Search Results (1,474)

Flotation tailings and metallurgical slags from mining often contain toxic Pb, Cd, and Zn. In this study, we evaluated the in situ immobilization of Pb, Cd, and Zn in a Pb–Zn flotation tailing and a smelting slag by adding representative amendments: phosphate-based (ammonium phosphate, phosphoric acid, glassy fertiliser), cementitious (Portland cement), and iron-based (bog iron ore) materials at 1–10% (w/w). Treated samples underwent EPA-TCLP and pH-dependent leaching tests (pH 3–10), with Pb, Cd, and Zn measured by atomic absorption spectroscopy. The untreated tailing leached hazardous Pb (~60 mg/L) and elevated levels of Cd (~0.7 mg/L) and Zn (~53 mg/L), whereas the untreated slag leached negligible metal concentrations. All amendments reduced metal release in a dose-dependent manner. Phosphate amendments were most effective (e.g., 10% H₃PO₄ cut tailing Pb by 80%, Cd by 60%, and Zn by 30%), while cement and iron additions had much weaker effects. Solid-phase XRD and SEM-EDS analyses indicated the formation of stable calcium–phosphate minerals on sulfide surfaces after phosphate treatment. These findings suggest that low-cost phosphate additives (~5–10%) can substantially immobilize Pb, Cd, and Zn in such wastes. However, under strongly acidic conditions (pH < 3), some remobilization occurred, highlighting the need for further validation. This work provides practical guidance for waste managers on selecting in situ stabilization strategies for Pb–Zn mine wastes. Full article

Cadmium (Cd) and lead (Pb) are ubiquitous toxic heavy metals in farmland soils, posing a threat to agricultural product safety and human health through food chain transmission. Biochar is widely used for in situ immobilization of heavy metals; however, systematic comparisons of the immobilization performance of rice straw biochar (RSB) and sugarcane bagasse biochar (SCB) under single and combined Cd–Pb contamination remain limited. This study systematically evaluated their immobilization performance and mechanisms through pot and batch adsorption experiments. Without altering total soil Cd and Pb contents, both biochars significantly regulated heavy metal bioavailability in the soil–plant system. In batch adsorption, RSB exhibited maximum Cd and Pb adsorption capacities 2.1 and 3.0 times those of SCB, respectively, with chemisorption as the dominant mechanism. In pot experiments, RSB reduced Pb uptake in pakchoi by 60.0% and 81.0%, but increased Cd uptake. SCB increased Cd uptake under single Cd contamination, had no significant effect on Pb under single Pb contamination, yet reduced Cd and Pb uptake under co-contamination by 44.4% and 31.6%, respectively. These differential effects are attributed to distinct mechanisms: Pb was primarily immobilized via stable mineral precipitation, whereas Cd was bound through weakly reversible ion exchange. Both biochars improved soil fertility and maintained core bacterial ecological functions without posing additional ecological risks. This study clarifies the feedstock-dependency and metal-specificity of biochar in remediating Cd- and Pb-contaminated farmlands, guiding precise biochar selection under varying contamination scenarios. Full article

Polymer-based composites with magnetic properties are promising materials that are able to combine the usual polymer features (low density, high electrical resistance, enhanced flexibility, and processability, etc.) with magnetic properties typically associated with ferro- or ferrimagnetic metals, alloys or metal oxide. The combination of recycled NdFeB powders with additive manufacturing techniques based on material extrusion enables the production of magnetic composites. The novelty of this approach lies in the use of 3D printing supported by an external magnetic field, which is used to align the particles during the printing process and thus improve the final magnetic properties. This approach represents a sustainable strategy for the recovery of electronic waste, converting it into high-value-added magnetic materials intended for additive manufacturing applications. Micrometric particles made of a Neodymium–Iron–Boron (NdFeB) alloy are compounded with a flexible thermoplastic matrix made of polybutylene adipate-co-terephthalate (PBAT). The NdFeB alloy is recovered from permanent magnets of obsolete hard drives and is demagnetized, ground to powder under an inert atmosphere, and finally sieved to a particle size below 50 µm. The obtained powder is mixed with the polymer using a twin-screw extruder. The composite material containing the NdFeB particles is then processed to obtain a calibrated filament, used for the fused deposition modeling (FDM) three-dimensional (3D) printing of magnetic composites. To improve the composite’s ferromagnetic behavior, the particles were aligned along the stacking direction of the layers during the 3D FDM process by printing directly onto a permanent magnet placed on the build plate. Composites containing up to 50% by weight of recycled NdFeB powder were successfully processed using FDM technology, exhibiting increased stiffness, with the storage modulus rising from 123 to 178 MPa at 20 °C, while magnetic field-assisted printing increased the remanence from 11 to 28 emu/g and improved the reduced remanence from 0.21 to 0.49, corresponding to an estimated fourfold improvement in the magnetic energy product. Full article

Biomass-derived carbon-based electromagnetic wave (EMW) absorbers have attracted significant attention for their abundant availability and environmentally friendly characteristics. A novel strategy combining biomass templates with a ZIF-67-assisted approach was developed to fabricate Co₃O₄@C composites via pyrolysis. This work demonstrates that the intrinsic structure of biomass templates can be effectively leveraged to regulate both the microstructure and the electromagnetic properties of the resulting composites, enabling tunable microwave absorption performance. Among the prepared samples, M3 exhibits the lowest reflection loss (RL) of −54.79 dB at a thickness of 4.61 mm, and achieves an effective absorption bandwidth (EAB) of 3.43 GHz at 2.82 mm. This superior performance originates from the synergistic optimization of impedance matching and the coupling of dielectric and magnetic loss mechanisms. The porous biomass-derived carbon framework not only enhances multiple scattering and impedance matching but also provides abundant interfaces to induce strong interfacial and dipole polarization. Meanwhile, the uniform in situ growth of ZIF-67-derived Co₃O₄ nanoparticles introduces enhanced magnetic loss through exchange resonance, while structural defects further promote multiple dielectric relaxation processes. This study presents a novel waste-to-value strategy for the rational design of hierarchical composite absorbers, offering high-performance EMW absorption while demonstrating a low-cost, environmentally friendly, and scalable route for converting natural wood waste into functional materials. This work not only provides new insights into constructing high-performance, lightweight, and cost-effective EMW-absorbing materials but also aligns with the principles of sustainable development, resource efficiency, and green chemistry. Full article

As a widely used sponge facility, the permeable pavement system (PPS) frequently exhibited a decline in pollutant removal after long-term operation. However, the long-term impacts of different cushion fillers on pollutant removal and ecological risk remain unclear. This study modified a conventional sand-based PPS (S1) by replacing the cushion layer with five materials: construction waste bricks (S2), coal gangue (S3), activated carbon (S4), carbon nanotubes (S5), and graphene (S6). A 5-year laboratory experiment evaluated the removal efficiency, fraction distribution, and ecological risk of heavy metals (HMs: Mn, Pb, Zn, Cu, Cd, Ni) from rainfall. The key findings demonstrated significant variations among fillers. S2 showed the poorest performance with a removal efficiency of 83.26% ± 13.02 across all HMs, whereas carbonaceous-modified systems (S4–S6) exhibited high removal efficiencies, exceeding 97.00% ± 1.89. Residual and Fe/Mn oxide states were predominant among the HMs, exceeding 43.69%, indicating enhanced metal immobilization. The ecological risks of carbon nanotubes and graphene were the highest, with risk indices of 1123.02 and 1129.63, respectively. These findings demonstrated that carbonaceous fillers achieved superior HM sequestration, leading to an overall reduction in ecological risk in the effluent of PPS after long-term operation. Overall, this study provided new perspectives on elucidating long-term removal efficiency and the ecological risk mitigation of PPS, and supported future application of carbonaceous fillers in sustainable PPS design and construction. Full article

This study developed a high-iron-phase steel slag-based silicate cement system through high-temperature reconstruction and multi-source solid waste synergistic modification. The effects of reconstruction temperature and Ca/Si ratio on burnability, mineral evolution, microstructure, and hydration performance were investigated. Results showed that carbide slag and bauxite significantly improved the sintering behavior of steel slag. At 1275 °C, the f-CaO content in reconstructed steel slag decreased sharply from 1.45% to 0.11%, while overburning and liquid-phase coating occurred at 1300 °C, hindering further reaction of residual f-CaO. Reconstruction promoted the conversion of low-reactivity γ-C₂S to active α-C₂S and the formation of well-crystallized C₄AF. The decomposition of the RO phase enabled Mg²⁺ and Mn²⁺ to solid-solve into spinel phases, thus improving volume stability. The Ca/Si ratio regulated intermediate phases: higher ratios favored C₄AF, whereas lower ratios promoted spinel or olivine phases. The optimal sample (1275 °C, 65% steel slag + 25% carbide slag + 10% bauxite) achieved a 28 d compressive strength of 107.56 MPa, 18.26% higher than the reference cement, owing to synergistic hydration of α-C₂S and C₄AF. The F4 sample showed the lowest residual CH content (11.31%) and the highest hydration efficiency. Full article

Coal rank exerts a fundamental control on the distribution of elements during density-based separation, yet this influence remains poorly understood. The primary objective of this study is to elucidate how coal rank governs the enrichment and partitioning of major, trace, and rare earth elements (REY) in float–sink products, and to assess the implications for clean coal utilization and critical metal recovery. To achieve this, three Late Paleozoic bituminous coals of different ranks from Shanxi Province, China, were subjected to density fractionation (1.3–1.8 g/cm³) combined with proximate and ultimate analyses, X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), and coal petrography. The results show that coal rank fundamentally governs element distribution and enrichment patterns. With increasing rank, the dominant inorganic minerals shift from clay minerals to carbonates, leading to pronounced differentiation in elemental affinities. In medium- to high-rank bituminous coals, chalcophile elements (e.g., As, Mo, Tl) associated with sulfides are significantly enriched in high-density fractions, whereas in high-rank bituminous coals, carbonate-related elements (e.g., Sr, Ca, Mg) show marked enrichment. Rare earth elements are primarily hosted in clay and phosphate minerals. Light rare earth elements dominate in medium- to high-rank coals, while middle rare earth elements increase in high-rank coals due to carbonate influence. Density-based separation effectively concentrates hazardous elements (e.g., As, Pb, Cd) in high-density tailings, demonstrating substantial potential for mitigating environmental risks. Meanwhile, critical metals such as lithium (Li), strontium (Sr), and REY are enriched in medium- to high-density products, with Li hosted in clay minerals and Sr strongly enriched in carbonate-rich high-rank coal (up to 1525 μg/g), indicating recoverable resources from coal processing wastes. Full article

The construction sector plays a pivotal role in Australia; however, it is also a significant contributor to construction and demolition (C&D) waste generation. This dual impact underscores the urgent need to adopt more sustainable approaches, such as the circular economy (CE). This study aims to systematically examine CE implementation for C&D waste management in the Australian construction industry. A SWOT-oriented content analysis is conducted to identify key strengths, weaknesses, opportunities, and threats influencing CE adoption. An integrated qualitative and semi-quantitative approach is adopted, including frequency analysis, SWOT-based intensity measurement, and mechanism-based strategic interaction analysis. The results identify nine strengths, twelve weaknesses, nine opportunities, and fourteen threats. Key strengths include resource efficiency, waste reduction, and technological innovation, while major barriers include limited industry awareness, high initial costs, and policy constraints. Despite external challenges such as regulatory barriers and conservative industry culture, emerging opportunities from policy development, market demand, and sustainability imperatives support CE advancement. Accordingly, ten targeted strategies are recommended, such as voluntary CE certification and recognition schemes, capacity-building measures, policy improvements, and aggressive strategies leveraging dominant strengths. Overall, the study provides a comprehensive and systematic framework to support effective CE implementation, offering practical and policy-relevant insights for advancing sustainable construction. Full article

In 2024, China generated approximately 130 million tons of food waste. This study focuses on food wastewater characterized by exceptionally high organic strength (chemical oxygen demand (COD) > 80 g·L⁻¹, total suspended solids (TSS) > 20 g·L⁻¹) content. Conventional continuous stirred tank reactors (CSTRs) inherently couple hydraulic retention time (HRT) and sludge retention time (SRT), making them prone to microbial washout under high organic loading. To overcome this limitation, this study employed two anaerobic sequencing batch reactors (ASBRs) for treating such high-strength food wastewater. This study systematically evaluated the impacts of temperature (mesophilic: 37 °C and thermophilic: 55 °C) and organic loading rate (OLR) on fermentation performance. Under stable operation (OLR = 5.6 kg_COD·m⁻³·d⁻¹; HRT = 16 days), the mesophilic ASBR achieved a specific methane yield of 307 mL CH₄·g_CODremoved⁻¹, an average COD removal efficiency of 81%, and a volatile fatty acids-to-total alkalinity (VFA/TA) ratio of 0.2, indicating robust process stability. In contrast, the thermophilic ASBR exhibited a VFA/TA ratio of 0.5, signaling incipient acidification. Microbial community analysis revealed significantly higher bacterial and archaeal alpha diversity in the mesophilic system. Notably, Methanothrix—a versatile acetoclastic methanogen—dominated the mesophilic archaeal community (66.65%), conferring functional redundancy and resilience against organic shock loads. By contrast, the thermophilic system was overwhelmingly dominated by the hydrogenotrophic Methanothermobacter (99.28%), resulting in low functional diversity and structural fragility. Compared with a benchmark mesophilic CSTR (specific methane yield: 276 mL CH₄·g_CODremoved⁻¹; COD removal efficiency: 70.6%), the mesophilic ASBR improved methane yield by 11%, COD removal efficiency by 15%, and operational stability (VFA/TA = 0.2 vs. 0.6). This work addresses a gap in ASBR applications for high-strength food wastewater treatment and provides experimental validation of the performance, stability, and scalability of mesophilic ASBRs. The proposed process represents a technically feasible, resource-efficient, and operationally robust solution for the valorization of organic wastewater with COD > 80 g·L⁻¹ and TSS > 20 g·L⁻¹. Full article

A quaternary solid-waste-based binder was prepared from low-titanium slag, municipal solid waste incineration (MSWI) fly ash, steel slag, and flue-gas desulfurization gypsum (FGDG) to clarify the activating effect of MSWI fly ash on low-titanium slag and its influence on hydrate evolution. Unlike conventional solid-waste-based binders in which MSWI fly ash is mainly regarded as a hazardous residue requiring stabilization, this study demonstrates its specific role as a Ca-rich alkaline activator for promoting low-titanium slag depolymerization and coordinated hydrate formation. The results showed that the compressive strength first increased and then decreased with increasing MSWI fly ash content. Considering both strength development and MSWI fly ash utilization, the optimum mixture was identified as low-titanium slag:MSWI fly ash:steel slag:FGDG = 43.0:17.2:25.8:14.0, with compressive strengths of 9.51 and 46.32 MPa at 3 and 90 d, respectively. These values corresponded to 5.66 and 1.04 times those of the reference mixture without MSWI fly ash, respectively. Ettringite and C-(A)-S-H gel were the main strength-contributing hydration products, while Friedel’s salt was identified as a chloride-bearing AFm phase. Moderate MSWI fly ash addition promoted alkaline activation and low-titanium slag depolymerization, leading to increased formation of ettringite, C-(A)-S-H gel, and Friedel’s salt, which contributed to improved compressive strength. In contrast, excessive MSWI fly ash disturbed the Ca-Si-Al balance and inhibited effective hydrate formation. These results demonstrate that MSWI fly ash can serve as an effective Ca-rich activator for low-titanium-slag-based low-carbon cementitious materials and provide a feasible route for the synergistic utilization of multiple solid wastes. Full article

Background: Colorectal cancer is a common malignancy and 5-fluorouracil (FU) remains a mainstay of chemotherapy despite its toxicity. As an important part of comprehensive tumor treatment, dual-protein (DP) nutritional intervention is attracting more and more attention. Methods: This study preliminarily evaluated the regulatory effects of DP intervention on colorectal cells of CT26 tumor-bearing mice, examining the dosage and administration methods of DP, as well as the anti-tumor effects of FU alone or in combination with DP. Results: The results showed that low- and medium-dose DP numerically increased spleen index and showed trends toward alleviating FU-induced thymic atrophy, splenic damage, nephrotoxicity, and myocardial injury. It also partly mitigated muscle wasting, prevented FU-induced shortening of the colorectal tract, and reduced intestinal injury. In addition, DP was associated with increased lymphocyte, monocyte, and platelet counts and decreased granulocytes, suggesting possible alleviation of chemotherapy-induced bone marrow suppression and a potential effect on hematopoietic function. Flow cytometry results indicated possible effects of DP on CD4⁺ T and CD8⁺ T cell proliferation or apoptosis, modulation of effector and memory phenotypes, reduced splenic neutrophil levels, balanced B cell function, and maintained natural killer cell activity. In addition, DP intervention also showed trends toward regulating hepatic lipid metabolism and partially alleviating FU-induced dyslipidemia and muscle damage. In addition, DP and FU could increase IL-2, IL-10, GM-CSF and IFN-γ and decrease IL-6 and TNF-α. Conclusions: In conclusion, a moderate dose (0.67 g/kg) of DP had the most favorable trends, and the pre-intervention mode was more effective. This study also provided exploratory data on the potential of DP in reducing chemotherapy-related toxicity. These findings will provide preliminary scientific support for nutritional therapy in colorectal cancer patients, as well as for the research, development, and application of dual-protein foods for special medical purposes. Full article

The safe immobilization of high-level waste (as actinide) remains a critical bottleneck in the disposal of high-level radioactive waste worldwide. Moreover, the higher specific surface area and surface energy of nano-scale powders enable the production of ceramic materials featuring denser crystal structures and superior strength, hardness, and toughness. Therefore, in this study, Gd³⁺ was used as a surrogate for actinides, and Nb⁵⁺ was introduced as a high-valence charge-compensating cation. Nano-scale powders of CaCO₃, ZrO₂, Gd₂O₃, TiO₂, and Nb₂O₅ were employed to prepare a series of defect-fluorite-derived ceramics, CaZr_1-xGd_xTi_2-xNb_xO₇ (x = 0.1–1.0), via a high-temperature solid-state reaction method, aiming to investigate the atomic substitution mechanisms, phase evolution, and chemical stability under high-valence charge compensation. Laboratory X-ray diffraction (XRD), synchrotron X-ray diffraction (SXRD), and backscattered scanning electron microscopy with energy-dispersive X-ray spectroscopy (BSEM-EDX) confirmed a phase evolution sequence from zirconolite-2M to zirconolite-4M and finally to pyrochlore. This behavior is consistent with that reported for other Ln³⁺-Nb⁵⁺ co-doped zirconolite systems. Rietveld refinement of the SXRD data further revealed, for the first time, the site-occupancy mechanism of Gd and Nb in zirconolite-4M. In both zirconolite-2M and zirconolite-4M, Gd preferentially occupies the Ca sites, whereas Nb substitutes at the Ti sites. In the pyrochlore structure, Ca, Zr, and Gd occupy the 16d sites, while Ti and Nb occupy the 16c sites. Static leaching tests following the MCC-1 protocol showed that pyrochlore exhibits the highest leaching resistance, whereas zirconolite-2M shows the lowest. After 28 days, the highest Gd leaching rate was 1.92(1) × 10⁻⁵ g m⁻² d⁻¹. These results provide new insights into actinide immobilization behavior and compositional design in zirconolite-based waste forms. Full article

With the rapid development of the edible fungus industry, the environmental pressure and resource waste caused by the massive generation of fungal residue have become increasingly prominent. Meanwhile, heavy metal wastewater pollution and the growing demand for clean energy pose dual challenges to sustainable development. This study focuses on Auricularia cornea var. Li. fungal residue, exploring the establishment of a multi-level resource utilization pathway integrating “porous carbon material preparation—heavy metal adsorption—photocatalytic hydrogen evolution.” Firstly, the Auricularia cornea var. Li. residue-based porous carbon material was examined by combining hydrothermal carbonization, activation and slow pyrolysis. In optimal conditions, the porous carbon obtained yielded a surface area of 675.56 m²/g and formed a composite pore structure consisting of micropores with coexisting micropore and mesopore. Secondly, we performed batch adsorption experiments to study the effects of solution pH, adsorbent dosage and contact time and the adsorption behavior via fitting adsorbing kinetic models. Under optimal conditions, Cd(II) removal efficiency reached 92.36% and an equilibrium adsorption capacity of 92.47 mg/g. We used Cd(II) adsorbed porous carbon as a cadmium source and converted into a CdS photocatalyst using a hydrothermal sulfidation process. The CdS prepared using sodium sulfide as a sulfur source gave an average hydrogen evolution rate of 668.01 μmol·g⁻¹·h⁻¹ and showed higher photocatalytic performance for water splitting to produce hydrogen. Full article

Cadmium (Cd) and lead (Pb) co-contamination in construction and demolition waste landfill soils presents a significant challenge to ecosystem health, necessitating effective remediation strategies. This study investigated a synergistic approach combining a composite amendment (compost, superphosphate, desulfurized gypsum) with seven plant species to elucidate the interactions driving metal immobilization and phytoextraction. The amendment significantly altered soil properties: it reduced total Cd while increasing its bioavailability, and enhanced soil fertility (e.g., elevated organic matter and total nitrogen). Plant responses varied: Solanum americanum Mill. and Tagetes patula L. exhibited high Cd phytoextraction capacity, whereas Lolium perenne L. sequestered Cd/Pb primarily in roots. The bacterial community shifted from an oligotrophic, stress-tolerant state (e.g., Sphingomonas-dominated) in contaminated soil to a copiotrophic, functionally active state (e.g., Streptomyces-enriched) in amended soil. Community structure was strongly correlated with available Cd, pH, and nutrient levels. Key microbial biomarkers were specifically enriched in different plant rhizospheres. In contrast, the fungal community exhibited minimal responsiveness. These findings demonstrate that remediation efficiency is governed by an integrated “amendment–plant–microbe” framework: amendments regulate metal bioavailability, plants execute extraction or stabilization, and the restructured microbiome supports nutrient cycling and plant health. This integrated remediation strategy directly supports the Sustainable Development Goals of the 2030 Agenda, especially on environmentally sound management of chemicals and wastes and land degradation neutrality. This mechanistic understanding underscores the necessity of combined biological and chemical strategies for sustainable remediation of co-contaminated soils, ultimately enabling ecological reclamation and safe recycling of such urban marginal lands into productive uses. Full article

The invasive plant Datura stramonium L. possesses strong reproductive capacity and ecological adaptability, showing a tendency to spread rapidly, especially in highly human-disturbed habitats. To explore its resource utilization pathway—turning waste into wealth—and to address toxic metal pollution in strongly human-disturbed areas (such as mining regions), this study evaluates its phytoremediation potential in contaminated soils on the Qinghai–Tibet Plateau. We established a non-planted control and three planting density treatments to compare the removal rates of Pb, Cd, Cr, and As. To our knowledge, this is the first study to assess how planting density influences the multi-metal phytoremediation performance of this invasive species in a high-altitude plateau environment. The results showed that planting significantly increased toxic metal removal rates, with overall efficiency generally improving at higher densities, particularly for Cr. Analysis of bioconcentration and translocation factors revealed distinct element-specific accumulation patterns. Pb and As were primarily enriched and retained in the roots. Interestingly, while Cd exhibited a strong localized tendency to accumulate in the leaves, its overall root-to-shoot translocation remained relatively restricted at the whole-plant level, similar to Cr. Overall, D. stramonium functions primarily through root stabilization for Pb, As, and Cr, alongside partial aboveground accumulation for Cd. However, given its toxic and invasive nature, any practical phytoremediation application requires strict post-harvest biomass management and ecological monitoring to prevent secondary spread. Full article