Showing papers in "Ozone-science & Engineering in 2013"
TL;DR: In this article, the authors present a review of the electrochemical generation of ozone from the original studies by Schonbein in the early 1800s to the present day, and are intended for specialists and nonspecialists in the field of electrochemistry.
Abstract: This article reviews work on the electrochemical generation of ozone from the original studies by Schonbein in the early 1800s to the present day, and is intended for specialists and nonspecialists in the field of electrochemistry. The experimental techniques employed to study the mechanism of electrochemical ozone generation are described, as is the most commonly quoted mechanism and the experimental evidence for the mechanism is summarized and discussed. The types of electrochemical cells employed are described, and the effects of temperature, anode type and composition, current density and electrolyte composition and pH are discussed.
82 citations
TL;DR: In this paper, a sequencing batch reactor was constructed to measure the ozone decay rate constant (kO3) in short time intervals of about 15 min. The batch reactor is filled during the production process, immediately after dissolving ozone in water by a static mixer.
Abstract: For real-time control of ozonation processes in water works, a sequencing batch reactor was constructed to measure the ozone decay rate constant (kO3) in short time intervals of about 15 min. The batch reactor is filled during the production process, immediately after dissolving ozone in water by a static mixer. On the basis of kO3 and the initial ozone concentration ([O3]0), and the experimentally determined ratio of the concentrations of •OH radicals to ozone (Rct), the degradation of micropollutants in ozone reactors (modeled as Continuously Stirred Tank Reactors - CSTRs) were calculated for compounds with known reaction rate constants with ozone and •OH radicals. Calculated degradation of atrazine, iopromide, benzotriazole and acesulfame are in good agreement with measured data. For acesulfame the following rate constants were determined in this study at 20 oC: reaction rate constant with ozone = 88 M−1s−1, reaction rate constant with •OH radical = 4.55 × 109 M−1s−1. For the ozone reaction an activati...
39 citations
TL;DR: In this paper, an overview of the literature on the occurrence and potential risks of pharmaceutical substances in the wastewater treatment plants (WWTP), natural waters and drinking water treatment plants served by the Great Lakes Basin (Canada and USA) between the years of 2007-2012.
Abstract: The present study is an overview of the literature on the occurrence and potential risks of pharmaceutical substances in the wastewater treatment plants (WWTP), natural waters and drinking water treatment plants served by the Great Lakes Basin (Canada and the USA) between the years of 2007–2012. Large number of pharmaceutical substances, including anti-inflammatories, lipid regulators, antidepressants, antibiotics, beta blockers, anti-epileptics, anti-hypertensions and stimulants, in high ng/L concentrations, has been reported in the WWTP influents. Most of these compounds have also been detected in the WWTP effluents at comparable concentrations with the exception of caffeine, cotinine and salicylic acid suggesting the inefficiency of conventional treatment processes in the degradation of pharmaceutical compounds. Decreasing surface water concentrations have been observed with the distance downstream of the discharge point due to the dilution effect. Surface waters located around septic systems and agric...
38 citations
TL;DR: Alternative process control parameters, specifically ozone to total organic carbon (O3:TOC) ratio, differential UV254 absorbance (ΔUV254), and differential total fluorescence ( ΔTF), were correlated with the inactivation of Escherichia coli, the bacteriophage MS2, and Bacillus subtilis spores in five secondary wastewater effluents.
Abstract: Dissolved ozone concentration integrated over time (CT) is a reliable indicator of disinfection efficacy in drinking water treatment. However, ozone CT may not be measurable in some wastewater ozone applications. In this study, alternative process control parameters, specifically ozone to total organic carbon (O3:TOC) ratio, differential UV254 absorbance (ΔUV254), and differential total fluorescence (ΔTF), were correlated with the inactivation of Escherichia coli, the bacteriophage MS2, and Bacillus subtilis spores in five secondary wastewater effluents. CT values greater than 9 mg-min/L were generally required for measurable inactivation of B. subtilis spores, and CT values of 1 and 2 mg-min/L consistently achieved greater than 6- and 5-log inactivation of MS2 and E. coli, respectively. The O3:TOC, ΔUV254, and ΔTF correlations for MS2 and B. subtilis were useful for predicting inactivation, while those of E. coli were characterized by greater variability. [Supplementary materials are available for this a...
35 citations
TL;DR: In this article, a comparison of surface Ti6Al4V titanium and EN-AW-2017A(PA6) aluminum alloys is presented, and the influence of ozone concentration on surface layer energetic activation is analyzed.
Abstract: The purpose of this article is to present energetic properties of surface Ti6Al4V titanium as well as surface EN-AW-2017A(PA6) aluminum alloy layers. Values of surface free energy after selected mechanical operations and ozonation were compared. In addition, the influence of different values of ozone concentration on surface layer energetic activation was analyzed. Dispersive and polar components of surface free energy were of particular concern. Comparative evaluation of shearing strength of Ti6Al4V titanium and EN-AW-2017A(PA6) aluminum alloy single-lap adhesive bonded joints were presented. Results can be used as pro-ecological methods of titanium and aluminum alloys preparing for applications where adhesive phenomenon is important.
34 citations
TL;DR: In this article, the authors used a birnessite-like porous manganese oxides (MnOx) with curling nanosheets (nodes less than 10 nm in thickness) for ozone decomposition at room temperature and high relative humidity.
Abstract: Lichen-like porous manganese oxides (MnOx) with birnessite-type structure, which were assembled with curled nanosheets (less than 10 nm in thickness), were deposited in situ on the surface of activated carbon (AC) via facile reduction of permanganate by AC, and were tested for the decomposition of ozone, a common air pollutant. Despite the low Mn loading (typically 0.04%–0.14%), the as-synthesized MnOx/AC catalysts exhibited high catalytic activity and stability for ozone decomposition at room temperature and high relative humidity, which can be attributed to the enrichment of the Mn element on the catalyst surface and a well-organized porous surface morphology of MnOx.
34 citations
TL;DR: In this paper, the accumulation of nitrogen-containing ions formed in aqueous solutions dispersed in air and treated with pulsed corona, dielectric barrier and spark electric discharges, was studied dependent on electric conductivity and pH of treated solutions.
Abstract: The accumulation of nitrogen-containing ions formed in aqueous solutions dispersed in air and treated with pulsed corona, dielectric barrier and spark electric discharges, was studied dependent on electric conductivity and pH of treated solutions. The impact of conductivity to the spark and corona discharge is determined by the increased ohmic losses in the reactor. In contrast, the character of dielectric barrier discharge is significantly changed with growing conductivity resulted in increased nitrite-to-nitrate ratio. In alkaline solutions the production of nitrites is increased for the spark and the barrier discharge; the corona discharge produce only nitrates. The amount of nitrates produced in pulsed corona discharge at energy doses characteristic for potable water treatment is about 100 times lower than their maximum permissible concentration.
32 citations
TL;DR: In this article, the authors used pulsed corona discharge as a means for advanced oxidation of paracetamol in aqueous solution and found that it appeared to be effective in the case of low-molecular carboxylic acids.
Abstract: Oxidation of paracetamol in aqueous solution was studied by using pulsed corona discharge as a means for advanced oxidation. Pulse repetition frequency, the delivered energy dose, and oxidation media were the main parameters evaluated. The pulsed corona discharge treatment appeared to be effective in oxidation of paracetamol: complete degradation of target pollutant together with partial mineralization was achieved at moderate energy consumption; oxidation proceeds faster in alkaline media, the fastest oxidation rate was observed in oxygen-enriched air. Low-molecular carboxylic acids were identified as the products formed in the reaction.
32 citations
TL;DR: In this paper, three different types of ultraviolet lamps were tested for the advanced oxidation process application on pre-treated surface water in a pilot plant, and the pilot setup consisted of three parallel reactors with either medium pressure, low pressure or dielectric barrier discharge UV lamps.
Abstract: Three different types of ultraviolet lamps were tested for the advanced oxidation process application on pre-treated surface water in a pilot plant. The pilot setup consisted of three parallel reactors with either medium pressure, low pressure or dielectric barrier discharge UV lamps. Four model compounds (atrazine, bromacil, ibuprofen and N-nitroso-dimethylamine (NDMA)) and 0, 5 or 10 ppm hydrogen peroxide were dosed. Low pressure lamps were shown to have the lowest energy demand, calculated as electrical energy per order, followed by dielectric barrier discharge lamps and then medium pressure lamps. Medium pressure lamps gave the highest formation of genotoxic activity and nitrite formation, whereas no formation of genotoxic activity was observed for either of the other lamp types.
30 citations
TL;DR: In this paper, experiments for degradation of the extensively marketed Ponceau 4R dye in aqueous solution and for oxidation of raw wastewater from a confectionary industry have been carried out by using ozone.
Abstract: Experiments for degradation of the extensively marketed Ponceau 4R dye in aqueous solution and for oxidation of raw wastewater from a confectionary industry have been carried out by using ozone. All the experiments were performed in a cylindrical semi-batch reactor at approximately 20 oC for 7200 s. A mass flow rate of 1.158 × 10−6 kg s−1 of ozone was continuously fed in the reactor. The pH of the azo dye aqueous solution (distilled water + Ponceau 4R) was always kept at approximately 5.8, while in the case of the raw wastewater the same factor was changed from 4.7 to 9.4 in two different experimental runs. Absorbance measurements at 508 nm show that the investigated azo dye found in the azo dye aqueous solution was completely degraded after only 600 s. At this initial period a substantial fall of TOC (Total Organic Carbon) (up to 45%) was noticed, but the rate was exponentially decreased at longer reaction times up to a TOC removal no higher than 60%. The ozonation was also responsible for reducing the a...
26 citations
TL;DR: The degradation ratio of phenol reached 100% at an initial phenol concentration of 40 mg/L in the O3/H2O2 process as discussed by the authors, and the optimum operating conditions in this study were determined as an H 2O2 concentration of 6.5 mM and a rotation speed of 1200 rpm.
Abstract: This article presents experimental investigation on the oxidative treatment of phenol in water by O3/H2O2 in a rotating packed bed (RPB). It was found that the phenol degradation ratio increased with increasing rotation speed, initial pH value of phenol solution, and temperature. The degradation ratio of phenol had a peak value with increasing H2O2 concentration. The optimum operating conditions in this study were determined as an H2O2 concentration of 6.5 mM and a rotation speed of 1200 rpm. Phenol degradation ratio reached 100% at an initial phenol concentration of 40 mg/L in the O3/H2O2 process.
TL;DR: Ozone and ultraviolet technologies are proposed as potential disinfecting agents for seawater as mentioned in this paper, and ozone is applied in the range 0.38 to 4.89 mg O3 L−1.
Abstract: Ozone and ultraviolet technologies are proposed as potential disinfecting agents for seawater. Ozone doses were applied in the range 0.38 to 4.89 mg O3 L−1. They permit to observe a complete disinfection as well as UV doses superior to 320 J L−1. Impacts of both processes on organic matter were also studied. UV absorbances were reduced in both cases but in higher proportion using ozone (up to 50% removal). Total organic carbon was slightly reduced by UV radiation, and ozonation achieves up to 10% mineralization. Ozone reaction proceeds with biochemical oxygen demand increase. Seawater ozonation, in addition, leads to the formation of residual oxidants that show an inhibitory effect on autochthonous microorganisms.
TL;DR: The attack of ozone to ofloxacin mainly takes place at the tertiary amine group of the piperazine ring, though some reactivity is also due to the quinolone structure and oxazine substituent.
Abstract: The ozonation of the quinolone antibiotic ofloxacin in water has been investigated with focus on kinetic parameters determination. The apparent stoichiometric factor and the second-order rate constants of the reactions of ozone and hydroxyl radical with ofloxacin were determined at 20 °C in the pH range of 4–9. The apparent stoichiometric factor was found to be about 2.5 mol O3/mol ofloxacin regardless of the pH. The rate constant of the reaction between ozone and ofloxacin was determined by a competitive method (pH = 6–9) and a direct ozonation method (pH = 4). It was found that this rate constant increases with pH due to the dissociation of ofloxacin in water. The direct rate constants of ofloxacin species were determined to be 1.0 × 102, 4.3 × 104 and 3.7 × 107 for cationic, neutral-zwitterion and anionic species, respectively. Accordingly, the attack of ozone to ofloxacin mainly takes place at the tertiary amine group of the piperazine ring, though some reactivity is also due to the quinolone structur...
TL;DR: In this paper, the rate constants of three NOM isolates were determined using the developed method, and the influences of NOM on the degradation of ibuprofen, an •OH-reactive pharmaceutical compound, can be quantitatively described.
Abstract: Natural organic matter (NOM) can simultaneously act as the initiator, promoter and inhibitor in water ozonation. This study presents an explicit method that can be used to determine these rate constants via the integration of the transient steady-state hydroxyl radical (•OH) model, the Rct concept and the pseudo first-order ozone decomposition model. The theoretical background of this method was provided, and the method was validated with model compounds. The rate constants of three NOM isolates were determined using the developed method. With these rate constants, the influences of NOM on the degradation of ibuprofen, an •OH-reactive pharmaceutical compound, can be quantitatively described. [Supplementary materials are available for this article. Go to the publisher's online edition of Ozone Science & Engineering for the following free supplemental resources: tables, figures, and equations.]
TL;DR: In this paper, the effect of ozone on the removal of dissolved organic matter (DOM) from a secondary effluent and its relation with the permeated flux behavior in an ultrafiltration membrane was determined.
Abstract: The focus of this work was to determine the effect of ozone on the removal of dissolved organic matter (DOM) from a secondary effluent and its relation with the permeated flux behavior in an ultrafiltration membrane. To assess the ozone action, the DOM of the secondary effluent was fractionated into its hydrophobic, transphilic and hydrophilic fractions, using XAD-8 and XAD-4 resins. Ozone increased the hydrophilic fraction from 32% to 42%, and this percentage remained unchanged after ultrafiltration of the secondary effluent. Permeate flux dropped to 52% in the first hour of membrane operation, but when ozone was applied as a pretreatment, it could be maintained at 84% within the first hour.
TL;DR: In this paper, an LED having an emission peak at 609 nm and a photo diode sensitive at visible light frequencies are used as the light source and the photo detector, respectively.
Abstract: The measurement of ozone concentration based on the visible photo absorption method is investigated. An LED having an emission peak at 609 nm and a photo diode sensitive at visible light frequencies are used as the light source and the photo detector, respectively. The transmittance is measured as a function of ozone concentration, which is in reasonable agreement with the Beer–Lambert relationship. The effective absorption cross-section can therefore be estimated from the fitting procedure. The concentrations determined by both the UV and visible photo absorptions agree well with each other in the range from 7.1 to 68.4 g/m3(N). The relative error in these concentrations is discussed on the basis of the Twyman–Lothian curve. The ozone measurement for the air-fed ozone generation is also investigated. The effect of photo absorption due to NOx species is unavoidable. The present results provide useful data if the ozone measurement based on the visible photo absorption method is applied to ozone monitoring ...
TL;DR: In this paper, a bioremediated soil containing residual oil was ozonated for up to 15 hours and a total of 102 compounds in the residual oil were analyzed by GC/MS and 36 diagnostic ratios were calculated based on quantitative or semi-quantitative results.
Abstract: Ozonation is an effective method to remove recalcitrant weathered oil in contaminated soil. The purpose of this study was to characterize the compositional changes of hydrocarbons in residual oil during ozonation. A bioremediated soil containing residual oil was ozonated for up to 15 h. A total of 102 compounds in the residual oil were analyzed by GC/MS and 36 diagnostic ratios (DRs) were calculated based on quantitative or semi-quantitative results in order to evaluate the susceptibility of the residual oil compositions to ozonation and the effects of ozonation on the fingerprint profile of the residual oil. The total ozonation removal rates were in the following order: triaromatic steranes (TAS) > steranes, polycyclic aromatic hydrocarbons, terpanes > alkanes. Ozone kept the fingerprints of n-alkanes, C27- to C34-terpanes, steranes and TAS, separately. Branched alkanes (i.e., pristane and phytane) showed a higher removal rate than n-alkanes. Ozone reactivity of PAHs depended on the number of rings, pres...
TL;DR: In this paper, the ozone yield and concentration in Dielectric Barrier Discharge of argon-oxygen mixtures in presence of various packing materials are discussed, such as zeolite molecular sieve 13X pellets, Pyrex beads, pyrex wool, and porous TiO2-beads.
Abstract: Assessments of ozone yield and concentration in Dielectric Barrier Discharge of argon-oxygen mixtures in presence of various packing materials are discussed. These include zeolite molecular sieve 13X pellets, Pyrex beads, Pyrex wool, and porous TiO2-beads, which presented differential reactive surfaces, nano cavities, photo-catalysis, and dissimilar ionic environments. Their utility was evaluated in conjunction with varied gas composition, flow rate, and electrical inputs. In a mixture of 3–21% O2 in argon, the ozone concentration ranged between 16–980 ppm, simultaneous measurements of in situ energy dissipation revealed its yield, G(O3) to change independently from 0.002 to 2.020 μmol J−1. TiO2 packing emerged as the most versatile material to produce O3 in high concentration and yield.
TL;DR: In this paper, the effectiveness of single oxidants and several AOPs was studied for the degradation of five selected emerging contaminants: Benzotriazole, N,N-diethyl-m-toluamide or DEET, Chlorophene, 3-Methylindole and Nortriptyline HCl.
Abstract: The effectiveness of single oxidants and several AOPs was studied for the degradation of five selected emerging contaminants: Benzotriazole, N,N-diethyl-m-toluamide or DEET, Chlorophene, 3-Methylindole and Nortriptyline HCl. First-order rate constants and half-life times for the degradation of each compound in ultra-pure water were deduced and compared. The AOPs were later applied to the degradation of these ECs present in three real waters: public reservoir water, and two secondary effluents from municipal wastewater plants. The effect of the variables on the ECs elimination was established. Finally, a cost estimation based on the operating costs was established for the degradation of 3-Methylindole by the single oxidants and AOPs tested.
TL;DR: In this article, the effectiveness of ozone treatment for the afterclearing of polyethylene terephthalate (PET) fibers has been examined, and the results indicated acceptable color and wash-fastness results comparable to those of reduction cleared samples for ozone treated samples.
Abstract: The effectiveness of ozone treatment for the afterclearing of disperse dyed poly (ethylene terephthalate) (PET) fibers has been examined. Two types of disperse dyed PET samples were selected among commercial mass production range of Akbaslar textile mill. The reduction clearing procedure applied during mass production was taken as the reference reduction clearing treatment; these reference samples were taken after dyeing and reduction clearing processes at the mill. Samples of disperse dyed PET were also taken before reduction clearing in order apply ozone treatment in the laboratory as the tested afterclearing method. Color and wash-fastness properties of the reduction cleared and ozone treated fabric samples were compared and reported. Results indicated acceptable color and wash-fastness results comparable to those of reduction cleared samples for ozone treated samples. The success of ozone treatment for the black dyed PET sample at 7.0% depth of shade was especially outstanding. Ozone treatment was app...
TL;DR: In this paper, reverse osmosis concentrate was treated by Fenton and O3/UV oxidation processes and the removal of halogenated compounds and the enhancement of biodegradability were examined.
Abstract: Due to process stability and excellent effluent quality, the use of membrane processes is rapidly expanding. However, a drawback is the production of concentrates and their proper disposal. In this study, reverse osmosis concentrate was treated by Fenton and O3/UV oxidation processes. The concentrate contains halogenated compounds, recalcitrant COD and low biodegradability. The removal of halogenated compounds and the enhancement of biodegradability were examined. Comparing the investigated processes, Fenton oxidation resulted in a better mineralization of organic matter; however, O3/UV oxidation achieved a better enhancement of the biodegradability. Furthermore, similar degradation of halogenated compounds were observed for both oxidation processes.
TL;DR: In this paper, the authors present a review of the occurrence data for a number of antibiotics and antibiotic resistance carriers along with the effectiveness of conventional and advanced technologies in the removal of antimicrobial contamination from various matrices.
Abstract: The effectiveness of conventional water treatment technology in preventing the dissemination of antimicrobial contamination has been questioned due to significant rates of antibiotic resistance elements found both in solid wastes and in effluents. This implies that preventive efforts must cover both solid waste quality and effluent quality monitoring. This article presents a review of the occurrence data for a number of antibiotics and antibiotic resistance carriers along with the effectiveness of conventional and advanced technologies in the removal of antimicrobial contamination from various matrices. Although the current literature suggests that the advanced oxidation processes are more promising, cost viable oxidant doses may not be sufficient to reach targeted removal efficiencies especially in biosolids and manure. As a result, antimicrobial contamination can inevitably reach natural waters and contaminate drinking water sources. In this context, a comparison of the effectiveness of three oxidation ...
TL;DR: In this paper, an assessment of both acoustic and hydrodynamic cavitations for intensifying ozone mass transfer was conducted simultaneously, and four process schemes were arranged to evaluate the effect of application of each kind of cavitation as well as both of them, on the ozonemass transfer process.
Abstract: Assessment of both acoustic and hydrodynamic cavitations for intensifying ozone mass transfer was conducted simultaneously. Four process schemes were arranged to evaluate the effect of application of each kind of cavitation as well as both of them, on the ozone mass transfer process. All processes were conducted at pH of 3 to avoid ozone natural self-decomposition initiated by hydroxide ions (OH−). The chemical and mechanical effects of cavitation were distinguished by using radical scavengers to suppress radical formation. The result showed that hydrodynamic and acoustic cavitations enhanced ozone mass transfer synergistically. The enhancement obtained from the acoustic cavitation was higher than that obtained from the hydrodynamic cavitation, and the chemical effects of cavitation were much significant than that of mechanical effects. The enhancement obtained due to chemical effects of cavitation was about twice the enhancement obtained due to mechanical effects when only one type of cavitation was comb...
TL;DR: In this paper, three optimum recipes were achieved and ozone was pretreated with ozone for 15 min before peroxide bleaching to save time and chemical savings in the bleaching process.
Abstract: It is well known that ozone can be used as a bleaching agent for cellulosic textile materials. In the context of this study, investigations were undertaken to optimize bleaching of linen fabrics using Box-Behnken Experimental Design. The bleaching process involved two distinct steps where linen fabrics were ozonated under different treatment times then the latter in a subsequent step were subjected to hydrogen peroxide bleaching under a variety of conditions. As a result of study, three optimum recipes were achieved and pretreatment with ozone for 15 min before peroxide bleaching supplies time and chemical savings.
TL;DR: In this article, a study was conducted on the efficacy of ozonation in removing dissolved organic matter (DOM) in biotreated textile effluents and effects on its biodegradability and adsorbability.
Abstract: A study was conducted on the efficacy of ozonation in removing dissolved organic matter (DOM) in biotreated textile effluents and effects on its biodegradability and adsorbability Results showed the efficient removal of color and fluorescence compounds were achieved through ozonation, due to increasing hydrophilicity and lowering molecular weight of DOM A significant biodegradability improvement was also observed, and DOM adsorbability on activated carbon was highly dependent on ozone dosage As the key parameter, consumed 38 g O3/ g TOC0 was the optimal dosage in the hybrid process combining ozonation with biological activated carbon (BAC) for wastewater reclamation
TL;DR: Ozone coupled with pre-chloramination was evaluated as an effective color removal and bromate control method for groundwater at Mesa Water's Well #8 as discussed by the authors, where ozone test procedure was employed to simulate the sidestream ozone injection.
Abstract: Ozone coupled with pre-chloramination was evaluated as an effective color removal and bromate control method for groundwater at Mesa Water's Well #8. A modified solution ozone test procedure was employed to simulate the sidestream ozone injection. Satisfactory color removal (<10 PtCo CU) was achieved with 2 mg/L of ozone in the presence or absence of preformed monochloramine or ammonia. While bromate formation was reduced by 67% and 83% with 0.3 and 0.6 mg/L of ammonia-N alone, respectively, 68% and 92% of bromate formation was suppressed with 1.0 and 2.0 mg/L of monochloramine as Cl2, respectively. Only the pre-treatment with 2.0 mg/L of monochloramine provided sufficient bromate control to meet its maximum contaminant level of 10 μg/L. UV and fluorescence analyses showed effective destruction of color-causing organics by ozone in the presence of preformed monochloramine.
TL;DR: In this paper, a gas-phase O3 oxidation was used to treat H2S emitted from wastewater treatment processes, and the reaction stoichiometry ratio ranged from 2.0 to 3.7, depending on the initial [O3]/[H2S] ratio.
Abstract: Gas-phase O3 oxidation is effective to treat H2S emitted from wastewater treatment processes. The reaction is fast for full-scale applications. In most cases, 67–96% of total H2S removed in 40-s reaction time was achieved within the first 8 s of reaction time. The initial [O3]/[H2S] ratio of 8 was sufficient to reduce H2S from up to 8 ppmv to less than 0.5 ppmv in 40-s reaction time. The reaction stoichiometry ratio of [O3]/[H2S] ranged from 2.0 to 3.7, depending on the initial [O3]/[H2S] ratio. The moisture content, dimethyl sulfide, and dimethyl disulfide in the odorous air influence H2S removal.
TL;DR: In this article, a semi-empirical equation is derived to provide a correlation between the ozone generation rate of a negative wire-to-plate corona discharge in both dry and humid air and a series of design/operating parameters.
Abstract: A semi-empirical equation is derived to provide a correlation between the ozone generation rate of a negative wire-to-plate corona discharge in both dry and humid air and a series of design/operating parameters. A basic correlation is first derived by applying dimensional analysis on negative wire-to-plate corona discharge in dry air. Further development on the basic correlation is carried out by integrating the influence of humidity. The derived equation is validated by previously reported experimental data and numerical model. The new semi-empirical equation is comprehensive and useful in guiding the design/operation of indoor corona devices under actual ambient operating conditions.
TL;DR: In this article, various analyses were performed to evaluate the ozone removal characteristics using natural manganese ore (NMO) at room temperature, and the results showed that NMO showed an excellent conversion rate (over 80%) even at space velocity 30,000 h−1.
Abstract: In this study, various analyses were performed to evaluate the ozone removal characteristics using natural manganese ore (NMO) at room temperature. NMO exists primarily in the form of MnO2, and the specific forms of manganese oxide are formed as the calcination temperature increases. The activity tests, XRD, BET, and XPS analyses confirmed that the dispersion of manganese site exposed to the surface was a critical factor for ozone removal using NMO. To evaluate the actual application of NMO as a catalyst for ozone decomposition, NMO was also made as a form of monolith; as a result, the catalyst showed an excellent conversion rate (over 80%) even at space velocity 30,000 h−1.
TL;DR: In this article, the effects of ozone and electron beam radiation on color removal of dyes mixture were studied and it was shown that a first-irradiation process is a better one and the absorbency data denote that ozonation after irradiation will result in higher values of decolorization.
Abstract: In this study, the effects of ozone and electron beam radiation on color removal of dyes mixture were studied. According to the obtained results, the COD data denote that a first-irradiation process is a better one and the absorbency data denote that ozonation after irradiation will result in higher values of decolorization. Therefore, it can be said that a process that first applies an electron beam and then uses ozonation is better than the reverse process. Using a new approach for interpretation of the experimental decolorization results, it has been shown that the calculated dye removal percentages based on ozone consumption are near to experimental decolorization results.