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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]

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]

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]

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]

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]

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]

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]

Co-precipitation was employed to synthesize copper-based layered double hydroxides, which were subsequently utilized as heterogeneous catalysts for the ozonation of 4-nitrophenol in aqueous solutions. Various analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), were utilized to characterize CuAl-CO3 and CuAl500.The catalytic activity of CuAl-CO3 was evaluated under different reaction conditions. Notably, at pH 11 and 25 °C, CuAl-CO3 exhibited high catalytic efficiency in the ozonation of 4NP. Increasing the catalyst dose, initial pH, and temperature led to enhanced 4NP degradation. An optimal pH of 11 and a catalyst dose of 0.3 g. L−1 resulted in the removal of 78.6% of the initial 4NP concentration. Additionally, ozonation proved to be more efficient at temperatures of 10 °C and 55 °C. The kinetics of 4NP ozonation over CuAl-CO3 and CuAl500 followed a pseudo-first-order reaction. Furthermore, the study demonstrated that CuAl-CO3 and CuAl500 exhibited stability and repeatability across multiple reaction cycles, highlighting their potential for continuous catalytic applications. Overall, this research emphasizes the effectiveness of CuAl-CO3 and CuAl500 as reliable heterogeneous catalysts for the ozonation of 4NP. The results contribute valuable insights into the development of advanced oxidation processes for the treatment of wastewater containing organic contaminants. [ABSTRACT FROM AUTHOR]

The current investigation aimed at evaluating the effect of different applied ozone dosages of 32.0, 38.0, 44.0 and 50.0 g.kg−1 on techno-functional properties, structural properties, molecular interactions and thermal properties of red sorghum flour. Ozonation led to an increase in the water absorption capacity (1.79 to 2.15 g/g), water solubility index (1.59 to 5.13%), oil absorption capacity (1.27 to 1.71 g/g), swelling power (7.68 to 8.31 g/g), foaming capacity (10.14 to 13.91) and stability and paste clarity (19.35 to 34.30%T); however, there was a decrease in the gel consistency (95.50 to 40.20 mm), flour dispersibility (92.36 to 89.21%), emulsion activity (8.50 to 7.00%) and stability (32 to 22.20%). This alteration in the functional properties could be attributed to the cleavage of various groups due to oxidation and resulting in increased electronegativity. Ozonation enhanced the total phenolic content (226.34 to 276.23 mg GAE/100 g), FRAP activity (8.14 and 12.65 µmol TE/g), in vitro starch digestibility while reduced the total flavonoid content (605.26 to 582.15 mg QE/100 g), DPPH (10.90 to 9.61%RSA) and in vitro protein digestibility. Scanning electron microscopy and Fourier transform infrared microscopy showed modification in the structure and molecular interaction attributing to the widening of the protein and compactness of the starch. Pearson's correlation coefficient and Principal component analysis (PCA) were employed for studying the relationship between different variables and for validation of changes due to ozonation. [ABSTRACT FROM AUTHOR]

Ozone is a strong oxidant, with application in the food industry, disinfection of hospital areas and wastewater treatment. Although microbial destruction with ozone gas and in an aqueous solution has been widely studied, the ability of ozonated mist to inactivate microorganisms remains unknown. Thus, this study aimed to evaluate the kinetic inactivation of Escherichia coli on surfaces by ozone mist, where concentrations up to 51 ppm of ozone were employed. Two scenarios were investigated: surfaces positioned tangentially and 46.5 cm above the mist output, also testing kinetic models of its inactivation (first order and Weibull distribution). Escherichia coli ATCC 25,922, used as reference strain, was inoculated on plate count agar ranging from 102 to 106 CFU/plate by exposing to ozone mist up to 5 minutes. The target bacterium was reduced by 99.99% (4 log cycles) with tangential exposure to the mist output, being considered a satisfactory sanitizer, based on the minimum 4 log required by the sanitary standard. Reduction of 1 log cycle was observed 46.5 cm above the mist output. The Weibull distribution model best represented the inactivation of E. coli over time; predicting that it would take 33 seconds for inactivation of 4 log units of the initial concentration of 106 CFU/plate in surfaces positioned tangentially to the ozone mist output and 7.8 minutes to not detect growth for initial concentration 102 CFU/plate for surface positioned 46.5 cm above the mist output. Thus, the present study demonstrated the effectiveness of ozone mist in inactivating E. coli and could satisfactorily model the kinetics of microbial destruction, allowing for a more assertive and efficient use of this sanitizer. [ABSTRACT FROM AUTHOR]

As a set of persistent organic pollutants (POPs) that cause serious harm to human and animal health, polycyclic aromatic hydrocarbons (PAHs) degradation has attracted attentions of many scholars. Ozonation is one of the promising techniques for removing PAHs from various aqueous solutions because of its molecular structures, rapid reaction with ozone (O3), and oxidation by-products of PAHs produced during ozonation are more biodegradable than initial PAHs. However, its application is constrained by the high cost of ozone production, and organic matter in water is only partially oxidized. In recent years, to improve the efficiency of the ozonation process and optimize economic efficiency, several methods of O3-based advanced oxidation processes (AOPs) (i.e. O3/UV, O3/H2O2, O3/H2O2/UV, O3/Fenton, O3/Catalyst) have been studied. These AOPs generate more HO• than molecular ozone. This review summarized recent developments relating to the degradation of PAHs via O3-based AOPs and their exciting mechanisms. Compared different processes characteristics in terms, such as radical species, operational conditions, by-products and their toxicity, and cost. We considered that O3/photocatalyst seems to be a better choice for PAHs degradation. Finally, the challenges and future trends of PAH degradation have prospected. [ABSTRACT FROM AUTHOR]

A nanostructure comprising Fe/Ag covered by ZnO was fabricated using a facile chemical method based on the degradation of 2,4-D using an ozonation system under the irradiation of UV/Visible light generated from an LED source. The Fe/Ag covered by ZnO was characterised using XRD, SEM and FTIR. The degradation of 2,4-D was studied as a function of variables pH, initial 2,4-D concentration, dose of catalyst and the time of irradiation by developing a quadratic model derived from central composite design (CCD). An independent kinetic study was then established under the basis of the optimised values of the independent factors obtained from CCD model. The optimised values of pH, 2,4-D initial concentration, dose of catalyst and time of irradiation were 5, 62 mgL−1, 0.078 gL−1 and 63 min, respectively. ANOVA results of the quadratic model showed the adjusted R2 of 0.97% and the value of 0.55 for the Lack of Fit (LoF). According to the kinetic study, the pseudo second model reveals a good fit on the experimental results (R2 = 0.98). Maximum removal of 80% was obtained in the optimum condition and in the presence of ozone. Considering the safety and technical restrictions of applying UV light as an activator agent in full scale treatment systems, it seems that the use of LED in the degradation systems acquires promising results in terms of pesticides degradation. [ABSTRACT FROM AUTHOR]

Food grains and their products must be free of insects, pests, and microbes to be considered safe for human consumption. The limitations associated with the use of harmful chemicals/pesticides for the disinfection of food grains have led to ongoing research into alternative decontamination methods such as ozone. Ozone has enormous potential for ensuring food security in the grain and food industries whilst retaining the functional and nutritional profile and augmenting the shelf life of grains and their products. Research indicates that ozone is an ecologically safe option for disinfecting food items without leaving any toxic residues in the commodities. This chapter highlights the production techniques of ozone, its mechanisms for inactivating various bacteria, insects, mycotoxin, and pesticide degradation along with qualitative changes in grains and their products. The challenges associated with the application of ozone treatment at an industrial scale have been also discussed. Ozone has the potential to be used as a green sanitization technique to achieve sustainable development goals (SDGs). [ABSTRACT FROM AUTHOR]

The objectives were to evaluate the ozonation effects on germination and disinfection of sashi inchi seeds. Seeds groups were treated applying concentrations of gaseous ozone of 5 and 20 mg/ L for 20 min. Others were immersed in water with dissolved ozone (0.5 and 1.0 mg/L) during 15 min. Ozone did not register negative effects on germination or on the quality of the seeds. Treatments with lower ozone concentrations recorded the best results in germination percentage and vigor indicator (86%, 94% and 84%). The gaseous phase was the most suitable one for treating the seeds (5 mg/L for 20 min). Only a treated group reached greater seedlings survival (53%), resisting the fungal attack. Applied disinfection allowed reducing the microbial load. [ABSTRACT FROM AUTHOR]

Pharmaceuticals are often found in the water environment and are not completely degraded by conventional treatment processes. There are some techniques, such as advanced oxidative processes (AOPs), which can promote, in addition to the total removal of contaminants, their mineralization, transforming them into CO2 and water. Thus, the objective of this work was to evaluate the mineralization capacity of the emerging pollutants caffeine and ampicillin, present in a real aqueous matrix, through ozonation. Factorial planning was carried out by Central Composite Design (CCD) under the Response Surface Methodology (RSM). Water samples were collected from Arroio Dilúvio, a river that cuts through the city of Porto Alegre (RS -- Brazil), which receives domestic, hospital, and industrial effluents in nature. The experiments were conducted from the analysis of the influence of pH, time, and ozone flow rate variables. The ozonation system consisted of an oxygen concentrator, an ozone generator, and a gas washer bottle. With removals of caffeine and ampicillin around 100 and 99.7%, respectively, a mineralization of 30.8% was also obtained under conditions of pH 8, with an applied ozone dosage of 830 mg.L-1. In this process, the gas phase concentration was at 16.7 mg.L-1 when applied to 200 mL sample for 10 minutes and ozone flow rate of 1 L.min-1. A linear relationship was observed between the real and predicted values, and it has been shown that the relationship of the residual plot confirmed a sufficient approximation of the method for the optimization process. Finally, the desirability function showed adequate operating conditions for the mineralization of compounds by ozonation. Therefore, it is considered that this technique is effective for the mineralization of the pharmaceuticals studied, and can be applied as a way of treating a contaminated real matrix. [ABSTRACT FROM AUTHOR]

Endocrine-disrupting compounds (EDCs) areconsidered as an emerging group of trace contaminants detected in the environment worldwide. Bisphenol A (BPA) is one of these toxic pollutants that arereleased mainlyfrom industries and can cause serious health and environmental problems.Thus, in this study, titanium dioxide and zirconium dioxide particles were deposited on pumice, and then the efficiencies of O3/nTiO2/H2O2 and O3/nZrO2/H2O2on BPA removal were studied under different operational conditions. The results showed thatBPA removal efficiency was increased by increasing the pH, contact time, catalyst dosage and concentration of H2O2 and maximum removal efficiency for both studied processes was ≈100% at optimum conditions, i.e. pH of 11, are action time of 30 min, catalyst dosages of 4 g/L for O3/nTiO2/H2O2 and 12 g/L for O3/nZrO2/H2O2, H2O2 concentration of 2 mmol/L for O3/nZrO2/H2O2and 5 mmol/L for O3/nTiO2/H2O2, and initial BPA concentrations of 20 mg/L.Increasing the catalyst dose to a certain level, increases the production of hydroxyl radicals, which, in turn, increases the degradation of BPA. The pumice XRD pattern coated with TiO2 and ZrO2 nanoparticles shows the main and derivative elements of pumice, including pyroxene, magnetite feldspar mica, and SiO2.FTIR spectra for TiO2 and ZrO2 nanoparticles showed that the peaks at 455 and 457 cm−1 are related to the C-N-C bands in amine functional groups. We found that the studied integrated catalytic ozonation processes (COP)have high efficiency in removing BPA, therefore it can be used as asuitable and effective methods for removal of such organic pollutants from aqueous solution. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increase in the interest on organic compounds originating from anthropogenic activities. The presence of these micropollutants in waterbodies can be detrimental for the aquatic organisms even at their trace concentrations. Removal of micropollutants from wastewater by conventional treatment methods is quite limited, thereby existing wastewater treatment plants are not capable of removing these micropollutants. This study investigated the removal of 27 micropollutants and conventional pollution parameters by ozonation of the effluent from a pilot-scale high-rate activated sludge system treating municipal wastewater. Different ozone dosages and contact times were tested during the study. Results revealed that 7 out of 27 micropollutants were detected in the effluent. Over 45% chemical oxygen demand (COD) removal and over 65% total suspended solids (TSS) removal were achieved by the ozonation process. Among the various ozone dosage and contact time combinations investigated in the study; 6 mg/L ozone dosage-20 min contact time, and 9 mg/L ozone dosage-10 min contact time alternatives resulted with the best treatment performance in terms of the removal of micropollutants, COD, TSS, and turbidity. A feasibility analysis was conducted to evaluate the best operational conditions from a techno-economic perspective and the results revealed that the unit cost for ozonation process ranged between 0.033 $/m3 and 0.043 $/m3. Additionally, considering the feasibility, 6 mg/L ozone dose – 20 min contact time combination was found as the optimum alternative. Based on the promising results obtained in this study, ozonation can be offered as a polishing step for the effluents of high-rate activated sludge systems for the improving of the effluent quality. [ABSTRACT FROM AUTHOR]

Organic contaminants such as Bisphenol A are classified as Contaminants of Emerging Concern (CECs). The inability of conventional water and wastewater treatments to remove CECs has made Advanced Oxidation Processes (AOPs) attractive for their removal from water sources. Oxidation species such as hydroxyl radicals are produced by AOPs that degrades and mineralize CECs found in water and wastewater. The present study focuses on using heterogeneous nano-metallic oxide embedded activated carbon (AC) for degrading Bisphenol-A (BPA) present in the water. The catalytic ozonation process was carried out using AC/Cu2O/ZnO as the catalyst. The bimetallic catalyst was characterized using BET, XRD, FESEM, Raman Spectra, and DLS. Total organic carbon (TOC) removal was 19% higher for catalytic ozonation when compared with non-catalytic ozonation. HPLC studies found that BPA was removed by 98%. The optimal conditions for degradation were 650 µg/L, pH 8 and 60 minutes. LC-MS/LC-Q-TOF was utilized to find the degradation pathway. [ABSTRACT FROM AUTHOR]

In this study, Fe3O4.MnO2.MoS2 nanocatalyst has been fabricated for the first time and applied in the photocatalytic ozonation (PCO) process. The efficiency of this ternary heterostructure nanocomposite was evaluated in the removal of Acid Blue 113 (AB113) dye with 100 mg.L−1 concentration utilizing response surface methodology (RSM). The optimal condition of the process was attained at pH = 3, using 2 mg of the nanocatalyst and 300 mg.L−1 ozone dosage applied over 20 min. High efficiency of AB113 removal (99%) was observed at the optimal condition. In addition, the performance of the synthesized catalyst in the PCO process was investigated in the treatment of a real textile effluent sample. The PCO has been found to be more efficient than the individual photocatalysis and catalytic ozonation methods due to the synergistic effect between the two oxidation systems. The results proved that Fe3O4.MnO2.MoS2 can be used as a highly efficient catalyst in the PCO process. [ABSTRACT FROM AUTHOR]

Gum Arabic (GA) samples with 6% (w/v) concentration in water were ozonated for 5, 30, and 60 min, corresponding to 0.0030, 0.0125, and 0.0140 g consumed ozone/L, respectively. Ozonation steadily reduced the viscosity, flow, and consistency index of GA suspensions significantly (P < 0.05). Although no apparent changes were observed in the general chemical structure of GA samples, an increase in the absorbance of -OH bends was detected by FTIR analysis. DSC peak temperatures (292.0 ± 0.1 to 281.0 ± 0.9 °C) and pH values of samples (4.84 ± 0.13 to 2.90 ± 0.09) were decreased upon ozonation. Small but statistically significant differences (P < 0.05) were obtained for water solubility and water absorption index of samples after ozonation. Phenolic compounds and radical scavenging activities in GA were increased significantly (P < 0.05) by ozonation. Ozonation, which is an environmental-friendly unit operation, would offer valuable contributions to relevant industries with improved properties of GA. [ABSTRACT FROM AUTHOR]

COVID-19 is a global health threat with a large number of confirmed cases and deaths worldwide. Person-to-person transmission through respiratory droplets and contact with aerosol-infected surfaces are the main ways in which the virus spreads. However, according to the updated literature, the new coronavirus (SARS-CoV-2) has also been detected in aqueous matrices, with the main route of transmission being feces and masks from patients diagnosed with the disease. Given the emergence of public health and environmental protection from the presence of lethal viruses and bacteria, this review article aims to report the major challenges associated with the application of ozonation in water contaminated with viruses and bacteria, in order to clarify whether these communities can survive or infect after the disinfection process and if it is efficient. Available data suggest that ozonation is able to increase the inactivation effect of microorganisms by about 50% in the logarithmic range, reducing infectivity. In addition, the evidence-based knowledge reported in this article is useful to support water and sanitation safety planning and to protect human health from exposure to cited contaminants through water. [ABSTRACT FROM AUTHOR]

This is an experimental study on the decolorization efficiency and the degradation of organic compounds from textile wastewater by the ozonation process in a batch system. The effects of different sample volumes of textile wastewater over time were investigated. The experiments were performed in a 1 L glass reactor with a magnetic stirrer and a bubble diffuser at the bottom to feed the ozone. The applied cumulative ozone dosage varied at 120 gO3 L−1, 60 gO3 L−1, and 30 gO3 L−1, and the total interaction time for each test was 1 h. To investigate the physicochemical properties of the textile wastewater (solid and liquid phases) before and after the treatment, multiple analytical characterization methods were used: Thermal Gravimetric Analysis, Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy, X-ray diffraction, Fourier Transform Infrared spectroscopy, and Spectrophotometer. The most perceptive change was observed in the color of the liquid medium, which turned from black to transparent, and a visual color number indicator known as DurchsichtFarbZahl (DFZ) was used for the evaluation of this process. Absorbance values decreased about 3.5 times after 5 min of treatment with a 0.15 L sample volume, and these values differed for tests with larger sample volumes. FTIR spectroscopy demonstrated that the bands' intensities associated with the C − H, C − N, and C − O decrease during treatment. On the other hand, it was possible to conclude that combining treatment methods to improve the degradation of persistent compounds after the ozonation process is necessary. Finally, the ozonation of the textile wastewater proved to be effective at removing color due to its high reaction capacity. [ABSTRACT FROM AUTHOR]

The catalytic ozonation process (COP) is an effective and advanced oxidation technology for the treatment of organic wastewater. However, high salinity has a negative impact on catalytic ozonation performance. In this work, tin oxide (SnOx) and manganese oxide (MnOx) doped γ-Al2O3 catalysts (SnOx-MnOx@Al2O3) were prepared by the incipient wetness impregnation method and characterized by SEM, XRD, BET, XRT, XPS and FT-IR techniques. The SnOx-MnOx@Al2O3 catalyst was applied to the catalytic ozonation of phenol in hypersaline wastewater, and the catalytic performance was evaluated by COD removal efficiency. When the mass ratio of MnOx to SnOx was 1:3, the pH was 7, the catalyst dosage was 40 g/L, the ozone dosage was 6 mg/(L·min), the NaCl concentration was 15 g/L and the COD removal efficiency of hypersaline phenol wastewater reached 93.8% after 240 min of catalytic ozonation treatment. Compared with the single ozonation process (SOP), the introduction of SnOx-MnOx@Al2O3 catalyst improved the COD removal efficiency by 32.3%. Cl− may quench surface •OH species and ozone to form Cl• and Cl2•− with low activity and high selectivity, resulting in the reduction of catalytic ozonation efficiency. The catalytic activity of the SnOx-MnOx@Al2O3 catalyst remained high after eight cycles. In conclusion, the SnOx-MnOx@Al2O3 catalytic ozonation system exhibits efficient and stable mineralization performance and is a promising strategy for the treatment of hypersaline organic wastewater. [ABSTRACT FROM AUTHOR]

Copper modified sepiolite (Cu-SEP) with high catalytic activity was successfully prepared and used in ozonation to remove oxalic acid from water. The influence of Cu-SEP dosage, initial pH, ozone dosage and initial oxalic acid concentration on the removal of oxalic acid in heterogeneous catalytic ozonation was investigated, and XRD, FTIR, SEM, TEM and XPS were employed to characterize the Cu-SEP to clarify its working mechanism in ozonation. The experimental results showed that under the optimal condition, the removal of oxalic acid could reach 95.8%. Cu element successfully replaced Mg in the sepiolite lattice to form the Cu-SEP, it existed mainly in the form of Cu2+. Cu-SEP contained abundant surface hydroxyl groups, which played an important role in the catalytic ozonation process. With the combination of free radical quenching experiment, the possible mechanism of Cu-SEP catalyzed ozonation to degrade oxalic acid was proposed. After ozonation, Cu-SEP retained the original structure, and exhibited excellent stability and reusability. [ABSTRACT FROM AUTHOR]

The utilization of gaseous ozone (a powerful oxidant) in air, for disinfection and sterilization purposes, has been extensively studied for diverse applications; however, the optimal deployment of this technology for textile disinfection is deserving of further research attention and is this the focus of this work. In this study, the penetration efficiency of ozone gas into hard-to-reach regions of different garment types is critically examined. The impacts of garment packing density, hanging orientation and ozonation duration are also considered, and the resultant disinfection efficiencies are comparatively analyzed. An ozonation chamber fitted with remote ozone detection is utilized for the ozonation of fabric swatches inoculated with Escherichia coli bacteria. The number of colony-forming units per cm2 and the bacterial lawn area fraction are evaluated pre- and post-ozonation to quantify the level of disinfection. This study shows that the attainment of sufficient ozone concentrations in hard-to-reach regions of different garment types coupled with the inter-garment spacing utilized are vital for effective decontamination. This study also demonstrates the effectiveness of ozonation as a necessary technology for decontamination, particularly in this era, where the sterilization of textiles and other materials is paramount for public health and safety. [ABSTRACT FROM AUTHOR]

This work studies the removal of o-cresol from wastewater by using ozonation followed by adsorption onto sodium natural bentonite (Na-Bent). The degradation of o-cresol was followed by UV-Vis. During ozonation, 2-methylbenzoquinone (2-mBQ) and 2-methylhydroquinone (2-mHQ) were identified as two of the main by-products, while the pH decrease suggested the breakage of aromatic compounds into smaller organic acids. After 30 min treatment, the o-cresol degradation for 250–62.5 mg/L solutions was found between 64–85%, respectively. Next, the wastewater containing persistent o-cresol and by-products was contacted with Na-Bent adsorbent. The solutions and physicochemical properties of Na-Bent were analysed, before and after adsorption, by UV-Vis, FTIR, XRD and N2 adsorption-desorption. Moreover, equilibrium and kinetic experiments were carried out to study the adsorptive properties of the Na-Bent. While sole ozonation or adsorption failed on the remediation of o-cresol solutions, the obtained results show that the contact of ozonated solutions with Na-Bent led to almost total removal of the o-cresol initial concentrations (between 96% and 99%). This excellent performance is assigned to the high volume of interlayer micropores and the suitable surface chemistry of this natural adsorbent. [ABSTRACT FROM AUTHOR]

A series of Zn-Al Layered Double Oxides (ZnAl-LDO) composites were prepared by the hydrothermal and calcination method via employing the Zn-Al Layered Double Hydroxide (ZnAl-LDH) as the precursors in the present study. The structural properties and the catalytic ozonation activity of ZnrAl-T composites synthesized with different Zn/Al molar ratios and calcination temperatures were systematically investigated. Diversified characterizations were applied to analyze the phase structure and chemical composition of ZnrAl-T composites. As the calcination temperature increased, the layered ZnAl-LDH structure could be entirely destroyed and the crystallinity gradually improved. With the Zn/Al mole ratio of 4.0 and calcination temperature of 500°C, the Zn4Al-500 composite obtained the outstanding catalytic ozonation performance for atrazine (ATZ) degradation with the pseudo-first-order constant of 0.5080 min−1, which was 5 times more than that in O3 alone. Meanwhile, the ATZ degradation efficiency was gradually enhanced from 44.1% to 99.9% within 3.0 min when the solution pH ranged from 3.0 to 10.0. Besides, the Zn4Al-500 composite exhibited splendid stability over multiple reaction cycles. In addition, the radical scavenging test and electron spin resonance measurement demonstrated that superoxide radical and hydroxyl radical are the dominant reactive species in O3/Zn4Al-500 process. Moreover, nineteen and ten transformation products were detected in O3 alone and O3/Zn4Al-500 process, and possible degradation pathways of ATZ were further elucidated. Overall, the Zn4Al-500 composite would provide a potential alternative for pollutants removal due to its high catalytic ozonation efficiency, stability, and reusability. [ABSTRACT FROM AUTHOR]

In this work, Lallemantia royleana seed mucilage (LRSM) was applied as a plant based coagulant in the initial stage of an integrated method for dye degradation. Photocatalytic ozonation (PCO) process was used under visible-light irradiation in the post-treatment stage. MnO2.MoS2 heterostructure nanocomposite was fabricated by hydrothermal synthesis and applied for the first time in PCO to mineralize Acid Blue 113 dye. The synthesized nanocatalyst was characterized by FT-IR, XRD, FE-SEM, TEM, DRS and BET. Characterization of the nanocatalyst showed that the composite consisted MoS2 with a sheet-like structure and MnO2 in the form of nanoparticles with different sizes in the range of 15–30 nm. By using the response surface methodology (RSM) approach, the best operational condition in the coagulation-flocculation (CF) stage has been acquired at pH 5.0, LRSM dose of 220 mg/L within 27 min. By applying the PCO process, complete decolorization has been attained using 11 mg of the catalyst and 0.2 g/L.h ozone dosage within 9 min. The use of LRSM along with MnO2.MoS2 nanocatalyst in the CF/PCO combined process for treating real wastewater samples indicates that the proposed technique is highly efficient and can be effectively employed to treat dye-containing industrial effluents. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate microbubble ozonation for the removal of toxic cyanobacteria, Microcystis aeruginosa. The microbubble ozonation (30 min) at 3.47 mg O3 L−1 decreased the M. aeruginosa concentration from 1.5 × 107 to 0.8 × 107 cell mL−1. However, the acute toxicity (48 h) to Daphnia magna (<24 h old) was considerably increased after the microbubble ozonation, possibly owing to the release of intracellular microcystins (MCs). Considering the release of toxic MCs, the microbubble ozonation was optimized at an environmentally relevant concentration (1.74 × 106 cell mL−1) of M. aeruginosa. Microbubble ozonation at 0.26–1.92 mg O3 L−1 for 30 min removed M. aeruginosa by 26 to 83% without any acute toxicity on D. magna. Moreover, D. magna feeding enhanced the removal rate from 85 to 100% for 48 h. These findings suggest that microbubble ozonation, possibly combined with D. magna biomanipulation, can be a promising tool to control toxic cyanobacteria in ambient water. [ABSTRACT FROM AUTHOR]

The structure of organic compounds is critical to their degradation rates in various advanced oxidation processes. In this research, 16 organic acids (such as oxalic acid, D-malic acid, oxamic acid, etc.) were used as model contaminants to investigate the mineralization efficiencies of catalytic ozonation with ZnAl layered double hydroxide (ZnAl-LDH). All tests organic acids could be effectively degraded during catalytic ozonation, and good reusability was observed since the unique structure of ZnAl-LDH was kept after the reaction. The effect of temperature on the oxidation of different organic compounds varied based on their molecular structures. In most cases, a proper temperature increase could promote the degradation of organic compounds by catalytic ozonation. The TOC removal kinetic constants had a good linear relationship with the temperature, which proved that the catalytic ozonation of organic matters conformed to the Arrhenius equation, in which the activation energy of various organic acids were between −9.0 and 51.0 kJ·mol−1, and the pre-exponential factors were between 0.003 and 2.45 × 106 min−1. By using linear regression model, it was found that the activation energies of organic acids had a greater correlation with quantum chemical parameters, such as Fukui(0)max, Fukui(+)max, EB3LYP, ELUMO, EHOMO and Bond orders(C-C)max. High correlation of Fukui(0)max and Fukui(+)max indicated the attacking of both free radicals and ozone molecule, respectively. Organic acids with lower energy and C-C bond orders were proved to be simple and readily degradable, and thus much easier to be mineralized during catalytic ozonation. [ABSTRACT FROM AUTHOR]

Catalytic ozonation including homogeneous and heterogeneous ozonation has been extensively used in water and wastewater treatment in recent years. The liquid homogeneous catalysts cause secondary pollution and have limited development prospects. The heterogeneous catalyst exists in solid form, which is easy to separate solid from liquid, convenient to operate, and has high catalytic ozone decomposition efficiency. It can effectively mineralize organic pollutants and has great development potential. The catalyst is the core part of the whole method. In this study, the mechanism of heterogeneous catalytic ozone oxidation is briefly introduced. Several common preparation methods of ozone catalysts are reviewed. Various catalytic ozonation catalysts such as metal oxides, metals/metal oxides on supports, and carbon-based materials are summarized in detail. The application of heterogeneous catalytic ozonation in the degradation of phenols, pesticides, dyes, drugs, and other toxic organic pollutants is reviewed. At present, the structure of the catalyst is unstable, the active components of the catalyst are easily lost, and the catalytic effect is lost. Therefore, the development of supported catalysts with good stability has become the main direction of current research. The preparation and application of heterogeneous catalytic oxidation are also reviewed, which will be beneficial to further research. [ABSTRACT FROM AUTHOR]

In this study, expanded graphite (EG) was prepared by the oxidation and intercalation of the natural flake graphite using perchloric acid and potassium permanganate at different expansion temperatures (300, 400, 500, and 600°C), and were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EG prepared at 500°C was found to be highly effective for the mineralization of oxalic acid aqueous solution during ozonation at pH 3, which was ascribed to the formation of hydroxyl radicals from the surface reaction of surface hydroxyl groups on EG with ozone. The performance of expanded graphite in this catalytic system was basically unchanged after three repeated use. The presence of Cl−, SO 4 2 − , HPO 4 2 − / H 2 PO 4 − and NO 3 − could inhibit the degradation of oxalic acid in catalytic ozonation with EG. Degradations of oxamic acid and pyruvic acid in catalytic ozonation with EG were pH-dependent, which were lower than that of oxalic acid. The degradations of oxalic acid and oxamic acid were identified as mineralization process by the determination of TOC, while pyruvic acid may transform into organic products such as acetic acid by O3/EG. Manganese ion (Mn2+) could promote the degradation of oxalic acid by O3/EG at pH 3 because permanganate was produced by O3/EG in oxalic acid solution and then reacted with oxalic acid readily at acidic pH. Catalytic ozonation by EG exhibited great application potential for the destruction of refractory organic compounds. [ABSTRACT FROM AUTHOR]

Since phosphorus (P) is a nonrenewable element essential for life, it is extremely important to understand its potential supply sources. This paper describes the behavior of P during the ozonation of waste activated sludge (WAS) as it is an important pool of P. Also, we investigated whether ozonation of WAS could be an effective method for both P recovery in solution and its bio- and plant-availability in solid residues based on the analysis by the Standards, Measurements, and Testing Program. The results showed that P was enriched in WAS at concentrations above 23 mg/g. Phosphorus transferred from the solid phase to the liquid phase, and the total P content in the liquid phase increased from 1.67 to 40.68 mg/L as the ozone dosage increased from 0 to 0.20 g O3/g MLSS. PO43–P was the main form of P in the liquid phase after ozonation, which is beneficial for P recovery. The P fraction analysis revealed that the released P mainly came from apatite P (AP) during ozonation. Additionally, P was more available in solid residues as the proportion of bio-available P (non-apatite inorganic P (NAIP) + organic P (OP)) improved from 73.6% in the raw WAS to 91.7% at an ozone dosage of 0.20 O3/g MLSS. In addition, the solid residues were suitable for plant availability at a moderate Fe/P ratio (0.91) after ozonation. Thus, ozonation is recommended as the preferable solution to achieve an advanced P supply in both the liquid phase and solid residues. [ABSTRACT FROM AUTHOR]

Ozone is a powerful oxidizing agent, so its effect on quality parameters must be considered prior to any potential food application. The effect of gaseous ozone on the quality-related attributes of onion bulbs was examined. Onions were exposed to different ozone concentrations (100, 200, 300 ppm) at pulse mode (i.e., frequency of exposures 1, 2, 3). The pungency imparting pyruvic acid and ascorbic acid contents decreased with an increase in the concentration of ozone and the number of exposures, while total phenol and flavonoid content increased to an effective concentration of 400 ppm of ozone. Higher concentrations inadvertently decreased the antioxidant properties. Ozone treatment resulted in a non-significant decrease in firmness, anthocyanin content, and color of onion. Scanning electron microscopic analysis exhibited structural breakdown in the tunic (outer surface) of ozone-treated onion. At higher concentrations, structural changes were observed up to the first bulb scale. [ABSTRACT FROM AUTHOR]

Macaúba (Acrocomia aculeata) is an oleaginous plant for use in biodiesel production. After harvest, the fruits of this palm tree have high water content, thus attracting microorganisms. Therefore, it is necessary to adopt appropriate fruit storage strategies to ensure oil quality. The objective of this study was to evaluate the effect of the combined use of drying and ozonation on the quality of macaúba fruit oil used to produce biodiesel. The fruits were dried at 60 °C and subsequently subjected to ozonation (treatments with different dosages and application intervals). The treatments with the combined use of drying and ozonation were efficient in maintaining FFA content below 5% for up to 45 days of storage. Furthermore, these treatments did not affect the oil content in the mesocarp of macauba fruits during 180 days of storage. Thus, the combined technique of drying and ozonation of macauba fruits without epicarps can become a viable alternative post-harvest. [ABSTRACT FROM AUTHOR]

In the present study, complex wastewater from the food industry was used to study the effect of ozonation and catalysed ozonation for chemical oxygen demand (COD) removal. The catalysts used were synthesized from agro-waste, activated carbon (AC) and plastic waste, multiwalled carbon nanotubes (MWCNTs)(MWCNT). The effect of various operating parameters, like ozone dosage, catalyst dosage, pH, on COD removal of food industry wastewater was investigated. The maximum COD removal was observed at ozone dose of 2gm/hr. MWCNTs(MWCNT) catalysed ozonation removes 85% COD and 48% total organic carbon (TOC) removal within 180 min at pH 9 and 74% COD and 36% TOC removal was observed for activated carbon catalysed ozonation for the same experimental conditions. A significant inhibition of COD removal was observed in the presence of tertiary-butyl alcohol. Using para-chlorobenzoic acid (p-CBA) as a probe compound, the hydroxyl radical exposure was determined for AC and MWCNT catalysed ozonation. The hydroxyl radical exposure was measured to understand the mechanism of catalytic ozonation and compare the performance of two different catalysts in terms of hydroxyl radical generation. It was found that hydroxyl radical exposure increases with increasing catalyst dose, which confirms the hydroxyl radical (OH.) pathway for COD reduction. The kinetic studies showed a 5.5time increment in rate for MWCNT catalysed ozonation and a 4 time increment for activated carbon catalysed ozonation when compared with standalone ozonation. The synergistic factor for MWCNTs and ozone was found to be 1.83 and for activated carbon and ozone, 1.5. Highlights Catalysts used were synthesized from waste. Application of activated carbon and multiwalled carbon nanotubes for catalytic ozonation of real food wastewater was investigated. Effectiveness of standalone ozonation and catalytic ozonation was identified and compared. A multiwalled carbon nanotube presents higher catalytic performance than activated carbon for ozonation of real food wastewater. Hydroxyl radical mechanism of catalytic ozonation was confirmed by using p-CBA as a probe compound. [ABSTRACT FROM AUTHOR]

This work investigated the modelling and optimisation of Aniline degradation using catalytic ozonation with Fe3O4@SiO2@TiO2 nanocomposite based on the response surface methodology (RSM). The sol-gel method was used to synthesise the magnetic nanoparticleFe3O4@SiO2@TiO2. The catalyst characteristics were analysed by FE-SEM, EDS, XRD, VSM and TEM. Effects of pH, contact time, catalyst loading, Aniline concentration, and radical scavengers on the degradation efficiency of Aniline were evaluated. Results showed that 93.35% removal efficiency of Aniline and 79.3% TOC reduction were obtained by Fe3O4@SiO2@TiO2/O3 process under optimised conditions (contact time = 60 min, catalyst loading = 1.7 g/L, pH = 10.0 and concentration of Aniline = 15 mg/L). Results proved that hydroxyl radicals were dominant radical groups for Aniline degradation in the catalytic ozonation process. After eight continuous using cycles, the results indicated that the Aniline removal efficiency decreased to <6%.In brief, the synthesised Fe3O4@SiO2@TiO2is a well synthesised, stable, efficacious and reusable catalyst and could be a desirable alternative material for wastewaters treatment containing Aniline. [ABSTRACT FROM AUTHOR]

Today, innovative productions have gained great importance to meet customer expectations. In this study, color stripping in reactive dyed knitted cotton fabrics with ozone technology was investigated. Furthermore, it was also aimed to obtain vintage effect by fading the color with the ozonation process. For this purpose, fabrics were dyed into three primer colors, namely yellow, red and blue, and also black color, then they were subjected to ozonation at different durations and the resulting stripping efficiency was evaluated in comparison with conventional caustic-hydrosulfite stripping method. From the color fading values (%), it is possible to say that yellow is the hardest and blue is the easiest to fade among the three primer colors. It was observed that as the ozonation time increased, the color lightened, but the actual fading occurred within the first 15 minutes, after which the change in color was smaller. Besides, it has been shown that if the ozonation is done for a very short time such as 5 minutes on reactive dyed fabrics, the vintage effect can be obtained. On the other hand, color stripping can be achieved as an alternative to caustic-hydrosulfite treatment, if the ozonation is performed for 15 minutes or longer. [ABSTRACT FROM AUTHOR]

In the present study, the ACF-TiO2 catalyst was synthesised and used as a catalyst for the destruction of toxic cyanide in both synthetic and real industrial wastewaters. The ACF-TiO2 catalyst was found to be micro-porous with the BET surface area of 163 m2/g. The effect of different operational parameters such as catalyst concentration, cyanide concentration, operation time, and ozone concentration were target parameters in the present study. The findings show that 500 mg/L of catalyst is the optimum value for the photocatalytical process to completely oxidise 25 mg/L of cyanide within 10 min. While it was found that 300 mg/L of catalyst in the presence of 200 mg/h ozone is enough to remove 25 mg/L cyanide within operation time of 24 min. Degradation of the cyanide in both investigated processes follow the pseudo-first-order kinetic and the reaction rate constant is almost 2 times higher in the photocatalytical process compared with catalytic ozonation process. Furthermore, the quenching tests using salicylic acid demonstrated the hydroxyl radical generation in the investigated process. Generation of highly oxidising hydroxyl radical makes the photocatalytical process a promising process for the transformation of noxious cyanide to much less toxic compounds (ammonia and nitrate). Accordingly, it can be concluded that ACF-TiO2 could be a catalyst for degradation and detoxification of cyanide. [ABSTRACT FROM AUTHOR]

A dynamic fluid system using ozonated water flowing over the bovine peritoneal membrane was developed. Histological analyses were performed to verify the maximum time of ozone exposure to maintain the viability of the biological material. The results indicate that the biological viability of the peritoneum tissue was impaired after 15 minutes of exposure (5.5 mg O3 (cm2)−1) to ozonated water in a dynamic condition. Thus, this biological sample can be submitted to the dynamic fluid system with ozonated water for 10 minutes at an applied ozone dose of 3.7 mg O3 (cm2)−1, without inducing significant changes to the tissue. [ABSTRACT FROM AUTHOR]

Iron and titanium doped γ-Al2O3 (γ-Fe-Ti-Al2O3) mesoporous catalysts were synthesized by evaporation-induced self-assembly using glucose as template, and applied to ozonation of ibuprofen in bromide-containing water. X-ray diffraction (XRD), nitrogen adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS) results showed that iron and titanium successfully doped into the skeleton of γ-Al2O3, uniform distribution, maintain the ordered mesoporous structure of γ-Al2O3, with larger specific surface area. The valence of titanium coexists with Ti4+ and Ti3+, and the valence of iron was Fe3+. Infrared spectra of chemisorbed pyridine (Py-FTIR) results showed that the doped titanium and iron into the framework position of γ-Al2O3 altered the surface acidity of the alumina surface, especially increasing the medium Lewis acid sites, which was conducive to the effective decomposition of ozone into active oxygen species. The γ-Fe-Ti-Al2O3 catalyst (Al/Fe = 25, Al/Ti = 75) enhanced the removal rate of ibuprofen in ozonation of bromide-containing water, and effectively blocked the formation of bromate. After the reaction of 60 min, the removal rate of TOC was increased from 54% of γ-Al2O3/O3 to 86% with γ-Fe-Ti-Al2O3/O3, while the ozonation alone was only 13%. Electron Paramagnetic Resonance (EPR) spectra showed that hydroxyl and superoxide radicals were reactive oxygen species, which was beneficial to the mineralization of organic matter. The capture experiment of Fe2+ ion confirmed that the electronic cycle of Fe2+ ion and Fe3+ ion was beneficial to block the formation of bromated. The addition of ibuprofen and humic acid can enhance the reduction of Fe3+ in the catalytic ozonation of γ-Fe-Ti-Al2O3, which further strengthened the blocking of bromate formation. [ABSTRACT FROM AUTHOR]

The degradation kinetics of different organic compounds in a rotating packed bed (RPB) were investigated in this work. Phenol, catechol, hydroquinone, and aniline that can react rapidly with ozone were chosen to be the model pollutants, and the lumped parameter models were established to characterize the reaction rate of fast ozonation of those organic compounds in the RPB. Correlations for the lumped parameters of the organic compounds degradation (A1) and COD removal (A2) were obtained by fitting the experimental data. The deviations between experimental and predicted A1 and A2 were generally within 25%, indicating that the ozonation rate model has a good predictability for fast ozonation between ozone and organic compounds in the RPB. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks have been extensively studied in catalysis owing to their unique physicochemical properties. However, this class of materials has not yet been directly applied to the catalytic ozonation of organic pollutants. In this study, MIL-100(Fe) was synthesized by a solvothermal method and characterized by powder X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, N2 adsorption–desorption and scanning electron microscopy. A range of reaction conditions such as pH, solute concentration and catalyst content were applied to investigate the catalytic activity of our MIL-100(Fe) sample for the ozonation of p-nitrophenol in water. According to the experimental results, at a neutral initial pH, the catalytic ozonation of p-nitrophenol proceeded mainly through radical reactions, whereas in the absence of the MIL-100(Fe) catalyst, ozone could react with p-nitrophenol via the direct reaction pathway. The catalyst achieved a conversion of up to 98% and chemical oxygen demand removal of up to 75%. Moreover, our MIL-100(Fe) catalyst retained this performance for seven cycles of operation, which offers potential applications for metal–organic frameworks as catalysts in wastewater treatment. [ABSTRACT FROM AUTHOR]

The present study investigates the use of UV light and the ozone process for doxorubicin, daunorubicin, epirubicin, and irinotecan degradation. The process was carried out using different pH values in hospital wastewater. The use of UV radiation reduces the concentration of anticancer drugs, but in all cases, this technology was not able enough to remove on the whole these contaminants from hospital wastewater. The best condition was achieved when using pH 9 for most of the analytes. Doxorubicin, daunorubicin, and epirubicin were degraded at 97.3%, 88.3%, and 99.0%, respectively. Irinotecan showed the lowest degradation, just 55.6%; a slightly higher degradation (63.8%) was obtained when pH 5 was used. Complete removal of doxorubicin, daunorubicin, epirubicin, and irinotecan was achieved when ozone treatment was used for all the pH studied. The results indicated that UV light and the ozone process can be used as a tertiary treatment to reduce the concentration of anticancer drugs in the effluents. Ozonation, therefore, proved to be more efficient than the photolysis process, when considering the percentual degradation of the original compounds in shorter timespans. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate the toxicity of ozone on Zabrotes subfasciatus (Boheman, 1833) in lima bean seeds, determine the instantaneous population growth rate (ri) of these insects exposed to lethal and sublethal ozone doses, and evaluate their effects on the physical and physiological characteristics of lima beans. Toxicity was determined by using estimates of lethal doses (mg/g) for 50% and 95% of adult insects (LD50 and LD95) at the top and bottom of the fumigation chamber. We found that LD95 values were 121.75 and 87.79 mg/g when the insects were distributed at the top and bottom of the chamber, respectively. The ri values decreased from 0.077 to 0.002 when the seeds were exposed to ozone, while they increased from 0.07 to 0.08 when the seeds were exposed to oxygen. The water content of the seeds decreased from 11.2% b.u to 10.38% b.u. when the ozone dose increased. The germination percentage increased from 67% to 93% when the ozone dose was increased. Conductivity decreased from 51.88 μS cm−1 g−1 to 32.47 μS cm−1 g−1 when the ozone dose increased. The apparent specific mass increased when the ozone dose increased from 732.44 m−3 to 738.51 m−3. Ozone is toxic to Z. subfasciatus and affects its instantaneous growth rate; however, it does not affect grain quality. Therefore, ozone has the potential to be used to control Z. subfasciatus in stored grains. [ABSTRACT FROM AUTHOR]

Municipal waste has the potential to be a significant source of energy production. This study investigated pretreatment methods such as NaOH, hydrothermal, and ozonation to increase biomethane production from municipal waste. In addition, these pretreatments were further evaluated using ultrasonic pretreatment after achieving optimal conditions by RSM CCD methods. The optimum pretreatment conditions were observed to be 8% NaOH concentration, 132 °C hydrothermal temperature, and O3 equal to 0.19 g/g TS. The maximum biomethane produced and achieved during the tests was 394 mL/kg TS, which increased to 410 mL/kg TS after ultrasonic pretreatment. The best sCOD reduction in the optimal pretreatment conditions and after the ultrasonic pretreatment was 87% and 91%, respectively. Also, in the absence of ozone pretreatment, the highest yields of biomethane and biogas occurred at a 6.4% concentration of NaOH and a temperature of 135 °C; however, in the presence of ozone, the yield of biomethane and biogas produced was greater and the inhibitory effect of sodium hydroxide also occurs in higher amounts. Experiments have shown that ozonation increases biomethane production rather than increasing biogas production (hence the ratio of methane to biogas). [ABSTRACT FROM AUTHOR]

All museums, especially those showing archaeological exhibits, confront numerous challenges in preventing microbial damage, and thus every effort should be made to conserve these building materials and pass them down to future generations. Archeological artifacts are a significant element of the world's cultural legacy. Microbial activity's impact on cultural asset deterioration is a global issue, and disinfecting them over time is a difficult undertaking. A novel comparative review between chemical, natural essential oils, and physical (ozone) conservation of archaeological objects against microbial deterioration was investigated. The chemical preservation of archaeological items can result in degradation (erosion and surface damage), as well as a risk to human health and the environment. Ozonation can be used to successfully reduce microbial burdens. Because of its great oxidizing strength and spontaneous decomposition, ozone may eventually replace chemical sanitizers as a typical sanitizing agent. As a result, new ecologically friendly safe natural essential oils methods for protecting archaeological artifacts are required to prevent them from microbial deterioration. The use of essential oils is esthetically acceptable for disinfection with negligible toxicity to humans and the environment, ensuring a good quality of life for employees and users for the preservation of cultural assets is the study's key recommendation. [ABSTRACT FROM AUTHOR]