Ozone Oxidation Process Research Articles

Degradation of 2-MIB in aqueous solution by ZnOOH catalyzed ozonation

In this study, ZnOOH was used as a catalyst and its efficiency in removing trace organic matter, 2-methylisoborneol (2-MIB), in conjunction with ozone was investigated. The catalyst was characterized by X-ray diffraction (XRD), the Brunauer-Emmet-Teller (BET) method and Fourier transform infrared spectrometry (FT-IR). The performance of the ozone oxidation process alone and the O3/ZnOOH system were both studied. Factors such as ozone dose, catalyst dosage, radical inhibitor and water qualities were analyzed to investigate their effects on catalysis activity and 2-MIB removal efficiency. Results showed that the removal of 2-MIB was better in O3/ZnOOH system. The removal efficiency increased with the increase of catalyst dosage. However, the increase became inconspicuous when the dose was higher than 400 mg. Tert-butanol inhibits the removal of 2-MIB, and this effect was even more obvious in O3/ZnOOH system. This indicates that O3/ZnOOH system promotes the hydroxyl radical production, and removal reaction process in this system follows the mechanism of hydroxyl radical reaction. The water qualities also affected the removal of 2-MIB. Tap water was better than distilled water in the degradation of 2-MIB, while the effect of Songhua River was the weakest.

Ultrasonic-assisted ozone oxidation process of triphenylmethane dye degradation: Evidence for the promotion effects of ultrasonic on malachite green decolorization and degradation mechanism

This study aimed to prove the promotion effects of ultrasonic on malachite green (MG) decolorization in the ultrasonic-assisted ozone oxidation process (UAOOP), and propose the possible pathway of MG degradation. The decolorization of MG followed an apparent pseudo first-order kinetic law (initial MG concentration 100–1000mg/L). When ultrasonic (US) was applied with ozone simultaneously, the apparent pseudo-first-order rate constant (Kapp) increased, and the time MG decolorized to the half of initial concentration (T1/2) shortened 185s (1000mg/L). Moreover, the stoichiometric ratio (Zapp) between O3 and MG was enhanced by US to 2.0mol, saving 11% oxidant addition, comparing to individual ozone process. These results indicated that the application of US can reduce reaction time and dose of ozone addition. The possible pathway of MG degradation included three major approaches. And the result suggested that the reaction between MG and hydroxyl radical was substitution reaction rather than adduct reaction.

Bromate Formation in Ozone and Advanced Oxidation Processes

Both the direct ozone reaction and the indirect hydroxyl radical reaction are important in ozonation of drinking water. This article investigates the effectiveness of ozone versus the advanced oxidation process of ozone coupled with hydrogen peroxide in the formation of bromate. The investigation was conducted on a pilot scale at various H2O2:O3 dose ratios of 0.1, 0.2, and 0.35 at different times of the year. The results of this study show a reduction in bromate with the addition of hydrogen peroxide to an ozone system versus ozone alone. It was also observed that bromate increased with increased H2O2:O3 ratios; however, concentrations were still lower than those in the ozone only system.

COD Removal of Rhodamine B from Aqueous Solution by Electrochemical Treatment

Abstract This study elucidates the COD removal of dye (Rhodamine B) through electrochemical reaction. Effects of current density (7.2 to 43.3 mA/cm 2 ), electrolyte type (NaCl, KCl, Na 2 SO 4 , HCl), electrolyte concentration (0.5 to 2.0 g/L), air flow rate (0 to 4 L/min) and pH (3 to 11) on the COD removal of Rhodamine B were investigated. The observed results showed that the increase of pH decrease the COD removal efficiency. Whereas, the increase of current density, NaCl concentration and air flow rate caused the increase of the COD removal of Rhodamine B. Key Words : COD removal, Electrochemical treatment, Rhodamine B, Ru-Sn-Sb electrode 1) 1. Introduction Textile industry produce considerable water pollution problem by discharging effluents. The effluent of textile industry process contains various types of pollutants such as dyes, detergents, surfactants and suspended solids (Robert et al., 2007). The effluent in textile industry has often been discharged over the discharge limit when it is treated only by the conventional treatment process such as the connected chemical and biological process, because the wastewater in textile industry has many recalcitrant materials. Therefore, the research for the advanced oxidation processes (AOPs) such as electron beam, Fenton oxidation, ozone oxidation, photo-catalytic and electrochemical processes is needed for the stable treatment of textile industry wastewater. Especially, the electrochemical oxidation process

Application of Ozonation, UV Photolysis, Fenton Treatment and other Related Processes for Degradation of Ibuprofen and Sulfamethoxazole in Different Aqueous Matrices

AbstractTwo pharmaceuticals ibuprofen (IBP) and sulfamethoxazole (SMX) were treated with ozone and advanced oxidation processes (AOPs): UV photolysis, O

오존접촉산화 공정과 Peroxone AOP 공정을 이용한 염색폐수방류수 고도산화 처리특성 연구

Effect of pH on ozone oxidation and peroxone AOP(Advanced Oxidation Process) process was analyzed and the optimal efficiency for both processes was obtained at pH 7.5. In case of ozone oxidation process, the efficiencies of color, <TEX>$COD_{Mn}$</TEX> and <TEX>$BOD_5$</TEX> removal were measured to 93%, 70% and 89% at a reaction time of 50 min(ozone dosage of 111.67mg/<TEX>$\ell$</TEX>). When reaction time increased to 90 min(ozone dosage of 201mg/<TEX>$\ell$</TEX>), the efficiencies of color, <TEX>$COD_{Mn}$</TEX> and <TEX>$BOD_5$</TEX> removal were increased by 3~5 %, indicating that the increment of removal efficiency was insignificant considering longer reaction time. Similarly, the ozone/<TEX>$H_2O_2$</TEX> ratio was optimized to 0.5 for peroxone AOP process. Removal efficiencies of color, <TEX>$COD_{Mn}$</TEX> and <TEX>$BOD_5$</TEX> were measured 95%, 81% and 94% at a reaction time of 50 min(ozone dosage of 111.67mg/<TEX>$\ell$</TEX>). When reaction time increased to 90min(ozone dosage of 201mg/<TEX>$\ell$</TEX>), the removal efficiency of color, CODMn, and BOD5 increased slightly by 1~5%.

A rapid and low energy consumption method to decolorize the high concentration triphenylmethane dye wastewater: Operational parameters optimization for the ultrasonic-assisted ozone oxidation process

This research set up an ultrasonic-assisted ozone oxidation process (UAOOP) to decolorize the triphenylmethane dyes wastewater. Five factors – temperature, initial pH, reaction time, ultrasonic power (low frequency 20 kHz), and ozone concentration – were investigated. Response surface methodology was used to find out the major factors influencing color removal rate and the interactions between these factors, and optimized the operating parameters as well. Under the experimental conditions: reaction temperature 39.81 °C, initial pH 5.29, ultrasonic power 60 W and ozone concentration 0.17 g/L, the highest color removals were achieved with 10 min reaction time and the initial concentration of the MG solution was 1000 mg/L. The optimal results indicated that the UAOOP was a rapid, efficient and low energy consumption technique to decolorize the high concentration MG wastewater. The predicted model was approximately in accordance with the experimental cases with correlation coefficients R 2 and R adj 2 of 0.9103 and 0.8386.

Combination of Sequential Batch Reactor (SBR) and Dissolved Ozone Flotation-Pressurized Ozone Oxidation (DOF-PO2) Processes for Treatment of Pigment Processing Wastewater

This study investigates the treatment of pigment wastewater using a sequential batch reactor (SBR) followed by dissolved ozone flotation-pressurized ozone oxidation treatement (DOF-PO 2 ). The process efficiency has been evaluated at the lab scale on the basis of water quality parameters. In addition, the effect of pure oxygen and air was investigated on the removal of COD, BOD, and TN in the SBR process. It was observed that under comparable conditions the removal efficiencies of these water quality parameters using pure oxy - gen and air were similar. The effect of the recycle rate was also investigated for its impact on the water quality parameters using different ozone dissolving pressures in a DOF process in order to optimise conditions. The results conclude that the use of an SBR and ozone contact by DOF-PO2 is a highly effective treatment for pigment wastewater and aids in the achievement of effluent discharge criteria.

Degradation of propoxycarbazone-sodium with advanced oxidation processes

The degradation of propoxycarbazone-sodium, an active component of commercial herbicide, in aqueous solution with ozone, UV photolysis and advanced oxidation processes: O3/UV, O3/UV/H2O2, H2O2/UV, and the Fenton process was studied. All these methods of degradation proved feasible. The kinetics of propoxycarbazone-sodium degradation in water followed the pseudo-first order equation for all studied processes except the Fenton treatment. The application of schemes with ozone demonstrated low pseudo-first order rate constants within the range of 10−4 s−1. Addition of UV radiation to the processes improved the removal of propoxycarbazone-sodium and increased the pseudo-first order rate constants to 10−3 s−1. The Fenton process was the most efficient and resulted in 5 and 60 s of half-life and 90% conversion time of propoxycarbazone-sodium, respectively, at 14 mM H2O2 concentration. UV treatment and the Fenton process may be recommended for practical application in decontamination of water or wastewater.

Identification of Degradation Products of Erythromycin A Arising from Ozone and Advanced Oxidation Process Treatment

The degradation products of the macrolide antibiotic erythromycin A (ERY) arising from direct ozone attack and hydroxyl radical attack are presented for the first time. Ozone treatment was carried out by spiking ozone stock solutions to solutions containing ERY-ERY:O3 = 1:5 and 1:10 (M:M), while, in parallel, t-BuOH was used as a hydroxyl radical (*OH) scavenger. The advanced oxidation processes (AOPs) O3/UV, O3/H2O2, and UV/H2O2 were carried out to recognize and verify possible differences between their primary degradation products; the initial concentrations were ERY:O3 = 1:5 (M:M), ERY:O3:H202 = 1:5:5 (M:M:M), or ERY:H202 = 1:5 (M:M), respectively. Six degradation products were identified from ozonation-one originates from direct ozone attack on the tertiary amine group, while the others arise from radical ion attack, which might be formed during degradation of O3 in water. Fewer primary degradation products were observed arising from *OH-based treatments (AOP) than from ozonation, possibly because the reaction of *OH radicals is non-selective and typically is diffusion-controlled. Four degradation products were detected by *OH radical attacks; two of them already were observed during ozonation, with one as an oxidized ERY molecule and the other as a non-oxidized fragment of the ERY molecule.

Treatment of E. coli HB101 and the tetM gene by Fenton’s reagent and ozone in cow manure

The destruction of antibiotic-resistant microorganisms at the source of contamination is necessary due to their adverse effects and to their increasingly widespread occurrence in the environment. To address this problem, Fenton and ozone oxidation processes were applied to synthetically contaminated cow manure to remove the tetM gene and its host, Escherichia coli HB101. The efficiency of the processes was evaluated by enumeration of E. coli HB101 and by PCR amplification of the tetM gene. The results of this study show that 56.60% bacterial inactivation (corresponding to a 0.36 log reduction) was achieved by a Fenton reagent dose of 50 mM H 2O 2 and 5 mM Fe 2+ without acidifying the manure. Despite the high organic content of cow manure, 98.50% bacterial inactivation (corresponding to a 1.83 log reduction) was obtained by the ozonation process with an applied dose of 3.125 mg ozone/g manure slurry. The PCR study revealed that the band intensity of the tetM gene gradually decreased by increasing the Fenton reagent and the applied ozone dose. However, significantly high doses of oxidants would be required to completely eliminate bacterial pollution in manure.

Effect of interfacial oxide on Ge MOSCAP and N-MOSFET characteristics

The effect of electrical quality of interfacial oxide on Ge MOSCAP and MOSFET characteristics is investigated. Different growth conditions are studied to optimize the interfacial layer. CV and D it measurements are done for accurate comparison of different gate dielectric stacks. Optimized ozone oxidation process is integrated with Co-induced dopant activation to fabricate Ge N-MOSFETs. Forty percent improvement in inversion electron mobility is demonstrated with optimized GeO 2 passivation. The highest electron mobility is reported in bulk Ge N-MOSFETs with GeO 2/Al 2O 3 gate dielectric stack.

Simultaneous Removal of Oxytetracycline and Sulfamethazine Antibacterials from Animal Waste by Chemical Oxidation Processes

Simultaneous degradation of oxytetracycline (OTC) and sulfamethazine (SMZ) antibacterials in synthetically contaminated cow manure (20 mg of antibacterials/kg of manure) in the presence and absence of bedding was investigated by the application of ozone, Fenton, and persulfate oxidation processes. Almost the complete removal of antibacterials was attained with all oxidation processes, which were combined with a pretreatment of manure with magnesium (Mg(2+)) salt desorption. Among the investigated oxidation processes, thermally activated persulfate oxidation with 25 mM Na(2)S(2)O(8) at 50 degrees C was also applied to the animal feeding operations wastewater, and the pseudo-first-order degradation rate constants of OTC and SMZ were found as 3.22 and 1.25 (1/h), respectively. Thermally activated persulfate treatment resulted in the reduction of 82% inhibition of OTC and SMZ to 7%, indicating the production of almost nontoxic degradation products in the wastewater.

Azo dye Acid Red 27 decomposition kinetics during ozone oxidation and adsorption processes

To elucidate the effects of ozone dosage, catalysts, and temperature on azo dye decomposition rate in treatment processes, the decomposition kinetics of Acid Red 27 by ozone was investigated. Acid Red 27 decomposition rate followed the first-order reaction with complete dye discoloration in 20 min of ozone reaction. The dye decay rate increases as ozone dosage increases. Using Mn, Zn and Ni as transition metal catalysts during the ozone oxidation process, Mn displayed the greatest catalytic effect with significant increase in the rate of decomposition. The rate of decomposition decreases with increase in temperature and beyond 40°C, increase in decomposition rate was followed by a corresponding increase in temperature. The FT-IR spectra in the range of 1000–1800 cm−1 revealed specific band variations after the ozone oxidation process, portraying structural changes traceable to cleavage of bonds in the benzene ring, the sulphite salt group, and the C-N located beside the -N = N- bond. From the 1H-NMR spectra, the breaking down of the benzene ring showed the disappearance of the 10 H peaks at 7-8 ppm, which later emerged with a new peak at 6.16 ppm. In a parallel batch test of azo dye Acid Red 27 adsorption onto activated carbon, a low adsorption capacity was observed in the adsorption test carried out after three minutes of ozone injection while the adsorption process without ozone injection yielded a high adsorption capacity.

Comparison of the ozonation and Fenton process performances for the treatment of antibiotic containing manure

An integrated treatment method based on magnesium salt extraction followed by chemical oxidation was used for the treatment of a veterinary antibiotic, oxytetracycline (OTC) contaminated cow manure since animal manure can be an important source for antibiotic pollution in the environment. Pretreatment with magnesium salt enhanced the efficiencies of subsequent oxidation processes by extracting 63.9% of OTC from the manure thereby making it more favorable for oxidation with the hydroxyl radicals produced by the Fenton and ozone oxidation processes. Both the 24 h Fenton oxidation process with 434 mM H 2O 2 and 43.4 mM Fe 2+ doses and the 1-h ozonation process with an applied ozone dose of 2.5 mg min − 1 provided more than 90% OTC removal from the manure slurry. However, the second-order OTC removal rate constant of Fenton process (119 M − 1 s − 1 ) was remarkably lower than that obtained with the ozonation process (548 M − 1 s − 1 ). The oxidant dose was a significant factor for the efficiency of the Fenton treatment but not for the ozone treatment. The efficiencies of both the Fenton and ozone oxidation processes were not affected by the pH adjustment of the manure slurry.

Half-Cycle Atomic Layer Deposition Reaction Study Using O[sub 3] and H[sub 2]O Oxidation of Al[sub 2]O[sub 3] on In[sub 0.53]Ga[sub 0.47]As

The effect of water and ozone as the oxidant in the atomic layer deposition (ALD) of aluminum oxide on the ammonium-sulfide-passivated In 0.53 Ga 0.47 As surface is compared using X-ray photoelectron spectroscopy (XPS) after each of the ALD process. While the first half-cycle of the aluminum precursor tri-methyl aluminum (TMA) reduces the residual native oxides to within detection limits of XPS, the ozone oxidation process causes significant reoxidation of the substrate in comparison to the water-based process. Subsequent TMA pulses fail to remove the excess interfacial oxides caused by ozone oxidation, resulting in the formation of an oxide interlayer.

Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes

The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O 3/UV radiation, H 2O 2/UV radiation, O 3/H 2O 2, O 3/H 2O 2/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O 3 or UV did not result in perceptible decomposition of HAAs within the applied reaction time. O 3/UV showed to be more suitable for the decomposition of DCAA and TCAA in water among the six methods of oxidation. Decomposition of DCAA was easier than TCAA by AOPs. For O 3/UV in the semi-continuous mode, the effective utilization rate of ozone for HAA decomposition decreased with ozone addition. The kinetics of HAAs decomposition by O 3/UV and the influence of coexistent humic acids and HCO 3 − on the decomposition process were investigated. The decomposition of the HAAs by the O 3/UV accorded with the pseudo-first-order mode under the constant initial dissolved O 3 concentration and fixed UV radiation. The pseudo-first-order rate constant for the decomposition of DCAA was more than four times that for TCAA. Humic acids can cause the H 2O 2 accumulation and the decrease in rate constants of HAAs decomposition in the O 3/UV process. The rate constants for the decomposition of DCAA and TCAA decreased by 41.1% and 23.8%, respectively, when humic acids were added at a concentration of 1.2 mg TOC/L. The rate constants decreased by 43.5% and 25.9%, respectively, at an HCO 3 − concentration of 1.0 mmol/L.

Hf–O–N and HfO 2 barrier layers for Hf–Ti–O gate dielectric thin films

Hf–O–N and HfO 2 thin films were evaluated as barrier layers for Hf–Ti–O metal oxide semiconductor capacitor structures. The films were processed by sequential pulsed laser deposition at 300 °C and ultra-violet ozone oxidation process at 500 °C. The as-deposited Hf–Ti–O films were polycrystalline in nature after oxidation at 500 °C and a fully crystallized ( o)-HfTiO 4 phase was formed upon high temperature annealing at 900 °C. The Hf–Ti–O films deposited on Hf–O–N barrier layer exhibited a higher dielectric constant than the films deposited on the HfO 2 barrier layer. Leakage current densities lower than 5 × 10 A/cm 2 were achieved with both barrier layers at a sub 20 Å equivalent oxide thickness.

운전조건에 따른 O3/UV, TiO2/UV 및 O3/TiO2/UV 시스템의 BTEX 증기처리에 관한 비교 연구

A multilayer tower-type photoreactor, in which <TEX>$TiO_2$</TEX>-coated glass-tubes were installed, was used to measure the vapor-phase BTEX removal efficiencies by ozone oxidation (<TEX>$O_3$</TEX>/UV), photocatalytic oxidation (<TEX>$TiO_2$</TEX>/UV) and the combination of ozone and photocatalytic oxidation (<TEX>$O_3/TiO_2$</TEX>/UV) process, respectively. The experiments were conducted under various relative humidities, temperatures, ozone concentrations, gas flow rates and BTEX concentrations. As a result, the BTEX removal efficiency and the oxidation rate by <TEX>$O_3/TiO_2$</TEX>/UV system were highest, compared to <TEX>$O_3$</TEX>/UV and <TEX>$TiO_2$</TEX>/UV system. The <TEX>$O_3/TiO_2$</TEX>/UV system accelerated the low oxidation rate of low-concentration organic compounds and removed organic compounds to a large extent in a fixed volume of reactor in a short time. Therefore, <TEX>$O_3/TiO_2$</TEX>/UV system as a superimposed oxidation technology was developed to efficiently and economically treat refractory VOCs. Also, this study demonstrated feasibility of a technology to scale up a photoreactor from lab-scale to pilot-scale, which uses (i) a separated light-source chamber and a light distribution system, (ii) catalyst fixing to glass-tube media, and (iii) unit connection in series and/or parallel. The experimental results from <TEX>$O_3/TiO_2$</TEX>/UV system showed that (i) the highest BTEX removal efficiencies were obtained under relative humidity ranging from 50 to 55% and temperature ranging from 40 to <TEX>$50^{\circ}C$</TEX>, and (ii) the removal efficiencies linearly increased with ozone dosage and decreased with gas flow rate. When applying Langmuir-Hinshelwood model to <TEX>$TiO_2$</TEX>/UV and <TEX>$O_3/TiO_2$</TEX>/UV system, reaction rate constant for <TEX>$O_3/TiO_2$</TEX>/UV system was larger than that for <TEX>$TiO_2$</TEX>/UV system, however, it was found that adsorption constant for <TEX>$O_3/TiO_2$</TEX>/UV system was smaller than that for <TEX>$TiO_2$</TEX>/UV system due to competitive adsorption between organics and ozone.

Color removal of distillery wastewater by ozonation in the absence and presence of immobilized iron oxide catalyst

Ozone is a strong oxidant, which can oxidize both biodegradable and non-biodegradable organics. The main objective of this study was to use iron oxide as a heterogeneous catalyst to enhance the ozone oxidation process. The wastewater used in this study was distillery wastewater, which was diluted 20 times before use. The diluted distillery wastewater was fed continuously in a downflow direction in an ozonation column. The iron oxide catalyst was coated on 10.3 mm diameter alumina balls (5.5 m 2/g specific surface area) by using Fe(NO 3) 3 as a precursor. The prepared catalyst was in the form of ferric oxide, and its loading was 0.07%. From the experimental results of both with and without the iron oxide catalyst, an increase in hydraulic retention time resulted in an increase in the treatment efficiencies of both chemical oxygen demand (COD) and color reduction, since the residence time of ozone increased. When the ozone mass flow rate increased, both COD and color reduction increased, resulting from an increase in the hydroxyl radical available in the system. The ozonation system with the iron oxide catalyst gave the highest efficiency in both COD and color removals because the hydroxyl free radical generated from the catalyst is more reactive than the ozone molecule itself.