Search Results (7,793)

Cadmium (Cd), a highly toxic and mobile heavy metal, has emerged as a severe environmental concern in global agroecosystems, posing a substantial threat to human health. Although prior studies have established that ZAT6 and ZAT10 positively regulate Arabidopsis tolerance to Cd toxicity, the underlying molecular mechanisms remain largely elusive. The present study provides evidence that a class I TCP transcription factor, TCP9, significantly enhances Arabidopsis tolerance to Cd toxicity through the direct activation of ZAT6 and ZAT10 expression. The real-time quantitative PCR (RT-qPCR) analysis indicates that the expression of TCP9 was induced under Cd toxicity. Meanwhile, the tcp9 mutant exhibited heightened sensitivity to Cd toxicity, accompanied by elevated Cd accumulation in both shoots and roots. Notably, the complemented lines exhibited phenotypic characteristics analogous to those observed in the wild-type (WT) plants. Further physiological and biochemical analyses revealed that, in comparison to WT, the tcp9 mutant displayed elevated hydrogen peroxide (H₂O₂) accumulation and reduced contents of catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) under Cd toxicity. Furthermore, TCP9 directly interacted with the promoters of ZAT6 and ZAT10 in vitro, facilitating their transcription and consequently enhancing plant tolerance to Cd toxicity. Overall, our findings showed that TCP9 enhances Cd tolerance via modulating ZAT6 and ZAT10, thereby identifying TCP9 as a potential key target for improving plant tolerance to Cd toxicity. Full article

This research proposes an approach based on a circular economy principle for the integral valorization of Sargassum from the Mexican Caribbean. The biomass was characterized through proximal and elemental analyses, and then an oxidative pretreatment was carried out to enhance a sequential processing scheme to extract sodium alginate and use the solid waste as a substrate for biogas production via anaerobic digestion. The oxidative pretreatment successfully reduces the recalcitrant content and the concentration of heavy metals. The sodium alginate extracted from treated biomass achieves a yield higher than 20%; the characterization of the polymer via nuclear magnetic resonance showed that the mannuronic-to-guluronic ratio was between 0.34 and 0.62, indicating the potential for its use for environmental and biomedical applications. The highest yield in methane production was 328 mL CH₄/g of volatile solids, with a purity of 90%, and was achieved using the waste from alginate extraction with an inoculum-to-substrate ratio of 1:1. The experimental data presented an excellent fit to a Gompertz model (R² > 0.99). The proposed valorization pathway improves the sustainability of Sargassum management, prioritizing the recovery of high-value compounds before energy production. This circular approach provides a framework for converting environmental challenges into opportunities in the Caribbean. Full article

A carbide-slag-activated slag-fly ash geopolymer (CSF) and waste gold tailings sand were used to co-stabilize mucky soil, aiming to promote the valorization of multiple industrial solid wastes and provide a low-carbon treatment approach for mucky soil in river and lake regions. Unconfined compression, direct shear, water stability, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), and heavy metal leaching tests were conducted to investigate the effects of CSF and gold tailings sand contents on the mechanical properties, water stability, microstructure, and environmental safety of the stabilized soil. The results showed that the unconfined compressive strength (UCS) and shear strength increased with increasing CSF content, whereas the strength gain became marginal when the CSF content exceeded 15%. With the CSF content fixed at 15%, both the strength and water stability initially increased and then decreased as the gold tailings sand content increased. The CSF15-G30 specimen exhibited favorable overall performance, with 7 d and 28 d UCS values of 0.65 and 1.53 MPa, respectively, representing increases of 25.0% and 12.5% relative to CSF15. Its cohesion and internal friction angle reached 88.21 kPa and 47.13°, corresponding to increases of 44.5% and 8.1%, respectively. The water stability coefficients at 7 d and 28 d were 76.9% and 87.6%, respectively. SEM-EDS observations indicated that the cementitious products generated by CSF, together with the filling and skeletal effects of gold tailings sand, enhanced interparticle bonding and matrix densification. Although the concentrations of leached heavy metals increased with increasing gold tailings sand content, all measured values remained below the relevant leaching-toxicity limits. These results demonstrate that an appropriate amount of gold tailings sand can effectively improve the mechanical properties and water stability of CSF-stabilized mucky soil while maintaining satisfactory environmental compatibility. Full article

Nickel release from metallic items is the leading cause of allergic contact dermatitis, and preventive strategies require both reliable detection tools and materials capable of limiting skin exposure. In this work, we propose dual-function bioplastic coatings based on starch, glycerol, and cellulose derivatives incorporating dimethylglyoxime (DMG) and a pH-10 borate buffer to enable colorimetric nickel sensing directly in the solid state. The Ni–DMG assay was first optimized in solution through UV-Vis spectroscopy and a Central Composite Face-Centered Design, identifying reagent concentrations that maximize linearity while minimizing detection limits. These conditions were transferred to bioplastic films prepared using carboxymethyl cellulose (CMC) or quaternized hydroxyethyl cellulose ethoxylate (QHECE). The materials were characterized by FT-IR spectroscopy and Principal Component Analysis, while gravimetric tests assessed hydrophilicity. Both bioplastics showed clear and reproducible colorimetric responses upon nickel exposure, and multivariate models built from RGB values and UV-Vis spectra enabled quantitative prediction of Ni²⁺ content. However, the proof-of-concept experiment revealed insufficient resistance to prolonged moisture, with films softening and partially losing cohesion under conditions mimicking skin perspiration. These results demonstrate that the sensing mechanism is robust, but the current bioplastic formulation requires improved water resistance before practical deployment as protective coatings for jewelry. Full article

Carrying out a series of fundamental studies in the field of physicochemical analysis, based on an approach that considers the phase state of alloys and accounts for the regular patterns of interaction of substances in multicomponent ores that are complex in both chemical and phase composition, makes it possible to formulate a number of scientifically substantiated practical recommendations. The aim of this work is to assess the degree of zinc sublimation from a magnesium alloy through the behavior of the Bjerrum–Guggenheim osmotic coefficient and the degree of dissociation of the congruent compound. The paper presents a method for processing phase equilibrium lines in a temperature–composition phase diagram, resulting in mathematical expressions for the liquidus and solidus lines on a unified analytical basis in the form of a semi-empirical dependence derived from the Schröder–Le Chatelier equation. Indirectly, through the Bjerrum–Guggenheim osmotic coefficient, the degree of dissociation of MgZn₂ in the Mg–Zn system was determined to range from 17% to 46%. This result is in good agreement with the conclusions of Nikolay Semyonovich Kurnakov regarding the degree of dissociation of congruent compounds inferred from the shape of the maximum on phase diagrams. For MgZn₂, this maximum is very smooth, i.e., the composition of the liquid phase changes continuously with deviation from stoichiometry, resulting in a symmetrical rounded peak. An experimental study was carried out using a SEM/EDS analytical complex to confirm the high volatility of zinc. The key zinc-concentrating phases were identified in the investigated processing products (slag, metal, and dust), which is consistent with the theoretical premises and explains the mechanism of zinc behavior during high-temperature processing of zinc-containing slags. The form of zinc occurrence in different phases was established. In the initial slag, the zinc content reaches 51.79%. In the metallic phase, zinc is detected as fine dispersed inclusions. In the collected dust (flue ducts), particles enriched in zinc up to 44.09 wt.% were identified. Full article

To reveal the effect of vanadium content on the viscous flow behavior of vanadium-containing hot metal, viscosity measurements and molecular dynamics simulations were conducted. The viscosity and melting characteristic temperature were measured. The local structures of Fe, V, and C atoms were analyzed using radial distribution functions, average coordination numbers, mean square displacements, and cluster evolution. Both viscosity and melting characteristic temperature increased with vanadium content. At 1300 °C, the viscosity increased from 11.8 to 19.9 mPa·s as the vanadium content increased from 0.20 to 0.30 wt%. The melting characteristic temperature increased from 1242 to 1323 °C. Structural analysis showed that increasing vanadium content promoted the redistribution of C atoms. The average coordination number of V–C increased from 7.780 to 8.218. In contrast, the coordination numbers of C–Fe and Fe–C decreased. The mean square displacements of Fe and C atoms also decreased, indicating that atomic diffusion was suppressed. Cluster evolution further showed that V–C structures could dissociate and recombine with Fe–C and Fe–V units. Therefore, increasing vanadium content reduced the fluidity of hot metal by increasing the melting characteristic temperature, strengthening V–C local coordination, and promoting complex cluster formation. Full article

Municipal solid waste landfill leachate represents one of the most environmentally challenging liquid effluents in modern waste management; however, its high nitrogen and phosphorus content renders it a potentially valuable nutrient source for microalgal phycoremediation. Here, Chlorella sp. and Scenedesmus sp. were cultivated for 15 days in CHU-10 standard medium and 50% (v/v) municipal landfill leachate from Nauta, Peru, and characterized across 33 biochemical variables, 14 physicochemical parameters, and 32 metal ions and trace elements. A sequential competitive multivariate pipeline comprising principal component analysis (PCA), hierarchical cluster analysis (HCA), permutational multivariate analysis of variance (PERMANOVA), and linear discriminant analysis (LDA) was applied to both the biochemical and bioremediation datasets. Leachate supplementation increased peak biomass density by 26.6–28.3% and elevated total protein by 56.9% in Chlorella sp. and 73.4% in Scenedesmus sp., while reducing total lipids by 37–46% and suppressing polyunsaturated fatty acid production. Both species achieved net biological removal efficiencies (NBRE) exceeding 86% for ammonium and ammonia; toxic elements, including Cd (~96%), Al (~92%), As (~90%), and Pb (~90%), were removed at higher NBRE than macro- and micronutrient categories. LDA achieved 100% leave-one-out cross-validation accuracy for species classification from both physicochemical and 32-element NBRE profiles. These findings indicate two complementary valorization directions, contingent on further biomass safety verification: leachate-grown Scenedesmus sp. shows a favorable combination of protein enrichment and nutrient removal for single-cell protein production integrated with bioremediation, while Chlorella sp. in standard medium shows a more favorable fatty acid profile for nutraceutical applications. Because leachate-grown biomass also accumulates inorganic and trace-element constituents from the medium, its suitability for protein or nutraceutical use requires direct heavy-metal characterization of the harvested biomass, independent of the demonstrated removal efficiency from the liquid phase. Full article

Cathodic protection (CP) is used in the marine industry to prevent corrosion of metal components in seawater but may also promote biofilm formation. When steel and copper alloy components are in contact, the latter is often subjected to higher applied CP voltages than otherwise required when a steel component is not present. In this study, the protection that CP offers in bronze alloys (RG-10 and CC492K) was assessed, both in controlled laboratory conditions and in real marine conditions in the Bay of Biscay (up to 3000 h), with various temperatures and methods: sacrificial anodes and impressed currents under different voltages. After the exposures, visual, scanning electron microscopy (SEM), X-ray diffraction (XRD) and corrosion rate analyses were performed. The results showed faster biofouling deposition on surfaces with a higher CP voltage, exposed to marine seawater, at the early stages. Subsequently, for longer exposure times, intermediate CP voltages offered less biofouling protection. XRD analyses showed the presence of calcareous compounds (calcite and aragonite), among others. Meanwhile, the corrosion observed in the laboratory was mediated by the amounts of deposited salts, with higher corrosion corresponding to higher CP voltages. Changes in temperature for the same CP voltage caused quantitative and qualitative differences in salt deposition. The higher Pb content of the CC492K alloy compared with the higher Cu and Sn contents of GR-10 did not manifest at the biofouling level, but different corrosion rates were measured (GR-10 < CC492K). Thus, the optimal CP protection conditions for marine and laboratory environments are not the same, because of the different conditions involved. Full article

Lake sediments act as important sinks for heavy metals and microplastics, yet the mechanisms governing their enrichment, coexistence, and combined ecological risks remain insufficiently understood. This study investigated sediments from Daihai Lake, China, systematically characterizing the occurrence features of microplastics (morphology, size, and composition) and their associated heavy metal contents. A composite pollution risk framework (Multi Feature Potential Ecological Risk Index) was developed to evaluate microplastics–heavy metals interactions using correlation analysis, principal component analysis, and cluster analysis. In addition, a two-dimensional pollution index was applied to assess combined ecological risks. Results showed that MP abundance ranged from 6.60 to 26.80 n·g⁻¹, with a decreasing trend from southwest to northeast. Microplastics were dominated by fragments, with a high proportion of small particles (<0.25 mm), and were mainly composed of polyethylene terephthalate and polypropylene. The average concentrations of heavy metals in sediments were ranked as follows: Mn (863 ± 78 mg·kg⁻¹); Cr (124 ± 28 mg·kg⁻¹); Zn (86 ± 17 mg·kg⁻¹); Ni (43 ± 10 mg·kg⁻¹); Cu (36 ± 0.1 mg·kg⁻¹); Pb (23 ± 5 mg·kg⁻¹); As (15 ± 4 mg·kg⁻¹); and Cd (0.20 ± 0.04 mg·kg⁻¹). The two-dimensional comprehensive index values ranged from 124 to 1032, with an average value of 365.0, exceeding the risk threshold (>100). Approximately 70% of sampling sites exhibited high composite pollution risks. Small-sized and fibrous microplastics showed significant positive correlations with multiple heavy metals, indicating strong carrier effects. Full article

Copper and lead contamination in loess areas poses a potential threat to soil environmental quality and sustainable land use, while the low permeability, high clay content, and strong buffering capacity of loess often limit the efficiency of conventional electrokinetic (EK) remediation. This study developed an enhanced EK system integrating novel hydrogel (NH) electrodes, a poly(diallyldimethylammonium chloride)-modified activated carbon/carbon fibre (MAC/CF) permeable reactive barrier (PRB), and a vertical voltage for the remediation of Cu- and Pb-contaminated loess. The effects of vertical voltage (0, 10, 20, 30, and 40 V) on EK behaviour, contaminant migration, and removal performance were investigated. The results showed that the MAC/CF PRB improved electrical stability, enhanced electroosmotic transport, and regulated pH evolution by providing conductive pathways and reactive sites for OH⁻ capture and metal adsorption. Compared with the system without a PRB, the accumulated electroosmotic flow (EOF) increased from approximately 680 to 980 mL. The vertical voltage further promoted Cu²⁺ and Pb²⁺ redistribution into the PRB and enhanced the migration–adsorption coupling process. The optimal voltage of 30 V achieved the best remediation performance, with Cu and Pb removal efficiencies of 69–80% and 32–36%, respectively, within 72 h at initial concentrations of 500 mg kg⁻¹. Mechanistic analysis revealed that the vertical voltage transformed the MAC/CF barrier from a passive adsorption layer into an electrically activated migration–capture interface. The synergistic effects of ion transport regulation, OH⁻ buffering, conductive network construction, and heavy metal adsorption effectively suppressed precipitation-induced focusing and improved remediation efficiency. This study provides a promising strategy for enhancing EK remediation of low-permeability and structurally sensitive soils. Full article

Ni60/WC composite coatings reinforced with various WC contents were fabricated on 45 steels via high-speed laser cladding. First-principles calculations were adopted to investigate the interfacial characteristics between Ni and WC. The microstructures of the coating were analyzed by a scanning electron microscope (SEM). The microhardness and wear resistance of the coatings were evaluated by a Vickers hardness tester and a friction and wear tester. Theoretical calculations indicate that the C-terminated WC (001) crystal plane achieves the most stable bonding with the Ni (111) surface through the hcp site, with an interface energy of 9.57 J·m⁻². The interface is mainly provided by Ni-W metal bonds and Ni-C covalent bonds. The microstructure results show that the WC particles have good metallurgical bonding with the Ni matrix. Thus, the good interface ensures efficient load transfer to hard WC particles. The microhardness rose markedly with the increase in WC content, reaching 760 HV_0.2 for the 40 wt.% WC, which is 1.8 times that of Ni60 coatings. Tribological experiments showed that appropriate WC content could significantly improve the wear resistance of the coating. Full article

Heavy metal contamination in agricultural soils threatens food security and ecosystem sustainability worldwide. Microbial inoculants have been widely used to alleviate heavy metal phytotoxicity, yet the factors determining their efficacy remain unclear. Here, we conducted a global meta-analysis of 774 paired observations from 70 studies to evaluate the effects of microbial inoculation on plant performance under heavy metal stress. Overall, microbial inoculation significantly increased plant biomass, with greater benefits under higher levels of metal stress. Combined bacterial and fungal inoculation consistently outperformed single inoculations, while non-mycorrhizal beneficial fungi produced the strongest positive effects among individual inoculants. Soil organic carbon and sand content were positively associated with inoculation efficacy, whereas mean annual temperature was negatively associated with inoculation efficacy. Our results demonstrate that microbial inoculation is an effective strategy for enhancing plant tolerance to heavy metal stress and that its efficacy is strongly influenced by inoculation strategy and soil properties. These findings provide a quantitative basis for optimizing microbial-assisted remediation and developing context-specific management strategies for contaminated agricultural soils. Full article

Modified biochar has become an efficient tool for modulating availability of heavy metals in soils. To identify a preferable material and explore the remediation mechanism of modified biochar for Pb-contaminated soil, H₂O₂-, HNO₃-, KMnO₄-, and CaCl₂-modified biochars were applied at three ratios (1%, 2% and 3% w/w) to immobilize Pb in alkaline soil from coal-based solid waste dumps. Results showed that HNO₃-BC exhibited abundant acidic functional groups, and KMnO₄-BC had increased pH and CEC content. The application of modified biochars significantly altered soil Pb fractions. Compared with biochar and the control, the application of HNO₃-BC and KMnO₄-BC decreased acid-extractable Pb and increased the residual Pb fraction in soil. HNO₃-BC was more effective than KMnO₄-BC in promoting Pb transformation from labile fraction into stable fraction. The content of soil available Pb significantly decreased with increasing application ratio of HNO₃-BC. The complexation between soil Pb and acidic functional groups on the biochar surface is considered the primary mechanism for reducing Pb mobility and availability in contaminated soils. This research demonstrated that HNO₃-BC can serve as a potentially effective amendment for the remediation of heavy metal-contaminated alkaline soils in northern China. Full article

In the search for efficient adsorbents for pollutants removal from water, we prepared novel composites of the metal–organic framework ZIF-67 and conducting 1-D nanostructured polyaniline sulfosalicylate (PANI-SSA) in different weight ratios (20–75 wt.% ZIF-67) using a mechanochemical method. Composites were characterized by FAAS, SEM-EDX, TGA, FTIR and Raman spectroscopies, N₂ sorption, electrical conductivity and zeta-potential measurements and explored as adsorbents for the removal of basic fuchsin (BF) dye from an aqueous medium. TGA revealed improved thermal stability of the composites compared to pure components, while FTIR and Raman indicated strong interactions between PANI-SSA and ZIF-67 causing partial dedoping of the polymer. Composites’ morphology depended on their composition, with 1-D nanostructures observed for lower ZIF-67 contents. All composites are excellent adsorbents for BF, having better adsorption performance than pristine PANI-SSA. The composite with 75 wt.% ZIF-67 exhibited the highest values of maximum adsorption capacity (910 mg g⁻¹) and removal efficiency (97.2%), exceeding those for pure ZIF-67. Adsorption processes followed pseudo-second-order kinetics fitting the Langmuir–Freundlich isotherm, indicating monolayer adsorption on a heterogeneous surface. Composite adsorbent can be efficiently regenerated by washing with ethanol and reused. The results highlight the synergistic effects of combining PANI and ZIF-67 into advanced materials for wastewater treatment. Full article

During forest exploitation, large amounts of wood biomass are left as residues after harvesting, even though this material could be valuable in reducing greenhouse gas emissions by replacing fossil fuels and serving as a source of bioactive compounds. Within the context of the European Union’s circular bioeconomy strategy, enhancing the efficacy and rational application of forest logging residues constitutes a critical future objective. To evaluate the possible use of the stumps as forest residue-derived woody biomass for the first time, the chemical composition and presence of bioactive compounds in the xylem and bark of F. angustifolia Vahl. ssp. pannonica Soó & Simon stumps were analyzed, including the content of cellulose, acid-insoluble lignin, acid-soluble lignin, ash, and extractives soluble in toluene–ethanol and hot water. In hot water extracts, total phenolic content, the antioxidant activity determined by scavenging capacity toward DPPH and HPTLC, the content of elements by ICP-OES, and the identification of bioactive compounds by UHPLC-DAD-ESI MS/MS were assessed. Considering the chemical composition, the quality of the xylem of the F. angustifolia (cellulose: 42.46 ± 0.45%; lignin: 25.05 ± 0.02%; hemicelluloses: 19.74 ± 0.46%) was similar to that of the stem. Hot water extracts of the bark of F. angustifolia stumps showed high total phenolic content (33.94 ± 1.43 mg GAE/g DW) and strong antioxidant potential (198.48 ± 3.33 μmol TE/g DW), while toxic metals were not detected. UHPLC-DAD-ESI-MS/MS analysis indicated phenylethanoid glycosides as the dominant compounds in the extracts. The analyzed stumps of Fraxinus angustifolia Vahl. in the “Morović” Forest Administration represent a valuable biomass with potential for further valorization. Full article