•Ozone-based AOP processes have higher treatment efficiency.•The reaction mechanism and application of various ozone-based AOP are discussed.•The combined methods are cost effective.
The wastewater ...reclamation is the need of today's world. Advanced oxidation processes (AOPs) are considered as a good option for removing recalcitrant organic materials in wastewater by oxidation reactions with powerful, non-selective hydroxyl radical (OH•). Ozone alone does not cause complete oxidation of some refractory organic compounds and has a low reaction rate. The ozone is combined with H2O2, UV light, catalyst, ultrasound to enhance the generation of hydroxyl radicals to increase the efficiency of the treatment process. The ozone-based AOPs have been proved to be effective in detoxifying an ample range of industrial effluents containing recalcitrant organics, pharmaceutical products, pesticides, phenols, dyes, etc. Ozone based AOP processes such as O3/UV, O3/H2O2, O3/Fe (II), O3/metal oxide catalyst, O3/activated carbon, O3/ultrasound, O3/Fenton, photocatalytic ozonation were discussed. A review of ozone-based AOP processes as a combination of ozonation with other techniques for the degradation and mineralization of recalcitrant organics present in the industrial/municipal wastewater based on the recently published work were reported.
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The reactions between chlorobenzene(CB) and ozone have been studied comprehensively in this paper. Chlorobenzene is a commonly found chlorinated aromatic volatile organic compound(VOC), and its ...emission into the atmosphere can cause harm to the ecosystem and human health. The frequent occurrence of mineral particles from sandstorms exerts a significant influence on the atmospheric chemistry of the troposphere. Mineral particles are abundant in SiO2 and Al2O3 content. Therefore, we investigated the homogeneous and heterogeneous reaction processes of CB and ozone in the atmosphere by using density functional theory (DFT) method at the M06-2X/6–311++g(3df,2p)//M06-2X/6–31+g(d,p) level. The atmospheric fate, reaction rate and toxicity evaluation of CB ozonation were studied in the gas-phase section. Toxicity evaluation results showed that ozonation of CB could effectively reduce its toxicity. For the heterogeneous process, we simulated three types of SiO2 clusters and nine types of (Al2O3)n clusters, and studied the configurations of CB adsorbed on the cluster surfaces. We found that adsorption of CB on the SiO2 clusters was achieved through hydrogen bonding, while adsorption of CB on the Al2O3 clusters was achieved through both hydrogen bonding and metal bonding. The energy for CB adsorption on the (Al2O3)n cluster surface was higher than that for the SixOy(OH)z cluster surface, and both types of clusters exhibited efficient adsorption of CB. As the SixOy(OH)z clusters grew larger, the rates for the reactions between O3 and CB increased. CB travelled long distances along the Al2O3 clusters, leading to an extended influence range.
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•The reaction mechanism of CB reacting with O3 in homogeneous and heterogeneous were studied.•Toxicity assessment showed that ozonolysis effectively reduced the ecotoxicity.•The Al2O3 clusters have a stronger adsorption effect on CB compared to the SiO2 clusters.•The environmental risks may increase due to the promotion of Al2O3 to the studied reactions.
Paracetamol (PCT) or acetaminophen is a widely prescribed drug to treat fever and mild to moderate pain. The PCT uptake by animals and humans is not complete, being excreted through their urine to ...contaminate the aquatic/natural environments. Trace amounts of this drug have been found in sewage sludge, hospital wastewaters, wastewater plant treatments, surface waters, and even drinking water. PCT denatures proteins and oxidize lipids in cells with damage of their genetic code. Its toxicity over macrophytes, protozoan, algae, bacteria, and fishes has been reported. Ozonation methods have been proposed as efficient treatments to solve this pollution. This comprehensive and critical review is focused on the application of ozonation processes to remove PCT polluted water from different sources, like natural waters, synthetic waters, and real wastewaters. The fundamentals, operating variables, and best results by direct ozonation and hybrid catalytic ozonation are described, with attention to produced reactive oxygen species and their oxidative action. Single ozonation, catalytic modification of materials, and hybrid non-catalytic processes are detailed as direct ozonation methods. Ozonation with metal-based catalysts and photolytic and photocatalytic ozonation as hybrid catalytic methods are analyzed. Sequential non-biological and biological treatments with ozone and ozonation for wastewater remediation in treatment plants are described. Reaction sequences proposed for PCT mineralization are finally discussed, showing the initial formation of hydroquinone and 2-hydroxy-4-(N-acetyl)-aminophenol and their consecutive evolution to ultimate carboxylic acids like oxalic and oxamic. The ability of the methods to destroy these acids and their iron- and/or copper-complexes explains their mineralization performance.
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•Rapid degradation of paracetamol by single ozonation in pure water, but with low mineralization.•Larger enhancement of drug mineralization by ozonation with metal-based catalysts.•More potent photolytic ozonation with Fe2+ and H2O2 than photocatalytic TiO2 ozonation.•Sequential treatments developed with wastewaters and in drinking water treatment plants.•Generated hydroquinone and 2-hydroxy-4-(N-acetyl)-aminophenol give oxalic and oxamic acids.
In this study, a co-catalytic route was explored to enhance the photo-ozone catalytic degradation of volatile organic compounds (VOCs). NiCo2O4 was loaded onto the surface of CeO2 nanoparticles to ...create a composite catalyst (10%NiCo2O4/CeO2). The integration of NiCo2O4 onto CeO2 enhanced the interaction between the catalyst and toluene, a representative VOC, resulting in significantly increased toluene adsorption without a corresponding increase in specific surface area. This integration also improved the utilization of charge carriers and conversion of ozone to O2−. Under visible light irradiation, H2O accumulated charge carriers at 10%NiCo2O4/CeO2's surface, facilitating both ozone utilization and toluene adsorption. Another benefit of NiCo2O4 loading was its ability to enhance the conversion efficiency of solar energy. Consequently, the toluene removal and mineralization efficiencies of 10%NiCo2O4/CeO2 were enhanced by 182% and 309% compared to CeO2, and by 201% and 357% compared to NiCo2O4, respectively. Overall, this study demonstrated a novel co-catalyst design strategy for enhancing the photo-ozone catalytic degradation of VOCs.
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•NiCo2O4 enhances toluene adsorption without increasing SBET.•NiCo2O4 loading enhances photothermal conversion efficiency.•NiCo2O4 loading creates extra Ov and thus increases ozone conversion.•H2O accumulates charge carriers and thus alters adsorption behavior.•A strong synergistic effect is observed for toluene degradation on 10%NiCo2O4/CeO2.
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•Simultaneous catalytic ozonation and photocatalysis (SCOP) process was developed.•Successful synthesis of MgMnO3 by a simple sol-gel method.•Efficient mineralization of antibiotics ...by MgMnO3-mediated SCOP.•Catalytic mechanism and degradation pathway were revealed.
Herein a novel coupling process of simultaneous catalytic ozonation and photocatalysis (SCOP) using a bifunctional catalyst for the antibiotics wastewater treatment was developed. MgMnO3, as the first example of bifunctional catalyst, was successfully prepared by a simple sol-gel method. In the MgMnO3-mediated SCOP process, the TOC removal of sulfamethoxazole, tetracycline, ciprofloxacin, and trimethoprim within 80 min reached 94.7 ± 0.9%, 88.4 ± 0.9%, 97.8 ± 1.0%, and 76.3 ± 0.9%, respectively, much higher than that in ozonation or photocatalysis (less than 20%). The first order kinetics reaction constant of TOC removal in the case of tetracycline degradation by SCOP is 2.58 × 10−2 min−1, which is 2.7, 23.0, and 6.2 times that by catalytic ozonation, photocatalysis, and photo ozonation, respectively. ESR spectra show that much more ·OH radicals are generated in SCOP than the sum in photocatalysis and catalytic ozonation processes, indicating the synergism between two processes and explaining the high mineralization efficiency in SCOP. Finally, eight intermediates were identified by LC-MS analysis and the initial degradation pathway of tetracycline in SCOP was proposed. Excellent treatment efficiency, high ozonation utilization (>93%) and low energy consumption (14.9 KJ/mg TOC) suggest that SCOP is a promising choice for antibiotics-containing wastewater treatment.
Ozone-based processes gained much attention in recent years. However, due to low oxidative stability and utilization rate, single ozonation process (SOP) is insufficient for complete mineralization ...of pollutants. As a result, the single ozonation process is performed in the presence of a catalyst, a process known as catalytic ozonation process (COP). A promising catalyst (Fe/BC) was prepared by impregnating iron on biochar surface to remove methylene blue from aqueous solution via heterogeneous catalytic ozonation process (HCOP). The prepared Fe/BC features were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller method (BET) before and after HCOP. Furthermore, the effect of various operating parameters such as ozone dose, catalyst dose, initial dye concentration, initial pH on the efficiency of SOP and HCOP were compared. In comparison to single ozonation process, the experimental study found that heterogeneous catalytic ozonation process has the highest efficiency. At pH 7.0, approximately 76% of methylene blue is removed during single ozonation process in 60 min. Heterogeneous catalytic ozonation process showed 95% methylene blue elimination from aqueous solution. The efficiency of heterogeneous catalytic ozonation process was decreased by 52% in the presence of hydroxyl radical (●OH) scavenger, indicating that hydroxyl is the major oxidant during heterogeneous catalytic ozonation process for the removal of methylene blue from aqueous solution. Fe/BC catalyst appears to have a lot of industrial promise, as well as the ability to remove methylene blue from aqueous solution via heterogeneous catalytic ozonation process.
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•The efficiency of SOP and HCOP was compared for MB removal.•The catalyst remains stable and efficient after 6 cycles.•About 76% and 95% MB decolorization achieved during SOP and HCOP, respectively.•The best MB decolorization achieved ozone dose 0.2 mg/ml of aqueous solution.
Over the last years, there has been a growing interest in the use of Advanced Oxidation Processes (AOPs) for the elimination of micropollutants. This work attempts to compare the efficiency of ...conventional UV, O3 and H2O2 based AOPs with a relatively new AOP based on plasma-ozonation, in terms of removal and energy efficiency. The experimental study is performed in a synthetic water matrix spiked with four different micropollutants: atrazine (ATZ), alachlor (ALA), bisphenol A (BPA) and 1,7-α-ethinylestradiol (EE2). For the different processes examined in this study, O3 – based AOPs are more effective compared to UV based techniques in terms of energy efficiency. Although the energy efficiency of plasma-ozonation falls between the energy cost of O3 and UV-based AOPs, the removal kinetics generally proceed faster compared to other AOPs, achieving complete elimination (>99.8% removal) of the target compounds within 20 min of treatment. Moreover, the results suggest that improvement in the mass-transfer in the plasma-ozonation setup permits to further decrease the energy cost of this process up to electrical energy per order (EE/O) values between 2.54 and 0.124 kWh m−³, which is already closer to the energy efficiency of ozonation (EE/O = 0.73–0.084 kWh m−³).
•Removal of micropollutants from water was studied with different AOPs.•Fastest micropollutant elimination was achieved with plasma-ozonation.•Energy costs decreased in the order: O3 based AOPs < plasma-ozonation < UV based AOPs.•Mass transfer efficiency plays an important role in performance of plasma-ozonation.
Ozonation, a viable option for improving wastewater effluent quality, requires process optimization to ensure the organic micropollutants (OMPs) elimination and disinfection under minimized byproduct ...formation. This study assessed and compared the efficiencies of ozonation (O3) and ozone with hydrogen peroxide (O3/H2O2) for 70 OMPs elimination, inactivation of three bacteria and three viruses, and formation of bromate and biodegradable organics during the bench-scale O3 and O3/H2O2 treatment of municipal wastewater effluent. 39 OMPs were fully eliminated, and 22 OMPs were considerably eliminated (54 ± 14%) at an ozone dosage of 0.5 gO3/gDOC for their high reactivity to ozone or •OH. The chemical kinetics approach accurately predicted the OMP elimination levels based on the rate constants and exposures of ozone and •OH, where the quantum chemical calculation and group contribution method successfully predicted the ozone and •OH rate constants, respectively. Microbial inactivation levels increased with increasing ozone dosage up to ∼3.1 (bacteria) and ∼2.6 (virus) log10 reductions at 0.7 gO3/gDOC. O3/H2O2 minimized bromate formation but significantly decreased bacteria/virus inactivation, whereas its impact on OMP elimination was insignificant. Ozonation produced biodegradable organics that were removed by a post-biodegradation treatment, achieving up to 24% DOM mineralization. These results can be useful for optimizing O3 and O3/H2O2 processes for enhanced wastewater treatment.
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•70 OMPs and 6 bacteria/viruses in sewage effluent were treated by O3 and O3/H2O2.•33 kO3 and 23 k•OH were newly reported, calculated from QSAR and GCM.•Good prediction of OMP removals using O3/•OH reactivity and exposure.•The microbial inactivation was lower than the linear kinetic model prediction.•O3/H2O2 minimized bromate formation but decreased microbial inactivation than O3.
Ozone is a strong oxidant and have been effectively used for the degradation and mineralization of organic pollutants. However, the increase in the toxicity and disposal of the recalcitrant organics ...standalone ozonation process is not effective and sustainable solution for the treatment of industrial wastewater containing recalcitrant. It is therefore necessary to provide a summary of success of hybrid ozonation process for industrial wastewater treatment along with the reaction mechanism for enhancing the molecular ozone reactivity. The paper presents a detailed review of hybrid ozonation process as a combination of two different techniques to enhance the hydroxyl radical formation thereby increasing the process efficiency. An extensive review on the mechanism and application of these hybrid ozonation processes for degradation, mineralization, detoxification of different organic pollutants present in the industrial wastewater is reported.
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This paper conducted catalytic ozonation of CB (chlorobenzene) over a series of MnOx based catalysts with different supports (Al2O3, TiO2, SiO2, CeO2, and ZrO2) at 120 °C. Mn/Al2O3 ...exhibited highest CB conversion efficiency, ca. 82.92 %, due to its excellent textual properties, O2 desorption, redox ability, and desirable surface adsorbed oxygen species and acidity. O3 conversion all approached nearly 100.0%, with residual <10 ppm. Mn/Al2O3 was further employed to investigate effect of temperature, O3/CB, and space velocity on CB conversion. Hereafter, catalytic ozonation of single and binary VOCs in different types was performed, i.e., CB, DCE (dichloroethane), DCM (dichloromethane), and PhH (Benzene). Conversion results demonstrated aromatics degraded easier than alkanes and more carbon atoms decreased difficulty, as CB∼PhH > DCE∼DCM, and DCE > DCM; but chlorinated substitution increased difficulty, as PhH > CB. Catalytic co-ozonation of CB/DCE indicated that DCE significantly improved CB conversion to reach totally degradation at low O3 input, but inhibited DCE conversion, especially at higher ratio of DCE/CB. Co-ozonation improved ozone utilization efficiency, and maintained the original property of catalyst. By contrast, CB/PhH co-ozonation displayed very mild effects. Finally, critical intermediates during catalytic CB ozonation, i.e., DCM, carboxyl and formic acid, were detected from mass spectrum results.
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