Dimethyl sulfide (DMS) is a representative reduced sulfur compound that is difficult to oxidize and remove, particularly under the high-humidity conditions commonly encountered in waste-treatment and biomass power plants. In this study, a practical strategy for DMS removal under high-humidity conditions was investigated by combining ozone oxidation with a low-cost iodate-impregnated activated carbon catalyst with moderate catalyst heating. Ozone was generated using a xenon excimer lamp, enabling a compact system design without the need for a pressure-swing adsorption oxygen generator and thereby making the system suitable for small-scale and distributed applications. The DMS removal performance was evaluated using a dynamic adsorption method under relative humidity (RH) conditions of 45% and 90%. At 25 degrees C and 45% RH, the treatment capacity and reaction rate constant were 15 wt% and 6.9 s(-1), respectively, whereas these values decreased to 1.5 wt% and 4.9 s(-1) at 25 degrees C and 90% RH, indicating that water vapor significantly interfered with DMS treatment through preferential adsorption. However, when the catalyst temperature was increased by 10 degrees C (from 25 degrees C to 35 degrees C) under high-humidity conditions, the treatment capacity and reaction rate constant improved to 2.8 wt% and 5.8 s(-1), respectively. This enhancement was attributed to the asymmetric adsorption behavior of DMS and water vapor, whereby moderate heating reduced water adsorption and restored sites available for DMS adsorption.
Closed-loop control of dielectric barrier discharge (DBD) loads remains challenging because the load voltage is usually difficult to measure directly in practical high-voltage systems, while the discharge behavior is strongly nonlinear and operating-condition dependent. To address this problem, this paper proposes a control-oriented linearized observation model for estimating the peak load voltage from the peak load current within a specified operating range. First, an equivalent electrical model of the DBD load is established based on the microscopic discharge processes, including capacitive behavior before breakdown, rapid ionization after gas-gap breakdown, and charged-particle recombination during current decay. Based on this model, the relationship between the peak load voltage and the peak load current is investigated through numerical analysis and experimental validation. The results show that, under fixed load structure and limited operating conditions, the peak voltage and peak current exhibit an approximately linear relationship. The proposed model is then applied as a voltage observer in the closed-loop voltage control of a DBD ozone generator. Experimental results demonstrate that the model can estimate the peak load voltage with acceptable accuracy in the tested operating range and can support stable closed-loop control. It should be noted that the model coefficients need to be re-identified when the DBD load structure, gas condition, or operating range changes significantly.
Plasma jet applications such as sterilization, surface modification, and material synthesis require precise control of reactive oxygen species (ROS). This study investigates the distribution characteristics of ROS produced by plasma jet (feed gases: H-2 or O-2) to elucidate their production and transport dynamics. A combined computational-experimental approach was used: a 0D-fluid Global Simulation quantified ROS densities, while COMSOL Multiphysics modeled their spatial distribution. Comparative analysis revealed distinct differences in ROS generation and propagation between the two gases. Quantemol Global Model (QGM) results showed that O-2-fed plasma generates significantly higher concentrations of atomic oxygen (O) and O-3, whereas H-2-fed plasma produces only trace oxygen-containing species, primarily due to O-2 diffusion from the surrounding atmosphere. Both simulation and experimental measurements demonstrated effective diffusion of ROS from O-2-fed plasma through agar, whereas H-2-fed plasma exhibited a non-diffusive, localized distribution. This localized behavior suggests sustained reactivity driven by alternative ROS formation pathways within the medium. By tuning the feed gas composition, plasma jet performance can be optimized for targeted applications: O-2-fed plasma is suited for processes requiring strong oxidizing agents, while H-2-fed plasma enables applications benefiting from persistent, localized reactivity. These findings offer valuable insights for advancing plasma-based biomedical technologies.
The ozone deposition velocity was investigated as a function of height and ozone treatment duration in order to better understand the decomposition of ozone in a column of grains. By analyzing the ozone deposition model, it was found that the ozone concentration was exponentially dependent on the ozone deposition velocity, porosity, pore shape factor and apparent flow rate of ozone gas. We found a model of ozone deposition velocity in the column of wheat grain for grade 4 hard red winter wheat (HRWW) with a moisture content of 10.3% at 22.0 degrees C and its coefficient of determination was 0.98. The ozone deposition velocity determined was applied to ozone treatment for grade 4 HRWW filled in a storage bin with a capacity of 18 m3. The saturation time, the residual ozone concentration, breakthrough time, etc. were calculated by using the ozone deposition velocity. The results demonstrate how ozone can be consumed and distributed throughout the grain storage bin, and the procedure to determine the deposition velocity can be applied to the optimization of ozone treatment for storage bins.
Tropospheric ozone (O3), an emerging climate change-induced stressor, enters leaf tissues via stomata, triggering reactive oxygen species (ROS) generation and suppressing key N assimilation enzymes like nitrate reductase and glutamine synthetase impairing nitrogen metabolism and reducing grain yield and nitrogen use efficiency (NUE) in rice. This study evaluated the impact of elevated O3 (e[O3]) on nitrogen (N) uptake, NUE components, and yield attributes across two contrasting seasons using Open Top Chambers (OTCs) with four treatments: UC (ambient, open field, 30 +/- 5 ppb), CC (ambient, OTC, 30 +/- 5 ppb), EO40 (40 +/- 5 ppb), and EO60 (60 +/- 5 ppb), across three N levels. Partial Least Squares Path Modeling (PLS-PM) was used to analyze trait interrelationships affecting grain yield. Results showed that e[O3] significantly reduced total N uptake (17-28%), agronomic NUE (27-35%), N recovery efficiency (22-28%), physiological NUE (6-10%), and partial factor productivity of N (14-23%) compared to CC. Grain yield declined by 14-23%, with greater reductions observed during Kharif season, likely due to higher stomatal conductance facilitating increased O3 uptake. Higher N application only partially mitigated O3-induced NUE impairment. PLS-PM identified spikelet fertility as the strongest direct yield determinant under O3 stress.
Topical ozone therapy is extensively utilized in dentistry due to its antimicrobial properties and its ability to promote tissue healing. Ozonated glycerin (OG) offers a water-soluble and odorless alternative to traditional ozonated oils; however, its oxidative characteristics and stability remain insufficiently characterized. This study systematically quantified the peroxide value and total oxidant concentration of OG through iodometric titration, established practical endpoints for the ozonation process, and evaluated residual ozone content using an ozone-specific analytical technique. Three batches of pure, undiluted glycerin were ozonated under varying reaction durations (5-15 days) and temperatures (10-26 degrees C), alongside one batch of 50% diluted glycerin subjected to ozonation for five days at 26 degrees C. The five-day ozonation at 26 degrees C yielded reactive peroxide concentrations ranging from approximately 6500 to 17,000 mg/L in undiluted glycerin and from 8400 to 11,300 mg/L in diluted glycerin. At 10 degrees C, the observed range was 1261 to 3624 mg/L. These results indicate that most peroxide formation occurs within the first two days, with diluted glycerin reaching roughly 75% of its maximum peroxide concentration after just one day. Based on the findings, OG should be prepared on a monthly basis and not stored for more than two months. Further research is warranted to elucidate the properties of OG and to broaden its clinical applications.
Diwali celebrations are often marked by widespread firecracker use, resulting in short-term degradation of air quality in Indian cities. This study evaluates the impact of Diwali on ambient air pollution across five urban locations in Bengaluru, such as Bapuji Nagar, BTM Layout, Jayanagar 5th Block, Peenya, and Silk Board over four consecutive years (2020-2023). The study aims to quantify shifts in particulate and gaseous pollutant levels during the pre-Diwali, Diwali, and post-Diwali periods, and identify the key pollutant groupings associated with Diwali-related emissions using Principal Component Analysis (PCA). Ambient concentrations of PM10, PM2.5, SO2, NO2, CO, NOx, NH3, VOCs and O-3 were analyzed during the pre-Diwali, Diwali, and post-Diwali periods. Significant increase in PM10, PM2.5, and SO2 levels were observed during Diwali at all locations with Bapuji Nagar and Silk Board showing the highest concentrations. PCA revealed strong correlations between particulate matter and SO2, indicating a common firecracker-related origin. Ozone showed an inverse pattern, likely due to reduced photochemical activity during heavy pollution episodes. Combined PCA plots across years confirmed consistent pollutant clustering during Diwali. Pollution levels during 2021 and 2022 were relatively lower, likely influenced by pandemic-related restrictions. These findings highlight Diwali as a recurring, episodic pollution event in Bengaluru and underscore the need for targeted, short-term mitigation and enforcement strategies to limit exposure during the festival.
Oxidation rate constants are critical parameters for the design and optimization of advanced oxidation processes (AOPs) employed to remove persistent organic pollutants from water. In this study, an interpretable, design-oriented modeling framework is developed to predict pseudo-first-order oxidation rate constants expressed as log10(k) for chlorophenols under photo-Fenton, Fenton, and photoperoxidation conditions, while direct UV photolysis is considered separately as a non-radical photochemical treatment. Experimental operating parameters, including pH, temperature, oxidant dosage, iron concentration, and radiation intensity, were integrated with Abraham solute descriptors to capture both process-level and molecular-level influences on oxidation kinetics. An Extreme Gradient Boosting (XGBoost) model was trained and interpreted using SHapley Additive exPlanations (SHAP). Model performance was evaluated using nested grouped cross-validation, with folds constructed to ensure prediction on previously unseen chlorophenol compounds. The optimized model achieved strong in-sample performance (training R2 = 0.94 +/- 0.10) and moderate generalization to unseen compounds (test R2 = 0.41 +/- 0.50; RMSE = 0.54 +/- 0.27 on log10(k)). Model interpretation revealed that oxidation kinetics are predominantly governed by operating conditions, while molecular descriptors related to polarizability and hydrogen bonding interactions modulate pollutant-specific reactivity. Overall, the proposed framework provides mechanistically interpretable insights that support rational AOP selection and operating-condition optimization.
This study aimed to describe the ozone saturation kinetics in paddy rice columns at different specific flow rates and heights, evaluate its efficacy against Sitophilus zeamais, and assess the effect on grain quality. A prototype of 15 cm diameter and 20 cm height was used. The inlet ozone concentration was 5.0 mg L-1, with ratios between grain layer heights (H) and the prototype diameter (D) of 0.6 and 1.2, and specific flow rates of 0.5, 1.0, 1.5, and 2.0 m3 min-1 t-1. Exposure time was 480 min, with residual ozone measured at intervals. Saturation times decreased with specific higher flow rates, ranging from 224 to 61 min (H/D - 1.2) and 185 to 47 min (H/D - 0.6), while saturation concentrations ranged from 1.07 to 2.70 mg L-1 ;(H/D - 1.2) and 1.38 to 2.95 mg L-1 ;(H/D - 0.6). Ozone treatments achieved 100% insect mortality, except for H/D of 0.6 and a specific flow rate of 0.5 m3 min-1 t-1, which resulted in 95% mortality. Moisture content and electrical conductivity remained stable, and only minor color changes were observed at H/D - 0.6 with higher specific flow rates. The chemical composition, including lipids, proteins, ash, and carbohydrates, was unaffected by ozonation.
This study investigates the diurnal and seasonal variations of ozone (O-3) and its precursors (NO, NO2, NOx, CO, SO2) over Bengaluru, India, during 2024. Results highlight distinct daily and seasonal cycles, with photochemical production enhanced during summer mornings (>3 mu g/m(3)/hr and sharp declines in winter evenings (<-3 mu g/m(3)/h). PCA reveals strong associations among O-3, NOx, PM2.5, and PM10. Outcomes of the study shows a distinct daily cycle with strong seasonal contrasts. In the early morning hours (1-6 a.m.), the ozone levels declined slightly due to titration by NO emissions and shallow planetary boundary layer height (PBLH) limiting dispersion. After sunrise, the photochemical production intensified and converting NO2 into O-3, with a deepening PBLH further enhancing vertical mixing. The strongest positive rates occurred in summer mornings (above 3 mu g/m(3)/h), supported by stronger radiation and higher temperatures. During evening hours (3-7 p.m.), ozone declined sharply, particularly in winter (below -3 mu g/m(3)/h), driven by reduced sunlight, collapsing PBLH, and traffic-related NO emissions. PCA highlighted strong linkages between O-3, NOx, PM2.5, and PM10, with seasonal variability shaped by meteorological drivers. Findings demonstrate that O-3 dynamics in Bengaluru are influenced by vehicular emissions, solar-radiation, underscoring the need for vehicular emission control and air-quality management strategies.
In the study and management of ozonation, a model that describes ozone (O3) concentration dynamics is a fundamental framework. However, the conventional initial O3 demand/pseudo-first-order model (IPM) is strongly dependent on the O3 dose and consequently constrains both basic and applied research. Therefore, we propose a new model that expands IPM by representing O3 consumption with two distinct second-order reactions. Using this model, O3 exposure was successfully predicted with a median absolute relative error (MdARE) of 4.8% for various combinations of water temperature and O3 dose within the calibrated range. Coupling our model with an existing hydroxyl radical (& centerdot;OH) model accurately reproduced the decay of p-chlorobenzoic acid (a & centerdot;OH probe compound) with a MdARE of 3.2%. Simulations using the new model revealed that (i) the O3 dose required for the removal of Cryptosporidium parvum oocysts is governed by water temperature rather than dissolved substances, (ii) the O3/& centerdot;OH contribution ratio to cis-1,2-dichloroethene oxidation is practically independent of O3 dose, and (iii) the removal efficiency of p-chlorobenzoic acid can be estimated with a MdARE of 14% through real-time monitoring of the O3 consumption rate. This study provides a versatile kinetic framework for mechanistic studies and practical applications in treatment operations.
Endometriosis is a chronic inflammatory gynecological condition that significantly impacts women's quality of life. Given the limitations of conventional therapies, complementary strategies are being explored. This randomized, double-blind, placebo-controlled clinical trial evaluated the safety and clinical effects of endovaginal medical ozone treatment as an adjuvant intervention in women with endometriosis. Thirty participants were allocated into placebo (OzP) and active treatment (OzA) groups. Weekly endovaginal applications were performed for 10 weeks. Clinical outcomes were assessed at baseline and post-treatment using the Numeric Pain Rating Scale (NPRS), Endometriosis Health Profile-30 (EHP-30), Female Sexual Function Index (FSFI), and Beck Anxiety Inventory (BAI). The OzA group demonstrated significant reductions in pain and improvements in quality of life, sexual function, and anxiety symptoms compared with OzP. No serious adverse events were observed, and the intervention showed a favorable tolerability profile. These findings suggest that endovaginal medical ozone treatment may represent a minimally invasive adjuvant strategy in endometriosis management.
Secondary ozonides (1,2,4-trioxolanes) formed from ozone reacting with unsaturated fatty acid esters in vegetable oils are the main active components of ozonated oils. When fatty acid chains contain multiple double bonds, the reaction pathway remains unclear. Two-dimensional nuclear magnetic resonance (2D NMR) effectively addresses the issue of signal overlap encountered in one-dimensional NMR (1D NMR) analysis of complex systems. In this study, methyl linoleate was employed as a model compound, and trilinolein was used for validation. The reaction products of both compounds with ozone were systematically analyzed using both 1D and 2D NMR techniques to elucidate product distribution across different stages of the ozonation process. Results indicate that, in the presence of multiple double bonds, ozone preferentially reacts with one of the double bonds, leading to the formation of an intermediate composed of 1,2,4-trioxolane and the unreacted carbon-carbon double bond along the fatty acid chain, followed by further ozonation of the remaining double bond to yield a bis(1,2,4-trioxolane) structure. The application of 2D NMR successfully resolved the characteristic peaks of the intermediates and final products, thereby confirming the proposed reaction pathway. This approach plays a crucial role in enhancing quality control in the preparation of ozonated oils.
