Search Results (703)

Background: The emergence and spread of antimicrobial-resistant bacteria (ARB) has become an urgent global concern as a silent pandemic. When taking measures to reduce the impact of antimicrobial resistance (AMR) on the environment, it is important to consider appropriate treatment of wastewater from medical facilities. Methods: In this study, a continuous-flow wastewater treatment system using ozone and ultraviolet light, which has excellent inactivation effects, was implemented in a hospital in an urban area of Japan. Results: The results showed that 99% (2 log₁₀) of Gram-negative rods and more than 99.99% (>99.99%) of ARB comprising ESBL-producing Enterobacterales were reduced by ozone treatment from the first day after treatment, and ultraviolet light-emitting diode (UV-LED) irradiation after ozone treatment; UV-LED irradiation after ozonation further inactivated the bacteria to below the detection limit. Inactivation effects were maintained throughout the treatment period in this study. Metagenomic analysis showed that the removal of these microorganisms at the DNA level tended to be gradual in ozone treatment; however, the treated water after ozone/UV-LED treatment showed a 2 log₁₀ (>99%) removal rate at the end of the treatment. The residual antimicrobials in the effluent were benzylpenicillin, cefpodoxime, ciprofloxacin, levofloxacin, azithromycin, clarithromycin, doxycycline, minocycline, and vancomycin, which were removed by ozone treatment on day 1. In contrast, the removal of ampicillin and cefdinir ranged from 19% to 64% even when combined with UV-LED treatment. Conclusions: Our findings will help to reduce the discharge of ARB and antimicrobials into rivers and maintain the safety of aquatic environments. Full article

With the ongoing advancement of industrialization and rapid urbanization, the emission of volatile organic compounds (VOCs) has increased significantly. As key precursors of PM_2.5 and ozone formation, VOCs pose a growing threat to the health of ecosystems. Due to their complex and dynamic transformation processes across air, water, and soil media, the ecological risks associated with VOCs have attracted increasing attention from both the scientific community and policy-makers. This study systematically reviews the core literature on the ecological impacts of VOCs published between 2005 and 2024, based on data from the Web of Science and Google Scholar databases. Utilizing three bibliometric tools (CiteSpace, VOSviewer, and Bibliometrix), we conducted a comprehensive visual analysis, constructing knowledge maps from multiple perspectives, including research trends, international collaboration, keyword evolution, and author–institution co-occurrence networks. The results reveal a rapid growth in the ecological impact of VOCs (EIVOCs), with an average annual increase exceeding 11% since 2013. Key research themes include source apportionment of air pollutants, ecotoxicological effects, biological response mechanisms, and health risk assessment. China, the United States, and Germany have emerged as leading contributors in this field, with China showing a remarkable surge in research activity in recent years. Keyword co-occurrence and burst analyses highlight “air pollution”, “exposure”, “health”, and “source apportionment” as major research hotspots. However, challenges remain in areas such as ecosystem functional responses, the integration of multimedia pollution pathways, and interdisciplinary coordination mechanisms. There is an urgent need to enhance monitoring technology integration, develop robust ecological risk assessment frameworks, and improve predictive modeling capabilities under climate change scenarios. This study provides scientific insights and theoretical support for the development of future environmental protection policies and comprehensive VOCs management strategies. Full article

Catalysts are ubiquitous in manufacturing industries and gas phase pollutant abatement but are not widely used in wastewater treatment, as high temperatures and concentrated waste streams are needed to achieve the reaction degradation rates required. Heating water is energy intensive, and alternative, low temperature solutions have been investigated, collectively known as advanced oxidation processes. However, many of these advanced oxidation processes use expensive oxidants such as perchlorate, hydroxy radicals or ozone to react with contaminants, and therefore have high running costs. This study has investigated microwave catalysis as a low-energy, low-cost technology for water treatment using NiO catalysts that can be heated in the microwave field to drive the decomposition of azo-dye contaminants. Using this methodology for the microwave-assisted degradation of two azo dyes (azorubine and methyl orange), conversions of >95% were achieved in only 10 s with 100 W microwave power. Full article

In this cross-disciplinary investigation, we uncover a suite of previously unexamined factors and their intricate interplay that hold causal relationships with the distribution of Trachurus japonicus in the northern reaches of the South China Sea, thereby extending the existing research paradigms. Leveraging advanced machine learning algorithms and causal inference, our robust experimental design uncovered nine key global and regional factors affecting the distribution of T. japonicus density. A robust experimental design identified nine key factors significantly influencing this density: mean sea-level pressure (msl-0, msl-4), surface pressure (sp-0, sp-4), Summit ozone concentration (Ozone_sum), F10.7 solar flux index (F10.7_index), nitrate concentration at 20 m depth (N3M20), sonar-detected effective vertical range beneath the surface (Height), and survey month (Month). Crucially, stable causal relationships were identified among Ozone_sum, F10.7_index, Height, and N3M20. Variations in Ozone_sum likely impact surface UV radiation levels, influencing plankton dynamics (a primary food source) and potentially larval/juvenile fish survival. The F10.7_index, reflecting solar activity, may affect geomagnetic fields, potentially influencing the migration and orientation behavior of T. japonicus. N3M20 directly modulates primary productivity by limiting phytoplankton growth, thereby shaping the availability and distribution of prey organisms throughout the food web. Height defines the vertical habitat range acoustically detectable, intrinsically linking directly to the vertical distribution and availability of the fish stock itself. Surface pressures (msl-0/sp-0) and their lagged effects (msl-4/sp-4) significantly influence sea surface temperature profiles, ocean currents, and stratification, all critical determinants of suitable habitats and prey aggregation. The strong influence of Month predominantly reflects seasonal changes in water temperature, reproductive cycles, and associated shifts in nutrient supply and plankton blooms. Rigorous robustness checks (Data Subset and Random Common Cause Refutation) confirmed the reliability and consistency of these causal findings. This elucidation of the distinct biological and physical pathways linking these diverse factors leading to T. japonicus density provides a significantly improved foundation for predicting distribution patterns globally and offers concrete scientific insights for sustainable fishery management strategies. Full article

Reverse osmosis (RO) concentrated water can be effectively treated with catalytic ozone oxidation technology, an effective advanced oxidation process. In order to provide a thorough reference for the safe treatment and reuse of RO concentrated water, this paper examines the properties of RO concentrated water, such as its high salt content, high levels of organic pollutants, and low biochemistry. It also examines the mechanism of its role in treating RO concentrated water and combs through its applications in municipal, petrochemical, coal chemical, industrial parks, and other industries. The study demonstrates that ozone oxidation technology can efficiently eliminate the organic matter that is difficult to break down in RO concentrated water and lower treatment energy consumption; however, issues with free radical inhibitor interference, catalyst recovery, and stability still affect its use. Future research into multi-technology synergistic processes, the development of stable and effective non-homogeneous catalysts, and the promotion of their use at the “zero discharge” scale for industrial wastewater are all imperative. Full article

Nematodes are among the organisms found in treated water. While generally considered harmless to human health, under certain conditions, they may serve as vectors for pathogenic viruses and bacteria, posing potential risks. Conventional disinfection processes in water treatment can contribute to the inactivation or removal of nematodes, but their effectiveness varies. This study, conducted at a water treatment plant (WTP) in Mashhad, Iran, aimed to determine the optimal dose and contact time of sodium hypochlorite and ozone for enhancing nematode inactivation in the affected surface water. This research combined primary disinfection using sodium hypochlorite at the existing WTP with a pilot ozone injection system to evaluate their individual and combined effectiveness. The results show that sodium hypochlorite at a concentration of 2 mg/L achieved 68% nematode inactivation. At 2.0 mg/L, with a 20 min contact time, ozone disinfection resulted in 39% inactivation. However, the combined application of sodium hypochlorite and ozone significantly improved efficiency, reaching 92% nematode inactivation when sodium hypochlorite and ozone were applied at 2 mg/L and 3 mg/L, respectively, with a 20 min ozone contact time. These findings indicate that, among the disinfection methods examined, the combined use of sodium hypochlorite and ozone is the most effective approach for nematode inactivation in drinking water, offering a promising strategy for improving water quality and safety. Full article

Background: Additional therapies (e.g., laser, photodynamic therapy, and ozone) have been reported to improve mechanical instrumentation and immune response in non-surgical periodontal therapy (NSPT). With this systematic review we evaluated the effectiveness of ozone therapy in reducing inflammation and progression of periodontal disease. Methods: Three electronic databases (PubMed, Scopus, and Cochrane Library) were searched for randomized and clinical trials on ozone therapy (gas, liquid, gel/oil) combined with NSPT. The study design followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and the risk of bias was assessed using the RoB-2 tool. Results: Eight of the twenty-two studies reviewed reported on gaseous ozone, nine on ozone water, and five on ozonated oil/gel as an adjunct to mechanical periodontal instrumentation, often with scaling and root planing (SRP). Ozone was found to be more effective than SRP alone in treating inflammation, as measured with the gingival index (VMD −0.32; 95% confidence interval (CI) (−0.41; −0.24); p < 0.00001) and compared to chlorhexidine (CHX) (ozone gel; VMD −0.10; 95% CI (−0.20; −0.01); p = 0.03). The study findings were inconsistent, however, with several reporting clinical and microbiological benefit while others observed no marked improvement with the addition of ozone therapy to NSPT. Conclusions: While ozone therapy may represent a useful adjunct to NSPT, further research with larger study groups is warranted to determine its effectiveness. Full article

This study investigated the degradation efficacy, kinetics, and mechanism of the ozone (O₃) process and two enhanced O₃ processes (O₃/peroxymonosulfate (O₃/PMS) and O₃/peroxymonosulfate/iron molybdates/biochar composite (O₃/PMS/FeMoBC)), especially the O₃/PMS/FeMoBC process, for the degradation of tetracycline (TC) in water. An FeMoBC sample was synthesized by the impregnation–pyrolysis method. The XRD results showed that the material loaded on BC was an iron molybdates composite, in which Fe₂Mo₃O₈ and FeMoO₄ accounted for 26.3% and 73.7% of the composite, respectively. The experiments showed that, for the O₃/PMS/FeMoBC process, the optimum conditions were obtained at pH 6.8 ± 0.1, an initial concentration of TC of 0.03 mM, an FeMoBC dosage set at 200 mg/L, a gaseous O₃ concentration set at 3.6 mg/L, and a PMS concentration set at 30 μM. Under these reaction conditions, the degradation rate of TC in 8 min and 14 min reached 94.3% and 98.6%, respectively, and the TC could be reduced below the detection limit (10 μg/L) after 20 min of reaction. After recycling for five times, the degradation rate of TC could still reach about 40%. The introduction of FeMoBC into the O₃/PMS system significantly improved the TC degradation efficacy and resistance to inorganic anion interference. Meanwhile, it enhanced the generation of hydroxyl radicals (^•OH) and sulfate radicals (SO₄^•−), thus improving the oxidizing efficiency of TC in water. Material characterization analysis showed that FeMoBC has a well-developed porous structure and abundant active sites, which is beneficial for the degradation of pollutants. The reaction mechanism of the O₃/PMS/FeMoBC system was speculated by the EPR technique and quenching experiments. The results showed that FeMoBC efficiently catalyzed the O₃/PMS process to generate a variety of reactive oxygen species, leading to the efficient degradation of TC. There are four active oxidants in O₃/PMS/FeMoBC system, namely ^•OH, SO₄^•−, ¹O₂, and •O₂⁻. The order of their contribution importance was ^•OH, ¹O₂, SO₄^•−, and •O₂⁻. This study provides an effective technological pathway for the removal of refractory organic matter in the aquatic environment. Full article

Ozonation has been promoted as a successful methodology for recovering effluents from wastewater treatment plants, with special emphasis on wastewater contaminated with pharmaceutical and personal care products (PPCPs). Still, ozonation reactions may generate potentially toxic by-products, jeopardizing human health safety, a critical aspect considering the use of reclaimed water. We aimed at understanding the potential impacts of ozonation on the quality of reclaimed water for human use through cell viability assays with human skin keratinocytes (HaCaT cell line). Under this context, the cytotoxicity of synthetic effluents contaminated with methyl- and propylparaben, paracetamol, sulfamethoxazole, and carbamazepine, both individually and in mixtures, was assessed before and after ozonation. The viability of HaCaT cells decreased after exposure to untreated synthetic effluents, denoting the cytotoxicity of the tested PPCPs singly and more prominently in mixtures (especially in those combining two and three PPCPs). A similar pattern was observed when testing effluents treated with ozonation. Since the parent contaminants were fully removed during ozonation, the observed cytotoxicity relates to degradation by-products and interactive effects among them. This study suggests that ozonation is poorly efficient in reducing cytotoxicity, as required for the safe use of ozone-treated reclaimed water in activities involving direct contact with human skin. Full article

This study investigates the emission characteristics and environmental impacts of pollutants from bagasse-fired biomass boilers through the integrated field monitoring of two sugarcane processing plants in Guangxi, China. Comprehensive analyses of flue gas components, including PM_2.5, NOx, CO, heavy metals, VOCs, HCl, and HF, revealed distinct physicochemical and emission profiles. Bagasse exhibited lower C, H, and S content but higher moisture (47~53%) and O (24~30%) levels compared to coal, reducing the calorific values (8.93~11.89 MJ/kg). Particulate matter removal efficiency exceeded 98% (water film dust collector) and 95% (bag filter), while NOx removal varied (10~56%) due to water solubility differences. Heavy metals (Cu, Cr, Ni, Pb) in fuel migrated to fly ash and flue gas, with Hg and Mn showing notable volatility. VOC speciation identified oxygenated compounds (OVOCs, 87%) as dominant in small boilers, while aromatics (60%) and alkenes (34%) prevailed in larger systems. Ozone formation potential (OFP: 3.34~4.39 mg/m³) and secondary organic aerosol formation potential (SOAFP: 0.33~1.9 mg/m³) highlighted aromatic hydrocarbons (e.g., benzene, xylene) as critical contributors to secondary pollution. Despite compliance with current emission standards (e.g., PM < 20 mg/m³), elevated CO (>1000 mg/m³) in large boilers indicated incomplete combustion. This work underscores the necessity of tailored control strategies for OVOCs, aromatics, and heavy metals, advocating for stricter fuel quality and clear emission standards to align biomass energy utilization with environmental sustainability goals. Full article

The widespread use of plastics in our daily life has caused many health problems. Conventional water treatment processes have low efficiency in the removal of microplastics from water. In this work, we investigated the efficiency of ozonation pretreatment followed by flocculation to remove microplastics from water. After the ozonation pretreatment, it was found that microplastic removal could be significantly enhanced by flocculation from 40% to 91%. The characterization results show that the ozonation-pretreated microplastics had rougher surfaces and larger amounts of surface hydroxyl groups and carbonyls, which might be responsible for their increased removal. However, there was still a small amount of microplastics that had not been removed. They floated on the surface of the solution and could not be effectively oxidized by ozone, thus not changing their surface properties. This further confirms the importance of hydroxyl groups. Full article

Reactive oxygen–nitrogen species (RONS) production in a Peltier-cooled hybrid dielectric barrier discharge (HDBD) reactor operated with humid air is characterized. Fourier-transform infrared spectroscopy (FTIR) is used to determine the RONS in the HDBD-produced gases. The presence of molecules ${\mathrm{O}}_3$, ${\mathrm{NO}}_2$, ${\mathrm{N}}_2$O, ${\mathrm{N}}_2{\mathrm{O}}_5$, and ${\mathrm{HNO}}_3$ is evaluated. The influence of HDBD reactor operation parameters on the FTIR result is discussed. The strongest influence of Peltier cooling on RONS chemistry is reached at conditions related to a high specific energy input (SEI): high voltage and duty cycle of plasma width modulation (PWM), and low gas flow. Both PWM and Peltier cooling can achieve a change in the chemistry from oxygen-based to nitrogen-based. ${\mathrm{N}}_2{\mathrm{O}}_5$ and ${\mathrm{HNO}}_3$ are detected at a low humidity of 7% in the reactor input air but not at humidity exceeding 90%. In addition to the FTIR analysis, the plasma-activated water (PAW) is investigated. PAW is produced by bubbling the HDBD plasma gas through 12.5 mL of distilled water in a closed-loop circulation at a high SEI. Despite the absence of ${\mathrm{N}}_2{\mathrm{O}}_5$ and ${\mathrm{HNO}}_3$ in the gas phase, the acidity of the PAW is increased. The pH value decreases on average by 0.12 per minute. Full article

The biological aging of titanium implants, marked by increased surface hydrophobicity and organic contamination, reduces bioactivity and delays osseointegration. A major challenge in implant dentistry is determining how to preserve surface hydrophilicity during storage, as conventional atmospheric conditions accelerate surface degradation. This pilot in vivo study aimed to evaluate ozone nanobubble water (NBW3) as a storage medium to prevent biological aging and enhance the early-stage osseointegration of glow discharge-treated titanium implants. Screw-type implants were stored in either NBW3 or atmospheric conditions and then implanted into femoral bone defects in Sprague Dawley rats. Removal torque testing, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and histological analysis of bone-to-implant contact (BIC) were performed 14 and 28 days post-implantation. At 14 days, the NBW3-stored implants demonstrated significantly higher removal torque (2.08 ± 0.12 vs. 1.37 ± 0.20 N·cm), BIC (65.74 ± 12.65% vs. 44.04 ± 14.25%), and Ca/P atomic ratio (1.20 ± 0.32 vs. 1.00 ± 0.22) than the controls. These differences were not observed at 28 days, indicating NBW3’s primary role in accelerating early osseointegration. The findings suggest that using NBW3 is a simple, effective approach to maintain implant surface bioactivity during storage, potentially improving clinical outcomes under early or immediate loading protocols. Full article

This paper presents a study on the optimization of 2,4-Dichlorophenoxyacetic (2,4-D) acid removal from synthetic wastewater by batch Fenton-Ozonation. The aim of this study is to evaluate the potential of the catalytic system Fe-L27 coupled to ozonation in the presence and absence of H₂O₂ as an effective and affordable technique for the treatment of organic pollutants in water. Fenton-like catalysts for the removal of 2,4-D in aqueous solutions were elaborated using catalysts synthesized by the wet impregnation method. The ACs and prepared catalysts were characterized by nitrogen adsorption–desorption isotherms at 77 K, TGA, XPS, SEM, and TEM. Their efficiency as Fenton-like catalysts was studied. In a first step, a response surface modeling method was employed in order to find the optimal parameters of the Fenton process, and then the optimal O₃/H₂O₂ ratio was established at laboratory scale. Finally, the investigated advanced oxidation processes were carried out at pilot scale. The results show that Fenton-like catalysts obtained by the direct impregnation method enhance the degradation rate and mineralization of 2,4-D. Full article

Aiming at the defects of the low mass transfer efficiency and large floor space of the traditional ozone process, a cross-tube ozone catalytic oxidation pilot plant was designed and developed. By implementing lateral aeration and a modular series configuration, the gas–liquid mass transfer pathways were optimized, achieving a hydraulic retention time of 25 min and maintaining an ozone dosage of 43 mg/L, which significantly improved the ozone utilization efficiency. During the pilot operation in an industrial park in Suzhou, Anhui Province, the average COD removal efficiency of the device for the actual biochemical tail water (COD 82.5~29.7 mg/L) reached 35.47%, and the effluent concentration was stably lower than 50 mg/L, which meets the stricter discharge standard. The intermediate products in the system were also analyzed by liquid chromatography–mass spectrometry (LC-MS), and the key pollutants were selected for degradation path analysis. Compared to the original tower process in the park, the ozone dosage was reduced by 46%, the reaction residence time was reduced by 60%, and the cost of water treatment was reduced to 0.067 USD, which is both economical and applicable to engineering. This process provides an efficient and low-cost solution for the deep treatment of wastewater in industrial parks, and has a broad engineering application prospect. Full article