Greenhouse gas (GHG) emissions from sanitary waste (SW) are not usually quantified in institutional inventories, which limits the ability to assess its management and associated carbon footprint. This study establishes emission factors (EF) for SW generated in a higher education institution (HEI), focusing on toilet paper. In 2022, 19 sanitary waste sources were monitored, obtaining a per capita generation of 3.02 g person−1 day−1 and an annual total of 356.87 kg of SW. Samples were characterized through proximate and elemental analyses, applying stoichiometric calculations for two disposal-site degradation pathways: Aerobic: 841.95 kg (total climate indicator) t−1 SW, and Anaerobic: 7041.97 kg (total climate indicator) t−1. The arithmetic mean of the aerobic and anaerobic EFs was 3941.96 kg (total climate indicator) t−1 SW. Based on an estimated annual mass of 1.12 t yr−1, emissions ranged from 0.35 to 6.71 t yr−1 (total climate indicator: CO2 + CH4-derived CO2e) depending on the scenario. Emissions could be reduced by over 90% when aerobic degradation or controlled methane capture predominates. The results suggest that separating SW at its point of generation and ensuring that it undergoes aerobic or energy-recovery treatment processes can limit its contribution to institutional GHG inventories. Having material-specific EF enables quantitative comparison among management strategies and guides continuous-improvement decisions.

Amid growing environmental pressure and increasing demand for resource sustainability, the efficient recovery of valuable metals from spent lithium-ion batteries (LIBs) has become a critical challenge in the field of resource recycling. Therefore, a novel approach is presented for selective lithium (Li) and manganese (Mn) separation from LiNixCoyMn1−x−yO2 by combining carbothermic reduction roasting and selective leaching. Low-cost glucose (C6H12O6) was selected as the reduction roasting reductant, which converts the cathode materials into water-soluble lithium carbonate (Li2CO3), water-insoluble cobalt (Co), nickel (Ni), and manganese oxide (MnO). Wet magnetic separation was employed to preferentially extract Li while simultaneously removing excess carbon from Ni, Co, and MnO. Under optimal roasting conditions at 600 °C for 90 min followed by wet magnetic separation with a liquid–solid ratio of 30 mL/g for 30 min, 95.42% of Li was preferentially extracted. Subsequently, at a formic acid (HCOOH) concentration of 1.6 mol/L, liquid–solid ratio of 6 mL/g, and leaching time of 30 min, 94.29% of Mn was selectively extracted from the wet magnetic separation products, whereas Ni and Co were leached at 6.13% and 7.22%, respectively. The acid-leaching residue can be recycled as a Ni-Co alloy.

Injection-molding purges are heterogeneous, bulky residues whose uncertain composition and irregular geometry hinder direct reinsertion, making cold shredding costly and maintenance-intensive. This work develops a low-infrastructure solar-assisted pre-processing route using a PMMA Fresnel lens to induce controlled sub-onset softening and enable clean shear cutting without destructive thermal histories. The sub-onset softening is here defined into a viscoelastically active range (at or above Tg for the amorphous phase) while remaining below the melting onset (Tm, onset) and below the onset of thermal degradation (Td, onset). The station was engineered via QFD and risk-oriented design tools, while a weighted Pugh matrix selected shear cutting over saw-based alternatives. A screening factorial DOE showed that lens height, angle, and their interaction significantly govern focal-spot diameter and receiver temperature, yielding linear relations for conservative set-point selection. Receiver benchmarking further indicated that copper reaches substantially higher temperatures than graphite under identical exposure conditions, supporting copper as the simplest, rapid-heating receiver. Under DOE-calibrated operation, tear-free shear cutting was achieved across representative purge families (PP–ABS, PC–ABS–PP, PA66, PA66-filler, and POM) without forced convection. From a recycling and waste-management perspective, the approach converts bulky purge scrap into mill-compatible feedstock with reduced mechanical resistance, lowering tool wear and fines generation, accelerating downsizing, and limiting stockpiling that elevates combustible-inventory fire risk. Overall, the proposed DOE-calibrated, operator-friendly framework improves recycling feasibility by enabling safer handling, more stable preprocessing throughput, and reduced reliance on disposal or long-term storage for heterogeneous industrial purges.

Sugarcane bagasse ash (SCBA) has been widely studied as a partial supplementary cementitious material; nonetheless, its hydration behavior and performance when combined with nanoscale modifiers remain insufficiently understood. The aim of this study is to assess the pozzolanic potential of SCBA, the hydration behavior of binary SCBA–cement composites and the mechanical performance of ternary mortars with silica nanoparticles (Si-NPs). SCBA reactivity was confirmed by a Chapelle index of ~300 mg Ca(OH)2/g, while hydration development in binary pastes (5–20 wt% SCBA) was quantified using TG/dTG and semi-quantitative XRD. Low SCBA replacement levels (5–10 wt%) enhanced the hydration degree by up to ~12% at 28 days compared with the reference paste. Ternary mortars incorporating 5 wt% SCBA and Si-NPs exhibited significant strength gains, with the optimal blend (2.5 wt% Si-NPs) achieving a 42% increase in 28-day compressive strength relative to the reference mortar. A sustainability assessment showed concurrent reductions in clinker intensity and CO2 intensity of approximately 33% and 32%, respectively. These findings support the sustainable and technical viability of combining agro-industrial waste and nanotechnology as complementary strategies for reducing clinker content while enhancing eco-efficiency in alternative cementitious composites.

Mineral processing may decisively influence recycled aggregate (RA) production, yet it is systematically underreported. This critical review screened 338 Scopus-indexed publications (2004–2024) and retained 204 studies after eligibility assessment. Reporting on comminution was limited: ~52% (105 studies) of studies did not explicitly mention crushing, while ~26% (53 studies) identified the crusher type, and only about 1% (two articles) reported operating conditions, which undermines reproducibility and cross-study comparability. RA quality is application-/market-dependent. The literature was classified into cement-based materials (46.1%), pavement applications (44.6%), and fundamental studies without application (9.3%). For cement-based materials, water absorption and compressive strength were the most frequently reported primary and secondary properties, respectively. For pavement applications, particle-size distribution and optimum moisture content predominated. Overall, mineral processing directly governs the primary attributes of recycled aggregates (RAs) and indirectly influences their secondary performance outcomes. The main gap identified in the literature is the lack of clear recommendations for processing procedures, which limits the reproducibility and comparability of reported results. To address this limitation, this article proposes a mineral-processing framework intended to standardize both RA processing and reporting practices, thereby improving crosslink study comparability, experimental reproducibility, and evidence-based specification according to end-use requirements.

This study investigated a feasible recycling and detoxification process for waste tire ash containing hazardous Zn and Al using acid leaching, followed by layered double hydroxide (LDH) synthesis. The novelty of this work is the direct conversion of a Zn/Al/Fe/Ca-rich real waste system into a phosphorus removal material, in which LDH-related uptake and secondary hydroxyapatite formation cooperatively immobilize phosphorus. Waste tire ash mainly consists of Zn, Al, Fe, Ca, and Si, most of which can be effectively leached with hydrochloric acid (HCl). The optimum leaching conditions for high extraction efficiency involved treatment with 10 M HCl for 10 min at 20 °C (solid–liquid ratio: 50 g/L). Under these conditions, the elution concentrations of Zn and Al from the residue decreased to 0.3 and 0.17 mg/L, respectively, meeting the Japanese leaching standards, whereas the raw ash showed significantly higher values. From the leached solution, LDH-containing products with high phosphorus removal capacity were synthesized at 40 °C for 2 h by adjusting the pH to 11.5. A phosphorus removal performance of 2.0 mmol/g was obtained owing to the formation of hydroxyapatite. The combined process of HCl leaching and LDH synthesis enables the detoxification of waste tire ash and the production of an environmental purification material.

Glass is a highly recyclable material that provides substantial environmental benefits, including savings in raw materials and energy as well as a reduction in CO2 emissions. To ensure the production of high-quality secondary raw materials, container glass from municipal waste separate collection must be accurately separated by color in recycling plants, where only minimal color mixing is tolerated. Color sorting is therefore a key step in glass recycling, as it directly affects both the quality and the market value of recycled cullet. Given the increasingly stringent color quality requirements for recycled glass and the high fraction of cullet used in container glass, advanced technological solutions are needed to improve sorting accuracy. In this study, a visible–near-infrared (VIS-NIR: 400–1000 nm) hyperspectral imaging (HSI) approach integrated with machine learning (ML) is proposed for the automated classification of post-consumer glass fragments from bottles and jars into five color categories: brown, dark green, light green, half-white and white. A hierarchical Partial Least Squares-Discriminant Analysis (PLS-DA) model combined with an object-based analysis strategy was developed to optimize color recognition. The proposed system achieved sensitivity and specificity values between 0.910 and 1.000, demonstrating excellent robustness and predictive capability. Validation on independent datasets confirmed the model’s reliability, with all color glass fragments correctly classified at the object level. The results highlight the potential of HSI-ML systems to enhance color sorting accuracy and process efficiency in recycling plants, contributing to improved material recovery and the advancement of sustainable, circular glass production.

The pursuit of alternatives to nonrenewable materials has stimulated the development of sustainable materials with improved performance, particularly polymer composites reinforced with plant-based fibers. In this study, eucalyptus fibers were thermally treated and evaluated as eco-friendly reinforcements for polyester composites, aiming to enhance their physical and mechanical properties. The fibers were subjected to heat treatments between 140 and 230 °C in a Macro-ATG oven, followed by analyses of anatomical characteristics and chemical composition. Composites containing 25% fiber reinforcement were produced using an orthophthalic unsaturated polyester matrix catalyzed with methyl ethyl ketone peroxide, with untreated fibers used as references. Thermal treatment induced significant modifications in fiber morphology and composition, including increases in cell wall fraction at 170 and 200 °C and higher cellulose contents at 140 and 170 °C. Mechanical performance was assessed through tensile, flexural (modulus of rupture—MOR), modulus of elasticity (EB), and impact tests. Composites reinforced with heat-treated fibers exhibited lower apparent density and, notably, those treated at 230 °C showed markedly reduced water absorption and enhanced tensile strength compared with the control. Overall, treatment at 230 °C proved most effective, highlighting the potential of thermally modified eucalyptus fibers as viable reinforcements for high-performance, bio-based polymer composites.

The recycling of industrial biomass waste, such as black liquor rich in lignin from the pulp and paper industry, represents a sustainable strategy to reduce environmental impact and promote resource valorization. Enzymatic depolymerization of lignin is considered a promising approach due to the high specificity of lignin-degrading enzymes. However, lignin’s poor solubility in aqueous and acidic conditions, combined with its structural complexity and recalcitrance, limits its enzymatic reactivity. In this study, Trametes versicolor laccase was used to depolymerize lignin following a sonication pretreatment designed to improve its solubility and reactivity. Response surface methodology (RSM) identified lignin concentration and sonication time as the most influential parameters for optimizing pretreatment efficiency. The enzymatic depolymerization process revealed a competition between condensation and depolymerization reactions. Characterization of the reaction products using GPC, FTIR, and NMR confirmed the formation of lignin-derived aromatic compounds. These findings highlight the effectiveness of sonication as a pretreatment method to enhance enzymatic lignin degradation. Future research will focus on integrating depolymerization and product separation processes to limit lignin repolymerization and increase the yield of depolymerized aromatic products.

Oily sludge is a complex emulsified waste consisting of water, oil, and solid particles. Conventional treatments are often inefficient, energy-intensive, and prone to causing secondary pollution. This study proposes a green demulsification technology based on ozone micro–nanobubbles (O3MNBs) by constructing an experimental system to analyze its effects and mechanisms of action on oily sludge treatment. The O3MNBs exhibited a mean particle size of 831 nm and generated a substantial amount of hydroxyl radicals (·OH, 250.4 μmol·L−1) in situ. Compared with conventional aeration, the dissolved ozone concentration and residence time in water of O3MNBs increased by 192% and 213%, respectively. During bubble collapse, intense pressure waves and high-speed microjets were generated to disrupt sludge aggregates, promoting the dispersion of sludge particles while simultaneously stripping oil films. Thus, the oil removal rate reached 41.5%, demonstrating the high demulsification efficiency of O3MNBs. Furthermore, ozone and ·OH attacked alkane C-H bonds in the oil phase, oxidizing hydrophobic films into hydrophilic products and decomposing surfactants that stabilize emulsions. This process promoted oil droplet coalescence and degradation into small organic molecules. After O3MNB treatment, the absorption peak of alkane C-H bonds gradually reduced, while a new C=O absorption peak appeared. This study provides a theoretical foundation and technical support for environmentally sustainable treatment of oily sludge by O3MNB application, offering an effective alternative to chemical demulsification without secondary pollution.