions by using two commercial polymeric membranes (denoted DK and HL, with an approximate molecular weight cut-off of 150–300 Da) up to a volume reduction factor (VRF) of 4. Membrane performance was assessed in terms of productivity and selectivity towards specific ions, including lithium. For most treated samples, the HL membrane exhibited higher permeate fluxes in comparison to the DK membrane. However, the DK membrane performed better in terms of lithium rejection than the HL membrane, with a negative rejection at VRF 4 observed for all treated samples. More than 90% of multivalent ions were rejected by both membranes independently of the VRF. The membrane ability to retain multivalent ions led to their progressive concentration in the retentate as the VRF increased. The extraction time did not impact the NF performance of both membranes in terms of ion rejection. For the DK membrane conditions of extraction of 96 h and pH 5 represented the best trade-off between flux, ion rejection, and total lithium recovery. Full article

The rising demand for lithium-ion batteries (LIBs), driven by the growing consumption of electronic devices and the expansion of electric vehicles, is leading to a concerning depletion of primary metal resources and a significant accumulation of electronic waste. This urgent challenge highlights the need for sustainable recovery methods to extract valuable metals from spent LIBs, aligning with circular economy principles. In this study, the preparation of spent batteries for the bioleaching process was achieved with minimal manipulation. This included a preliminary discharge to ensure safety in subsequent processes and a brief crushing to facilitate the access of leaching agents to valuable metals. Unlike most studies that grind batteries to obtain powders between 70 and 200 microns, our approach works with particles sized around 5 mm. Additionally, our preparation process avoids any thermal or chemical treatments. This straightforward pre-treatment process marks a significant advancement by reducing the complexity and cost of processing. A systematic study was conducted on various fractions of the large particle sizes, using Fe (III) produced through bio-oxidation by A. ferrooxidans and biogenically obtained H2SO4 from A. thiooxidans. The highest metal extraction rates were achieved using the unsorted fraction, directly obtained from the black mass after the grinding process, without additional particle separation. When treated with bio-oxidized Fe (III), this fraction achieved a 95% recovery of Cu, Ni, and Al within 20 min, and over 90% recovery of Co, Mn, and Li within approximately 30 min. These recovery rates are attributed to the combined reducing power of Al and Cu already present in the black mass and the Fe (II) generated during the oxidation reactions of metallic Cu and Al. These elements actively facilitate the reduction of transition metal oxides into their more soluble, lower-valence states, enhancing the overall metal solubilization process. The extraction was carried out at room temperature in an acidic medium with a pH no lower than 1.5. These results demonstrate significant potential for efficient metal recovery from spent batteries with minimal pre-treatment, minimizing environmental impact. Additionally, the simplified residue preparation process can be easily integrated into existing waste management facilities without the need for additional equipment. Full article

Due to the increasing volumes of plastic waste generated from electric and electronic devices, research has focused on the investigation of recycling methods for their safe handling. Pyrolysis converts plastics from waste electric and electronic equipment (WEEE) into valuable products (pyrolysis oil). Nevertheless, the frequent presence of flame retardants, mainly brominated flame retardants (BFR), hinders pyrolysis’s wide application, since hazardous compounds may be produced, limiting the use of pyrolysis oils. Taking the aforementioned into account, this work focuses on the recycling, via pyrolysis, of various plastic samples gathered from WEEE, to explore the valuable products that are formed. Specifically, 14 plastic samples were collected, including parts of computer peripheral equipment, remote controls, telephones and other household appliances. Considering the difficulties when BFRs are present, the study went one step further, applying XRF analysis to identify their possible presence, and then Soxhlet extraction as an environmentally friendly method for the debromination of the samples. Based on the XRF results, it was found that 23% of the samples contained bromine. After each Soxhlet extraction, bromine was reduced, achieving a complete removal in the case of a remote control sample and when butanol was the solvent. Thermal pyrolysis led to the formation of valuable products, including the monomer styrene and other secondary useful compounds, such as alpha-methylstyrene. The FTIR results, in combination with the pyrolysis products, enabled the identification of the polymers present in the samples. Most of them were ABS or HIPS, while only three samples were PC. Full article

Indium, widely used as indium-tin oxide (ITO), has been recognized as a strategical metal for audiovisual, optoelectronic systems, semiconductors and photovoltaic fields. An increasing shortage and unflexible mineral supply have led indium to be recovered from secondary sources, such as waste electrical and electronic equipment (WEEE). The main step for indium hydrometallurgical recovery from WEEE is the electrowinning process using sulfate baths, giving lower environmental impact and improved workplace safety conditions. In this investigation, a titanium cathode has been employed for the study of the indium electrowinning process in a sulfate-based bath. This study was focused on analyzing current efficiency (CE), specific energy consumption (SEC) and deposit morphology and structure as the temperature, current density, pH and electrolyte composition were varied. Prior to conducting electrowinning tests, a conventional three-electrode cell was used to perform cyclic voltametric assessments of the electrodeposition reactions on the Ti electrode at room temperature. The indium electrowinning tests on Ti cathodes presented CE values higher than 90%, with low energy consumption at low current densities, showing a negligible influence of additive agents in the bath, different from results obtained with other cathodes in other works. Moreover, the increase of the current density beyond 75 A/m² produced significant effects by etching the electrode surface with 1M HF. In particular, at the conclusion of this investigation, good results are obtained without additives, by etching the titanium cathode and operating at higher current density between 100 and 200 A/m² at pH 2.3 and different temperatures (40 °C and 60 °C). Finally, indium deposits were analyzed by XRD and SEM in order to determine the influence of operative conditions on the structure and surface morphology. Full article