Search Results (949)

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

This paper presents a field case study of a mechanical failure that occurred in the bottom-hole assembly (BHA) during composite plug milling after hydraulic fracturing operations. The failure sequence was reconstructed using field hook load and torque records, operational documentation, and inspection of the damaged components recovered from the borehole. The results indicate that the critical condition developed progressively and was associated with increasing resistance to drill string movement, insufficient hole cleaning, and repeated attempts to continue milling and release the partially immobilized assembly. The observed damage pattern, together with the presence of residual cuttings and metallic debris in the borehole, supports the conclusion that the loss of the BHA section at the hydraulic safety sub resulted from the interaction of several adverse operational factors acting simultaneously, particularly the combined action of pull-up force and rotation under deteriorating borehole conditions. A supporting strength assessment of the hydraulic safety sub was used to relate characteristic operating points to the admissible working range of the connector. The study shows that hook load and torque data provide the greatest practical value when interpreted jointly and in their operational context rather than as isolated peak values. The findings support safer planning and execution of plug-milling and stuck-pipe remediation operations in highly deviated wells. Full article

Bismuth is widely recognized for its natural abundance, moderate cost, and low toxicity, making it an attractive alternative to the expensive and toxic transition metals commonly employed in heterogeneous catalysis. In this work, we report the immobilization of bismuth onto a series of SBA-15 materials and their application for nitrophenol reduction and iodine uptake. Particular attention was given to anchoring bismuth on three nitrogen-containing mesostructured silicas in comparison with its deposition on the unmodified silica support. Remarkably, nitrogen-containing ligands directed the nucleation and growth of crystalline bismuth nanosheets, whereas the pristine SBA-15 afforded atomically dispersed and amorphous metal particulates. Bismuth loaded on SBA-NNH₂ represents an optimal balance between porosity, accessibility, and metal–ligand interaction. Crystalline nanosheets displayed interesting catalytic activity for the reduction of nitrophenol to the corresponding aromatic amine, even at low bismuth loading (k_app = 3.8 × 10⁻³ s⁻¹), and exhibited recyclability. Upon reduction, bismuth loaded on SBA-NNH₂ stands as the best scavenger for iodine adsorption, reaching 442 mg.g⁻¹. On the whole, these findings highlight the role of the N-ligands in directing the growth of bismuth particles and the capability of the resulting bismuth-supported materials for iodine scavenging and for sustainable catalysis in fine and pharmaceutical chemistry. Full article

This study used UV-Vis absorption spectroscopy to investigate the interactions of flavonoids—baicalein (with ortho-dihydroxyl on the A-ring) and apigenin (with 4′-monohydroxyl on the B-ring)—with metal ions (Co²⁺, Ce⁴⁺) and membrane–mimetic systems (CTAB/SDS micelles, liposomes, vesicles). It revealed how flavonoid spectral properties related to molecular structure and microenvironment. Key findings were as follows: pH affected absorption spectra by altering phenolic hydroxyl protonation. Metal chelation depended on hydroxyl position: baicalein’s A-ring ortho-dihydroxyl formed a stable charge-transfer complex with Cu²⁺. In acidic medium, apigenin reduced Ce(IV) more effectively than baicalein, which contradicted the classic antioxidant role of ortho-dihydroxyl groups. This showed that reaction microenvironments could change hydroxyl reactivity and electron transfer paths. Membrane–mimetic systems (liposomes/vesicles) raised apparent pKa, enhanced solubility and stability. The study first quantified distinct ΔpKa values for different flavonoids (e.g., quercetin vs. baicalein), which were linked to intramolecular H-bonding and membrane preference. Quercetin’s B-ring ortho-dihydroxyl enabled the formation of hydrophobic interfacial anions in nanocarriers under alkaline pH, ensuring high stability. Kaempferol showed sustained leakage. These findings provided a basis for structure-guided flavonoid carrier design, bioavailability, and antioxidant delivery. By integrating reaction microenvironment, membrane interface effects, and carrier stability, this work clarified flavonoid bioactivity mechanisms and supported targeted delivery strategies. Full article

The removal of sulfur compounds such as ethyl mercaptan from natural gas remains a critical challenge due to their detrimental effects on downstream processes, catalyst poisoning, and environmental emissions. In this study, a series of halloysite-supported transition metal oxide catalysts was synthesized and evaluated for the removal of sulfur compounds from natural gas at 25 °C, 200 psi, and 36 mL/min, using 0.5 g of the catalyst. The nanotubular structure and dual surface chemistry of halloysite promote enhanced metal dispersion and improved mass transfer. Single-metal (manganese, copper, zinc, and nickel) catalysts were developed and tested, after which a multi-metal oxide (base) catalyst comprising a composite of the single metals (Zn-Cu-Mn-Ni) was developed as a base catalyst to combine adsorption-active and redox-active functionalities, and its performance was further enhanced by the addition of palladium as promoter. A combination of analytical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), provided evidence that highly dispersed metal oxide phases were formed and the halloysite structure was preserved. XPS data showed the presence of oxidation states of metals that were active (Zn²⁺, Cu²⁺, Ni²⁺, Mn³⁺/Mn⁴⁺ and Pd²⁺), an indication of a redox-active surface for sulfur interaction. Results from the breakthrough experiments showed that the base catalyst significantly improved sulfur removal compared to single-metal catalysts, while the Pd-promoted catalyst exhibited the highest performance, with a breakthrough time of 630 min. Palladium was incorporated at low loading as a promoter, enhancing adsorption performance while maintaining a favorable balance between efficiency and material cost. This enhancement is attributed to synergistic interactions between adsorption-active sites and redox-active species, as well as improved electron transfer facilitated by palladium. The results demonstrate that rational design of multi-metal oxide catalysts supported on naturally occurring halloysite provides an effective and scalable approach for sulfur removal from natural gas, with strong potential for industrial applications. Full article

Heavy metal pollution remains a major global environmental challenge due to persistent ecological risks and potential threats to food safety. Microbial remediation and phytoremediation represent sustainable alternatives to conventional treatments; however, their effectiveness is strongly influenced by number of factors including nutrient availability. This review critically examines how nutritional regulation governs microbial metabolism, plant physiological responses, and rhizosphere interactions to enhance heavy metal transformation and removal. Metal bioavailability depends on type, concentration, soil pH, redox potential, and microbial processes. Interventions including fertilizers, chelating agents, inoculation with arbuscular mycorrhizal fungi and plant-growth-promoting rhizobacteria enhance phytoremediation processes through regulating plant nutrient and heavy metal uptake, while selection between ammonium/nitrate changes rhizosphere pH consequently affects plant metal uptake. Similarly, nutrients, i.e., phosphate, iron, zinc and manganese competitively affect metal uptake. Organic amendments enhance phytostabilization, especially for selenium and mercury, while enhancing chromium reduction. Sulfur-reducing bacteria precipitate metals as insoluble sulfides with 90% efficiency. In addition, soil amendments including plant-growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and metal-chelating agents can be strategically used to enhance the phytoextraction from metal from contaminated soils. We suggest that the future integration of modern approaches such as multi-omics and cisgenesis supported by artificial intelligence tools can help to accurately predict the efficiency of nutrient regulation strategies and their remediation outcomes, thereby supporting evidence-based soil management. Full article

Dry reforming of methane (DRM) converts the greenhouse gases methane (CH₄) and carbon dioxide (CO₂) into syngas (hydrogen (H₂) and carbon monoxide (CO)). Despite its numerous advantages, DRM has not yet been industrialized due to catalyst deactivation and competing side reactions. While Ni-based catalysts have been widely used, they are prone to increased carbon deposition and sintering, and although bimetallic systems and oxygen-based supports have shown promise, their effects on carbon deposition are yet to be fully understood. In this study, carbon nanotube (CNT)-supported Pt-Ni catalysts incorporating mixed oxides of CeZrO₂ and CeZrLaO₂ were investigated to evaluate the impact of support composition and metal–support interactions in DRM. The catalysts were synthesized and subsequently tested in DRM. Catalysts supported on CNTs displayed higher CH₄ and CO₂ conversions compared to conventional ceria–zirconia, highlighting the beneficial role of the carbon nanotube support in improving dispersion and accessibility of the metal active sites. Addition of Pt was found to promote reverse water–gas shift (RWGS) reaction, whereas the addition of La was found to decrease catalytic activity. Despite the formation of a Ni-Pt alloy, the obtained catalysts favored RWGS over DRM. These findings illustrate key limitations and design considerations for optimization of CNT-supported bimetallic catalysts in DRM. Full article

Mining activities severely degrade soil quality, impairing ecosystem functioning by reducing organic matter and increasing metal toxicity, which limits plant establishment. This study evaluated the effects of vermicompost and arbuscular mycorrhizal fungi (AMF) on plant growth, manganese (Mn) dynamics, and plant–soil interactions associated with early ecosystem recovery in Mimosa caesalpiniifolia cultivated in mining-degraded soil. A greenhouse experiment was conducted in a 3 × 2 factorial design, with three vermicompost doses (0, 60, and 120 g kg⁻¹) and two inoculation treatments (with and without Claroideoglomus etunicatum). Vermicompost significantly increased shoot and root biomass. AMF inoculation enhanced shoot and root biomass by 25% and 16%, respectively. Although vermicompost reduced mycorrhizal colonization, AMF increased spore density. The highest vermicompost dose reduced Mn concentrations in shoots and roots by up to 44% and 39%, respectively. AMF altered Mn partitioning by decreasing shoot Mn and increasing root retention, suggesting the potential for phytostabilization. Mn toxicity was reduced by 74% with vermicompost and 24% with AMF. Overall, vermicompost and AMF contributed independently to improved plant establishment and regulated Mn dynamics, supporting early indicators relevant to ecosystem recovery and their potential use in sustainable strategies for the ecological restoration of mining-degraded soils. Full article

The integration of catalytic methane decomposition (CMD) with CO₂ gasification (Reverse Boudouard Reaction) offers a promising chemical looping route for carbon-negative hydrogen and syngas production. This work systematically investigates the gasification reactivity of six carbon morphologies, CNTs, CNFs, activated carbon, graphite, graphene, and CMD-derived carbon, with and without Ni addition. First, activity tests and characterization (XRD, XPS, Raman) revealed that CMD-derived carbon outperformed all other benchmarks due to its highly amorphous nature (sp³/sp² = 0.98), which provides a high density of reactive sites. Second, kinetic analysis showed that the incorporation of 5 wt% Ni on CMD carbon reduced the activation energy (E_a) from 435.3 kJ mol⁻¹ to 114.6 kJ/mol, the lowest among all samples. This 74% reduction confirms that structural defects in CMD carbon act as anchoring sites for Ni, facilitating a strong metal–support interaction (MSI) that promotes CO₂ activation. Third, an investigation into structural synergy revealed that higher Ni loadings (>5 wt%) increased the activation energy (up to 171.2 kJ mol⁻¹). This trend is attributed to Ni agglomeration and weakened MSI, which reduces the active catalytic interface. These findings demonstrate that the efficiency of CO₂ valorization is highly sensitive to carbon morphology, providing a clear optimization strategy for integrated chemical looping methane-to-syngas energy cycles. Full article

Algae rarely occur as solitary phototrophs in nature or engineering; instead, they are embedded in complex bacterial consortia that control their physiology, productivity and ecological performance. The phycosphere, a microscale niche rich in algal exudates, promotes extensive metabolic exchange and chemical signaling, defining these associations. Bacteria capitalize on the dissolved organic carbon released by algae, providing growth supporting molecules such as vitamins, trace metals, and siderophores, as well as regenerated inorganic nutrients. Bidirectional beneficial interactions range from obligate mutualism to facultative commensalism and antagonism, depending on environmental context and community membership. Bacterial partners can stimulate algal growth, morphogenesis, and stress tolerance, as well as modulating defense and programmed cell death during the decline and bloom succession of algae resulting from algicidal taxa. Metabolic cooperation, QS signaling, extracellular enzyme activity, and chemically induced gene expression produce the exometabolome in the phycosphere, which in turn reprograms gene expression in all partners. Recent advances in multi-omics toolboxes, single-cell isotopic analyses, and microfluidics have greatly enhanced our understanding of the functional and spatiotemporal orientation of algal microbiomes. Ecologically, algal–bacterial interactions manage the phytoplankton community structure, control HABs, and modulate carbon and nutrient fluxes in both marine and freshwater realms. Biotechnologically, engineered algal–bacterial consortia are a promising tool for enhancing biomass production, stabilizing large-scale cultivation, improving wastewater treatment, and upgrading biofuels and fine chemicals. Despite these notable research advances, the context- and species-dependent complexity of multispecies interactions remains a major obstacle to their practical modeling and scalable implementation. Integrative research frameworks that combine molecular, ecological, and bioengineering approaches are urgently needed to unlock the full potential of sustainable applications in the future. Full article

Quantifying the mixture effects on humans exposed remains challenging because mixture components are correlated and may act bidirectionally by exhibiting nonlinear dose-response relationships, which may contribute to subclinical organ dysfunction. The liver is a vital organ in the body with broad functions, making it vulnerable to injury as it is the first organ exposed to circulating toxicants, which can precipitate hepatic damage. Our study’s objective was to evaluate the combined and component-specific associations of a multi-chemical exposure mixture of heavy metals, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (dioxins), and polychlorinated dibenzofurans (furans), with liver biomarkers, and to compare concentration-based results with the toxic equivalent (TEQ) potency of the weighted results for dioxin-like compounds. In an unweighted analytic sample of U.S. adults from NHANES 2003–2004 with 947 complete cases, we examined heavy metals (cadmium, lead, and mercury), PCBs (12 congeners), dioxins (7 congeners), and furans (10 congeners) in relation to eight liver biomarkers (albumin, ALP, ALT, AST, GGT, LDH, total bilirubin, and total protein). We applied multi-exposure linear regression, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR), with parallel TEQ-based models using WHO 2005 TEFs for dioxin-like PCBs, dioxins, and furans. Across mixture methods, the mixture structure was chemically sparse, with a limited set of recurring contributors. Total bilirubin showed the most consistent positive mixture association across qgcomp and BKMR and persisted under TEQ weighting, with prominent PCB- and dioxin-like contributions (notably PCB81/PCB TEQs and dioxin-related components). Albumin demonstrated inverse mixture patterns in BKMR and TEQ-BKMR, with dioxin-like components (notably Dioxin3 and Dioxin3_TEQ) repeatedly emerging as key drivers. For ALT, ALP, AST, GGT, LDH, and total protein, overall mixture effects were frequently attenuated or null in qgcomp despite structured component weights, indicating bidirectional sub-mixtures and internal counterbalancing. BKMR PIPs similarly concentrated on a small number of dominant predictors (e.g., lead for ALP, mercury for ALT, PCB28 for AST, and cadmium and PCB189 for LDH), while interaction summaries provided limited evidence of stable non-additivity. Using multiple complementary mixture methods, we identified outcome-specific mixture patterns suggesting hepatobiliary vulnerability. TEQ concordance supports toxicological relevance of the dioxin-like axis, while metals and non–dioxin-like mechanisms likely contribute additional pathways. Full article

The Yangtze River Economic Belt supports over 400 million people and contributes nearly half of China’s GDP, yet decades of industrialization, urbanization, and agricultural intensification have resulted in severe contamination and pressing environmental challenges. This systematic review synthesizes three decades of peer-reviewed and governmental data to examine the spatiotemporal distribution, sources, and ecological and human health risks of major pollutants, including heavy metals, microplastics, persistent organic pollutants, and excess nutrients. While point-source emission of heavy metals such as cadmium, lead, and mercury have decreased by 35–42% since 2013 following policy interventions like the 10-Point Water Plan and the Yangtze River Protection Law, legacy contaminants in sediments and diffuse agricultural inputs continue to pose significant risks. Cadmium levels in rice still exceed food safety standards, arsenic in groundwater surpasses health guidelines, and microplastic flux into the East China Sea has reached 8.3 × 10¹² particles per year. Nutrient surpluses also drive extensive algal blooms, causing substantial economic losses. This review evaluates remediation strategies such as dredging, phytoremediation, wetland restoration, and AI-enhanced monitoring, which show removal efficiencies of 60–90% at reduced costs. However, critical gaps remain in understanding chronic mixture toxicity, the long-term fate of emerging contaminants, and pollutant–climate interactions. We propose an integrated basin-wide roadmap combining zero-liquid-discharge mandates, green infrastructure, and adaptive, performance-based governance to secure the Yangtze’s ecological and economic sustainability. This framework offers a transferable model for large-scale watershed management worldwide. Full article

Due to the constant need to develop biocompatible materials with osteoconductive and osteoinductive properties, the main objective of this study was to evaluate and characterize the carbon fiber obtained from fiber polyacrylonitrile textile carbon fiber (PAN), in the different forms: non-activated carbon fiber felt (NACFF) and activated carbon fiber felt (ACF) with silver (Ag-ACF), gold (Au-ACF), copper (Cu-ACF), palladium (Pd-ACF) and platinum (Pt-ACF), on the cell behavior and osteogenesis of mesenchymal cells. For characterization: scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman analysis. In vitro analysis was performed on rat mesenchymal stem cells. For each experimental group, 5 wells (n = 5) were made where cell proliferation (CP): cell viability (CV), mineralization nodule formation (MNF), total protein content (PT) and alkaline phosphatase activity (APC) were quantified, and cell morphology was analyzed by direct fluorescence, genotoxicity and cell interaction by SEM. The data passed the normality test and was followed by the one-way ANOVA test, followed by the Tukey test, using the conventional significance level of 5%. All the samples were statistically similar in terms of cell proliferation, except for the Ag-ACF group in relation to the control group (C). For cell viability, C obtained greater viability than the other groups, while ACF obtained a statistical difference and was superior to the Ag-ACF, Cu-ACF, Pt-ACF groups, being statistically similar to the Au-ACF and Pd-ACF groups. In the evaluation of ACP, the Ag-ACF and Cu-ACF groups were lower than the C, and other groups; for the characterization tests Au-ACF and Pd-ACF showed a more homogeneous metal distribution compared to the other groups. Cu-ACF and Ag-ACF showed some toxicity and low induction of osteoblastic differentiation. Although platinum showed relative cellular viability, a high micronucleus count was reported for this ion. In conclusion, ACF has the potential to be developed as a future biomaterial with good cell viability. Carbon fibers incorporated with gold and palladium ions showed potential for future application as supports for bone repair. Full article

This research systematically investigated the catalytic pyrolysis of Arab Heavy (AH) and Arab Light (AL) crude oils using NiO supported on Al₂O₃ or ZSM-5 in a microwave-assisted reactor, with particular emphasis on hydrogen (H₂) generation and value-added chemicals. To understand how both the catalyst and feedstock affect reaction products, gas and liquid products as well as catalyst activity were carefully examined. The production of H₂ and olefins was significantly enhanced by the NiO/Al₂O₃ catalyst, especially when using AL crude. This is most likely due to favorable metal-support interactions that increase the dehydrogenation activity. However, when paired with lighter feedstock, NiO/ZSM-5 greatly increased paraffin production and encouraged light alkane synthesis in both phases. GC-MS and FTIR spectroscopy confirmed that NiO/Al₂O₃ produced liquid products richer in aromatics while also containing a significant fraction of paraffins. Remarkably, the AL over NiO/Al₂O₃ combination showed very little liquid recovery, indicating that gas generation was higher in these reaction conditions. These results showed how H₂ selectivity and hydrocarbon routes in NiO/ZSM-5 and NiO/Al₂O₃ are controlled by various microwave-catalyst interactions. This work further highlights the importance of matching catalyst properties with feedstock type to control product selectivity, with NiO/Al₂O₃ showing particular promise for H₂-focused applications. Full article

Developing eco-friendly metal oxide nanoparticles (NPs) with plant-based reducing and stabilizing agents offers a sustainable alternative to traditional chemical methods. Nonetheless, the detailed mechanisms by which phytochemicals influence NPs formation, antimicrobial properties, and cytocompatibility remain poorly understood, especially in systems mediated by Vaccinium. This study aimed to synthesize TiO₂ NPs and ZnO NPs using Vaccinium corymbosum (blueberry) extract, analyze their structural and surface characteristics, assess their antimicrobial effectiveness and cytotoxicity, and explore potential molecular mechanisms through computational docking. ZnO NPs were produced via alkaline precipitation (pH 12) from ZnCl₂, while food-grade TiO₂ was mixed with blueberry extract. A comprehensive characterization was carried out using techniques like X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission and scanning electron microscopy (TEM/SEM), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) for polyphenol profiling. The antimicrobial activity was tested against Escherichia coli and Salmonella Typhimurium, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Cytotoxicity was assessed using Gallus gallus domesticus leukocytes and Artemia salina bioassays, and molecular docking simulations were performed to examine polyphenol interactions with the bacterial DNA gyrase subunit B (GyrB). XRD analysis confirmed the presence of wurtzite ZnO (with a crystallite size of 18.2 nm) and anatase TiO₂ (12.8 nm after functionalization). HPLC identified key polyphenols, including quercetin, cyanidin, malvidin, and cyanidin-3-glucoside, with patterns indicating stronger adsorption onto TiO₂ NPs surfaces. ZnO NPs showed higher antimicrobial effectiveness (>90% inhibition at 2 mg/mL; MIC 0.5–1 mg/mL) compared to TiO₂ (72% inhibition at 16 mg/mL; MIC 8–16 mg/mL). Cytotoxicity results indicated concentration-dependent effects. Molecular docking simulations revealed favorable binding energies (−6.2 to −8.4 kcal/mol) for blueberry polyphenols with GyrB, suggesting potential synergistic antimicrobial effects and ROS production. The study highlights a successful green synthesis of bioactive TiO₂ NPs and ZnO NPs using Vaccinium corymbosum extract, where polyphenol surface functionalization enhances both colloidal stability and biological activity. This comparative research offers mechanistic insights into how polyphenol-coated NPs work and supports the development of eco-friendly antimicrobial oxide nanomaterials. Full article