Using strategies employed in synthetic chemistry, we investigated the chemicals found in lithium iron phosphate (LFP) spent battery via an initial dichloromethane (DCM) extraction of the individual cathode and anode. The pre- and post-treated electrodes and DCM extracts were examined using a range of analytical techniques. A total of 26 compounds were identified, which included the following: (1) some of the benchmark materials, LFP, lithium hexafluorophosphate (LIPF6), polyvinylidene fluoride (PVDF), graphite and carbon black; (2) NMR spectroscopy of DCM extract revealed five main chemicals, which were ethylene and propylene carbonate solvents, LiPF6, lithium tetrafluoroborate (LiBF4), and an unknown fluorochemical; (3) analysis of the water-treated DCM extract revealed 21 chemicals by GCMS, several fluorochemicals; (4) 12 chemicals were found in both cathode and anode and three only in the anode; (5) only 13 of the 21 chemicals could be properly named, whilst four had some notable functionality and three could not be identified; and (6) ICP analysis revealed high levels of Al, Cu, Fe, V, and Zn in both electrodes and spent electrolyte. The high number of chemicals present in the spent electrolyte and electrodes suggest battery manufacturers use many proprietary chemicals to enhance battery properties. This procedure allows insight and identification of chemicals present in waste LIBs which will require advanced chemical techniques to recover high yields and purity of recycled materials and the need to dispose of hazardous waste.
The automotive sector is the third-largest consumer of plastics in Europe, after packaging and construction, and its demand is expected to grow. Plastic recycling at the end of vehicle life remains low, with 80% of plastics ending up in energy recovery or landfills. Three vehicle models (SEAT Ibiza Gen. IV and SEAT Leon Gen. II and III) with two trim versions (Reference and Formula Racing) were examined to identify the most critical plastic components from an exergy perspective. Ecodesign measures were defined by considering both the disassemblability of vehicle components and their recyclability potential as key criteria to evaluate end-of-life recovery pathways and guide material and design optimization strategies. The proposed methodology classified the measures into three types: (1) substitution of high-exergy plastics with lower-impact alternatives; (2) use of recycled plastics instead of primary materials, with substitution rates depending on the material; and (3) reuse of components in new models, evaluated by disassemblability and end-of-life condition. Results show that Type 1 measures achieved savings up to 70 MJ, mainly in the floor covering and engine compartment insulator, while Type 2 measures provided larger reductions, up to 1.7 GJ, mainly in bumpers and carpets. Type 3 measures showed reuse potential for paddings and insulators but faced limitations in carpets and dashboards. Findings highlight the importance of material selection and implementing disassembly and recycling strategies to reduce the exergy of vehicle plastics.
Municipal Solid Waste (MSW) is a common problem in all cities worldwide; it is expected to increase to 3400 billion tons by 2050. In Mexico, an average of 108,146 tons of MSW are generated daily. Artificial Intelligence (AI) is a computer tool that allows the development of systems that facilitate the recycling process. However, most AI programs focus on classifying paper, plastic, glass and metal; therefore, wood and textile waste have received little attention. Using texture techniques such as Local Binary Pattern (LBP), Gray-Level Co-occurrence Matrix (GLCM), Histogram of Oriented Gradients (HOG), Canny/Sobel edge detection, Fractal Dimension (FD), feature values were extracted and integrated from 4396 images belonging to wood and textile categories. Using the Random Forest Importance method, the most significant features were selected to train three Machine Learning (ML) algorithms. Multilayer Perceptron (MLP) achieved the best performance in accuracy with 96.70%, followed by Random Forest (RF) at 95.45% and Support Vector Machine (SVM) with 95.22%. The implementation of these comparisons will serve as a basis for the development of new technological tools with low computational cost that carry out a proper waste separation.
The European woodworking and furniture sector faces increasing sustainability challenges, including dependence on virgin raw materials and low recycling rates of furniture waste, highlighting the need for integrated environmental and economic assessments to support circular solutions. The purpose of this study is to evaluate and compare the environmental and economic performance of boards produced with different proportions of Polyethylene Recycling Waste (PRW) sourced from a Portuguese plastic recycling company, using an integrated Life Cycle Assessment and Life Cycle Costing approach. The environmental performance was assessed following ISO standards using the ReCiPe 2016 Midpoint (H) method, while the economic analysis included internal and external costs. First, the environmental and economic performance of PRW was assessed per 1 kg of material. Subsequently, four board formulations produced at pre-industrial scale, in a Portuguese company, were compared per 1 m3 of board: 100PRW; 80PRW20FW (with 20% furniture waste, FW); 80PRW20PE (with 20% virgin polyethylene, PE); and 80PRW20PU (with 20% virgin polyurethane, PU). Results show that waste-based boards (100PRW and 80PRW20FW) consistently present lower environmental impacts and improved cost-efficiency compared to formulations incorporating virgin polymers, particularly PU. Global warming and terrestrial ozone formation were the main contributing impact categories, largely driven by energy consumption. The dominant impact stage varied by formulation, with pressing prevailing in waste-based options and raw material production in virgin-polymer-based boards. These findings demonstrate that increasing the share of waste materials can significantly improve both environmental and economic performance, supporting the transition towards circular material solutions in the furniture sector. This study provides a novel contribution by integrating LCA and LCC in the assessment of pre-industrial PRW boards, offering practical insights for industry decision-making and sustainable material design.
Developing practical low-cost adsorbents for dye-contaminated wastewater remains a critical challenge, especially for persistent cationic dyes such as crystal violet (CV). Here, raw rockmelon skin (RMS), an abundant fruit-processing residue, and its NaOH-modified derivative (NaOH-RMS) were investigated as adsorbents for CV adsorption. Alkaline treatment altered the biomass's characteristics and affected its adsorption behaviour. Equilibrium was reached within 120 min, and the kinetic data were best fit by the pseudo-second-order model. Equilibrium analysis showed that the Freundlich model best described RMS. In contrast, NaOH-RMS was better represented by the Langmuir model, indicating that alkaline treatment altered the adsorption behaviour of the biomass surface. The Langmuir-derived maximum adsorption capacities were 343.7 mg g-1 for RMS and 295.2 mg g-1 for NaOH-RMS, indicating that NaOH modification did not increase the maximum adsorption capacity. Adsorption was spontaneous across 298-343 K, and both materials retained satisfactory removal performance over five regeneration cycles, particularly under basic desorption conditions. Overall, NaOH treatment altered the adsorption behaviour from heterogeneous adsorption on RMS to a more Langmuir-type adsorption pattern on NaOH-RMS, despite not increasing the maximum adsorption capacity. These findings support the valorisation of fruit-processing residues as practical adsorbents for dye-contaminated wastewater.
Variability in life cycle assessment (LCA) results for metal recycling technologies arises from multiple sources, including allocation methods, recycling route, regionality of impacts, and type of waste treated. Among these factors, waste composition is particularly critical, as it directly influences process performance by affecting auxiliary material consumption and emissions. This work investigates four waste categories: metals from incineration bottom ash (MBA), waste-printed circuit boards (WPCBs), industrial waste from gold refining (GRA), and spent automotive and industrial catalysts (SCs). The Climate Change (CC) for 1000 kg of waste was estimated at 3251 & times; 103 kg CO2eq for WPCBs, 3923 & times; 103 kg CO2eq for MBA, 1569 & times; 103 kg CO2eq for GRA, and 2101 & times; 103 kg CO2eq for SCs. A sensitivity analysis was performed to assess the influence of allocation methods on results for 1 kg of recycled metal. The highest variability in CC across waste categories was observed for gold (up to 8477%) with the black-box economic allocation method, while different allocation methods reached 21,700% for WPCBs. These results highlight the strong influence of methodological choices and waste characteristics, emphasizing the need for transparent and consistent LCA reporting.
Aluminum multifunctional housings can enhance circularity in electronics by replacing polymer enclosures while integrating heat sinking and electronic functions via laser direct structuring (LDS). Within the ALU4CED concept, we applied an IR-compatible LDS lacquer on aluminum, formed conductive tracks by electroless Cu/Ni/Au metallization, assembled components, and assessed end-of-life recyclability. Controlled remelting trials compared three disassembly levels: complete housings with PCBs and components, housings without PCBs, and housings with only integrated tracks. Metal yield rose from 81.4% for complete assemblies to 93.2% after PCB removal, while leaving integrated LDS tracks did not measurably penalize recovery. Only the complete electronics variant showed critical contamination (Cu = 1.64 wt.% vs. 0.25 wt.% limit for EN AC 4343); after PCB removal, composition remained close to the reference and major elements (Si, Mg, Fe) stayed within specification. Prefil testing indicated very low total inclusion content (0.006/0.001/0.002 mm2 & centerdot;kg-1), confirming high melt cleanliness despite coatings. Following remelting -> billet casting -> extrusion, tensile properties (Rm approximate to 120-123 MPa, Rp0.2 approximate to 59-61 MPa, A approximate to 29-33%) were comparable to the reference profile. These results demonstrate the technological feasibility of closed-loop recycling for LDS functionalized aluminum housings and inform clear Design-for-Recycling guidance: design for rapid PCB removal, allow LDS layers to remain during melting, and maintain compatibility with the 4343 family to enable efficient internal recycling.
Urban plastic waste management in large metropolitan regions remains constrained by low recovery rates despite growing policy attention. This study adopts a sustainability-oriented innovation (SOI) perspective to examine how policy-technology integration reshapes system-level performance in urban plastic waste systems. Using Bangkok as a representative case, a system-level model integrates plastic waste generation growth, time-dependent behavioural adoption of separation at source, contamination-sensitive sorting efficiency, and mass-balance material flows. Three scenarios are assessed: Business-as-Usual, separation-at-source policy only, and an integrated policy-technology system with advanced sorting. Results show that the baseline system remains stagnant at approximately 3.1% recovery. Policy intervention alone increases recovery gradually, reaching around 20% by 2045 despite participation approaching an 85% ceiling. In contrast, integrating policy with advanced sorting generates non-linear gains, surpassing 20% recovery within two years and reaching approximately 47% by 2045, driven by substantial contamination reduction. A Monte Carlo sensitivity analysis extends the integrated pathway to 2060. The median recovery trajectory stabilises at 68%, while the probability of achieving more than 70% recovery rises to 28% by 2040 and plateaus at 33% thereafter. The findings demonstrate that circular economy performance is probabilistic and depends on system-level alignment between behavioural participation, material quality, and technological capability.
This study investigates the reuse of mussel shell waste as a secondary raw material in bio-cement mortars designed for the additive manufacturing of artificial reefs for marine habitat restoration. The novelty of the research lies in combining a high recycled shell content (60 wt.%), low-clinker cement, and two 3D-printing techniques: Extruded Material Systems (EMS) and Powder-Based Systems (PBS). Mechanical performance was evaluated through flexural and compressive tests after 7, 28, and 91 days under both air and freshwater curing conditions, while environmental impacts were assessed through Life Cycle Assessment (LCA). The LCA evaluated both the environmental performance of shell-based mixtures compared with conventional materials and the impacts associated with the investigated fabrication techniques. The best-performing bio-mixtures achieved compressive strengths up to 46.01 MPa and flexural strengths up to 9.91 MPa after freshwater curing, demonstrating the suitability of shell-based mortars for submerged applications. LCA results showed reduced impacts in land use and mineral resource depletion compared with conventional mixtures, despite slightly higher energy and water demands associated with shell pre-treatment. The results demonstrate the technical and environmental feasibility of integrating aquaculture waste into sustainable 3D-printed marine restoration solutions.
This study proposes the development of a recycling process for the reintegration of dental zirconia waste into CAD/CAM systems for rapid prototyping, with the objective of demonstrating the feasibility of manufacturing functional products from recycled zirconia obtained from a commercial dental laboratory. The proposed methodology aims to explore a simple and economically viable process, which involves the purification and processing of a heterogeneous zirconia powder, followed by the fabrication of pre-sintered blocks suitable for CAD/CAM applications. The recycled bulk ceramic was characterized and compared with commercial zirconia through density measurements, X-ray diffraction, scanning electron microscopy, Vickers hardness, flexural strength testing, and sintering shrinkage analysis. The results indicated that, although recycled zirconia exhibits lower property values than the commercial reference material, it retains adequate characteristics for specific practical applications. Consequently, to demonstrate industrial feasibility, four components were designed using CAD and machined using CAM from the recycled blocks, simulating a rapid prototyping process. The fabricated components exhibited a smooth and flawless surface, were mechanically robust and solid to the touch, and showed well-defined contours with sharp edges. Dimensional analysis demonstrated high accuracy, with an average percentage error of 0.53% +/- 0.14. These findings demonstrate that high-value ceramic waste can be reintegrated into the production chain as functional industrial components through a process that is closely aligned with the real conditions of industrial recycling, while also mitigating environmental contamination from hazardous industrial waste.
The excessive generation and improper disposal of Construction and Demolition Waste (CDW) represent one of the main environmental challenges in the sector. However, its potential for reuse and recycling enables the mitigation of these impacts through sustainable practices. In this context, the present study aimed to estimate reference values for the Federal District, Brazil, regarding the environmental impacts associated both with the transportation stage of CDW—from its point of origin to the processing facility—and with the operations involved in its conversion into recycled aggregates, through the application of a simplified Life Cycle Assessment approach. The analysis focused on quantifying the consumption of electricity, water, and fossil fuels, as well as carbon dioxide emissions and the generation of contaminant residues throughout the analyzed process. The system boundary adopted corresponds to a “cradle-to-gate” scope, with a declared unit of 1 tonne of recycled aggregate. Additionally, a survey of scientific studies providing life cycle inventory data related to aggregate production was conducted, enabling a consistency analysis with the data obtained in this study. Primary data related to the recycled aggregate production process were collected through direct field observations, in situ measurements, and the analysis of operational records from the studied facility. For the year 2024, the environmental indicators obtained showed that the production of 1 tonne of recycled aggregate required 1.23 kWh of electricity, 5.65 L of water, and 2.14 L of diesel, in addition to resulting in emissions of 6.64 kg CO2 eq and the generation of 2.3 kg of contaminant waste.
Municipal solid waste management (MSWM) systems in Latin America are constrained by limited access to high-resolution operational data, compelling local authorities to depend on aggregated national statistics that are inadequate for behaviorally informed intervention design. This limitation is particularly evident in the State of Mexico, which generates about 16,187 tons of waste every day but only recycles only 11%. In this context, this study introduces a diagnostic data science framework to identify behaviorally grounded citizen segments and their defining attributes, supporting evidence-based decision-making in MSWM. Primary survey data from 560 households across three municipalities were used, and a three-stage analytical pipeline was implemented to account for contextual heterogeneity. First, k-means clustering was applied to identify behavioral segments. Second, random forest classifiers were used to validate cluster coherence and quantify feature importance. Third, the Apriori algorithm was used to extract association rules that capture recurrent material-mixing behaviors. The results revealed municipality-specific segmentation structures (Tequixquiac: K = 6; Tlalpujahua: K = 3; Xalatlaco: K = 2), with material-specific disposal behaviors emerging as stronger segmentation drivers. Random forest classifiers validated cluster coherence with 100% accuracy, confirming that segments represent behaviorally distinct archetypes. The proposed framework converts raw behavioral data into actionable municipal visions. This approach focuses on finding diagnostic patterns instead of making predictions by utilizing machine-learning-driven MSWM research.
The building sector is a major source of CO2 emissions and construction waste, motivating the development of sustainable materials and end-of-life recycling strategies. Bio-concretes, combining mineral binders with plant-based aggregates, offer low density and favorable hygrothermal performance but remain insufficiently studied with respect to recyclability, particularly for gypsum-based materials. This study experimentally investigates the thermal recycling of gypsum–hemp bio-concrete, in which gypsum acts as the binder and hemp shiv as the aggregate. Thermogravimetric analysis of individual constituents and the bio-concrete was conducted to identify a temperature range enabling gypsum dehydration without hemp degradation. Controlled oven treatments at selected temperature–time couples were then applied to determine optimal recycling conditions, followed by the bio-concrete remanufacturing using 100% recycled constituents. Physical, thermal, and mechanical properties were evaluated before and after recycling under controlled conditions. Results show that a treatment at 180 °C for 60 min enables effective gypsum dehydration (18–20% mass loss) while preserving hemp integrity. Recycled gypsum–hemp bio-concrete exhibits increased density (368 to 587 kg·m−3) and compressive strength (0.05 to 0.52 MPa), accompanied by a moderate increase in thermal conductivity (0.081 to 0.096 W·m−1·K−1). These findings demonstrate the feasibility of 100% thermal recycling of gypsum–hemp bio-concrete without constituent separation.
Distributed recycling of high-density polyethylene (HDPE) into filament for use in material extrusion 3D printing has been proposed as part of a circular economy. There is a gap in the understanding of the potential for HDPE to release contaminants that are potentially hazardous to human health during reuse. Herein, HDPE from post-consumer packaging waste was sorted into food and non-food (NF) streams and virgin HDPE was taken as a benchmark material. All materials were extruded into filaments and recycled multiple times while monitoring emissions. In general, particle and organic chemical emissions decreased by 93 to 99% and 73 to 99%, respectively, with increased reprocessing cycle without appreciable decline in mechanical (Young’s modulus decreased by 5 to 16%), processability (melt flow index stable from 0.2 to 0.7 g/10 min for waste plastics), and thermal properties (crystallinity ranged from a 6% decrease to a 9% increase) of plastics. An exception was a sub-stream of NF plastic that had increased particle emissions (up to 3100%) with reprocessing cycle. Reductions in emissions during filament extrusion appeared to be more influenced by reprocessing cycle than by any specific process step (grinding, etc.). The progressive decline in emissions without appreciable loss of polymer integrity could be exploited to pre-condition HDPE to reduce potential hazardous emissions prior to extruding into filament. This work helps fill the knowledge gap on approaches to recycling plastics in distributed settings such as home-based businesses, which is critical for developing effective recommendations for controls to enable safe work practices such as the use of ventilation to minimize exposures.
The effective utilization and effective valorization of various organic industrial wastes have become increasingly important issues. One significant area for enhancing the circular economy is the processing of waste generated from vegetable oils and animal fats. This article focuses on the processing and use of soapstocks, which result from the chemical reaction between fatty acids and alkali. These soapstocks represent the most significant portion (approximately 70–90 wt% by weight) of waste produced by the oil and fat industry. The raw material for this study was soapstock obtained from the neutralization of sunflower oil at the PJSC “Zaporizhzhya Oil and Fat Plant,” designed by the Belgian company “De Smet.” The soapstock yield was found to be 9.95 wt% based on 100 wt% oil. Through a series of treatments involving water, acid, and multiple washes, a low-sulfur fuel component was produced that nearly meets the standards for boiler fuels as outlined in DSTU 4058-2001 and PN-C-96024:2020, except for the heat of combustion. It fully complies with the requirements specified in ISO 8217:2024. The sulfur content of the final product was determined to be 0.12 wt%. Additionally, the fuels produced contained 75.33 wt% carbon, 11.64 wt% hydrogen, and 12.00 wt% oxygen. Due to the relatively low oxygen content, the resulting product exhibits approximately twice the heat of combustion of similar fuels derived from other waste streams in the oil and fat industry.
This preliminary study investigates the viability of substituting high-performance Aalborg white Portland cement (CEM I 52.5 R) with five diverse industrial byproducts: wood ash, silica waste, clay brick, glass fibre, and calcined sewage sludge ash. Sewage sludge ash was produced in a laboratory from two different sludges from wastewater treatment plants in the Latvian cities of Jelgava and Liepaja. The research evaluates the influence of substitution levels ranging from 5% to 20% on the rheology of fresh material and its early-age mechanical performance (day 7). Results indicate that particle morphology largely dictates workability; porous and angular materials, such as wood ash, clay brick, and sewage sludge ash, reduce flowability, whereas non-absorbent milled glass fibres unexpectedly improve spread diameter. Regarding mechanical performance, glass fibre and clay brick waste demonstrated the highest potential, exceeding the 48–62 MPa reference compressive strengths by achieving up to 69 MPa at a 10% substitution level. Conversely, wood ash and silica waste exhibited significant strength degradation at higher substitution levels, due to agglomeration and high water demand. This approach not only identifies viable waste streams for cement substitution but also diverts significant industrial waste from landfills, thereby reducing CO2e emissions and advancing more sustainable construction practices.
