Search Results (924)

Loading dissolved organic matter (DOM) onto iron–manganese oxides (FeMnOx) was a promising strategy for enhancing the hexavalent chromium (Cr(VI)) removal from wastewater. To optimize this process and gain deeper mechanistic insight, this study systematically investigated the DOM loading characteristics onto FeMnOx and its subsequent effect on Cr(VI) adsorption. DOM loading onto FeMnOx was significantly affected by the initial concentration of DOM and pH, with optimal loading conditions identified as a DOM concentration of 75 mg/L, pH of 4, ionic strength of 0.005 mol/L, temperature of 50 °C, and contact time of 4 h. During loading, FeMnOx preferentially adsorbed low-molecular-weight/low-aromaticity components such as tryptophan-like (C1) and fulvic acid-like (C2) substances. The adsorption process followed a non-uniform monolayer surface adsorption and involved multiple stages dominated by chemical interactions. DOM coating on FeMnOx significantly enhanced the Cr(VI) removal, and the maximum adsorption capacity under optimal loading conditions increased from 18.46 mg/g to 23.26 mg/g. Characterization by SEM-EDS, BET, ICP-MS, XPS, FTIR, and CV revealed that a moderate DOM loading (55–75 mg/L) enhanced the material’s surface reducibility and mesoporous structure. This improvement was attributed to the reduction of surface Mn(IV) to more-reactive Mn(III) by reductive functional groups in DOM, thereby promoting Cr(VI) adsorption and reduction. In contrast, excessive DOM loading (105 mg/L) formed a dense organic layer that masked active sites and hindered electron transfer, ultimately compromising the long-term reductive capability. These findings elucidate the concentration-dependent regulatory role of DOM in modifying FeMnOx properties, providing a theoretical foundation for the rational design of efficient DOM–metal oxide composites for heavy metal remediation in aquatic environments. Full article

Biopolymers are increasingly explored as safer and more sustainable food packaging materials. This study evaluated the migration behavior of intentionally and non-intentionally added substances (IAS and NIAS), as well as the safety of gelatin and xanthan gum blends reinforced with microcrystalline cellulose, with and without oxygen plasma treatment, incorporating glycerol and limonene as plasticizers. Migration tests were conducted according to European Union (EU) Regulation No. 10/2011 using simulants of different polarities, and IAS/NIAS were analyzed by gas chromatography–mass spectrometry and ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry (GC–MS and UPLC-QTOF-MS). Films containing limonene were also evaluated for antioxidant activity. Results showed that plasticizer migration is strongly influenced by simulant polarity, glycerol predominantly migrated into hydrophilic media, whereas limonene and its derivatives exhibited higher migration in fatty simulants. Ethanol 95% acted as a conservative worst-case simulant, promoting extensive migration, while substantially lower migration levels were observed in isooctane and tenax plasma treatment resulted in modest changes in volatile compound migration, while significantly enhancing the antioxidant activity of limonene-containing films. Although overall migration levels were low under most of the tested conditions, NIAS formation, particularly from limonene degradation, highlights the need to account for chemical stability and simulant type when assessing bio-based films. Overall, the study demonstrates that film composition, surface modification, and simulant characteristics jointly influence migration behavior and functional performance under the evaluated conditions reinforcing the need to adapt current regulatory frameworks to the specific behavior of biopolymeric packaging materials. Full article

Elucidating the response mechanisms of seashore paspalum (Paspalum vaginatum) roots to salt stress is crucial for breeding salt-tolerant varieties. This study aimed to investigate the morphological, physiological, and surface electrochemical responses of seashore paspalum roots to salt stress. The salt-tolerant genotype Sealsle2000 and salt-sensitive genotype 17U-45 were subjected to 300 mM salt stress for 4 and 8 days. Results showed that salt stress exerted a more pronounced inhibitory effect on root growth than on shoot growth, with Sealsle2000 exhibiting less growth inhibition compared to 17U-45. Under salt stress, Sealsle2000 adsorbed more Na⁺ on the root surface and sequestered them within the roots than 17U-45; furthermore, Sealsle2000 was able to maintain higher K⁺/Na⁺ ratios. In terms of physiological mechanisms, Sealsle2000 maintained higher activities of superoxide dismutase and catalase, as well as elevated levels of osmotic adjustment substances (proline and soluble sugars) in roots, which collectively alleviated membrane lipid peroxidation damage and osmotic stress. Compared to 17U-45, Sealsle2000 possessed more negative charges and functional groups on the root surface, which contributed to its higher Na⁺ adsorption capacity and enhanced salt tolerance. Collectively, these findings establish a theoretical framework for understanding the salt tolerance mechanisms of seashore paspalum and other plants. Full article

Per- and polyfluoroalkyl substances (PFASs) have raised considerable concern due to their ubiquity, persistence, bioaccumulation, and toxicity. However, cost-effective, high-performance adsorbents for PFAS removal from aquatic environments remain limited. Here, we synthesized a porous graphitic biochar adsorbent (Zn-BBC) from banana peel waste via zinc chloride (ZnCl₂) activation and applied it to removing ten legacy and alternative PFASs from water. Zn-BBC achieved removal efficiencies > 95% for all target PFASs. The adsorption of PFASs onto Zn-BBC followed pseudo-second-order (PSO) kinetics, suggesting chemisorption. Additionally, the adsorption isotherms were well described by the Sips model, indicating surface heterogeneity. Zn-BBC exhibited robust performance over a broad pH range (3–9). Coexisting ions (CO₃²⁻, SO₄²⁻, Zn²⁺, Ca²⁺, and Mg²⁺), tested individually at 10 mM each, had negligible effects on the adsorption of the PFASs examined, except for perfluorobutanoic acid (PFBA). In contrast, humic acid (10 mM) significantly reduced the removal rates of PFBA, perfluorohexanoic acid (PFHxA), and hexafluoropropylene oxide dimer acid (GenX). Nevertheless, in river and lake waters, Zn-BBC achieved >85.0% removal of all PFASs except PFBA. In regeneration experiments, Zn-BBC exhibited excellent reusability. Experimental characterization and density functional theory (DFT) calculations jointly revealed that PFAS adsorption involves electrostatic interactions, hydrophobic interactions, π-CF interactions, surface complexation, and hydrogen bonding. These results suggest that Zn-BBC is a promising sorbent for PFAS removal in water. Full article

Hydrogen sulfide (H₂S) commonly exists in natural gas, syngas, and coal-derived gas, and the elimination of H₂S from industrial gases is essential before application. In this study, we utilized low-cost lignite as a raw material. After acid-washing pretreatment, nitrogen-containing substances (urea or dicyandiamide) were incorporated into the coal, and two types of N-modified activated carbon desulfurizers for ambient-temperature H₂S removal were prepared via an in situ loading method, integrating the synthesis of activated carbon with the loading of active components. When the dicyandiamide content was 9 wt.%, and the oxygen concentration for desulfurization was 5%, the breakthrough time reached 550 min with a corresponding breakthrough sulfur capacity of 79.6 mg/g. Characterization revealed that the dicyandiamide-N-modified desulfurizer possessed elevated oxygen and nitrogen contents, which may partially augment the density of surface alkaline active sites. This enhancement is likely to induce alkalization of the interfacial water layer, thereby potentially accelerating H₂S dissociation into HS⁻ and subsequently facilitating its oxidative conversion to elemental sulfur via reaction with oxygen. Full article

Biofilm-associated infections remain a major barrier to wound healing, implant integration, and chronic infection management. Rare-earth oxides (REOs) have emerged as promising antibiofilm materials, though their mechanisms, limitations, and translational potential are still being defined. Cerium oxide (CeO₂) serves as the benchmark due to its redox adaptability, oxygen-vacancy-driven catalytic activity, and host compatibility. In contrast, non-ceria REOs show antibiofilm effects under more restricted conditions, often requiring surface functionalization, composite architectures, or hybrid organic–inorganic interfaces—such as polyphenol coatings or hydroxyapatite-based composites—to achieve comparable activity. Across systems, biofilm control arises not from bactericidal potency but from matrix-level mechanisms including extracellular polymeric substance (EPS) destabilization, extracellular DNA (eDNA) sequestration, redox modulation, and quorum-sensing interference. Preclinical and near-clinical evidence, particularly in chronic wound models, supports the translational relevance of these mechanisms, though the evidence base remains preliminary. This review synthesizes mechanistic data across cerium-, samarium-, lanthanum-, and strontium-based systems to establish a unified framework for REO-mediated biofilm disruption. REOs are positioned as biofilm-modulating platforms that complement antibiotics, enhance healing, and improve outcomes. Design rules emphasize controlled redox activity, targeted coordination chemistry, functional surface engineering, and host-compatible performance, alongside regulatory and manufacturing guidance for future development. Full article

Infection urinary stones account for approximately 10–15% of all urinary stones worldwide, with a rising incidence observed in recent decades, particularly in countries with a high Socio-Demographic Index (SDI). This trend has been partially attributed to dietary changes, including increased consumption of processed foods. Heavy metals belong to a group of substances, the source of which can be both food and the human environment. Among many heavy metals, in this study, we focus on copper and investigate its influence on the nucleation and growth of struvite crystals, the primary component of infection urinary stones. Experiments were conducted in artificial urine, both in the presence and absence of Proteus mirabilis, a urease-producing bacterium commonly associated with infection urinary stones. In a bacteria-free system, bacterial urease activity was mimicked by the addition of aqueous ammonia solution. Our results demonstrate that the presence of copper in artificial urine induces a slight shift in the struvite crystallization toward lower pH values, indicating that crystal formation initiates earlier compared to a control test. Additionally, the amount of precipitated struvite increases modestly in the presence of copper. Struvite crystals formed in copper-containing artificial urine are larger and exhibit altered habit and morphology. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirm that copper does not incorporate into either the bulk or surface structure of the struvite crystals. X-ray diffraction (XRD) data show that struvite remains the sole crystalline phase, consistent with the control samples. Microbiological assays reveal that copper, at the concentrations tested, does not affect the viability of P. mirabilis, indicating an absence of bacteriostatic or bactericidal effects. To elucidate the physicochemical mechanisms underlying copper’s influence on nucleation and growth of struvite, speciation analysis of chemical complexes was performed. This revealed the formation of various copper complexes in artificial urine, including Cu(OH)⁺, CuCit⁻, CuC₂O₄, Cu(OH)₂, CuHPO₄, Cu(NH₃)²⁺, Cu(NH₃)₂²⁺, and Cu(NH₃)₃²⁺. These chemical complexes modulate the equilibrium and formation of complexes with Mg²⁺ and PO₄³⁻ (e.g., MgHCit, MgCit⁻, MgOH⁺, MgC₂O₄, MgSO₄, MgHPO₄), contributing to the observed shift in struvite crystallization to lower pH values. Full article

Greenhouse gas emissions associated with plastic production and disposal span the entire plastic life cycle, establishing a direct link between plastic pollution and climate change. This review demonstrates that micro- and nanoplastics (MNPs) also function as active components of climate feedback systems by disrupting marine trophic structures, altering microbial assemblages, and diminishing the ocean’s capacity for carbon storage. Synthesized evidence further indicates that environmental degradation of polymers enhances surface reactivity, facilitating the sorption and transport of persistent contaminants, including per- and polyfluoroalkyl substances (PFAS) and antibiotic-resistant bacteria (ARB). These interactions amplify combined risks to ecosystems and public health under climate change scenarios. This review also reveals that many existing remediation strategies prioritize waste reduction or physical removal while failing to account for contaminant–plastic–climate interactions, thereby limiting their long-term effectiveness. By integrating climate-related processes, polymer transformation, and contaminant dynamics, this review identifies critical knowledge gaps and underscores the need for mitigation strategies that jointly address plastic pollution, climate feedbacks, and emerging public health threats. Full article

Per- and polyfluoroalkyl substances (PFASs) have attracted attention as emerging contaminants due to their persistence, bioaccumulation, and toxicity risks. This study investigated the characteristics, sources, mass loads, and ecological risks of 17 PFASs in surface waters and sediments from Dianchi Lake and its tributaries. During the wet season, the PFAS concentrations in the lake and river waters ranged from below the MDL (N.D.) to 11.21 ng/L and N.D. to 20.79 ng/L, respectively, while in the sediments, they were N.D. to 10.21 ng/g dry weight (dw) and N.D. to 9.63 ng/g dw. In the dry season, the lake and river water concentrations were N.D − 9.49 ng/L and N.D. − 15.67 ng/L, with those in sediments ranging from N.D. to 11.47 ng/g dw and from N.D. to 9.93 ng/g dw. Distribution coefficient analysis indicated that long-chain PFASs and sulfonic acid groups were preferentially enriched in sediments. In rivers, major sources included industrial discharges, domestic inputs, metal electroplating activities, and atmospheric deposition. In the lake, PFASs were mainly derived from mixed sources, atmospheric deposition, and riverine inflow, the latter being dominant. The PFAS loads from tributaries were estimated at 24.75 kg in the wet season and 8.79 kg in the dry season. The risk quotient values were low in waters (0.01) but ranged from 0.01 to 1 in sediments, indicating low to moderate risk, primarily from long-chain PFASs. Although ecological risk is limited, persistent inputs and contributions from tributaries highlight the necessity for continued monitoring and management. The results of this study deepen the understanding of PFAS contamination in this and other similar plateau lake basins, providing references for environmental management. Full article

Bacterial biofilms remain a major challenge in clinical infections due to their dense extracellular polymeric substance (EPS) matrix and strong resistance to conventional antibiotics. This study reports manganese dioxide (MnO₂) nanoparticles capable of autonomous navigation toward bacterial clusters, mechanical penetration of biofilm structures, redox-driven membrane disruption, and synergistic oxidative stress. The nanoparticles exhibit directional movement attributed to a combination of negatively charged surface potential, asymmetric topology, and catalytic reactivity toward bacterial metabolites. MnO₂ demonstrates potent antibiofilm activity against MRSA and MDR E. coli (>98% eradication) and partial activity against Pseudomonas aeruginosa. Time-lapse microscopy, EPR spectroscopy, XPS analysis, and SEM imaging reveal that MnO₂ disrupts both EPS and cell membranes while maintaining structural integrity throughout treatment. Cytotoxicity assays confirm ≥85% viability in human fibroblasts and keratinocytes at therapeutic concentrations. MnO₂ shows controlled biodegradation into Mn²⁺ ions, which participate in physiological pathways and undergo renal clearance. These findings support MnO₂ nanoparticles as promising biofilm-targeting agents for topical formulations, wound care, and implant coatings. Full article

Preventing spoilage in food products, particularly in those highly susceptible to rapid deterioration like mutton, has been a persistent challenge in the food industry. In this study, an Active Biological Film (ABF) was developed using chitosan (CS) and whey protein isolate (WPI), with the addition of 0.01 wt% titanium dioxide (TiO₂) and 0.1 wt% white pepper essential oil (WPEO). This ABF was applied to preserve fresh mutton at super-chilling temperatures of −1.7 ± 0.2 °C. The effects of ABF on myofibrillar protein (MP) oxidation and structural characteristics, as well as on the microbial status, physicochemical properties, and sensory quality of mutton, were systematically evaluated. The results demonstrated that, compared to the control group (CK), ABF treatment significantly enhanced the total sulfhydryl content, protein solubility, and zeta potential of MPs, while reducing carbonyl content, surface hydrophobicity, and particle size. MPs in the ABF group showed a higher α-helix proportion and a lower random coil content, along with a notable increase in intrinsic fluorescence intensity. Scanning electron microscopy (SEM) revealed a denser gel structure. Additionally, ABF effectively inhibited microbial growth in mutton, delayed pH increase, reduced thiobarbituric acid-reactive substances (TBARS) and total volatile basic nitrogen (TVB-N), and improved sensory scores, extending mutton shelf life by over 10 days. Therefore, the ABF effectively inhibited oxidation in MPs, maintained their structural integrity, and preserved mutton quality during super-chilling storage. Full article

Adjuvants are chemical substances used in vaccines to enhance immunogenicity. Among them, aluminum-based nanoparticles are some of the oldest and most widely employed adjuvants in vaccine formulations. A key function of aluminum adjuvants is thought to involve acting as an antigen depot, enabling slow antigen release and providing sufficient time for effective immune activation. Therefore, understanding antigen–adjuvant interactions is essential, as these interactions influence antigen stability, release kinetics, and overall vaccine performance. In this study, we investigated how the physicochemical properties of aluminum hydroxide nanoparticles modulate antigen–protein interactions and affect protein stability. Nanoparticles synthesized under acidic (pH ≈ 5.0) to near-neutral (pH ≈ 7.1) conditions exhibited lower crystallinity, reduced hydroxyl density, and higher interfacial hydration, whereas those prepared under basic conditions (pH ≈ 9.0) displayed increased crystallinity, enriched surface hydroxyl groups, and markedly reduced hydration. Antigen proteins bound to low-crystallinity aluminum hydroxide nanoparticles showed improved thermal stability, while those associated with highly crystalline nanoparticles exhibited reduced thermal stability. Complementary ITC study further suggests that these stability differences are accompanied by changes in their interaction behavior. These findings indicate that the structural and interfacial properties of aluminum hydroxide nanoparticles strongly influence their interactions with antigen proteins and the resulting physical stability. Together, our results demonstrate that the balance among crystallinity, hydroxyl organization, and interfacial hydration governs the thermal behavior of antigen proteins adsorbed onto aluminum hydroxide. This work provides a rational design principle for engineering aluminum-based adjuvants that optimize antigen–protein stability in vaccine formulations. Full article

Per- and polyfluoroalkyl substances (PFASs) are persistent and mobile contaminants of global concern, and, while granular activated carbon (GAC) is widely used for their removal, it is limited by the high regeneration and disposal costs. This study investigates surface-modified clinoptilolite zeolites as low-cost and thermally regenerable alternatives to GAC for PFAS removal from water. Natural clinoptilolite was modified through acid washing, ion exchange with Fe³⁺ or La³⁺, grafting with aminosilane (APTES) or hydrophobic silane (DTMS), dual APTES + DTMS grafting, and graphene oxide coating. The adsorption performance was evaluated for perfluorooctanoic acid (PFOA, C8) and perfluorobutanoic acid (PFBA, C4) at 100 µg L⁻¹ in single- and mixed-solute systems, with an additional high-concentration PFOA test (1 mg L⁻¹). PFAS concentrations were quantified by liquid chromatography–tandem mass spectrometry (LC–MS/MS) using a SCIEX 7500 QTRAP system coupled to a Waters ACQUITY UPLC I-Class. Raw zeolite showed limited PFOA removal (4%), whereas dual-functionalized APTES + DTMS zeolites achieved up to 93% removal, comparable to GAC (97%) and superior to single-silane or metal-exchanged variants. At lower concentrations, modified zeolites effectively removed PFOA but showed limited PFBA removal (<25%), highlighting ongoing challenges for short-chain PFASs. Overall, the results demonstrate that dual-functionalized clinoptilolite zeolites represent a promising and scalable platform for PFAS remediation, particularly for mid- to long-chain compounds, provided that strategies for enhancing short-chain PFAS binding are further developed. Full article

This study assesses the presence and distribution of per- and polyfluoroalkyl substances (PFAS) and polybrominated diphenyl ethers (PBDEs) in the surface waters of the Itupararanga Reservoir and the Sorocaba River, Brazil. Samples collected during the dry and rainy seasons were analyzed to determine their composition, spatial distribution, and seasonal variability. Results indicate the ubiquitous presence of PFAS, with significantly higher concentrations in the dry season, suggesting point sources of contamination, such as industrial and domestic discharges. Perfluorobutanoic acid (PFBA), Perfluorooctane sulfonate (PFOS), and Perfluorooctanoic acid (PFOA) were the predominant compounds, while 6:2 Fluorotelomer sulfonate (6-2FTS) stood out for its abundance in areas with industrial activity. For PBDEs, marked seasonal variability was observed, with higher concentrations during the rainy season, suggesting the mobilization of these compounds by surface runoff. BDE-209 was the most abundant congener, representing over 58% of the total concentration of PBDEs detected. Concentrations of PFAS and PBDEs in the study area are comparable to those reported globally, although there are differences associated with industrial practices and local environmental dynamics. The increased presence of short-chain PFAS and Deca-BDEs highlights the need for ongoing monitoring and the implementation of regulatory measures to mitigate contamination in water sources used for human consumption. Full article

Electrocatalytic CO₂ reduction is a promising approach to mitigate rising atmospheric CO₂ levels while converting CO₂ into valuable products such as CH₄. Conversion into other useful substances further expands its potential applications. However, the efficiency of the CO₂ reduction reaction (CO₂RR) is strongly influenced by device geometry and CO₂ mass transfer in the electrolyte. In this work, we present and evaluate microchannel electrocatalytic devices consisting of a porous Cu cathode and a Pt anode, fabricated via metal-assisted chemical etching (MACE). The porous surfaces generated through MACE enhanced reaction activity. To study the impact of the distance between electrodes, several devices with different channel heights were fabricated and tested. The device with the highest CH₄ selectivity had a narrow inter-electrode gap of 50 μm and achieved a Faradaic efficiency of 56 ± 11% at an applied potential of −5 V versus an Ag/AgCl reference electrode. This efficiency was considerably higher than that of the device with larger inter-electrode gaps (300 and 480 μm). This reduced efficiency in the larger channel was attributed to limited CO₂ availability at the cathode surface. Bubble visualization experiments further demonstrated that the electrolyte flow rate had a strong impact on supplied CO₂ bubble morphology and mass transfer. At a flow rate of 0.75 mL/min, smaller CO₂ bubbles were formed, increasing the gas–liquid interfacial area and thereby enhancing CO₂ dissolution into the electrolyte. These results underline the critical role of electrode gap design and bubble dynamics in optimizing microchannel electrocatalytic devices for efficient CO₂RR. Full article