Search Results (107)

Safe drinking water is essential, yet millions of people remain exposed to contaminated supplies. Conventional treatments such as chlorination and UV light can kill microbes, but they also create harmful byproducts, face resistance issues, and are not always sustainable. Green-synthesized nanomaterials (GSNMs) are emerging as an eco-friendly alternative. Produced with plants, microbes, algae, and natural polymers, these materials merge nanotechnology with green chemistry. Among them, silver, zinc oxide, copper oxide, titanium dioxide, and graphene-based nanomaterials show strong antimicrobial effects by disrupting membranes, generating reactive oxygen species (ROS), and damaging genetic material. Compared with chemically made nanoparticles, GSNMs are often safer, cheaper, and more environmentally compatible. Nevertheless, concerns about toxicity, environmental fate, and large-scale use remain. This review highlights recent progress in GSNM synthesis, antimicrobial mechanisms, and safety considerations, highlighting their potential to enable sustainable water disinfection while identifying critical areas for further research. Full article

The secondary contamination of nodularin disinfection by-products (NOD-DBPs) is a problem worthy of attention. In this study, prototypical NOD-R-DBPs were prepared, and their toxicity was assessed using conventional protein phosphatase (PPs) inhibition assay, confirming that structural changes in “Adda³” during chlorination are key factors leading to a significant reduction in NOD-R toxicity. However, some NOD-R-DBPs still exhibit certain levels of toxicity (2.8–81% of NOD-R). To elucidate the mechanism underlying the potential inhibitory effect of NOD-R-DBPs on protein phosphatase 2A (PP2A), molecular simulations were employed to establish interaction models between prototypical NOD-R-DBPs and PP2A using homology modeling strategies, and molecular docking was used to obtain candidate interaction parameters between prototypical NOD-R-DBPs and PP2A. Structural changes in “Adda³” weakened the hydrogen bonds “Adda³”Asn₁₁₇ and “Adda³”His₁₁₈. Subsequently, the disruption of “Adda³” altered key interactions between NOD-R-DBPs and PP2A (hydrogen bond Mdhb⁵ ← Arg₈₉, ionic bond Glu⁴-Arg₈₉, metal bond His₂₄₁-Mn₁²⁺, etc.). The changes in these interactions further altered the interactions between conserved amino acids and the catalytic center Mn²⁺ (ionic bond Asp₅₇-Mn₂²⁺), thereby increasing Mn²⁺ exposure. Meanwhile, the retained interactions promoted the binding of -PO₄ with the conserved amino acids His₁₁₈ and Arg₈₉. Prototypical NOD-R-DBPs retained the aforementioned key interactions and thus exhibit potential inhibitory effects on PP2A. The varying degrees of damage to the Adda³ structure led to significant differences in the inhibitory effects of different NOD-R-DBPs on PP2A. Full article

Ensuring the long-term integrity of structural materials in extreme environments is a critical challenge in the design of equipment for nuclear fuel cycle operations. In particular, the durability of materials exposed to high temperatures and chemically aggressive environments during the processing of irradiated reactor components remains a key concern. This study investigates the high-temperature corrosion behavior of 12Cr18Ni10Ti austenitic stainless steel in the reaction chamber of a beryllium chlorination plant developed for recycling irradiated beryllium reflectors from the JMTR (Japan Materials Testing Reactor). The chlorination process was conducted at temperatures ranging from 500 °C to 1000 °C in a chlorine-rich atmosphere. Post-operation analysis of steel samples extracted from the chamber revealed that uniform wall thinning was the predominant degradation mechanism. However, in high-temperature regions near the heating element, localized forms of damage, specifically pitting and intergranular corrosion, were detected, indicating that thermal stresses exacerbated localized attack. These findings contribute to the assessment of the service life of structural components under extreme conditions and offer practical guidance for material selection and design optimization in high-temperature chlorination systems used in nuclear applications. Full article

Corrosion of refractory materials in NaCl–KCl melts is a major issue affecting the service life of linings in aluminum metallurgy, where these salts serve as the basis for covering and refining mixtures. The aim of this study was to comprehensively evaluate the corrosion resistance of alumina-silicate refractory materials (ASRM) with a high SiO₂/Al₂O₃ ratio in contact with melts of varying NaCl–KCl ratios. Static crucible corrosion tests were conducted in accordance with the technical specification CEN/TS 15418:2006. Macro- and microscopic analysis, chemical analysis (AAS), and semi-quantitative EDX analysis enabled detailed monitoring of the depth of melt infiltration, microstructural changes, and element distribution within the material. The results demonstrated that as the NaCl content in the melt increased, there was a significant rise in both the depth of infiltration and the degree of material degradation. A linear regression model confirmed a very strong positive correlation between NaCl content and the extent of damage (R² = 0.967). Chemical analysis revealed that the silicon content decreases in the infiltrated zone, while aluminum remains stable, indicating superior corrosion resistance of Al₂O₃ compared to SiO₂. EDX analysis also confirmed increased concentrations of sodium and chlorine in the infiltrated areas, complementing the AAS results and providing more precise mapping of the distribution of corrosion products within the material structure. These findings provide a quantitative basis for optimizing the composition of refractory materials and designing protective strategies to extend their service life under the aggressive operating conditions of aluminum production. Full article

Microplastics (MPs) and nanoplastics (NPs) can affect microbial abundance and activity, likely by damaging cell membrane components. While their effects on anaerobic digestion are known, less is understood about their impact on microbes involved in contaminant bioremediation. Chlorinated volatile organic contaminants (CVOCs) such as tetrachloroethene (PCE) and explosives like hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are common in the environment, and their bioremediation is a promising cleanup strategy. This study examined how polystyrene (PS) and polyamide 6 (PA6) MPs and NPs influence CVOC and RDX biodegradation. PS particles did not inhibit the CVOC-degrading community SDC-9, but PA6 MPs impaired the reductive dechlorination of trichloroethene (TCE) to cis-1,2-dichloroethene (cis-DCE), causing a “cis-DCE stall” with no further conversion to vinyl chloride (VC) or ethene. Only 45% of TCE was dechlorinated to cis-DCE, and Dehalococcoides mccartyi abundance dropped 1000-fold in 35 days with PA6 MPs. In contrast, neither PA6 nor PS MPs and NPs affected RDX biotransformation. These results highlight the significant impact of PA6 MPs on CVOC biodegradation and the need to consider plastic pollution in environmental management. Full article

The corrosion behaviour of lean duplex S32101 (1.4162—X2CrMnNiN21-5-1) stainless steel was assessed in various corrosive environments relevant to the pulp and paper industry. Electrochemical techniques, including open-circuit potential measurements and cyclic polarisation, were used to evaluate the corrosion resistance of S32101 stainless steel in various acidic, saline, and industrial liquors such as black, green, and white liquors, as well as dissolved chlorine dioxide bleaching solutions. To evaluate the extent of damage and corrosion mechanisms, post-exposure surface analysis was conducted using scanning electron microscopy (SEM). The results showed that S32101 experienced pitting corrosion in chloride-containing solutions, particularly in salt and acidified-salt environments. Corrosion rates increased with rising temperatures across all solutions. The highest corrosion rate of 3.17 mm/yr was observed in the highly alkaline white liquor at 50 °C, whilst chlorine dioxide induced the least aggressive effects at all temperatures. The suitability of S32101 stainless steel in handling pulp and paper liquors is shown in its corrosion resistance against the bleaching medium and low-temperature saline solutions, but it is not recommended for prolonged exposure to high alkaline liquors or chloride-rich solutions. Full article

Chlorine-based plasma is widely used in key etching applications. However, while etching the wafer materials, chlorine plasma can cause damage to the internal components of the etching chamber, which adversely affects the equipment’s lifespan. As a result, selecting appropriate coating materials for the chamber’s internal components is essential for mitigating corrosion. The etch resistance of these coatings directly impacts not only the quality of wafer production but also the operational safety and maintenance cycle of the etching equipment. In this study, three yttrium oxyfluoride coatings with different oxygen contents (3%, 6%, and 9%) were prepared using atmospheric plasma spraying technology. The etch resistance of these YOF coatings, as well as yttrium oxide coating, was systematically investigated under a Cl₂/O₂ plasma environment. Transmission electron microscopy analysis revealed that at the initial stage, Cl⁻ formed a protective layer on the surface of the YOF coatings, effectively slowing down further etching by Cl⁻. Among the samples, the YOF 6% coating exhibited the best etching resistance, which is primarily attributed to its higher capacity for Cl⁻ adsorption. Overall, YOF coatings demonstrated excellent resistance in chlorine-based plasma environments, with YOF 6% in particular showing great potential as an ideal protective material for etching chamber components. Full article

Gaseous chlorine dioxide (ClO₂) is a potent antimicrobial agent used to control microbial contamination in food and water. This study evaluates the bactericidal activity of gaseous ClO₂ released from a sodium chlorite (NaClO₂) pad against Campylobacter jejuni. Exposure to a low concentration (0.4 mg/L) of dissolved ClO₂ for 2 h resulted in a >93% reduction of C. jejuni, highlighting the bacterium’s extreme sensitivity to gaseous ClO₂. To elucidate the molecular mechanism of ClO₂-induced bactericidal action, transcriptomic analysis was conducted using RNA sequencing (RNA-seq). The results indicate that C. jejuni responds to ClO₂-induced oxidative stress by upregulating genes involved in reactive oxygen species (ROS) detoxification (sodB, ahpC, katA, msrP, and trxB), iron transport (ceuBCD, cfbpABC, and chuBCD), phosphate transport (pstSCAB), and DNA repair (rdgB and mutY). Reverse transcription-quantitative PCR (RT-qPCR) validated the increased expression of oxidative stress response genes but not general stress response genes (spoT, dnaK, and groES). These findings provide insights into the antimicrobial mechanism of ClO₂, demonstrating that oxidative damage to essential cellular components results in bacterial cell death. Full article

Marine environment-induced apparatus failures have led to substantial losses in marine engineering. Graphite/copper composites, known for their excellent electrical conductivity and wear resistance, are extensively utilized in various electric contact devices. However, research on the current-carrying friction and wear behavior of graphite/copper composites in marine environments is still limited. This study investigates the effects of mating materials, graphite content (30 wt.% and 45 wt.%), and electric voltage on the friction and wear mechanisms of graphite/copper composites in seawater. The results show that under seawater coupled with electricity, no mass loss was observed in the 30 wt.% graphite composites after friction tests against different counterparts. Electric voltage (3 V) affects the composite’s damage mechanism, inducing delamination wear, arc erosion and accelerating corrosion. Specifically, the electricity factor promotes oxidation recreations while inhibiting chlorine formation. Notably, when the composite is paired with gold-coated copper, it undergoes electrochemical reactions, leading to the formation of needle-like copper oxide. These oxides alter the surface morphology, elevate the mass of worn composites, and raise the friction coefficient of the tribopair to approximately 0.3, an increase from 0.2. Full article

Background/Objectives: Glioblastoma (GBM) is the deadliest type of brain tumor and photodynamic therapy (PDT) is a promising treatment modality of GBM. However, insufficient photosensitizer distribution in the GBM critically limits the success of PDT. To address this obstacle, we propose tumoritropic neutrophils (NE) as active carriers for photosensitizer delivery to achieve GBM-targeted PDT. Methods: Isolated mouse NE were loaded with functionalized hexagonal boron nitride nanoparticles carrying the photosensitizer chlorin e6 (BNPD-Ce6). In vitro experiments were conducted to determine drug release from the loaded NE (BNPD-Ce6@NE) to mouse GBM cells and consequential photo-cytotoxicity. In vivo experiments were performed on mice bearing intracranial graft GBMs to demonstrate GBM-targeted drug delivery and the efficacy of anti-GBM PDT mediated by BNPD-Ce6@NE. Results: BNPD-Ce6@NE displayed good viability and migration ability, and rapidly released BNPD-Ce6 to co-cultured mouse GBM cells, which then exhibited marked reactive oxygen species (ROS) generation and cytotoxicity following 808 nm laser irradiation (LI). In the in vivo study, a single intravenous bolus injection of BNPD-Ce6@NE resulted in pronounced Ce6 distribution in intracranial graft GBMs 4 h post injection, which peaked around 8 h post injection. A PDT regimen consisting of multiple intravenous BNPD-Ce6@NE injections each followed by one extracranial tumor-directed LI 8 h post injection significantly slowed the growth of intracranial graft GBMs and markedly improved the survival of host animals. Histological analysis revealed massive tumor cell damage and NE infiltration in the PDT-treated GBMs. Conclusions: NE are efficient carriers for GBM-targeted photosensitizer delivery to achieve efficacious anti-GBM PDT. Full article

The degree of soil salinization is still on the rise. In saline environments, NaCl is the main substance that causes plant salt damage, with the toxicity of ions under salt stress primarily involving sodium (Na⁺) or chloride (Cl⁻). However, fewer studies have focused on Cl⁻ stress. This study investigated the differences in the growth and physiology of five blueberry varieties under Cl⁻ stress, aiming to understand the mechanisms of Cl⁻ tolerance and the physiological responses to Cl⁻ stress in these varieties. Five blueberry varieties (‘Northland’, ‘PL19’, ‘Duke’, ‘Reka’, and ‘Bonnie’) were used as test materials. This study examined the changes in growth and physiological indices of blueberry plants under different concentrations of Cl⁻ (A1–A6: 50, 100, 150, 200, 250, and 300 mmol/L) treatments. A control treatment (CK) was included to serve as a baseline for comparison. We comprehensively evaluated the Cl⁻ tolerance of these five varieties to screen for chlorine-tolerant varieties. This study examined the concentration-dependent changes in growth and physiological indices of blueberry plants, including plant height, leaf area, chlorophyll content, electrical conductivity, levels of soluble sugar (SS), malondialdehyde (MDA), proline (Pro), and soluble protein (SP), as well as the activities of superoxide dismutase (SOD) and catalase (CAT). The results revealed that as the Cl⁻ concentration increased, the growth of all blueberry varieties was inhibited; plant height, leaf area, and chlorophyll content consistently declined, whereas electrical conductivity showed a steady increase. SS and MDA content exhibited a biphasic response, with an increase at lower Cl⁻ concentrations followed by a decrease at higher concentrations. The activities of SOD and CAT in ‘Duke’ consistently increased with rising Cl⁻ levels. In ‘PL19’ and ‘Reka’, chlorophyll content decreased with increasing Cl⁻, while their proline content rose initially and then declined. In contrast, the other varieties generally showed an increasing trend in proline content. Similarly, the soluble protein content of ‘Northland’ and ‘PL19’ increased at lower Cl⁻ levels and decreased at higher concentrations, whereas ‘Bonnie’, ‘Duke’, and ‘Reka’ displayed an overall declining trend. Principal component analysis indicated that the Cl⁻ tolerance of the blueberry varieties ranked as follows: ‘Duke’ > ‘Bonnie’ > ‘Reka’ > ‘PL19’ > ‘Northland’. These findings lay a foundation for blueberry cultivation in saline–alkaline soils and support the selection and development of new, chlorine-tolerant varieties. Full article

Several car manufacturers have encountered corrosion in certain mechanical components caused by chlorine in fuel. The current regulations governing the quality of fuel allowed for trade are briefly described. Next, this paper analyzes the possible origin of chlorine in damaged components. In particular, the phenomenon of corrosion found in EGR valves and EGR coolers is analyzed. The analyses conducted to determine the nature of the corrosion and its origin are illustrated. Finally, the effects of the phenomenon on engine operation are analyzed, depending on the type of damaged component. Full article

Solvents are particularly hazardous among the mixture of pollutants found in the air, as their low vapor pressure allows them to reach the atmosphere, causing damage to ecosystems, and producing secondary deleterious effects on living organisms through a wide variety of possible reactions. In response, innovative, sustainable, and ecological methods are being developed to recover solvents from industrial wastewater, which is typically contaminated with other organic compounds. This study describes the procedure for recovering acetone from a residue from the pharmaceutical industry. This compound contains a high amount of solid organic compounds, which are generated during the manufacture of medicines. The treatment consisted of performing a simple solar distillation using a single-slope glass solar still, which separated the acetone from the mother solution. Under ideal circumstances, the use of solar radiation allowed an efficiency rate of 80% using solar concentration by means of mirrors to increase the temperature and 85% without the use of mirrors in the production of distilled acetone, which was characterized to evaluate its quality using instrumental analytical techniques: NMR, IR, and GC. The results obtained indicate that the acetone recovered by this procedure has a good quality of 84%; however, due to this percentage obtained, its reuse is limited for certain applications where a high degree of purity is required, such as its reuse for pharmaceutical use; for this reason, it was proposed to use said compound to eliminate the organic impurities contained in the catalyst waste granules used in a Mexican oil refinery. The resulting material was examined by SEM and EDS, revealing a high initial carbon content that decreased by 29% after treatment. Likewise, as an additional study, a study was carried out to evaluate the characteristics of the residues obtained at the end of the distillation where rubidium, silicon, carbon, nitrogen, oxygen, and chlorine contents were observed. Full article

2,6-Dichloro-1,4-benzoquinone (2,6-DCBQ) is an emerging chlorinated disinfection byproduct (DBP) in bodies of water. However, this compound poses an unknown toxic effect on cyanobacteria. In this study, the toxicological mechanisms of 2,6-DCBQ in Microcystis aeruginosa (M. aeruginosa) were investigated through physiological and nontargeted metabolomic assessments. The results show that 2,6-DCBQ inhibited the growth of M. aeruginosa, reduced its photosynthetic pigment and protein contents, increased the levels of reactive oxygen species, damaged the antioxidant defense system, and aggravated the cytomembrane. Meanwhile, 2,6-DCBQ stimulated the production and release of microcystin-LR (MC-LR) and altered the transcripts of genes associated with its synthesis (mcyA, mcyD) and transport (mcyH). In addition, nontargeted metabolomics of M. aeruginosa cells exposed to 0.1 mg/L 2,6-DCBQ identified 208 differential metabolites belonging to 10 metabolic pathways and revealed the considerable interference caused by 2,6-DCBQ among ABC transporters, the two-component system, and folate biosynthesis. This study deepens the understanding of the physiological and nontargeted metabolomic responses of M. aeruginosa exposed to 2,6-DCBQ, offers insights into the toxic effect of 2,6-DCBQ on M. aeruginosa, and provides a theoretical basis for the ecological risk assessment of emerging DBPs in accordance with water quality criteria. Full article

Dichlorobenzene is beneficial to industries, however, the release of this compound into the environment causes significant damage to ecosystems and human health, as it exhibits resistance to biodegradation. Here, we show that chlorophenol and resorcinol are synthesized from 1,3-dichlorobenzene in a water ice environment (1) directly on a poly-crystalline gold surface and (2) after low-energy (<12 eV) electron irradiation of admixture films. For the latter, at energies below 5.5 eV, the electrons solely decompose the chlorinated compound into radicals that further undergo reaction with surrounding water molecules. At higher energies (i.e., >5.5 eV) additional fragments, e.g., hydroxyl radicals, produced from the dissociation of water molecules, may also be involved in the chemistry. The present results may suggest strategies for potential eco-friendly, sustainable, and scalable processes for the mitigation of these halogenated compounds such as cold plasma and radiation, in which low-energy (<10 eV) electrons are predominantly produced. Full article