Search Results (474)

In recent years, organic dye contamination has posed a significant threat to water safety. This study presents a novel composite photocatalyst comprising graphitic carbon nitride quantum dots (g-C3N4QDs) supported on a copper-based metal–organic framework (Cu-MOF) for efficient visible-light degradation of organic pollutants. The g-C₃N₄QDs were synthesized via a facile strategy and subsequently immobilized onto the Cu-MOF support. Comprehensive characterization including SEM, TEM, XRD, BET, UV-Vis DRS, PL, and EIS confirmed the successful formation of a heterostructure, revealing that an optimized loading of g-C₃N₄QDs significantly enhanced light absorption, facilitated charge separation, and increased the specific surface area, with the optimal composite exhibiting 273 m²/g compared to 112 m²/g for the pristine Cu-MOF. Electrochemical analyses indicated a 2.38-fold enhancement in photocurrent density and a reduced interfacial charge transfer resistance, reflecting superior electron–hole pair separation. Crucially, the optimized g-C₃N₄QDs/Cu-MOF composite demonstrated exceptional photocatalytic performance, achieving 96.6% degradation of Congo red (100 mg/L) within 30 min under visible light irradiation, substantially outperforming the 77.6% degradation attained by the pristine Cu-MOF. This enhancement is attributed to the synergistic effects of improved light harvesting, efficient interfacial charge transfer across the heterojunction, and an enlarged active surface area. The composite exhibits considerable potential as a high-performance and stable photocatalyst for purifying dye-contaminated wastewater. Full article

Objectives: This study aimed to evaluate the cytotoxic effects of Ti6Al4V particles and implantoplasty (IP)-treated surfaces on human fibroblasts and osteoblasts, and to investigate the influence of these particles on multispecies oral biofilm formation. Methods: Ti6Al4V particles generated during implantoplasty were collected. Human fibroblasts (HFF-1) and osteoblast-like cells (SaOs-2) were used to assess cytotoxicity through indirect lactate dehydrogenase (LDH) assays. Multispecies biofilms composed of Streptococcus oralis, Actinomyces viscosus, Veillonella parvula and Porphyromonas gingivalis were evaluated based on colony-forming units (CFUs) and metabolic activity. Fibroblasts and osteoblasts were co-cultured with biofilm-contaminated particles for 2, 4 and 6 h. Cell morphology and biofilm association were examined by phase-contrast microscopy, while metabolic activity was measured spectrophotometrically. Results: IP-treated surfaces showed no significant cytotoxicity (metabolic activity > 92%, LDH < 20%). Ti6Al4V particles selectively promoted A. viscosus and V. parvula growth (metabolic activity increases of ≈192% and ≈203%; CFU significantly higher versus controls, p < 0.05). Co-culture with biofilm-contaminated particles drastically reduced cell activity (fibroblasts < 25%, osteoblasts < 10%), whereas bacteria-free particles did not. Conclusions: Biofilm-contaminated particles released during implantoplasty markedly impair fibroblast and osteoblast cytocompatibility and selectively alter bacterial growth, whereas IP-treated surfaces per se are biocompatible. Minimizing particle dissemination and bacterial contamination during IP is therefore crucial. Full article

Exocarpium Citri Grandis (ECG) is a distinctive medicinal and edible product originating from southern China and is often covered with a layer of characteristic “white frost” (WF). This study investigated the composition, formation mechanism, microbial safety, and anti-inflammatory activity of the WF. Multi-technique analyses revealed that WF mainly consisted of crystalline naringin (~80% of total mass). Drying-induced shrinkage and rupture of oil glands on ECG suggested metabolite migration and surface crystallization as the key mechanisms for WF formation. Microbial profiling revealed no significant differences in fungal and bacterial communities between WF and non-frost (NF) samples, and none of eight common mycotoxins was detected, confirming its microbial safety. Brewing tests demonstrated that water boiling for 30 min achieved efficient extraction of naringin, with higher yields in WF samples than in NF samples. In RAW264.7 cells, both WF and NF extract significantly inhibited lipopolysaccharide-induced NO production as well as the secretion and transcription of TNF-α, IL-6, IL-1β, iNOS, and NF-κB, with WF extract showing a stronger effect. Overall, these findings indicate that WF originates from endogenous flavonoid crystallization rather than microbial contamination and enhances the anti-inflammatory activity. This study provides a scientific basis for quality evaluation, processing optimization, and standardization of ECG products. Full article

This study presents the effects of using pyrite aggregate in field concretes on the mechanical, surface performance, and algal growth tendency of concrete. The substitution of pyrite influences the process of hydration, as the gradual release of its iron- and sulfur-bearing components shifts the reaction mechanism, leading to differences in phase formation and some modification in the pore structure of the cement matrix. Three different concrete mixes (PB0, PB2.5%, and PB7.5%) were designed by replacing 0%, 2.5%, and 7.5% of the total weight of sand and crushed sand with ground pyrite as a fine aggregate. Prismatic specimens of 80 × 100 × 200 mm were produced from these mixtures and mechanical properties such as flexural, splitting tensile, and abrasion were investigated after 28 days of curing. Then, to determine the effect of pyrite on concrete surface properties, pyrite was substituted on the surface of three concrete specimens produced in 50 × 240 × 500 mm dimensions at rates of 0, 1, and 3 kg/m². These specimens were divided into two groups: one group was exposed to clean water drops at a constant flow rate in a closed environment, and the other group was exposed to dirty water in an open environment, and observed for 2 months. At the end of the process, sections of 50 × 80 × 200 cm³ were taken from the specimens and friction, abrasion and flexural tests were carried out. The results of the study demonstrate that a 7.5% pyrite substitution improves both flexural and shear strength by 38%. At the same time, pyrite substitution prevented algal growth on the surface of field concrete under clean water and delayed its formation in those under contaminated water. Finally, it was observed that pyrite, when used in concrete mix and surface applications, optimizes mechanical performance and environmental durability. Full article

Perfluorooctanoic acid (PFOA) contamination poses serious environmental risks due to its persistence and mobility. Conventional ex situ method using preformed layered double hydroxides (LDHs) shows limited performance, particularly under complex leachate conditions. This study developed an effective in situ Zn/Al LDH strategy for enhanced PFOA removal. Batch experiments, solid-phase characterization, and theoretical simulations were conducted to elucidate the adsorption mechanism and the effect of fluoride ion (F⁻). The results demonstrated that the in situ method exhibited superior performance in the presence of fluoride, achieving a PFOA adsorption density of up to 54.93 mmol/mol-Al, which is significantly higher than that of the ex situ method (26.76 mmol/mol-Al). Unlike the competitive adsorption observed in the ex situ method, the in situ process relies on synergistic mechanisms: F⁻ participates in LDH formation as an interlayer anion and coordinates with Zn²⁺ and Al³⁺ to regulate LDH growth, thereby optimizing the surface chemical environment for PFOA capture. Molecular dynamics (MDs) and density functional theory (DFT) further showed that preferentially adsorbed F⁻ affects hydrogen-bond networks and stabilizes PFOA through inner and outer sphere complexation. Overall, these findings clarify the fluoride-regulated adsorption mechanism and demonstrate the potential of in situ LDH coprecipitation for PFAS remediation in leachates. Full article

This work presents a facile mechano-thermal route for the synthesis of carbon-decorated, hollow, mesoporous α-Fe₂O₃ microspheres. Comprehensive characterization (XRD, XPS, FT-IR, SEM/EDX, TGA, zeta-potential) confirmed the formation of phase-pure hematite with nanoscale crystallites (~19 nm), substantial residual surface carbon (~40 wt%) consistent with Fe–O–C linkages, and a positive surface charge (+15.9 mV). The hierarchical hollow/mesoporous architecture enables fast ion transport and provides extensive interior binding sites, resulting in rapid Pb(II) uptake that reaches 92% removal in ≈15 min at pH 5.0. The adsorption follows a Langmuir isotherm (q_max ≈ 70.6 mg/g) and pseudo-second-order kinetics, indicative of chemisorption coupled to efficient mass transfer into internal sites. The composite also exhibits antibacterial activity against Escherichia coli and Staphylococcus aureus, demonstrating its potential for simultaneous mitigation of heavy metal contaminants and pathogens. Full article

This study investigates the hydraulic connection of surface karst features within the Northern segment of the Edwards Balcones Fault Zone Aquifer, using a combination of 2D and pseudo-3D Electrical Resistivity Tomography (ERT) at an outcrop near Salado, Texas. The study site features several surface fractures whose hydrological functions are not well understood. Nine ERT profiles and two pseudo-3D models were used to evaluate the connection between surface fractures and subsurface karst conduits. Karst features at the study site were physically evaluated using characteristics such as morphology, which resulted in the identification of three surface fractures (F1, F2, and F3). The ERT results showed several high-resistivity anomalies interpreted as a poorly fractured zone and low-resistivity water-filled conduits within the Edwards Formation. Furthermore, the result reveals that slow hydraulic connectivity exists in F1 and F2; however, F3 presents a low-resistivity zone that extends vertically into the subsurface, which suggests that F3 may serve as a potential recharge feature to the Edwards Aquifer. These findings are corroborated by a water percolation test, as water penetrated more at F3 compared to F1 and F2. This study showed that the combined application of 2D and pseudo-3D ERT can successfully delineate potential recharge pathways in an exposed karst system, thereby constituting a supportive approach providing critical insight into recharge and the vulnerability of karst aquifers to contamination. Full article

The widespread disposal of pharmaceutical waste, particularly diclofenac (DCF), poses a significant threat to aquatic ecosystems. The current degradation methods, including biological treatments and standalone advanced oxidation processes, often prove insufficient, leaving residual DCF concentrations. This study proposes a novel solution using a rapidly synthesized graphene oxide/hydroxyapatite (GO/HAp) nanocomposite via wet-chemical precipitation to enhance DCF degradation through synergistic sonophotocatalysis. The synthesized nanocomposite’s structure was confirmed using Fourier transform infrared spectroscopy FTIR, x-ray diffraction XRD, and scanning electron microscope SEM analyses, revealing the successful formation of a hexagonal HAp phase on GO sheets. Optimization of the sonophotocatalytic parameters revealed that pH and loading significantly influenced degradation, while time had a less pronounced effect. The optimal conditions (a pH pf 4, 45 mg GO/HAp, 30 min) achieved a remarkable 93.86% DCF degradation, significantly outperforming standalone photocatalysis (72.76%) and sonolysis (63.76%). This enhanced performance is attributed to the synergistic effect of sonophotocatalysis, which increases the active surface area and radical generation, coupled with the high surface area and adsorption capacity of the GO/HAp nanocomposite. This research demonstrates that rapid wet-chemical synthesis of the GO/HAp nanocomposite, coupled with an optimized sonophotocatalytic process, offers a potent, accelerated, and efficient method for degrading DCF, paving the way for improved pharmaceutical wastewater treatment. Ultimately, this research provides a foundation for developing effective water treatment solutions to combat pharmaceutical contaminants. Full article

The development of advanced semiconductor-based catalysts for the rapid degradation of emerging pharmaceutical pollutants in water remains a critical challenge in environmental science. In this study, we present the synthesis, characterization, and catalytic performance of zinc oxide (ZnO) microtetrapods decorated with plasmonic Ag nanoparticles. These microtetrapods have been designed to enhance piezo-, photo-, and piezo-photocatalytic degradation of metronidazole (MNZ), a persistent antibiotic contaminant. ZnO microtetrapods were synthesized by high-temperature pyrolysis and using atmospheric-pressure microwave nitrogen plasma, followed by photochemical deposition of Ag nanoparticles at various precursor concentrations (0–1 mmol AgNO₃). The structural integrity of the samples was confirmed through X-ray diffraction (XRD) analysis, while the morphology was examined using scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Additionally, spectroscopic analysis, including Raman, electron paramagnetic resonance (EPR), and photoluminescence (PL) spectroscopy, was conducted to verify the successful formation of heterostructures with adjustable surface loading of Ag. It has been shown that ZnO microtetrapods decorated with plasmonic Ag nanoparticles exhibit Raman-active properties. A systematic evaluation under photocatalytic, piezocatalytic, and combined piezo-photocatalytic conditions revealed a pronounced volcano-type dependence of catalytic activity on Ag content, with the 0.75 mmol composition exhibiting optimal performance. In the presence of both light irradiation and ultrasonication, the optimized Ag/ZnO composite exhibited 93% degradation of MNZ within a span of 5 min, accompanied by an apparent rate constant of 0.56 min⁻¹. This value stands as a significant improvement, surpassing the degradation rate of pristine ZnO by over 24-fold. The collective identification of defect modulation, plasmon-induced charge separation, and piezoelectric polarization as the predominant mechanisms driving enhanced reactive oxygen species (ROS) generation is a significant advancement in the field. These findings underscore the synergistic interplay between plasmonic and piezoelectric effects in oxide-based heterostructures and present a promising strategy for the efficient removal of recalcitrant water pollutants using multi-field activated catalysis. Full article

There is an urgent need to evaluate the toxicity of xenobiotics and environmental mixtures for preventing loss in water quality for the sustainability of aquatic ecosystems. A simple prebiotic chemical pathway based on malate formation from pyruvate (pyr) and glyoxalate (glyox) is proposed as a quick and cheap screening tool for toxicity assessment. The assay is based on the pyr and glyox (aldol) condensation reactions, leading to biologically relevant precursors such as oxaloacetate and malate. Incubation of pyr and glyox at 40–70 °C in the presence of reduced iron Fe(II) led to malate formation following the first 3 h of incubation. The addition of various xenobiotics/contaminants (silver, copper, zinc, cerium IV, samarium III, dibutylphthalate, 1,3-diphenylguanidine, carbon-walled nanotube, nanoFe₂O₃ and polystyrene nanoparticles) led to inhibitions in malate synthesis at various degrees. Based on the concentration inhibiting malate concentrations by 20% (IC20), the following potencies were observed: silver < copper ~ 1.3-diphenylguanidine ~ carbon-walled nanotube < zinc ~ samarium < dibutylphthalate ~ samarium < Ce(IV) < nFeO₃ < polystyrene nanoplastics. The IC20 values were also significantly correlated with the reported trout acute lethality data, suggesting its potential as an alternative toxicity test. The pyr-glyox pathway was also tested on surface water extracts (C18), identifying the most contaminated sites from large cities and municipal wastewater effluents dispersion plume. The inhibition potencies of the selected test compounds revealed that not only pro-oxidants but also chemicals hindering enolate formation, nucleophilic attack of carbonyls and dehydration involved in aldol-condensation reactions were associated with toxicity. The pyr-glyox pathway is based on prebiotic chemical reactions during the emergence of life and represents a unique tool for identifying toxic compounds individually and in complex mixtures. Full article

Background: Small-scale food animal production is common worldwide but often underestimated as a source of antimicrobial resistance. This study aimed to determine the prevalence of MRSA and VRE-E. faecium, and ESBL-E. coli bacteria among workers and within the production environment of low-capacity slaughterhouses, as well as to analyze the antimicrobial resistance patterns of these bacteria and their ability to form biofilms. Methods: The measurements were carried out in three low-capacity slaughterhouses in Poland. Bioaerosol samples, swabs from the production environment fomite and carcasses, meat samples, and swabs from workers’ hands and nostrils were taken. The strains’ susceptibility to antibiotics was assessed using the disk diffusion method, and their biofilm-forming potential was assessed using the microplate method. Isolates were also tested for the presence of genes related to biofilm formation and resistance to antiseptics. Results: In this study, 13.8%, 20.5%, and 14.9% of the samples (n = 268) were positive for MRSA, ESBL-E. coli, and VRE-E. faecium, respectively, with the highest detection rates on pork carcasses and surfaces. MRSA and ESBL-E. coli bacteria were also detected in swabs from workers’ hands and nasal swabs, and in bioaerosol samples. Most isolates revealed multidrug resistance, including 89% of MRSA, 76% of ESBL-E. coli, and 83% of VRE-E. faecium. The majority of them were also capable of biofilm formation—81%, 65%, and 75%, respectively—emphasizing their survival capabilities in slaughterhouse environments. Conclusions: The slaughterhouse workers are regularly exposed to antibiotic-resistant bacteria such as MRSA, ESBL-E. coli, and VRE-E. faecium. To reduce these risks, it is essential for small slaughterhouses to strictly follow hygiene protocols, enhance the separation between clean and contaminated areas, improve ventilation, and ensure the use of protective measures. Full article

Microplastics (MPs) are increasingly reported as contaminants in sewage sludge, with wastewater treatment plants retaining approximately 10³–10⁶ particles kg⁻¹ of dry sludge. Anaerobic digestion (AD), widely applied for sludge stabilization and energy recovery, does not consistently remove these particles; MPs frequently persist and, at elevated or sensitive loadings, have been shown to affect methane production, microbial communities and sludge quality. In parallel, thermal hydrolysis and related pretreatments are being implemented at full scale to enhance sludge biodegradability, exposing embedded MPs to high temperature and pressure prior to AD. This review compiles and analyzes experimental studies on MPs in sludge pretreatment and AD systems, with an emphasis on how pretreatment severity, MP type, particle size and concentration influence MP transformation and process performance. Reported data indicate that intensified pretreatment accelerates MP aging, causing fragmentation, oxidative surface modification and additive release, while subsequent AD generally induces limited further MP degradation but can be negatively affected through reduced methane yields, shifts in microbial consortia and altered behavior of co-contaminants. Mechanisms implicated include leaching of plastic additives, enhanced oxidative and physiological stress, and formation of plastisphere biofilms that perturb syntrophic interactions. Mitigation approaches, including optimized thermal hydrolysis–AD configurations and the use of carbonaceous sorbents, are assessed with regard to their effects on MP-associated inhibition and their practical constraints. Analytical limitations, uncertainties in MP mass balances and environmental fate, and key research needs for evaluating MP risks and designing MP-resilient sludge treatment and biosolid management strategies are identified. Full article

Layered double hydroxides (LDHs) have gained increasing attention as versatile materials in environmental remediation, particularly for wastewater treatment. Their unique structural properties, such as tunable metal cation composition, interlayer anion exchange, and structural memory effects, make them suitable materials for a broad range of applications. In addition to these intrinsic properties, thermally treated LDH-derived mixed metal oxides have emerged as a key focus, exhibiting enhanced activity through tailored structural, electronic, and textural properties. This review presents an up-to-date and systematic overview of recent advancements in the design and application of LDH-based materials, with a focus on photocatalytic degradation of organic dyes, adsorption of contaminants, and light-activated antimicrobial activity. The review also explores emerging photocatalytic applications in correlation with surface engineering, heterojunction formation, and thermal activation to enhance the overall efficiency. In addition, the synergy between antimicrobial activity and photocatalysis is discussed in the context of achieving multifunctional microbial control in water treatment. Finally, current challenges and future perspectives are addressed, including recyclability, scale-up potential, and the development of LDH composites as sustainable alternatives to conventional photocatalysts. This review aims to support researchers in advancing LDH-based technologies toward more efficient and versatile environmental remediation solutions. Full article

Aflatoxins remain among the most challenging food contaminants to monitor due to their structural diversity, low abundance, and the chemical complexity of cereal- and nut-based matrices. In this study, a multifunctional Cu/β-cyclodextrin@carboxylated graphene oxide (Cu/β-CD@CGO) nanocomposite was synthesized through a green, two-step procedure and employed as a high-affinity nanosorbent for trace extraction of AFB₁, AFB₂, AFG₁, and AFG₂. The architecture integrates three complementary components: β-cyclodextrin for inclusion-driven molecular recognition, copper nanoparticles that establish coordination interactions with lactone-bearing aflatoxins, and CGO nanosheets that supply extensive π-rich surfaces and abundant carboxyl functionalities. Comprehensive characterization (FTIR, Raman, XPS, SEM, EDX-mapping, and HRTEM) confirmed the formation of a uniform, porous hybrid network. Under optimized d-SPE conditions, the nanocomposite enabled quantitative recovery (92.0–108.5%) of aflatoxins from pistachio, maize, and rice extracts while achieving sub-ng kg⁻¹ detection limits and excellent reproducibility. The results demonstrate that the Cu/β-CD@CGO platform provides a robust, selective, and sustainable alternative to conventional immunoaffinity or polymeric sorbents, offering strong potential for routine surveillance of aflatoxins in complex food systems. Full article

This study aimed to explore innovative sorbent materials for the remediation of contaminated marine environments, with a focus on metal removal from seawater. Adsorption tests were carried out to evaluate the performance of single-cell proteins (SCPs), a protein-rich biomass derived from industrial by-products, in comparison with commercial activated carbon (AC). Given the increasing need for sustainable and effective approaches in sediment remediation and water treatment, identifying alternatives to conventional sorbents is of particular relevance. Results showed that SCPs exhibited higher affinity for Cr than for Zn, while multi-metal solutions improved adsorption, suggesting synergistic interactions possibly linked to surface charge effects and ternary complex formation. Importantly, SCPs demonstrated competitive and, in some cases, superior performance compared to AC, highlighting their potential as an innovative and sustainable material. Moreover, when the absorbent materials were combined, SCP and AC mixes outperformed both the individual adsorbents and the expected additive efficiencies, achieving significantly higher removal yields for both metals, particularly at low concentrations. Overall, these findings suggest that SCPs, alone or in combination with AC, represent a promising strategy for the removal of heavy metals from marine systems, offering new opportunities for the treatment of contaminated sediments and seawater. Full article