Search Results (2,631)

The disposal of tunnel waste slag has emerged as a major ecological challenge. Highway pavement bases require large quantities of graded crushed stone as fill material, but large-scale quarrying of such stone also poses significant environmental problems. An innovative approach involves crushing tunnel waste slag into graded crushed stone for use as fill material, offering an economical and environmentally friendly solution to both issues. However, the performance of this recycled graded crushed stone needs to be carefully evaluated. This study employed particle flow analysis software to simulate the California Bearing Ratio (CBR) test process, followed by analysis and verification to assess its performance. A CBR model was developed and validated, the meso-mechanical parameters of the penetration process were analyzed, and the results were examined in terms of both CBR values and particle contact force fields. The findings indicated that different particle stiffness ratios $k_n/k_s$ had no significant effect on the CBR test, while the friction coefficient $\mu$ showed a linear positive correlation with the CBR value. It was also concluded that the slenderness ratio of the contact force field first increased and then decreased with an increase in the stiffness ratio $k_n/k_s$. As the friction coefficient $\mu$ increased, the slenderness ratio of the contact force field decreased accordingly. This study provides valuable insights into the influence of meso-mechanical parameters on the performance indicators of graded crushed stone pavement and offers a promising approach for the processing and reuse of tunnel waste slag to alleviate ecological pressures. Full article

A comparative study on the adsorption of ciprofloxacin (CIP) and sulfamethoxazole (SMX) onto CO₂-activated biochars derived from leather tannery waste (ABT) and Sargassum brown macroalgae (ABS) is presented. N₂ physisorption revealed that ABS possesses a higher Langmuir surface area (1305 m²/g) and a hierarchical micro–mesoporous structure, whereas ABT exhibits a lower surface area (412 m²/g) and a predominantly microporous texture. CHNS and FTIR analyses confirmed the presence of N-, O-, and S-containing heteroatoms and functional groups on both adsorbents, enhancing surface reactivity. Adsorption isotherms fitted well to the Langmuir model, with ABS showing superior maximum capacities of 256.41 mg/g (CIP) and 256.46 mg/g (SMX) compared to ABT (210.13 and 213.00 mg/g, respectively). Kinetic data followed a pseudo-second-order model (R² > 0.998), with ABS exhibiting faster uptake due to its mesoporosity. Over eight reuse cycles, ABS retained >75% removal efficiency for both antibiotics, while ABT declined to 60–70%. pH-dependent adsorption behavior was governed by the point of zero charge (pH_PZC≈ 9.0 for ABT; ≈7.2 for ABS), influencing electrostatic and non-electrostatic interactions. These findings demonstrate that ABS is a highly effective, sustainable adsorbent for antibiotic removal in water treatment applications. Full article

This study investigates how digital lifestyles and cognitive fatigue influence sustainable behaviour and energy awareness among Generation Z. Drawing on environmental psychology and social science perspectives, it explores behavioural and cognitive mechanisms linking digital overexposure with pro-environmental engagement. A cross-sectional survey conducted among 683 Polish secondary-school students examined the relationships between digital activity, fatigue, self-regulation, and sustainability practices such as waste segregation, reuse, and consumption moderation. The results show that higher digital fatigue and problematic online use are negatively associated with sustainability engagement, supporting the view that cognitive overload reduces individuals’ capacity for mindful, sustainability-oriented action. Using k-means clustering and robust regression analyses based on ordinary least squares (OLS), this study identifies distinct sustainability behaviour profiles among Generation Z and examines how digital fatigue and problematic online use predict lower engagement in pro-environmental practices. Importantly, educational level moderated this effect, suggesting that energy and sustainability literacy can buffer the adverse consequences of digital exhaustion. The findings contribute to the growing field of digital sustainability and highlight the need to integrate digital well-being and environmental education into youth and social policy frameworks. Full article

Modernizing municipal roads requires rehabilitation strategies that ensure adequate structural performance while reducing environmental and economic burdens. Although cold in-place recycling with foamed bitumen (CIR-FB) has been widely investigated, integrated assessments combining mechanistic–empirical modeling with LCA and LCCA remain limited—particularly for municipal roads in Central and Eastern Europe, where reclaimed asphalt pavement (RAP) quality, climatic conditions and budget constraints differ from commonly studied regions. This study compares two reconstruction variants for a 1 km road section: a conventional design using virgin materials (V₁-N) and a recycling-based alternative (V2-Rc) incorporating RAP from the existing wearing and binder layers and reclaimed aggregate (RA) from the existing base. CIR-FB mixture testing (stiffness ≈ 5.25 GPa; foamed bitumen = 2.5%, cement = 2.0%) was integrated into mechanistic–empirical fatigue analysis, material-flow quantification, LCA and LCCA. The V₂-Rc variant achieved a 3–21-fold increase in fatigue life compared to V₁-N at equal thickness. Material demand decreased by approximately 27%, demolition waste by approximately 39%, and approximately 92% of the existing pavement was reused in situ. Transport work was reduced five-fold (veh-km) and more than six-fold (t-km). LCA showed a 15.9% reduction in CO₂-eq emissions, while LCCA indicated approximately 19% lower construction cost, with advantages remaining robust under ±20% sensitivity. The results demonstrate that CIR-FB, when supported by proper RAP/RA characterization, can substantially improve structural, environmental and economic performance in municipal road rehabilitation. Full article

The recycling and reuse of wood have gained importance as strategies for reducing construction waste, lowering costs, and promoting circular practices in the built environment. This study evaluates the performance of recycled wood particle/epoxy composites (WPECs) for façade applications by prototyping panels produced from granulated degraded wood bonded with epoxy resin and coated with intumescent fire-retardant paint. The panels were design to meet standards for ventilated façade applications in accordance with EN 310-93 and ASTM D1037-06a and relevant building codes for facade cladding. Three replicates of each panel type were tested under controlled laboratory conditions to assess water absorption, equilibrium moisture content, capillarity, fire resistance, and mechanical performance. Moisture measurements were performed at immersion and drying intervals of 12, 24, 36, 72, and 120 h for four WPEC types manufactured with pine, beech, oak, and olive fibers. Statistical evaluation using SPSS (one-way and two-way ANOVA) confirmed significant species effects across most parameters. Results indicated that olive and oak WPECs provided the highest dimensional stability under moisture exposure, with olive additionally demonstrating superior compressive strength (35.45 MPa) and hardness (˂10,000 N). Pine and beech WPECs exhibited intermediate bending strength (≈10 MPa) and elasticity, while oak contributed stable swelling values despite lower strength. Fire resistance tests suggested relative improvements, although further standardized evaluation is needed. Collectively, olive and oak WPECs emerged as the most promising façade materials, combining durability, mechanical strength, and sustainability. Full article

The increasing challenges posed by climate change demand holistic approaches to mitigate ecosystem degradation. In Mediterranean-type regions—biodiversity hotspots facing intensified droughts, fires, and biological invasions—such strategies are particularly relevant. Among invasive species, Acacia longifolia produces substantial woody and leafy biomass when removed, offering an opportunity for reuse as soil-improving material after adequate processing. This study aimed to evaluate the potential of invasive A. longifolia Green-waste compost (Gwc) as a soil amendment to promote soil recovery and native plant establishment after fire. A field experiment was carried out in a Mediterranean ecosystem using Arbutus unedo, Pinus pinea, and Quercus suber planted in control and soils treated with Gwc. Rhizospheric soils were sampled one year after plantation, in Spring and Autumn, to assess physicochemical parameters and microbial community composition (using composite samples) through Next-Generation Sequencing. Our study showed that Gwc-treated soils exhibited higher moisture content and nutrient availability, which translated into improved plant growth and increased microbial richness and diversity when compared with control soils. Together, these results demonstrate that A. longifolia Gwc enhances soil quality, supports increased plant fitness, and promotes a more diverse microbiome, ultimately contributing to faster ecosystem recovery. Transforming invasive biomass into a valuable resource could offer a sustainable, win–win solution for ecological rehabilitation in fire-affected Mediterranean environments, enhancing soil and ecosystem functioning. Full article

Background: The healthcare sector plays a significant role in environmental degradation, particularly through energy consumption, emissions, and resource use associated with hospital operations. Despite growing global awareness of the impacts, environmental sustainability remains only partially embedded with the design, planning, management, and evaluation of hospital facilities, and empirical evidence is still limited. Methods: This exploratory study employed a mixed-method, two-phase approach. First, a scoping literature review identified key environmental dimensions and approaches for environmental sustainability in hospitals infrastructures. Second, a structured survey was distributed to Italian hospitals from Lombardy Region, between May and June 2024, to assess environmental performance and environmental strategy adoption. Results: Eight (n = 8) core environmental sustainability dimensions emerged from the review: energy efficiency, resource and waste management, transportation and mobility, materials and construction, environmental compliance, emissions, site sustainability, and design strategies. The subsequent based on these dimensions, gathered responses from (n = 18) healthcare facilities from Lombardy region, Italy. Findings revealed substantial gaps, since key measures such as on-site renewable capacity, water reuse systems, environmental certification application and health-island mitigation practices appear to be adopted sporadically. In addition, many of the surveyed facilities show consumption levels that exceed the benchmarks outlined in the literature. Discussion: The findings of this study reveal a notable misalignment between the sustainability debate, maturity promoted in the academic literature and the actual practices implemented in the Italian regional context. This mismatch highlights the importance of developing more uniform evaluation tools, policy requirements, and strengthening the organizational capabilities, to improve environmental performance in Italian hospital facilities. Full article

Second cheese whey (SCW), a major by-product of ricotta cheese production, poses significant environmental challenges due to its high organic load. Biohydrogen (bio-H₂) and poly-β-hydroxybutyrate (PHB) production offer a sustainable reuse of SCW, that provides ideal nutrients for microbial growth. This study aimed to convert SCW into Bio-H₂ and PHB using a 5-liter tubular bioreactor in a sequential lactic fermentation and photofermentation system. Two lighting conditions were tested: white LED (WL) and selected LED (SL). Optimal results were achieved with a co-inoculum of Lactococcus lactis MK L84 and Lacticaseibacillus paracasei MK L49 at pH 4.5–5.5, followed by photofermentation with Rhodopseudomonas palustris 42OL under SL condition. The process yielded an average of 0.47 L of H₂ per liter of substrate and 1.66% wPHB/wCDW. This approach successfully transformed dairy waste into high-value products, promoting circular economy principles. Full article

This review examines how the integration of circular bioeconomy principles with digital technologies can drive climate change mitigation, improve resource efficiency, and facilitate sustainable biorefinery development. This highlights the urgent need to transition away from fossil fuels and introduces the bio-circular economy as a regenerative model focused on biomass valorization, reuse, recycling, and biodegradability. This study compares linear, circular, and bio-circular approaches and analyzes key policy frameworks in Europe, Latin America, and Asia linked to several UN Sustainable Development Goals. A central focus is the role of digitalization, particularly artificial intelligence (AI), the Internet of Things (IoT), and blockchain. Examples include AI-based biomass yield prediction and biorefinery optimization, IoT-enabled real-time monitoring of material and energy flows, and blockchain technology for supply chain traceability and transparency. Applications in agricultural waste valorization, bioplastics, bioenergy, and nutraceutical extraction are also discussed in this review. Sustainability tools, such as automated life-cycle assessment (LCA) and Industry 4.0 integration, are outlined. Finally, future perspectives emphasize autonomous smart biorefineries, biotechnology–nanotechnology convergence, and international collaboration supported by open data platforms. Full article

Mechanical milling is a relevant preliminary processing operation that is widely used for the reuse of various types of agro-industrial waste. The objective of this study was to conduct milling experiments of hazelnut (Corylus avellana L.) shell waste at different times (0.5, 1 and 1.5 min) and subsequently evaluate the particle size distribution (PSD) of the powders obtained by sieving methodology. In addition, flowability parameters were determined for the particles retained on the sieves, and their morphology and microstructure were examined using several microscopy techniques. The results demonstrated that the hazelnut shells were successfully fractionated under the milling conditions investigated (short milling times ≤ 1.5 min), and the histograms of the PSD exhibited a wide dispersion of sizes (≤1.7 mm). The particles retained from sieve₁₀₀ to residue exhibited poor or no flow, attributable to the high degree of cohesion between them. Morphological analysis based on optical microscopy and image analysis revealed that there was an increase in the aspect ratio parameter when the particle size decreased, meaning that the particles had elongated shapes. Microscopic analysis (SEM, AFM and CLSM) showed that the particles exhibited complex shapes and a comparable microstructure, comprising tightly packed clusters of sclerenchyma cells. From the microscopy images obtained (SEM and AFM), it was inferred that the cracks generated during blade impacts propagate along the middle lamella of the cells, allowing the cluster-like arrangement to be preserved. The CLSM results demonstrated that as the size of hazelnut shell particles decreases, the exposure of lignin on its surface is favored. The findings of this study demonstrate that hazelnut shell waste can be readily pre-processed using a blade grinder, thereby facilitating its reuse in applications that demand fine particle sizes (e.g., bioadsorption of pollutants and the production of biocomposite materials). Likewise, the results concerning the flowability parameters, microstructural arrangement, and morphological features of the different particle fractions obtained are crucial variables that must be considered. These variables significantly influence the possible applications for the revalorization of this type of agro-industrial waste. Full article

Worldwide, large volumes of industrial residues, such as water treatment sludge (WTS), biomass ash (BA), iron slag (IS), and quarry fines (QF), are generated with limited reuse. This study evaluates their potential as additives for two soils, using two types of soils as matrices. A comprehensive laboratory program (particle size distribution, Proctor compaction, Atterberg limits, falling-head permeability, oedometer consolidation, consolidated undrained triaxial tests, and scanning electron microscopy) was performed on soil–residue mixtures across practical dosages. Optimal mixes balanced strength and transport properties: 15% WTS lowered hydraulic conductivity (k) into the 10⁻⁹ m/s range while reducing plasticity; 20% BA rendered the soil non-plastic but increased k into the 10⁻⁸–10⁻⁷ m/s range; 50% IS increased friction angle while maintaining k ~10⁻⁸ m/s; and QF produced modest changes while preserving k ~10⁻⁹ m/s. These findings support the sustainable reuse of these industrial wastes for soft soil stabilization, also contributing to the circular economy in the industrial and construction sectors, and are aligned with the United Nations’ sustainable development goals 6, 9, 11, 12, and 15. Full article

Circular economy emphasizes sustainability and resource efficiency by extending product life cycles and minimizing waste. This study explores the reuse of polyamide press felts from the paper industry for removing endocrine disruptors (EDCs) from water, aligning with circular economy principles. EDCs, as defined by the WHO, are external substances that disrupt endocrine functions and can cause adverse health effects even at very low concentrations. Common EDCs include industrial chemicals, pesticides, pharmaceuticals, and natural hormones, with bisphenol A (BPA) and 17β-estradiol (E2) being particularly problematic in water due to their health risks. Polyamide, valued for its strength and durability, is widely used in press felts but becomes waste after its industrial use. Reusing these felts is both environmentally and economically beneficial, as the production of polyamide involves high costs and significant impacts. This study investigates the adsorption capacity of polyamide felts for BPA and E2, a process favored for its simplicity, cost-effectiveness, and efficiency in water treatment. Results show that polyamide felts achieve a 75% initial deposition efficiency, adsorbing up to 135 μg BPA and 130 μg E2 per gram of felt. Thus, reusing polyamide felts effectively reduces EDCs in water, supporting water security and advancing the circular economy. Full article

The depletion of natural resources remains a major global challenge, emphasizing the need to develop sustainable processes that enable both metal recovery and waste recycling. This study investigates the leaching of valuable metals from lead smelting slag using methanesulfonic acid (MSA), a biodegradable and environmentally benign reagent. Batch experiments were performed under different MSA concentrations (0.35–1.4 M) and temperatures (22–80 °C). Metal dissolution increased nearly linearly with acid concentration up to 1 M, with maximum recoveries after 60 min of 85% Zn, 64% Pb, 75% Cu, and 68% Fe. Copper dissolution was governed by the oxidation of Cu₂S, while Fe leaching was affected by pH variations that promoted re-precipitation. Kinetic modeling indicated mixed chemical–diffusion control mechanisms, with activation energies of 22.6 kJ mol⁻¹ for Zn and 31–33 kJ mol⁻¹ for Pb, Cu, and Fe. Beyond efficient metal extraction, the process generated a leach residue with reduced concentrations of base metals and a mineralogical composition dominated by stable calcium-silicate phases, improving its potential suitability for reuse in construction or mining backfill applications. Overall, methanesulfonic acid proved to be an effective and sustainable lixiviant, combining high metal recovery with the generation of recyclable slag, thereby contributing to circular metallurgical practices. Full article

Phosphate is a crucial non-renewable mineral resource, mainly utilized in producing fertilizers that support global agriculture. As phosphorus is an indispensable nutrient for plant growth, phosphate holds a key position in ensuring food security. While deposits are distributed worldwide, the largest reserves are concentrated in Morocco. The Benguerir phosphate mining in Morocco generates heterogeneous waste (i.e., including overburden, tailings, and phosphogypsum) that complicates management and valorization, which is the beneficial reuse or value recovery from waste materials (e.g., use in cover systems, buffering, or other engineered applications). Therefore, it is essential to characterize their mineralogical properties to evaluate their environmental impact and possibilities for reuse or site revegetation. To do so, we integrate VNIR–SWIR reflectance spectroscopy with HandHeld X-ray fluorescence (HHXRF) to characterize phosphate waste rock and assess its reuse potential. For this purpose, field samples (n = 104) were collected, and their spectral reflectance was measured using an ASD FieldSpec 4 spectroradiometer (350–2500 nm) under standardized laboratory conditions. Spectra were processed (Savitzky–Golay smoothing, convex-hull continuum removal) and matched to ECOSTRESS library references; across the dataset, library matching achieved mean RMSE = 0.15 ± 0.053 (median 0.145; 0.085–0.350), median SAM = 0.134 rad, median SID = 0.029, and mean R² = 0.748 ± 0.170, with 84% of spectra yielding R² > 0.70. In parallel, HHXRF major and trace elements were measured on all samples to corroborate spectral interpretations. Together, these analyses resolve carbonate–clay–phosphate assemblages (dolomite commonly dominant, with illite/smectite–kaolinite, quartz, and residual carbonate-fluorapatite varying across samples). Elemental ratios (e.g., Mg/Ca distinguishing dolomite from calcite; K/Al indicating illite) reinforce spectral trends, and phosphate indicators delineate localized enrichment (P₂O₅ up to 23.86 wt % in apatite-rich samples). Overall, the combined workflow is rapid, low-impact, and reproducible, yielding coherent mineralogical patterns that align across spectroscopic and geochemical lines of evidence and providing actionable inputs for selective screening, targeted material reuse, and more sustainable mine reclamation planning. Full article

Wastewater treatment plants (WWTPs) have been identified as the major sources of contaminants of emerging concern (CECs) in water bodies, as they are not designed to remove organic micropollutants efficiently. Consequently, many technologies have been explored for WWTP upgrading, including activated carbon adsorption. However, the high production cost and environmental challenges associated with activated carbon production limit its application in industrial settings. Therefore, a wide range of alternative materials has been investigated as potential replacements. In this study, biochar produced from waste raspberry biomass was evaluated as an adsorbent for the removal of pharmaceuticals and pesticides quantified in the secondary effluent of municipal WWTP. The results showed that the biochar efficiently removed almost all detected compounds, except for three compounds (clarithromycin, propranolol, and linuron). The wastewater pH (6–8) did not significantly affect removal efficiency significantly, and kinetic tests demonstrated rapid adsorption. The potential for biochar reuse was confirmed through three consecutive batch adsorption cycles. A comparative study between biochar and powdered activated carbon (PAC) revealed some differences in efficiency, primarily attributed to the larger surface area of PAC. π-π interactions, hydrogen bonding, and pore-filling were proposed as possible adsorption mechanisms based on the adsorption efficiency and biochar characterization. Full article