Ozone Production with Dielectric Barrier Discharge from Air: The Influence of Pulse Polarity

ABSTRACT

This research aims to study the effects of different pulse modes of the power supply on ozone production from air. Single positive, negative as well as the bipolar voltage pulses (positive–negative and negative–positive) with a repetition rate of 300 Hz have been applied to coaxial dielectric barrier discharge arrangement. Results reveal that at fixed specific input energy (SIE), which is defined as the ratio of power to gas flow rate, the ozone generation efficiencies for different pulse modes are in the sequence of positive > positive–negative > negative–positive > negative, and the difference between positive and positive–negative pulse becomes considerable with SIE higher than 500 J/L. Results also reveal that the maximum NO₂ concentration is obtained at 400 J/L. Moreover, utilizing bipolar pulse can reduce N₂O production with SIEs higher than 250 J/L and hinder NO₂ production with SIEs higher than 350 J/L.     

Ozone Production in a High Frequency Dielectric Barrier Discharge Generator

Factors that affect the performance of an expanded-mesh dielectric barrier discharge ozone cell were investigated. A gas feed pf 94% O₂, 4% Ar and 1% N₂ was used. An improvement in the productivity (g ozone/kWh) of about 20 % was achieved by doubling the gas flow rate through the cell. Decreasing the cell operating frequency (in the range 72 kHz to 19 kHz) increased the productivity of the ozone generator at constant power. The ozone production increased approximately in proportion to the input power; however productivity did not vary significantly with power above a minimum level. As the cell voltage was increased the dependence of productivity on power or frequency was reduced. Changing the feed gas temperature between ? 5^°C and + 42^°C had no effect on productivity. Finer meshes drew more power than coarser ones for a given voltage. Using a thinner mesh for the centre electrode increased productivity. The best results were obtained with a 6 × 3 × 1.86 mm titanium mesh giving a productivity of 110 g ozone/kWhr at 30–60 W, 1500–1900V and 23 KHz.     

Ozonation of Reactive Orange 122 Using La3+-Doped WO3/TiO2/Sep Photocatalyst

La³⁺/WO₃/TiO₂/sep composites have been prepared by the sol–gel method. The degradation of dye was studied under the influence of various operational parameters such as initial pH, amounts of catalyst, concentrations of the dye, and ozone flow rate. The mineralization of Reactive Orange 122 has been confirmed by chemical oxygen demand measurements. The color removal of dye was found to follow a pseudo–first-order kinetics. Maximum color and chemical oxygen demand removal were 99.9% and 90% respectively, at a dye concentration of 200 mg/L, ozone flow rate of 2.0 L/min., 0.05 g/L weight of catalyst, and pH of 6.9 in 4 h. In addition, the catalyst was characterized by X-ray diffraction spectra, Fourier-Transform Infrared Spectroscopy, scanning electron microscopy, and a transmission electron microscope. This work could be a good candidate as a practical application for photocatalytic dye degradation.     

Effects of O3, O3/H2O2 and Coagulation on Natural Organic Matter and Arsenic Removal from Typical Northern Serbia Source Water

The objectives of this study were to investigate the effects of ozone and the O₃/H₂O₂ process on FeCl₃ coagulation efficiency for the removal of the high content of natural organic matter (NOM) and arsenic (As) from groundwater (DOC = 9.27 ± 0.92 mg/L; 51.7 ± 16.4 µg As/L). Arsenic and NOM removal mechanisms during coagulation/flocculation are well investigated. However, data concerning arsenic removal in the presence of NOM, which is the subject of this article, are still insufficient. Laboratory and pilot plant test results have shown that the competition of NOM and As for adsorption sites on the coagulant surface have great influence on coagulation/flocculation efficiency for their removal. With both oxidation pre-treatments, arsenic content after the coagulation process was less than 2.0 µg/L in treated water. Application of ozone has a lower influence on coagulation efficacy in terms of DOC reduction, compared to the O₃/H₂O₂ process with the same ozone dose.     

Fertiliser timing and use of inhibitors to reduce N<Subscript>2</Subscript>O emissions of rainfed wheat in a semi-arid environment

Nitrogen (N) management is critical to the profitability of grain production systems, however careful management of fertiliser is needed to minimise environmental impacts. We investigated the effect of five N fertilisation strategies on nitrous oxide (N₂O) emissions and nitrogen use efficiency (NUE) of rainfed wheat grown on a clay soil in a temperate, semi-arid environment of south eastern Australia during 2013 and 2014. Treatments included urea application (50 kg N/ha) at sowing with and without nitrification inhibitor (3,4–dimethylpyrazole phosphate) and surface broadcasting of urea with and without urease inhibitor (n-butyl thiophosphoric triamide) at the end of tillering plus an unfertilised control. Daily N₂O emissions were low and responsive to in-season rainfall and fertiliser addition at sowing. Cumulative emissions from sowing until harvest were highest where N was applied at sowing in 2013; 160 g N₂O-N/ha, while the 0 N control emitted 28 g N₂O-N/ha (over 201 days). Emissions during 2014 were 77% lower than 2013 due to dry seasonal conditions; cumulative emissions were 49 g N₂O-N/ha where N was applied at sowing, with background emissions of around 0 g N₂O-N/ha (over 177 days). Inhibitors showed limited scope for reducing N₂O emissions in this environment, however deferring N application until the end of tillering reduced N₂O emissions. Grain yield responses to fertiliser were significant; increasing grain yield by 11–31% and NUE was generally high (recovery efficiency?>?68%). However, deferring N application until the end of tillering in 2014 reduced yield (??19%) and recovery of applied N (??74%).     

Ozone Formation from the Reaction Of O2-Activated N2 Molecules and a New Type of Ozone Generator with Fine Wire Electrode

Experiments using an ozone generator which has a fine steel wire electrode are described. Various conditions of the wire electrode ozone generator such as wire diameter, volume density of wire electrode, applied voltage and the effects of SF₆ addition also are reported. The efficiency of the wire electrode ozone generator in air exceeded that of the usual ozone generator for 0.1 mm wire diameter and 0.156 g cm^?3 volume density of wire over the entire range of applied voltage. This efficiency increases by adding 0.08% SF₆ in air. Increase of ozone and NOX formation in the air ozone generator can be explained by the reactions of O₂ and activated N₂.     

Enhancement of Energy Yield for Ozone Production via Packed-Bed Reactors

The present work aims to enhance the energy yield of ozone production via packed-bed reactors. It has been experimentally demonstrated that ozone concentration and corresponding energy yield achieved by packed-bed reactors are significantly higher than that achieved by DBD only. The so-called packed-bed reactor is constructed by packing granular dielectric pellets within a DBD reactor. Two kinds of dielectric materials including glass beads and Al₂O₃ pellets are tested. Experimental results indicate that an ozone generator packed with Al₂O₃ pellets results in a higher ozone production compared with one packed with glass beads. The maximum ozone production takes place when Al₂O₃ pellets with diameter of 2 mm are packed. The maximum ozone concentration, ozone production rate, and energy yield achieved in this study are 61 gO₃/m³, 3.7 gO₃/hr, and 173 gO₃/kWh, respectively. The highest ozone concentration and energy yield achieved with the packed-bed reactor are about 8 and 12 times high as those with DBD reactor, respectively. Although the packed-bed reactors have a shortcoming of high temperature, it can be solved by adding a cooling system and the ozone generation can be improved thereof. As a result, the packed-bed reactor is a promising and state-of-the-art technology for ozone generation based on this study.     

Energy Conversion and Temperature Dependence in Ozone Generator Using Pulsed Discharge in Oxygen

A detailed reaction kinetic model consisting of 10 species and 63 reactions is developed to investigate the energy conversion and temperature dependence in an ozone generator using oxygen pulsed discharge. The energy conversion ratios of total electric energy converted into reaction heat, heat carried by gas and heat loss to ambient, namely η_reaction, η_gas and η_loss, are obtained for the first time. The ratio of reaction heat η_reaction decreases substantially with increasing specific energy and inlet gas temperature, which represents how much energy is utilized effectively to synthesize ozone. Correspondingly, η_loss and η_gas increase gradually. η_reaction declines from 55.4% to 27.7% at inlet gas temperature of 298 K when specific energy changes from 0.06 J/cm³ to 0.78 J/cm³. The detailed reaction pathway including the degree of transformation among species for ozone formation is also obtained via kinetics simulation. Meanwhile, sensitivity analysis and rate-of-production analysis for the four most important species O₃, O, O(1D) and O₂(b¹∑) obtained from the reaction pathway are executed to understand quantitatively the temperature dependence of sensitivity coefficient and production rate for each individual reaction. The production rate of ozone via the most important ozone generation reaction O+O₂+O₂ = > O₃+O₂ increases linearly with the increase of gas temperature, as well as the destruction rates of ozone via the most important ozone decomposition reactions O₃+O₃ = > O₂+O₂+O₂ and O₃ + O = > O₂(b¹∑)+O₂.     

The Effect of Gaseous Diluents on Ozone Generation from Oxygen

Ozone generation in a negative corona discharge has been experimentally investigated using both a pure oxygen and in binary mixtures of oxygen with several gases. The concentration of ozone (O₃) in such mixtures is found to be dependent both on the input energy density η, dissipated in unit volume of gas mixture and on the type and the concentration of the additives. The experimentally measured dependencies of ozone concentration on the input energy density (O₃) = f(η) have been fitted using the Vasiliev–Kobozev–Eremin formula and the specific rate coefficients for ozone formation K_f and ozone decomposition K_d have been calculated. Using Ar, N₂ or CO₂ as admixtures, an increase in the specific rate coefficient for ozone generation was observed for increasing concentrations of added gaseous impurity into oxygen. In contrast, admixtures with SF₆ or CCl₂F₂ caused a substantial reduction of K_f values. The absolute values of ozone concentration at constant input energy density were observed to decrease with decreasing concentrations of oxygen in all mixtures.     

Nitrous oxide production from soil experiments: denitrification prevails over nitrification

Nitrous oxide is produced in soils and sediments essentially through the processes of nitrification and denitrification, although several rival processes could be competing. This study was undertaken in order to better understand the controlling factors of nitrification, denitrification and associated N₂O production as well as the contribution of these two processes to the average N₂O production by soils and sediments. With this aim, soil and sediment samples were taken in contrasting periods and different land use types, each time at different depths (upper and lower soil horizons). They were incubated in separate batches in specific conditions to promote denitrification and nitrification: (1) a complete anaerobic environment adding KNO₃ for the denitrification assay and (2) an aerobic environment (21 % O₂) with addition of NH₄Cl for the nitrification assay. Potentials of nitrification and denitrification were determined by the rates of nitrate either reduced (for denitrification) or produced (for nitrification). Overall, denitrification potential varied from 70 to 2,540 ng NO ₃ ^— -N g^?1 dry soil h^?1 and nitrification potential from 30 to 1,150 ng NO₃ ^?-N g^?1 dry soil h^?1. Nitrous oxide production by denitrification was significantly (P < 0.05) greater in topsoils (10–30 cm) than in subsoils (90–110 cm), ranging, respectively, from 26 to 250 ng N₂O-N g^?1 dry soil h^?1 versus 1.5 to 31 ng N₂O-N g^?1 dry soil h^?1, i.e., a mean 19.5 versus. 6.0 % of the NO₃ ^? denitrified for the upper and lower horizons, respectively. Considering the N₂O production in relation with the nitrate production (e.g., nitrification), no significant difference (P < 0.05) was found in the soil profile, which ranged from 0.03 to 6 ng N₂O-N g^?1 dry soil h^?1. This production accounts for 0.21 and 0.16 % of the mean of the NO₃ ^? produced for the top and subsoils, respectively. On the basis of the average production by both top- and subsoils, N₂O production by denitrification is clearly greater than by nitrification under the measurement conditions used in this study, from 30- to 100-fold higher. Such a high potential of N₂O emission must be taken into account when reducing nitrate contamination by increasing denitrification is planned as a curative measure, e.g. in rehabilitation/construction of wetlands.     

Characterization of the ozone zero phenomenon by infrared spectroscopy

The presence of a small amount of nitrogen in the feed gas is necessary to generate ozone efficiently out of oxygen. Operating an ozone generator with ultra-pure oxygen for extended periods results in highly deteriorated ozone generation efficiency. In extreme cases, when the nitrogen levels in the feed gas are in the lower ppm range, the efficiency of the ozone generation process even drops to zero. In this article, we present our results concerning the correlation between the N₂O₅ concentration in the off-gas and the ozone generation efficiency. After the ozone generator is run for a well-defined amount of time with an oxygen–nitrogen mixture, the N₂ supply is shut off, and the behavior of the system is monitored by near-infrared spectroscopy. Different surface materials lead to different temporal behavior of both the nitrogen oxide levels and the ozone concentration after shutting down the nitrogen supply. The measurements show a good correlation between the evolution of ozone generation efficiency and the changes of the N₂O₅ concentration in the off-gas.     

Experimental Study of Ozone Generation by Negative Corona Discharge in Mixtures of N2 and O2

Ozone generation by negative DC corona discharge in N₂-O₂ mixtures has been experimentally investigated using a coaxial wire-cylinder corona reactor operating at room temperature and atmospheric pressure. The experiments have been carried out under different gas flows (15 cm³ min^?1 to 200 cm³ min^?1) and gas compositions (5% to 90% of O₂), and the effect of these parameters on the corona current, the ozone density and the efficiency of the ozone generator have been analyzed. The global rate coefficients for ozone formation and destruction have also been evaluated, and their values compared with those reported by other authors. The maximum efficiency for ozone production was found in gas mixtures with oxygen content about 70–80%.     

Season and location–specific nitrous oxide emissions in an almond orchard in California

Almonds are an important commodity in California and account for around 15% of the state’s fertilizer nitrogen (N) consumption. Motivated by strong correlations typically observed between fertilizer N inputs and emissions of the potent greenhouse gas and ozone depleting molecule nitrous oxide (N₂O), this study aimed to characterize spatial and temporal patterns in N₂O emissions in an almond orchard under typical agronomic management. N₂O fluxes were measured for a total of 2.5 years, including 3 growing seasons and 2 dormant seasons. Measurements targeted two functional locations, defined as tree rows and tractor rows. In conjunction with the flux measurements, we determined driving variables including soil ammonium (NH₄ ⁺) and nitrate (NO₃ ^?), dissolved organic carbon (DOC), soil water-filled pore space (WFPS), soil pH, air temperature and precipitation. Cumulative annual N₂O emissions were low (0.65 ± 0.07 and 0.53 ± 0.19 kg N₂O–N ha^?1 year^?1 in year 1 and 2, respectively), likely due to the coarse soil texture and microject sprinkler irrigation and fertigation system. Emission factors (EF), conservatively calculated as the ratio of N₂O emitted to fertilizer N applied, were 0.25 ± 0.03% and 0.19 ± 0.07% for year 1 and 2, respectively, which is below the IPCC EF range of 0.3–3%. Correlation analyses between N₂O and driving variables suggested that overall N₂O production was limited by microbial activity and nitrification was likely the major source process, but specific drivers of N₂O emissions varied between seasons and functional locations.     

Impact of mineral N fertilizer application rates on N2O emissions from arable soils under winter wheat

Nitrogen fertilizers are a major source of nitrous oxide (N₂O) emissions from arable soils. The relationship between nitrogen application rates and N₂O emissions was evaluated during the growth period of winter wheat (~140 days) at six field sites in north-western Germany. Nitrogen was applied as calcium–ammonium–nitrate, with application rates ranging between 0 and 400 kg N ha^?1. One trial was conducted in 2010, three trials in 2011 and two trials in 2012. Additionally, post-harvest N₂O emissions were evaluated at two field sites during autumn and winter (2012–2013). The emission factors (during the growth period) varied between 0.10 and 0.37 %. Annual N₂O emissions ranged between 0.46 and 0.53 % and were consistently lower across all sites and years than to the IPCC Tier 1 default value (1.0 %). Across all sites and years, the relationship between N₂O and N application rate was best described by linear regression even if nitrogen amounts applied were higher than the nitrogen uptake of the crop. Additionally, annual N₂O emissions per unit of harvested wheat grain were calculated for two field sites to assess the environmental impact of wheat grain production. Yield-scaled N₂O emissions followed a hyperbolic function with a minimum of 177 and 191 g N₂O–N t grain yield^?1 at application rates of 127 and 150 kg N ha^?1, followed by an increase at higher N application rates. This relationship indicates that wheat crop fertilization does not necessarily harm the environment through N₂O emissions compared to zero fertilization. Thus, improving nitrogen use efficiency may be the best management practice for mitigating yield-scaled N₂O emissions.     

The combination of photocatalysis process (UV/TiO2(P25) and UV/ZnO) with activated sludge culture for the degradation of sulfamethazine

The major factors affecting the removal efficiency of sulfamethazine (SMT) by photocatalysis process in the presence of TiO₂ P25 or ZnO, namely the pH, the amount of catalyst and the initial SMT concentration were examined. The obtained results showed the absence of adsorption of SMT on the catalysts and the absence of degradation of SMT by direct photolysis under UV light in the absence of catalyst. The variation of the pH solution in the range 4–9 did not cause any significant degradation of SMT. The optimal amounts of each catalyst were, respectively, 0.5 and 0.25 g/L for TiO₂ P25 and ZnO. Increasing the initial SMT concentration impacted negatively the removal efficiency, which decreased from 31% to 13% and from 100% to 27% in the presence of TiO₂ P25 and ZnO in the presence of 10 mg/L and 50 of SMT after 30-min reaction time, respectively. The obtained results showed better efficiency of ZnO than TiO₂ P25 regarding both removal efficiency and chemical oxygen demand (COD) abatement. However, removal efficiency and COD abatement were not complete, even after 7 h of photocatalysis, about 92% and 41%, respectively. The biodegradability was examined after photocatalysis performed in the following conditions: [SMT]₀ = 50 mg/L, pH = 6, T = 25°C, ω = 360 rpm and 0.5 g/L of TiO₂ P25 or 0.25 g/L of ZnO. In these conditions, the removal efficiencies were, respectively, 26% and 41% in the presence of TiO₂ P25 and 55 and 92% in the presence of ZnO after 4 and 7 h of pretreatment times, respectively. The BOD₅/COD ratio increased substantially and, respectively, from 0 to 0.25 and from 0 to 0.16 in the presence of TiO₂ P25 and ZnO after 7 h of irradiation. Even if the limit of biodegradability (0.4) was not achieved, a subsequent biological treatment was considered in the presence of TiO₂ P25, leading to 58% COD abatement after a 28-day culture.     

Ozone Production Influenced by Increasing Gas Pressure in Multichannel Dielectric Barrier Discharge for Positive and Negative Pulse Modes

This paper describes the influence of gas pressure on the conversion of O₂ to O₃ and the ozone production efficiency in a multichannel dielectric barrier discharge (DBD) reactor utilizing positive and negative pulses. Results show that conversion of O₂ to O₃ is continuously enhanced by the increase of gas pressure (0.1–0.24 MPa) while the rising speed of oxygen conversion with the increasing gas pressure at fixed specific input energy is reduced above 0.15 MPa. The maximum ozone generation efficiency is increased with increasing gas pressure (0–0.2 MPa) while positive pulse exhibits higher energy efficiency. The maximum ozone generation efficiency is suppressed with further increase of gas pressure (0.2–0.24 MPa) while no significant difference in ozone generation efficiency is observed for two unipolar pulse modes. Results also show that 0.2 MPa is the optimal working gas pressure to obtain the maximum ozone generation efficiency and increasing gas pressure would lead to remarkable increase of ozone generation efficiency for ozone production at high energy densities in multichannel DBD.     

EFFECTS OF pH,INITIATOR, SCAVENGER,AND SURFACTANT ON THE OZONATION MECHANISM OF AN AZO DYE (ACID RED-151) IN A BATCH REACTOR

In this study, an initiator (Fe²⁺) and a scavenger (CO₃ ^2?) were used at different concentrations in a batch reactor to investigate the reaction mechanism of ozonation of a model azo dye, namely Acid Red-151 (AR-151). Also, the effect of a nonionic surfactant known as a major pollutant in many industrial wastewaters, namely polyethylene glycol (PEG), was observed on the degradation rate of AR-151. The experimental parameters and their ranges were: pH (2.5–10), initiator (0.8–50 mg/L of Fe²⁺), surfactant (10–200 mg/L of PEG), and scavenger (10–500 mg/L of CO₃ ^2?); the initial concentration of the azo dye was kept constant at 20 mg/L in all the experiments. Results showed that decomposition of ozone was enhanced with increasing pH and increasing initiator (Fe²⁺) concentration at a scavenger concentration of 100 mg/L, when there is no dye in the medium. A scavenger concentration of 100 mg/L CO₃ ^2? was not sufficient to terminate the chain reactions of ozone decomposition. It was concluded that the dominant mechanism in the degradation of AR-151 was its direct oxidation with ozone molecules in water. The data obtained for the dye and chemical oxygen demand (COD) removals and total oxidation rate constants at different operating conditions were assessed in order to estimate the possible contribution of dye-oxidation by free radicals.     

Enhancement of Ozone Mass Transfer by Stainless Steel Wire Mesh and Its Effect on Hydroxyl Radical Generation

ABSTRACT

In order to improve the mass transfer efficiency of ozone in water, stainless steel wire mesh (SSWM) corrugated structure was packed into a microbubble ozone reactor to enhance the mass transfer efficiency. The results showed that the SSWM/O₃ system could effectively improve the mass transfer efficiency. When the concentration of ozone in the liquid phase reached a stable state, it was about 21 mg/L, which was about 14% higher than that of ozone alone; the apparent mass transfer coefficient (K_La) was 0.7255 min^?1, which was about 51% higher than that by ozone alone systems. The hydroxyl radicals in the SSWM/O₃ system were more generated than that of ozone alone. After 6 min of operation, the concentration of hydroxyl radicals increased by 60 µmol/L compared with that in ozone alone system. The Chemical Oxygen Demand (COD) removal efficiency of biologically treated leachate by SSWM/O₃ system was about 10% higher than that of ozone alone system after 120 min of reaction. The effects of pressure, temperature, ozone inlet concentration, and flow rates on the ozone concentration in the liquid phase and the generation of hydroxyl radicals were also investigated. The results indicated that reactor pressure has little effect on ozone concentration in liquid phase, but increasing pressure helps to generate ·OH; ozone concentration and ·OH generation in liquid phase increase with the increase of inlet ozone concentration and flow rate; ozone concentration in the liquid phase decreases with the increase of temperature, but ·OH generation increases with the increase of temperature. Our results indicate that the system consisting of SSWM and microbubble column reactor is an efficient process for the intensification of ozone-based advanced oxidation processes.     

Ozonation of Phenol-Containing Wastewater Using O3/Ca(OH)2 System in a Micro Bubble Gas-Liquid Reactor

The degradation of phenol in aqueous solution was investigated in an integrated process consisting of O₃/Ca(OH)₂ system and a newly developed micro bubble gas-liquid reactor. The effects of operating parameters such as Ca(OH)₂ dosage, reactor pressure, liquid phase temperature, initial phenol concentration and inlet ozone concentration on degradation and mineralization (TOC removal) were studied in order to know the ozonation performance of this new integrated process. It is demonstrated that the degradation and TOC removal efficiency increased with increasing inlet ozone concentration and increasing Ca(OH)₂ dosage before 2 g/L, as well as decreasing initial phenol concentration. The optimum Ca(OH)₂ dosage should exceed Ca(OH)₂ solubility in liquid phase. The reactor pressure and liquid phase temperature have little effects on the removal and TOC removal efficiency. When Ca(OH)₂ dosage exceeded 3 g/L, the degradation and TOC removal of phenol almost reached 100% at 30 and 55 min, respectively. The intensification mechanism of Ca(OH)₂ assisted ozonation was explored through analysis of the precipitated substances. The mechanism for Ca(OH)₂ intensified mineralization of phenol solution is the simultaneous removal of CO₃^2- ions, as hydroxyl radical scavengers, due to the presence of Ca²⁺ ions. Results indicated that the proposed new integrated process is a highly efficient ozonation process for persistent organic wastewater treatment.     

Energy conversion and temperature dependence in ozone generator fed by synthetic air

A homogenous chemical kinetic model consisting of 21 species and 118 reactions is applied to investigate energy conversion and its temperature dependence in ozone generator fed by synthetic air. The portion of electric energy converted into reaction heat, gas heating and heat loss to surroundings (by convection) in terms of the total electric energy input, the conversion ratios η_reaction, η_gas, and η_loss, are obtained. The detailed reaction pathway including the degree of transformation among species for ozone production is also obtained via simulation of the reaction kinetics. In addition, sensitivity analysis and rate-of-production analysis for the three foremost species O₃, O, and N₂(A) are performed to understand quantitatively the temperature dependence of sensitivity coefficient and production rate for each individual reaction. η_reaction shows a steep rise at low specific energy, but then suffers a gradual decrease at high specific energy. η_loss has a contrary behavior. And η_gas increases steadily with the increase of specific energy. The η_reaction peak of 35.1% is achieved at specific energy of 0.17 J/cm³ at the conditions under investigation. Additionally, inlet gas temperature only has a small effect on energy conversion. Moreover, high gas temperature in discharge gap is confirmed to be not favorable for ozone formation from the view of reaction heat. The sensitivity coefficients of reactions with electron participation are sensitive to gas temperature. O+O₂+O₂→O₂+O₃ and O+O₂+N₂→N₂+O₃ account for about 70% and 30% of generated ozone respectively at the given conditions. And e+O₂→e+O+O, N₂(A)+O₂→N₂O+O, and N₂(A)+O₂→O+O+N₂ are responsible for about 51.3%, 14.7%, and 32.0% of oxygen atom, respectively.