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This study assessed the removal efficiency of ammonia nitrogen from tannery wastewater by combining electrocoagulation, ozonation, and ion exchange technologies. For this purpose, an electrocoagulation reactor equipped with aluminum electrodes, an ozonation tank, and a filtration system with zeolite were employed. The electrocoagulation treatment applied the response surface methodology with a 3k factorial design with the following two factors: current intensity (I) ranging from 3 to 7A, and treatment time (t) from 10 to 30 min; the removal percentage of total suspended solids (TSS) is set as a response variable. Results indicate that the treatment time and current intensity were significant for the removal of total suspended solids TSS, at a confidence level of p < 0,05. Under these conditions, a TSS, removal efficiency of 98% was achieved. Through the electrocoagulation process, the chemical oxygen demand (COD) was reduced by 58%, while in the ozonation tank, an additional 23% of COD was removed. The filtration stage demonstrated that 13X HP zeolite can exchange ions with the ammonia nitrogen from tannery wastewater, wherein a 39% removal efficiency is reached at equilibrium. Thus, the integration of various treatment methods is a viable alternative to reduce wastewater from the tannery industry. The novelty of this research lies in the integration of three methods for treating tannery wastewater. The results show that the combination of these treatments provides a more effective solution for removing the pollutant load, especially nitrogen, compared to the use of individual treatment methods alone. The study opens new perspectives for optimizing multi-stage treatment processes. [ABSTRACT FROM AUTHOR]

Food dyes with a diverse set of colorants stimulate appetite and enhance aesthetic charm of food on table but at the same time these dyes contaminate the aquatic and biological ecosystems due to their cytotoxic and carcinogenic potentials. Herein, we report magnetite catalyzed removal of sunset yellow dye from water through catalytic degradation and ozonation. The magnetite catalyst revealed about 83% catalytic degradation and 92% catalytic ozonation performance toward sunset yellow dye at 100 and 25 min, respectively. Furthermore, the persulphate/magnetite/O3 hybrid system revealed superior performance compared to the persulphate/magnetite under identical conditions. Kinetic studies revealed that the dye degradation data followed second-order kinetics, suggesting that the dye removal process is physicochemical in nature. This study further demonstrates that the persulfate/magnetite/O3 hybrid system can efficiently decompose sunset yellow dye in aqueous solution compared to the Fenton's reagent and simple catalytic decomposition processes which is attributed to its unique structural features. [ABSTRACT FROM AUTHOR]

This study investigated the degradation of sulfolane using pressurized ozonation under varying initial concentrations and the influence of different catalysts and peroxymonosulfate activation methods on the degradation efficiency. Initial sulfolane concentrations of 1 mg L−1, 20 mg L−1, and 100 mg L−1 were tested over 120 min, revealing a degradation efficiency of 73%, 41%, and 18%, respectively. The addition of various metal ions (Zn2+, Mg2+, Cu2+, Ni2+, and Co2+) demonstrated that only zinc and magnesium enhanced degradation, with zinc achieving a 92% removal efficiency and magnesium achieving 86%. Different doses of magnesium and zinc were further tested, showing optimal degradation at specific concentrations. The combination of PMS with ozonation was explored, revealing that zinc activation did not significantly enhance degradation, while NaOH activation achieved near-total degradation, with a 100 mg L−1 NaOH concentration. Varying PMS concentrations indicated that altering pH was more effective than changing PMS dosage. Finally, the impact of pH changes in both reverse osmosis water and tap water matrices confirmed that higher pH levels significantly improved degradation efficacy, achieving up to 98% removal with NaOH concentrations of 50 mg L−1 in reverse osmosis water. These results suggest that optimizing pH and catalyst type are critical for enhancing sulfolane degradation in pressurized ozonation systems. [ABSTRACT FROM AUTHOR]

In this study, the toxic and teratogenic effects of three commercial drugs and their active ingredients on Xenopus laevis embryos before and after ozonation were evaluated using the Frog Embryos Teratogenesis Assay–Xenopus (FETAX). First, the median lethal concentration (LC50) and, if data were available, the median effective concentration, teratogenic index and minimum growth inhibitory concentration were determined for each drug substance without ozonation. Then, the active substance amounts of three selected nominal concentrations (LC50/2, LC50, and LC50×2) of each test substance before ozonation were measured by HPLC analysis and the toxicity of these substances was evaluated after 2, 3, 4, and 5 h of ozonation. In addition, degradation products that may occur during ozonation were evaluated by LC-MS analysis. The 96-h LC50s of Dolphin–diflunisal, Dichloron–diclofenac sodium, and Apranax–naproxen drug–active substance pairs were determined to be 22.3 and 11.1, 25.7 and 18.7, and 47.8 mg active substance/L and 45.3 mg/L, respectively. According to the FETAX test results, the Dolphin–diflunisal drug–active ingredient pair did not cause growth retardation in exposed embryos. Dichloron–diclofenac sodium and Apranax–naproxen drug–active ingredient pairs were both teratogenic and growth inhibitory. In the second stage of the study, in which the effectiveness of ozonation in eliminating the toxic effects of drugs is evaluated, it is seen that ozonation is partially successful in eliminating the toxic effects of Dolphin–diflunisal and Dichloron–diclofenac sodium pairs, but insufficient for eliminating the effects of the Apranax–naproxen pair. [ABSTRACT FROM AUTHOR]

Bir-MnO2 was synthesized through a hydrothermal method and modified into H-Bir by nitric acid acidification. The mechanism of its action in ozonation was explored by characterization. H-Bir possessed more oxygen vacancies and lower average oxidation state (AOS) than Bir-MnO2. The oxygen vacancies and surface hydroxyl groups are the main active sites of this catalyst. Under the reaction conditions of initial pH=7 , ozone dosage of 7 mg/L , initial pollutant concentration of 10 mg/L , and catalyst dosage of 0.5 g/L for 40 min , the degradation rates of H-Bir catalyzed ozonation of p-nitrobenzoic acid (PNBA) and 4-chlorobenzoic acid (PCBA) reached 82.68% and 85.83%, respectively. Differences in the degradation factors affecting PCBA and PNBA were found in the performance study of H-Bir catalyzed ozonation. The combination of density functional theory (DFT) and catalytic ozonation experiment results revealed the difference between the degradation of PNBA and PCBA in the H-Bir/O3 system. It was deduced that the nitro, chlorine and carboxyl groups were the main reaction sites. Possible degradation pathways for the two pollutants were also proposed. [ABSTRACT FROM AUTHOR]

• CuMn 2 O 4 @LR and MnO 2 –Co 3 O 4 @LR showed good application potential and stability. • The above granular catalyst enhanced ozone mass transfer in catalytic ozonation. • CuMn 2 O 4 @LR and MnO 2 –Co 3 O 4 @LR catalyzed ozone decomposition to more •OH, •O 2 −, H 2 O 2. • The large-size supporter is more beneficial for O 3 mass transfer than the small one. Catalytic ozonation is an effective wastewater purification process. However, the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency (OUE), poor organic degradation performance, and high energy consumption. Therefore, there is an urgent need to develop efficient supported catalysts that can enhance mass transfer and performance. However, the reaction mechanism of the support on ozone mass transfer remains unclear, which hinders the development of catalytic ozonation applications. In this study, lava rocks (LR)-supported catalysts, specifically CuMn 2 O 4 @LR and MnO 2 Co 3 O 4 @LR, were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity, stability, and high OUE. Addition of CuMn 2 O 4 @LR or MnO 2 Co 3 O 4 @LR increased IBP removal efficiency from 85% to 91% or 88%, and reduced energy consumption from 2.86 to 2.14 kWh/m3 or 2.60 kWh/m3, respectively. This improvement was attributed to LR-supported catalysts enhancing mass transfer and promoting O 3 decomposition to generate •OH and •O 2 −, leading to IBP degradation. Furthermore, this study investigated the effects of ozone dose, supporter sizes, and catalyst components on ozone-liquid mass transfer. The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer. Larger-sized LR (k L a= 0.172 min−1) exhibited better mass transfer compared to smaller-sized supports. Based on these findings, it was concluded that both CuMn 2 O 4 @LR and MnO 2 Co 3 O 4 @LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater, and LR showed good credibility as a catalyst supporter. Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalytic ozonation performances for seven CeO 2 catalysts with different morphologies and exposed facets are disclosed. • CeO 2 nanorods with (1 1 0) and (1 0 0) facets exposed show the best performance. • A linear relationship between Frenkel-type OV density and O 3 decomposition rate is revealed regardless of morphology and exposed facet. • DFT calculation and experimental data reveal OV boosts O 3 activation on both the Ce and hydroxyl sites of CeO 2. Morphology and facet effects of metal oxides in heterogeneous catalytic ozonation (HCO) are attracting increasing interests. In this paper, the different HCO performances for degradation and mineralization of phenol of seven ceria (CeO 2) catalysts, including four with different morphologies (nanorod, nanocube, nanooctahedron and nanopolyhedron) and three with the same nanorod morphology but different exposed facets, are comparatively studied. CeO 2 nanorods with (1 1 0) and (1 0 0) facets exposed show the best performance, much better than that of single ozonation, while CeO 2 nanocubes and nanooctahedra show performances close to single ozonation. The underlying reason for their different HCO performances is revealed using various experimental and density functional theory (DFT) calculation results and the possible catalytic reaction mechanism is proposed. The oxygen vacancy (OV) is found to be pivotal for the HCO performance of the different CeO 2 catalysts regardless of their morphology or exposed facet. A linear correlation is discerned between the rate of catalytic decomposition of dissolved ozone (O 3) and the density of Frenkel-type OV. DFT calculations and in-situ spectroscopic studies ascertain that the existence of OV can boost O 3 activation on both the hydroxyl (OH) and Ce sites of CeO 2. Conversely, various facets without OV exhibit similar O 3 adsorption energies. The OH group plays an important role in activating O 3 to produce hydroxyl radical (∙OH) for improved mineralization. This work may offer valuable insights for designing Facet- and OV-regulated catalysts in HCO for the abatement of refractory organic pollutants. [ABSTRACT FROM AUTHOR]

In this study, selected mechanical properties of fruits of six varieties of Japanese quince (Chaenomeles japonica) were investigated. The influence of their storage time and the applied ozone at a concentration of 10 ppm for 15 and 30 min on water content, skin and flesh puncture force, deformation to puncture and puncture energy was determined. After 60 days of storage, the fruits of the tested varieties showed a decrease in the average water content from 97.94% to 94.39%. No influence of the ozonation process on the change in water content in the fruits was noted. The tests showed a significant influence of ozonation and storage time on the increase in the punch puncture force of the skin and flesh, deformation and puncture energy of the fruits. In order to establish the relationship between storage conditions for various varieties and selected mechanical parameters, a novel machine learning method was employed. The best model accuracy was achieved for energy, with a MAPE of 10% and a coefficient of correlation (R) of 0.92 for the test data set. The best metamodels for force and deformation produced slightly higher MAPE (12% and 17%, respectively) and R of 0.72 and 0.88. [ABSTRACT FROM AUTHOR]

Discharge from Wastewater Treatment Plants (WWTPs) can result in the emission of organic micropollutants (OMPs) and microplastics (MPs) into the aquatic environment. To prevent this harmful release, a pilot plant consisting of an ozonation followed by a granular activated carbon (GAC) filter was operated at a WWTP in Germany, and its side-effects on the concentrations of nitrogen (N) and phosphorous (P) compounds were measured. Over 80% of OMPs and transformation products were removed during the operating time (around 6000 bed volumes) no matter the ozone dose (from around 0.1 to 0.5 mgO3/mgDOC), except for Diatrizoic acid, whose breakthrough appeared at 3500 BV. Formation of the oxidation by-product, NDMA, increased with higher ozone doses, but the concentration remained below 100 ng/L. Bromate was formed at a higher ozone dose (>0.4 mgO3/mgDOC) but at a low concentration—below 10 µg/L. The MP particles detected in the inflow (PE, SBR, PP, and PS) were effectively eliminated to a high degree, with a removal rate of at least 92%. Carbon parameters (COD, DOC, and SAC254) were removed further by the pilot plant, but to different extents. As expected, nitrate was formed during ozonation, while nitrite's concentration decreased. Further, nitrite decreased and nitrate increased within the GAC filter, while ammonium was eliminated by at least 90%. Total P concentration decreased after the pilot, but the concentration of PO4-P increased. [ABSTRACT FROM AUTHOR]

The degradation of ciprofloxacin hydrochloride (CFX), an extensively utilized antibiotic for bacterial infections, has been studied through the application of advanced oxidation processes (AOPs) including hydrodynamic cavitation (HC), ozonation (O3), the Fenton reaction, chemical oxidation, and hybrid AOPs such as HC/O3 and Fenton/O3. Among these, the hybrid combination of HC/O3 demonstrated the highest CFX degradation of 99.82 % within 180 min having an initial concentration of 1000 ppm. The optimization of the HC/O3 process was conducted by varying parameters including initial concentration, pH, ozone (O3) gas flowrate, and temperature. Throughout the degradation process, CFX underwent intermediate formation, which gradually degraded over time. [ABSTRACT FROM AUTHOR]

A pilot-scale investigation of ozonation combined with electrolysis (E-O3) was performed to treat concentrated wastewater from a reverse osmosis system from the printing and dyeing industry. It was found that E-O3 only exhibits an efficiency advantage after the removal of carbonate ions. The synergy of ozone and electrolysis lies not only in the generation of hydroxyl radicals, but also in the degradation of organic compounds. Moreover, the combination of electrolysis and ozonation has an inhibitory effect on the decrease in pH, which plays an important role in the synergistic generation of hydroxyl radicals. This pilot-scale study holds reference significance for the engineering applications of the E-O3 technology. [ABSTRACT FROM AUTHOR]

The present study employed an NH2-MIL-68 (Al) composite for investigating the efficiency of the catalytic ozonation process for degradation of acid blue 113 dye (AB113) from an aqueous media. A facile one-step solvothermal method was used to synthesise NH2-MIL-68 (Al). The effect of varied operational parameters such as pH (3–11), initial dye concentration (20–100 mg/L), catalyst dosage (0.4–2 g/L), and contact time (12–36 min) was optimised via the use of a central composite design (CCD) through response surface methodology (RSM). The results of the study indicated that the highest degradation of the dye was 79.9% at pH (9), initial dye concentration (20 mg/L), catalyst dosage (2 g/L), and contact time (36 min). Additionally, the reusability experiments showed that the efficiency of the process was above 85% after 5 consecutive times of NH2 -MIL-68 (Al) reuse. This research has conclusively highlighted that MIL-68 is a promising potential candidate to remove organic dyes from water and wastewater. [ABSTRACT FROM AUTHOR]

• Ozonation enhanced the formation potential of regulated DBPs from Phe chlorination. • CH with highest yield of 21.31+1.05 ug/mgPhe was enhanced to 3 times after ozonation. • The DBPs formation rates in the first 6 h were much higher than subsequent time. • Br− promoted brominated DBPs generation and elevated the total cytotoxicity. • Ozonation enhanced the BIF of THMs, while reduced that of DHAAs. As a strong oxidizing agent, ozone is used in some water treatment facilities for disinfection, taste and odor control, and removal of organic micropollutants. Phenylalanine (Phe) was used as the target amino acid to comprehensively investigate variability of disinfection byproducts (DBPs) formation during chlorine disinfection and residual chlorine conditions subsequent to ozonation. The results showed that subsequent to ozonation, the typical regulated and unregulated DBPs formation potential (DBPsFP), including trichloromethane (TCM), dichloroacetonitrile (DCAN), chloral hydrate (CH), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and trichloroacetamide (TCAcAm) increased substantially, by 2.4, 3.3, 5.6, 1.2, 2.5, and 6.0 times, respectively, compared with only chlorination. Ozonation also significantly increased the DBPs yield under a 2 day simulated residual chlorine condition that mimicked the water distribution system. DBPs formations followed pseudo first order kinetics. The formation rates of DBPs in the first 6 hr were higher for TCM (0.214 hr−1), DCAN (0.244 hr−1), CH (0.105 hr−1), TCAcAm (0.234 hr−1), DCAA (0.375 hr−1) and TCAA (0.190 hr−1) than thereafter. The peak DBPsFP of TCM, DCAN, CH, TCAcAm, DCAA, and TCAA were obtained when that ozonation time was set at 5–15 min. Ozonation times > 30 min increased the mineralization of Phe and decreased the formation of DBPs upon chlorination. Increasing bromine ion (Br−) concentration increased production of bromine- DBPs and decreased chlorine-DBPs formation by 59.3%–92.2%. Higher ozone dosages and slight alkaline favored to reduce DBP formation and cytotoxicity. The ozonation conditions should be optimized for all application purposes including DBPs reduction. [Display omitted] [ABSTRACT FROM AUTHOR]

In this research, ozone gas was used at concentrations of 2 and 5ppm in different stages of brined ultrafiltered cheese production and then the samples were subjected to microbial and chemical (protein, pH 4.6-SN/TN, TCA-SN/TN, PTA-SN/TN, fat, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA)) analyses during ripening. Ozone treatments included: ozonation of concentrate simultaneously with starter inoculation (OA), ozonation of concentrate before starter inoculation (OB), ozonation of concentrate and brine (OC), ozonation of brine (OD) and control (C). Based on the results, the values of the cheese proteolysis products (pH 4.6-SN/TN, TCA-SN/TN, and PTA-SN/TN) and their protein and fat contents significantly (p ≤ 0.05) increased and decreased, respectively, over the ripening period. The level of MUFA also experienced a significant (p ≤ 0.05) decrease until day 35 of the ripening, followed by an increase until the end of the ripening period. The highest levels of pH 4.6-SN/TN, TCA-SN/TN, and PTA-SN/TN were associated with samples OB5, OC5, and OC5, respectively, whereas the control exhibited the lowest values for these parameters. The fat content of the OA5 sample was significantly (p ≥ 0.05) lower than other samples. On most ripening days, ozonation of the samples did not significantly change their MUFA levels. The PUFA content of the treated samples was also variable on different treatment days. The counts of mold and yeast initially increased until day 70 but subsequently decreased until the end of the ripening period. Throughout the ripening period, the mold and yeast counts of the OA5 and OC5 samples were significantly (p ≤ 0.05) lower than the other treatments. As a result, the use of ozone treatment increased the shelf life of the cheese samples and also enhanced the production of products resulting from proteolysis. [ABSTRACT FROM AUTHOR]

• O 3 reacts with KET to form Criegee intermediates through ring-opening. • HO· can greatly promote the degradation of KET in UV/O 3 process. • Kinetics modeling in UV/O 3 was performed to study the effect of parameters on efficiency. • Some products still have eco-toxicity effects on aquatic organisms. Ketoprofen (KET), as a non-steroidal anti-inflammatory drug frequently detected in aqueous environments, is a threat to human health due to its accumulation and low biodegradability, which requires the transformation and degradation of KET in aqueous environments. In this paper, the reaction process of ozone-initiated KET degradation in water was investigated using density functional theory (DFT) method at the M06-2X/6-311++g(3df,2p)//M06-2X/6-31+g(d,p) level. The detailed reaction path of KET ozonation is proposed. The thermodynamic results show that ozone-initiated KET degradation is feasible. Under ultraviolet irradiation, the reaction of ozone with water can also produce OH radicals (HO·) that can react with KET. The degradation reaction of KET caused by HO· was further studied. The kinetic calculation illustrates that the reaction rate (1.99 × 10−1 (mol/L)−1 sec−1) of KET ozonation is relatively slow, but the reaction rate of HO· reaction is relatively high, which can further improve the degradation efficiency. On this basis, the effects of pollutant concentration, ozone concentration, natural organic matter, and pH value on degradation efficiency under UV/O 3 process were analyzed. The ozonolysis reaction of KET is not sensitive to pH and is basically unaffected. Finally, the toxicity prediction of oxidation compounds produced by degradation reaction indicates that most of the degradation products are harmless, and a few products containing benzene rings are still toxic and have to be concerned. This study serves as a theoretical basis for analyzing the migration and transformation process of anti-inflammatory compounds in the water environment. [ABSTRACT FROM AUTHOR]

Nowadays, it is still a challenge to prepared high efficiency and low cost formaldehyde (HCHO) removal catalysts in order to tackle the long-living indoor air pollution. Herein, δ-MnO 2 is successfully synthesized by a facile ozonation strategy, where Mn2+ is oxidized by ozone (O 3) bubble in an alkaline solution. It presents one of the best catalytic properties with a low 100% conversion temperature of 85°C for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr). As a comparison, more than 6 times far longer oxidation time is needed if O 3 is replaced by O 2. Characterizations show that ozonation process generates a different intermediate of tetragonal β-HMnO 2 , which would favor the quick transformation into the final product δ-MnO 2 , as compared with the relatively more thermodynamically stable monoclinic γ-HMnO 2 in the O 2 process. Finally, HCHO is found to be decomposed into CO 2 via formate, dioxymethylene and carbonate species as identified by room temperature in-situ diffuse reflectance infrared fourier transform spectroscopy. All these results show great potency of this facile ozonation routine for the highly active δ-MnO 2 synthesis in order to remove the HCHO contamination. [ABSTRACT FROM AUTHOR]

Antibiotics have several negative effects on aquatic ecosystems and are difficult to degrade using traditional water/wastewater treatment methods. As a result, new treatment techniques must be employed to eliminate these contaminants from aquatic environments. Research on the relationship between the decomposing process of antibiotics and different factors by new technologies is scarce. This research focuses on the capability of ozone micro-nano bubbles (OzMNBs) to eliminate the antibiotics ciprofloxacin (CIPR) and levofloxacin (LEVO) in aqueous solutions. We studied the CIPR and LEVO decomposition to different variables through the central composite design method. The main variables included pH, ozonation time, and initial antibiotic concentration. The correlation coefficients of the quadratic model obtained by using the software, Design Expert version 13.0.1. Analysis of variances proved the significance of models and main factors. Verification tests also confirmed that the final optimum conditions of the antibiotics decomposition were: pH 9, ozonation for 40 min and, initial antibiotic concentration of 5 mg/L. In optimum conditions, removal rate of about 97% and 100% was obtained for CIPR and LEVO, respectively. The order of influence of various factors on CIPR and LEVO decomposition were obtained and the interactions between the main factors were also investigated. At the last stage of the research, the efficiency of OzMNBs in the removal of total organic carbon and mineralization of the solutions containing CIPR and LEVO under optimum conditions was examined. [ABSTRACT FROM AUTHOR]

The study investigates the effect of different parameters for the removal of SO2 and NOx through a wet process concurrently. Two separate processes have been compared for the removal of flue gases, that is, Ozone/UV and H2O2/UV. The research aims to develop a comparative study for the removal of SO2 and NOx simultaneously using Ozone/H2O2 and UV light and find the energy consumption (also known as EEO) for each process. Combining UV with O3 and H2O2 play a crucial role in generating hydroxyl radicals. Different combinations of Ozone/H2O2, flue gas, and UV intensity were studied at different pH and temperatures of the solution to achieve maximum removal of the flue gases. For, the ozonation process it was observed that the removal% of flue gases increases with increasing UV intensity, and at higher UV intensity (250 W), the removal% for NOx is 92% and SO2 is 95% simultaneously at optimum temperature 308 K. For H2O2/UV process (250 W UV intensity), removal% for NOx is 95% and SO2 is 100% at 313 K, 0.3 LPM flow rate of flue gases. The EEO values obtained for both processes were less than 1 for 95% NOx/SO2 removal efficiency. [ABSTRACT FROM AUTHOR]

Photocatalytic ozonation is considered to be a promising approach for the treatment of refractory organic pollutants, but the design of efficient catalyst remains a challenge. Surface modification provides a potential strategy to improve the activity of photocatalytic ozonation. In this work, density functional theory (DFT) calculations were first performed to check the interaction between O3 and TiO2−OH (surface hydroxylated TiO2) or TiO2−F (surface fluorinated TiO2), and the results suggest that TiO2−OH displays better O3 adsorption and activation than does TiO2−F, which is confirmed by experimental results. The surface hydroxyl groups greatly promote the O3 activation, which is beneficial for the generation of reactive oxygen species (ROS). Importantly, TiO2−OH displays better performance towards pollutants (such as berberine hydrochloride) removal than does TiO2−F and most reported ozonation photocatalysts. The total organic carbon (TOC) removal efficiency reaches 84.4 % within two hours. This work highlights the effect of surface hydroxylation on photocatalytic ozonation and provides ideas for the design of efficient photocatalytic ozonation catalysts. [ABSTRACT FROM AUTHOR]

Ozone-based advanced oxidation processes (AOPs) have emerged a promising avenue for water treatment, offering effective removal of micropollutants. Recent research underscores the potential of ozone microbubbles to enhance ozone mass transfer during water treatment, particularly when combined with pre-treatment steps. This study aimed to evaluate the efficacy of three different combined processes (chlorine/KMnO4/PAC pre-treatment followed by ozonation) in removing atrazine, a common micropollutant from natural source water. Results revealed that all combined processes achieved higher atrazine removal rates compared to individual pre-treatment or ozonation methods. Notably, the highest atrazine removal rates were observed under alkaline pH conditions, with treatment outcomes influenced by oxidant dose and pH levels. Among the combined processes, chlorine pre-treatment followed by ozonation emerged as the most effective approach, achieving a removal rate of 59.7% that exceeded the sum of individual treatments. However, this treatment efficacy was affected by water quality parameters, particularly the presence of organic matter and elevated ammonia nitrogen concentration (> 0.5 mg/L). This study highlights the potential for utilizing ozone micro/nanobubbles to enhance ozone mass transfer and offers valuable insights for optimizing the combined application of pre-treatment and ozonation strategies for efficient atrazine removal from natural water sources. [ABSTRACT FROM AUTHOR]

The textile industry uses high amounts of water and dyestuffs, and accordingly, wastewater containing significant amounts of dyestuffs is produced, which have to be treated before being discharged to the environment. The aim of this study is the treatment of synthetic wastewater containing 50 mg/L Acid Violet 90 dyestuff with catalytic ozonation process have been investigated by using n.CeO2, n.ZnO and n.CeO2/n.ZnO (1:1, m:m) nanocatalysts. The process optimization has been performed with the pH, ozone dose, catalyst dose and reaction time parameters. While the optimum conditions have been determined as pH 3, 600 mg/L ozone dose, 10 min reaction time, for all three catalysts, catalyst doses have differed as 50 mg/L for n. CeO2, 30 mg/L for n.ZnO and n.CeO2/n.ZnO. The removal efficiencies of AV 90 have been achieved as 97.04, 96.2 and 95.7% for n.CeO2, n.ZnO and n.CeO2/n.ZnO catalysts, respectively. Kinetic analyses showed that color removal of AV 90 dyestuff followed First order kinetics with R2 values of 0.9987 (n.CeO2), 0.9912 (n.ZnO) and 0.9923 (n.CeO2/n.ZnO) and reaction rate constant values have been calculated as 0,3435 (n.CeO2), 0,3551(n.ZnO) and 0,3226 (n.CeO2/n.ZnO) min−1. [ABSTRACT FROM AUTHOR]

In this study, the aim is to assess the toxicity of tannery wastewater treated with electrocoagulation and ozonation to determine the suitability of the approach for application, while maintaining the environmental quality of receiving water bodies and/or sewer systems. For this, an electrocoagulation reactor and an ozonation tank were built considering current intensity (I), treatment time (T), and ozone concentration O3 as operating factors. Acute toxicity tests were conducted using Lactuca sativa L. lettuce seeds for the raw sample (MI), sample treated with electrocoagulation (EC), and sample treated with EC and ozonation (EC + OZ). The toxicity parameters assessed in this study were the absolute germination (AG), germination index (GI), and average inhibition concentration (EC50). The electrocoagulation reactor achieved 92% removal efficiency for total suspended solid (TSS) and 10% removal efficiency for chemical oxygen demand (COD) with a current intensity of 7A and a treatment time of 30 min. In addition, the COD was further reduced in the ozonation tank by 18% with an ozone dosage of 10 g/h and a contact time of 30 min. Despite these treatments, EC50 values indicated acute toxicity in all three samples. The ANOVA analysis (p value of 0.05) revealed no significant differences between the GI values for the three samples, suggesting that toxicity did not decrease substantially, despite treatment. This is attributed to the incomplete removal of the pollutant load, expressed as COD, and formation of recalcitrant and toxic compounds during treatment processes. This work demonstrates the importance of including the "toxicity" variable in the assessment of treatments to conduct them in an integral way and preserve the environmental quality of receiving water bodies. [ABSTRACT FROM AUTHOR]

Due to enormous quantities with hazards and complexity in nature is a big challenge for effective treatment of wastewater from pharmaceutical processes including herbal extraction through conventional methods of distillation. The situation is further aggravated in countries facing high rising population, urbanization, and industrialization resulting in the generation of industrial wastes. The study has been carried out in the herbal extraction industry by conducting stage-wise sampling of ETP based on the conventional method and further coupled with ozonation as an advanced treatment to comply with regulatory standards. Additionally, the same process was studied that implementing the best available technology (BAT) by providing ETP with advanced technology modules such as MBR (membrane bioreactor) + RO + O3 has not only resulted in compliance with standards but also reuse of treated wastewater into the process and utilities has been proved to be techno-economically a viable and sustainable option. Modifying existing aeration tanks and advanced oxidation through ozone injection post-biological treatment has resulted in COD and BOD reduction of 96.42% and 99.0% respectively. Whereas in the case of MBR + RO + O3, the values of pH, BOD, COD, TSS, and sulfide have been observed as 8.32, 2.0 mg.L-1, 14.0 mg.L-1, 1.0 mg.L-1 and 0.0 mg.L-1 respectively and 98% recovery of treated effluent, thus saving 44 KL.day-1 of freshwater resulting into significant financial benefits of Rupees 12.59 lacs annually, which otherwise was outsourced through tankers. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of blast furnace slags (BFSs) as catalysts in the ozonation process to degrade complex contaminants such as bezafibrate (BFZ) at different pH levels. The findings reveal that the presence of BFS enhances degradation efficiency, achieving a 10% improvement at pH 10 and a 30% improvement at pH 5.5 compared to simple ozonation. The highest degradation efficiency was observed in the Ozonation–BFS system at pH 10, with 90% decomposition of BFZ. These results were corroborated through ozone consumption analysis, BOD5 measurements, and the identification of oxalic acid as the final decomposition product. Due to the complexity of the reaction system, kinetic characterization was performed using non-parametric modeling based on differential neural networks. The model indicated that the observed reaction rate for BFZ degradation in the presence of ozone and BFS was 4.12 times higher at pH 5.0 and 1.08 times higher at pH 10.0 compared to simple ozonation. These results underscore the potential of using BFS in catalytic ozonation processes for the effective treatment of recalcitrant contaminants in wastewater. [ABSTRACT FROM AUTHOR]

Ultrafiltration (UF) technology is an efficient shale gas flowback water treatment method. However, severe membrane fouling is the primary restriction on the application of UF technology. Here, we studied the impact of three pretreatments: precipitative softening (PS), precipitative softening, followed by ozonation (PS-O) and ozonation, followed by precipitative softening (O-PS), on pollutants' removal efficiencies and membrane fouling. The results showed that (1) the hardness, bacteria, scaling trend and compatibility with formation water exceeded the requirements for water reuse; (2) pretreatments effectively increased water flux and prolonged ultrafiltration membrane life, and both of them followed the order of PS-O process > O-PS process > PS process; (3) the fouling mechanism was changed from the complete blocking model to the standard blocking model by the PS process and the addition of ozonation enhanced the correlation of standard blocking model; (4) the quality of fracturing liquid prepared by the effluent treated by the PS-O-UF process was the best and satisfied the requirements of slick water. This paper indicated that the PS-O-UF process was suitable for the treatment of Changning shale gas flowback water for reuse. [ABSTRACT FROM AUTHOR]

AbstractAntibiotics, posing a major threat to life on earth and water causing propagation of antibiotic resistant bacteria and antibiotic resistant mutant genes. Traces of these antibiotic toxins are found both in aquatic as well as terrestrial ecosystem. Various techniques, that is, ozonation, membrane filtration, Fenton process, etc., are applied for their removal but have many shortcomings, so adsorption is picked as efficient, simple and relatively safe removal technique. This review article discusses the classification of antibiotics, effect of their unnecessary application and removal methods of their remnants from water sources. Also, compares adsorptive removal of antibiotics remnant with other primitive and advance techniques, suggesting adsorption as one of the effective techniques. [ABSTRACT FROM AUTHOR]

A diatomite-modified Fe2O3 (Fe2O3/Dia) catalyst was prepared to catalyze the ozonation degradation of sulfachloropyridazine sodium (SPDZ). The chemical oxygen demand (COD) was used as the index of pollutant degradation. The catalytic ozonation experiment showed that the COD removal rate of SPDZ was 87% under Fe2O3/Dia catalysis, which was much higher than that obtained when using Fe2O3 as the catalyst. The characteristics of the Fe2O3/Dia catalyst were investigated, and the successful synthesis of the Fe2O3/Dia composite catalyst was proved by XRD, XPS, SEM, FTIR, BET and other characterization methods. The catalytic mechanism of degradation by ozone with Fe2O3/Dia was analyzed. According to free-radical trapping experiments and an in situ electron paramagnetic spectrometer characterization analysis, the main oxidizing species in the catalytic Fe2O3/Dia ozone system is ·OH. The intermediates in the degradation process of SPDZ were detected and analyzed in detail by liquid chromatography-coupled mass spectrometry. The degradation mechanism and three degradation paths of SPDZ were proposed. [ABSTRACT FROM AUTHOR]

In this study, the treatment of synthetic wastewater containing 10 mg/L Bisphenol A (BPA) has been investigated by the catalytic and photocatalytic ozonation process. n.TiO2 nanocatalysts have been used in catalytic (COP) and photocatalytic (PCOP) ozonation processes. Optimum parameters have been determined as pH 6.32, 1200 mg/L ozone dose, 50 mg/L n.TiO2 catalyst dose and 12.5 min reaction time for COP. Optimum parameters have been found as pH 6.32, 1200 mg/L ozone dose, 50 mg/L n.TiO2 catalyst dose, 18 Watt UV light intensity, and 10 min reaction time for PCOP. The removal efficiencies of BPA have been obtained as 95.51% and 98.09% for COP and PCOP, respectively. Kinetic analyses showed that BPA removal has been carried out Pseudo second order kinetics with R2 values of 99.1 for both processes. [ABSTRACT FROM AUTHOR]

Clean water is a necessity for all life to survive and flourish. However, natural waters are being continuously contaminated due to the release of waste streams in water. Hence, it is important to remove pollutants from wastewater to fulfill human needs. Conventional treatment methods are neither efficient nor economical for wastewaters that especially contain refractory toxic pollutants. This requires novel techniques like Advanced oxidation processes (AOPs), that may successfully degrade persistent micropollutants more efficiently. In this study, an azo dye Acid Red 1 was removed by three AOPs, namely Photocatalytic oxidation, Ozonation and Photocatalytic Ozonation, by employing heterogenous catalysts. TiO2 was used as photocatalyst, whereas Fe-Zeolite has been further added as Ozonation catalyst. The study revealed that photocatalysis degraded only 28% Acid red dye after 15 min, whereas for ozonation, the degradation percentage was 95% in same time. In combined photocatalytic ozonation process using TiO2, 95% degradation was achieved in just 9 min and treatment time further reduced to 5 min when Fe-zeolite was added. Optimization studies for initial concentration, UV intensity and catalyst loading were performed. Finally, rate constants and Electrical Energy per Order (EEO) values were determined for all AOPs, and mechanism was proposed. [ABSTRACT FROM AUTHOR]

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The performance of catalytic ability of MFe2O4/MoS2 in the ozonation process was investigated in this work. The synthesized MnFe2O4/MoS2 was optimize prepared and then characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, and magnetic saturation strength. The results showed that when Cphenol = 200 mg/L, initial pH = 9.0, Q = 0.10 L/min, and CMnFe2O4/MoS2 = 0.10 g/L, MnFe2O4/MoS2 addition improved the degradation efficiency of phenol by 20.0%. The effects of pH, catalyst dosage, and inorganic ions on the phenol removal by the MnFe2O4/MoS2 catalytic ozonation were investigated. Five cycle experiments proved that MnFe2O4/MoS2 had good recyclability and stability. MnFe2O4/MoS2 also showed good catalytic performance in the treatment of coal chemical wastewater pesticide wastewater. The MnFe2O4 doped with MoS2 could provide abundant surface active sites for ozone and promote the stable cycle of Mn2+/Mn3+and Fe2+/Fe3+, thus generating large amounts of •OH and improving the degradation of phenol by ozonation. The MnFe2O4/MoS2/ozonation treatment system provides a technical reference and theoretical basis for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

The removal of persistent organic micropollutants (OMPs) from secondary effluent in wastewater treatment plants is critical for meeting water reuse standards. Traditional treatment methods often fail to adequately degrade these contaminants. This study explored the efficacy of a hybrid ozonation membrane filtration (HOMF) process using CeO2 and CeTiOx-doped ceramic crossflow ultrafiltration ceramic membranes for the degradation of OMPs. Hollow ceramic membranes (CM) with a 300 kDa molecular weight cut-off (MWCO) were modified to serve as substrates for catalytic nanosized metal oxides in a crossflow and inside-out operational configuration. Three types of depositions were tested: a single layer of CeO2, a single layer of CeTiOx, and a combined layer of CeO2 + CeTiOx. These catalytic nanoparticles were distributed uniformly using a solution-based method supported by vacuum infiltration to ensure high-throughput deposition. The results demonstrated successful infiltration of the metal oxides, although the yield permeability and transmembrane flow varied, following this order: pristine > CeTiOx > CeO2 > CeO2 + CeTiOx. Four OMPs were examined: two easily degraded by ozone (carbamazepine and diclofenac) and two recalcitrant (ibuprofen and pCBA). The highest OMP degradation was observed in demineralized water, particularly with the CeO2 + CeTiOx modification, suggesting O3 decomposition to hydroxyl radicals. The increased resistance in the modified membranes contributed to the adsorption phenomena. The degradation efficiency decreased in secondary effluent due to competition with the organic and inorganic load, highlighting the challenges in complex water matrices. [ABSTRACT FROM AUTHOR]

In this work, Ce-doped Mn/γ-Al2O3 catalysts (Mn (Cex)/γ-Al2O3) with different Ce/Mn molar ratios were prepared for catalytic ozonation of pollutants in petroleum refinery wastewater (PRW). Results showed that compared to Mn/γ-Al2O3 catalyst, the performances of Mn (Cex)/γ-Al2O3 catalysts were notably improved, especially Mn (Ce0.20)/γ-Al2O3 catalyst demonstrated the highest activity and improved stability for the degradation of PRW (> 97% of chemical oxygen demand (COD) in PRW was removed and the molecules of petroleum-derived pollutants were almost completely degraded in 1.5 h treatment, and the catalyst showed no obvious decrease in activity after 5 cycles). The results of catalyst characterization confirmed that doping Ce changed the growth characteristics of the catalysts, increased the content of active phase α-MnO2 in the catalysts and led to the growth of α-MnO2 along crystal planes (310) preferentially, prevented catalyst particles from growing, and also enhanced the dispersion of those catalyst particles. Moreover, electron paramagnetic resonance (EPR) experiments revealed that Mn (Ce0.20)/γ-Al2O3 catalyst promoted the production of more hydroxyl radicals (•OH) and superoxide anion (•O2−). The influences of catalyst dose, O3 concentration and pH on the degradation were also investigated. This work provided a theoretical basis and an experimental reference for the preparation of highly active Mn-based catalysts for deep ozonation of PRW by HCOP. [ABSTRACT FROM AUTHOR]

In this study, a novel NiAl2O4/NiO@γ-Al2O3 catalyst was prepared by the impregnation-calcination method and used for the catalytic ozonation of tartrazine wastewater. The NiAl2O4/NiO@γ-Al2O3 catalyst were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption experiments. It was found that NiAl2O4/NiO@γ-Al2O3 significantly improved the removal of chemical oxygen demand of the dye wastewater from 40% for the direct ozone oxidation to 65%, and the ozone concentration depletion for catalytic ozonation was 120% of that for ozone alone. The catalytic activity of the catalyst did not significantly decrease after reuse for six cycles and leaching concentration of metal ions less than 1%. However, the toxicity of the dye wastewater was greatly reduced after the catalytic ozonation. The pyridine Fourier transform infrared spectroscopy showed the catalytic ozonation reaction was related with Lewis acid sites. The presence of hydroxyl radicals, superoxide anion radicals, and singlet oxygen was verified by an electron paramagnetic resonance, and the quenching experiments confirmed that the removal of organic pollutants from the tartrazine wastewater mainly relied on hydroxyl radicals and singlet oxygen. Therefore, the NiAl2O4/NiO@γ-Al2O3 could be an effective catalyst for the rapid catalytic ozonation of dye wastewater. [ABSTRACT FROM AUTHOR]

The combination of ozone and hydrogen peroxide (O3/H2O2), or the peroxone process, has often been used as an advanced oxidation process (AOP) in groundwater remediation and drinking water applications. This historical precedent sometimes leads to the misconception that H2O2 addition is required to achieve AOP conditions during ozonation. This is not the case for secondary or tertiary wastewater effluent applications, in which ozone reacts with abundant dissolved organic carbon (DOC) to generate hydroxyl radicals (∙OH). This study demonstrates the use of ozone with and without H2O2 addition to yield ∙OH exposures (up to 10−9 M-s) capable of achieving > 0.5-log10 attenuation of the industrial contaminant and probable human carcinogen 1,4-dioxane. This low molecular weight compound is commonly used as a surrogate when establishing AOP design criteria for potable reuse applications. DOC-normalized ozone doses (i.e., O3/DOC ratios) of ~ 1.0 and ~ 1.3 achieved 0.5-log10 attenuation of 1,4-dioxane with O3/H2O2 and O3, respectively. Also, a predictive model based on ∙OH exposure was accurate within approximately ± 10%. These results suggest that ozonation's role as an AOP, even in the absence of H2O2, should be acknowledged in regulatory frameworks to reduce unnecessary treatment redundancy and facilitate broader implementation of potable reuse. [ABSTRACT FROM AUTHOR]

Delignification has an important role in biomass utilization framework of Empty Fruit Bunch of Palm Oil (EFB). EFB from Sulawesi Island with high lignin reached 45% was a challenge. Innovation for delignification should be delivered to remove lignin but keep holocellulose, cellulose, and hemicellulose. Treated EFB improved accessible the holocellulose for subsequent process like enzymatic process. Delignification would remove or break down lignin to increase the accessibility. Delignification by ozonized NaOH solution conducted at ambient temperature to save energy and low NaOH concentration, 3.2%. Ozonization NaOH solution with 500 ppm H2O2 would produce hydroxyl radical (OH°), an oxydator. ORP, TDS, and TSS of black liquor was observed to assess any suspended and dissolved solid of EFB. Treated EFB was analized for its component, lignin, and holocellulose. At higher NaOH solution was the higher TSS in ozonized NaOH solution. The highest TSS by ozonized 0.8 M NaOH reached 50.810 ppm. Unfortunately, the holocellulose was also decomposed as well. Thus, the yield was decrease since both lignin and holocellulose degraded. Optimal delignification was figure out at 0.4 M or 1.6% NaOH whereas lignin decreasing and holocellulose increasing by 30.8% and 27.17%, respectively. XRD analysis clarified improvement of this delignification for crystallinity increased 8.5%, 69%, closer to α-cellulose. Morphology by SEM showed remove the impurities successfully and Si, Nb, Mg, and Ca detected by EDS. [ABSTRACT FROM AUTHOR]

The development of technologies for highly efficient treatment of emissions containing low concentrations of volatile organic compounds (VOCs) remains an important challenge. Catalytic oxidation with ozone (catalytic ozonation) is useful for the oxidative decomposition of VOCs, particularly aromatic compounds, under ambient temperature conditions. Only inexpensive transition metal oxides are required as catalysts, and Mn-based catalysts are widely used for catalytic ozonation. This review describes the oxidation reaction mechanisms, reaction pathways of aromatic hydrocarbons, and dependence of the catalytic ozonation activity on the reaction conditions. The reasons why Mn oxides are effective in catalytic ozonation are also explained. The structure of the catalytic active sites and the types of supporting materials contributing to the reaction are also discussed in detail, with the aim of establishing a VOC control technology. In addition, recent progress in catalytic oxidation processes using ozone as an oxidant has been outlined, focusing on catalyst materials and reaction conditions. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysts for catalytic ozonation are elaborately designed with commendable intrinsic activity, while their industrial applications are limited by inadequate mass transfer of ozone (O3). In this work, it is demonstrated that engineering the surface aerophilicity of heterogeneous catalyst enables fast mass transfer of O3 reactant, giving rise to much enhanced catalytic ozonation performance. Taking active 4A zeolite catalyst as an example, the aerophilicity of spherical 4A zeolite can be greatly enhanced by coating polytetrafluoroethylene (PTFE) with low surface energy, and the optimized sample exhibits a 99.5% removal of atrazine (ATZ) within 20 min (corresponding to a k of 0.269 min−1), much better than 4A zeolite without surface aerophilicity engineering (k≈0.156 min−1). The PTFE coating does not change the ozone activation mechanism and degradation pathways for ATZ, further demonstrating that the enhanced ozonation activity is attributed to the enhanced mass transfer process. In addition, the general applicability of this surface aerophilicity and the potential ozonation application for industrial wastewater treatment are both demonstrated. [ABSTRACT FROM AUTHOR]

Municipal waste biomass could be valorized as an alternative feedstock to produce compounds beneficial for agricultural applications. The foliar spray application of biostimulants emerges as a promising and innovative technique due to its environmental safety and ability to enhance crop yields. In recent years, the exploitation of biopolymers obtained through alkaline hydrolysis of the solid anaerobic digestate from municipal biowastes has attracted researchers' interest. The aim of this study is to investigate the effects on lettuce growth of a product obtained through alkaline hydrolysis from municipal biowaste, Biopolymers (BPs), and of a derivate subjected to a further oxidation process, Biopolymers Oxidate (BPs OX). The effects of the treatments at various concentrations were evaluated by monitoring plant growth and observing the trends in the activities of the main enzymes involved in the nitrogen metabolic pathway of lettuce. Results suggest that the best treatments in terms of fresh weight were achieved by using BPs at 10 mg/L and BPs OX at 100 mg/L, increasing yield by around 28% and 34%, respectively. The innovative aspect of this work was to make easier for farmers the biopolymers application by testing a foliar spray methodology for BPs and BPs OX, which has never been tested before in any crop. [ABSTRACT FROM AUTHOR]

Anaerobic digestion of animal manure generates biogas and removes biodegradable organic matter, while most of the nitrogen and phosphorous remains at very high levels after the process. A subsequent microalgae culture in the digestate provides nutrient uptake at very low operational and installation costs. However, the dark color of manure digestate prevents light penetration, reducing the rates of algae growth. Ozonation was researched as a strategy for color removal followed by microalgae culture. Although similar biomass production was achieved in treated and untreated digestates (1.09 vs. 0.99 g L−1), the positive effect of ozonation was evidenced by the significantly higher rates of photosynthetically produced oxygen: 0.804 and 0.18 mg O2 mg−1 TSS min−1, respectively, in ozonated and untreated digestates, revealing a four times higher rate of algae activity. However, this considerable higher activity was not correlated with better performance in nutrient removal since the microalgae treatment was assayed at a considerably reduced scale with a high ratio of illumination per volume. An operational costs analysis revealed that ozonation could be competitive against other strategies of color reduction such as dilution or coagulation/flocculation processes. [ABSTRACT FROM AUTHOR]

Ni‐Mn@KL ozone catalyst was prepared for the efficient treatment of reverse osmosis membrane concentrates. The working conditions and reaction mechanism of the ozone‐catalyzed oxidation by Ni‐Mn@KL were systematically studied. Then, a comprehensive CRITIC weighting–coupling coordination evaluation model was established. Ni‐Mn@KL was characterized by scanning electron microscopy, BET, X‐ray diffraction, X‐ray photoelectron spectroscopy, energy‐dispersive spectrometry, and X‐ray fluorescence spectrometry and found to have large specific surface area and homogeneous surface dispersion of striped particles. Under the optimum working conditions with an initial pH of 7.9 (raw water), a reaction height‐to‐diameter ratio of 10:1, an ozone‐aeration intensity of 0.3 L/min, and a catalyst filling rate of 10%, the maximum COD removal rate was 60.5%. Free‐radical quenching experiments showed that OH oxidation played a dominant role in the Ni‐Mn@KL‐catalyzed ozone‐oxidation system, and the reaction system conformed to the second‐order reaction kinetics law. Ni‐Mn@KL catalysts were further confirmed to have good catalytic performance and mechanical performance after repeated utilization. Practitioner Points: Ni‐Mn@KL catalyst can achieve effective treatment of RO film concentrated liquid.High COD removal rate of RO membrane concentrated liquid was obtained at low cost.Ni‐Mn@KL catalyst promotes ozone decomposition to produce ·OH and O2−· oxidized organic matter.The Ni‐Mn@KL catalyst can maintain good stability after repeated use.A CRITIC weight–coupling coordination model was established to evaluate the catalytic ozonation. [ABSTRACT FROM AUTHOR]

Fly ash, a type of solid waste generated in power plants, can be utilized as a catalyst carrier to enhance its value-added potential. Common methods often involve using a large amount of alkali for preprocessing, resulting in stable quartz and mullite forming silicate dissolution. This leads to an increased specific surface area and pore structure. In this study, we produced a catalyst composed of MnOx/NiOOH supported on fly ash by directly employing nickel hydroxide and potassium permanganate to generate metal active sites over the fly ash surface while simultaneously creating a larger specific surface area and pore structure. The ozone catalytic oxidation performance of this catalyst was evaluated using sodium acetate as the target organic matter. The experimental results demonstrated that an optimal removal efficiency of 57.5% for sodium acetate was achieved, surpassing even that of MnOx/NiOOH supported catalyst by using γ-Al2O3. After loading of MnOx/NiOOH, an oxygen vacancy is formed on the surface of fly ash, which plays an indirect oxidation effect on sodium acetate due to the transformation of ozone to •O2− and •OH over this oxygen vacancy. The reaction process parameters, including varying concentrations of ozone, sodium acetate, and catalyst dosage, as well as pH value and the quantitative analysis of formed free radicals, were examined in detail. This work demonstrated that fly ash could be used as a viable catalytic material for wastewater treatment and provided a new solution to the added value of fly ash. [ABSTRACT FROM AUTHOR]

Textile wastewater is among the most polluted types of industrial waste. Wastewater treatment in the textile industry is notoriously difficult because of the use of complex chemicals and dyes in the textile production steps, and conventional methods are not enough to treat these. Textile wastewater, known for its high pollution levels, poses challenges for treatment due to complex chemicals and dyes. A comparative study was conducted on simple ozonation and catalytic ozonation (CO) using alum to degrade methylene blue (MB). The authors analyzed various factors like time, pH, catalyst loading and ozone dosages during the study. Results showed that catalytic activity in ozonation depends on pH and ozone flow. The maximum MB elimination was achieved at pH 6.6 and 200 V ozone flow. Scanning electron microscopy (SEM) was used to characterize the surface morphology of the catalyst, Fourier transform infrared spectroscopy (FTIR) was used to identify the important functional groups, and energy dispersive X-ray spectroscopy (EDS) was used to characterize the catalyst's elemental composition. Compared to simple ozonation, CO showed higher removal in the initial phase. Real textile wastewater analysis confirmed the effectiveness of alum catalysts in achieving significant removal of MB (87%) through this novel cost-efficient process. Highlights: Methylene Blue was treated with the catalytic ozonation method, with first ever use of alum as a novel ozonation catalyst. Both simple ozonation and catalytic ozonation were efficient treatment processes; however, maximum removal efficiency for Methylene Blue of 86% was achieved by alum based catalytic ozonation process. On optimizing pH to 6.6, maximum removal efficiencies for Methylene Blue improve to 85% and 99% for simple ozonation and catalytic ozonation processes, respectively. The improved results for catalytic ozonation are owed to predominant hydroxyl radical mechanism. [ABSTRACT FROM AUTHOR]

Oxidative degradation of 1,2-dichlorobenzene using different loadings of metal (Mn, Ni, V, and Fe) supported on CeO2 was studied. All metal (Mn, Ni, V, and Fe) loaded CeO2 catalysts were synthesized using the method called wet impregnation and the as-synthesized catalyst materials were characterized using different analytical instruments such as FT-IR, SEM-EDX, XRD, BET, ICP-OES, and TEM methods. The oxidation reactions of 1,2-dichlorobenzene were studied by bubbling substrate (1,2-dichlorobenzene) with ozone (0.0794 mg/L) into a glass reactor via a porous bubbler of porosity 2 over a period of 24 h. A 2.5 % Fe/CeO2 catalyst was found to be the most active catalyst with a percentage conversion of 62 % within 24 h of ozonation. The oxidation products were identified using GC-MS and FT-IR spectroscopy was used to study the functional groups present in the ozonation product. The ozonation products that were identified are mucochloric acid and 3,4-dichloro-2,5-furandione. All the V loaded on CeO2 catalysts produced 100 % mucohloric acid at the end of ozonation (24 h). [ABSTRACT FROM AUTHOR]

Due to low degradability of plastic materials, high usage, and low cost, microplastics (MPs) is becoming ubiquitous environmental pollutant. Wastewater treatment plants (WWTP) are one of main sources, where most of the MPs from wastewaters ends in waste sludge. Anaerobic digestion is one of most promised techniques of waste sludge management. The aim of this paper was to evaluate the impact of polyethylene terephthalate (PET) and polypropylene (PP) microplastics in the waste sludge with and without ozonation as possible pretreatment, on biogas and methane production with OxiTop® method. In the first set of experiments, PET inhibited (up to 6% at 0.1 g L−1) or promoted (up to 3% at 1 g L−1) methane production but increased cumulative biogas production (up to 38% at 0.5 g L−1). PP inhibited methane production (up to 5% at 0.5 g L−1) but its impact on biogas production was dependent upon concentration of MPs added. In the second set of experiments, pretreatment of non-contaminated waste sludge by ozonation (3.54 gozone h−1) inhibited methane yield. Longer time of ozonation of PP-contaminated waste sludge reduced inhibition of methane yield, while in the case of PET-contaminated waste sludge, it was increased. [ABSTRACT FROM AUTHOR]

Catalysts for the efficient catalytic decomposition of ozone to generate reactive free radicals to oxidize pollutants are needed. The graphite-supported CeO2 catalyst was optimally prepared, and its activity in ozonation was evaluated using the degradation of diethyl phthalate (DEP) as an index. The stability of CeO2/graphite catalyst and the influence of operating conditions on its catalytic activity were investigated, and the mechanism of CeO2/graphite catalytic ozonation was analyzed. CeO2/graphite had the highest catalytic activity at a Ce load of 3.5% and a pyrolysis temperature of 400 °C with the DEP degradation efficiency of 75.0% and the total organic carbon (TOC) removal efficiency of 48.3%. No dissolution of active components was found during the repeated use of CeO2/graphite catalyst. The ozone dosage, catalyst dosage, initial pH, and reaction temperature have positive effects on the DEP degradation by CeO2/graphite catalytic ozonation. The presence of tert-butanol significantly inhibits the degradation of DEP at an initial pH of 3.0, 5.8, or 9.0, and the experimental results of the •OH probe compound pCBA indicate that the CeO2/graphite catalyst can efficiently convert ozone into •OH in solution. The DEP degradation in the CeO2/graphite catalytic ozonation mainly depends on the •OH in the bulk solution formed by ozone decomposition. [ABSTRACT FROM AUTHOR]

The advancement of atomically precise dinuclear heterogeneous catalysts holds great potential in achieving efficient catalytic ozonation performance and contributes to the understanding of synergy mechanisms during reaction conditions. Herein, we demonstrate a "ship-in-a-bottle and pyrolysis" strategy that utilizes Fe2(CO)9 dinuclear-cluster to precisely construct Fe2 site, consisting of two Fe1-N3 units connected by Fe-Fe bonds and firmly bonded to N-doped carbon. Systematic characterizations and theoretical modeling reveal that the Fe-Fe coordination motif markedly reduced the devotion of the antibonding state in the Fe-O bond because of the strong orbital coupling interaction of dual Fe d-d orbitals. This facilitates O-O covalent bond cleavage of O3 and enhances binding strength with reaction intermediates (atomic oxygen species; *O and *OO), thus boosting catalytic ozonation performance. As a result, Fe dinuclear site catalyst exhibits 100% ozonation efficiency for CH3SH elimination, outperforming commercial MnO2 catalysts by 1,200-fold. This research provides insights into the atomic-level structure-activity relationship of ozonation catalysts and extends the use of dinuclear catalysts in catalytic ozonation and beyond. [ABSTRACT FROM AUTHOR]

The decomposition processes of plutonium hydroxo compounds formed under ozonation conditions in MOH (M = Li, Na, K) solutions of various concentrations were studied by UV-Vis spectroscopy using a modified nonlinear least squares method. The influence of the nature of alkali on the kinetics and mechanisms of spontaneous reduction of alkaline solutions of hydroxo compounds of plutonium(VII) was discovered. This influence and the "anomalies" in the UV-Vis spectra for ozonized plutonium solutions are associated with the presence in the systems of iron compounds in the form of impurities in commercially available LiOH, NaOH, and KOH (analytically pure, chemically pure, and ultrapure grade). Even trace amounts of impurities in alkaline solutions of plutonium compounds change the mechanisms of their reduction through the active participation of iron in redox processes. They include the oxidation of iron to ferrate(VI) ions FeO42–, followed by reduction to Fe3+, probably through the stage of formation of an intermediate with a hydroxo derivative of plutonium(VI). As a result of the analysis of large arrays of spectral data, the spectra of individual components corresponding to compounds of plutonium(VI, VII) and iron (VI) were isolated. [ABSTRACT FROM AUTHOR]

The present study evaluates the application of heterogeneous catalytic ozonation for the removal of micropollutants from wastewater effluent in a pre-industrial-scale unit, consisting of a post-filtration, an ozone dilution, a catalytic ozonation, and a final biological stabilization step. The important step of ozone dilution is optimized by the use of a hollow fiber membrane that minimizes the loss of ozone gas due to the transfer of ozone to the liquid phase mainly by diffusion. It is observed that the efficiency of this sub-system is maximized for the dead-end operation of the membrane and the introduction of ozone gas to the shell side and liquid phase to the lumen side of the membrane module. Under these conditions, the concentration of dissolved ozone is directly dependent on the ratio of ozone gas feed to the wastewater flow subjected to post-treatment. Regarding the removal of MPs, part of their degradation already takes place at this stage (i.e., during ozone dilution), while after the post-treatment of wastewater effluent in the catalytic ozonation bed, the MP degradation yield ranges from 35% up to complete removal, depending on the type and properties of the specific MP. The addition of a final biological filtration bed to the overall treatment unit significantly increased its performance, regarding the removal of MPs, enhancing it by an additional removal rate that can reach up to 30%. [ABSTRACT FROM AUTHOR]