Ozone Flow Research Articles

Comparative study of ozone-based AOPs for degradation of Reactive Red 120

The present work focuses on the comparative study of ozone-based advanced oxidation processes (AOPs): O3, O3/UV and O3/UV/PS to degrade synthetic wastewater containing Reactive Red 120 (RR120) dye. The effect of various parameters: pH, ozone flow rate, initial concentration of dye, persulfate dosage and UV light intensity was analyzed to assess the performance efficiency of AOPs. All three AOPs' performance was evaluated on decolorization, %TOC removal and ozone consumption. The highest degradation rate of 86.83% was achieved for O3/UV/PS, followed by 71.53% and 66.82% for O3/UV and O3 respectively. This better efficiency of O3/UV/PS is attributed to the fact that persulfate ions (S2O8 2-) upon activation produce sulfate radical (SO4 - ●), which is a powerful oxidant capable of degrading a wide variety of recalcitrant organic compounds. The study reveals that the efficiency of degradation of RR120 follows the order: O3/UV/PS > O3/UV > O3.

Genotoxicity Response of Fibroblast Cells and Human Epithelial Adenocarcinoma In Vitro Model Exposed to Bare and Ozone-Treated Silica Microparticles

Indoor air pollutants (IAP), which can pose a serious risk to human health, include biological pollutants, nitric oxide (NO), nitrogen dioxide (NO2), volatile organic compounds (VOC), sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), silica, metals, radon, and particulate matter (PM). The aim of our work is to conduct a multidisciplinary study of fine silica particles (<2.5 μm) in the presence or absence of ozone (O3), and evaluate their potential cytotoxicity using MTS, micronucleus, and the comet test in two cell lines. We analyzed A549 (human basal alveolar epithelial cell adenocarcinoma) and Hs27 (human normal fibroblasts) exposed to dynamic conditions by an IRC simulator under ozone flow (120 ppb) and in the presence of silica particles (40 μg/h). The viability of A549 and Hs27 cells at 48 and 72 h of exposure to silica or silica/ozone decreases, except at 72 h in Hs27 treated with silica/ozone. The micronucleus and comet tests showed a significant increase in the number of micronuclei and the % of DNA in the queue, compared to the control, in both lines in all treatments, even if in different cell times/types. We found that silica alone or with more O3 causes more pronounced genotoxic effects in A549 tumor cells than in normal Hs27 fibroblasts.

Comparison of ozonation, Fenton, and photo-Fenton processes for the treatment of textile dye-bath effluents integrated with electrocoagulation

This study aims to investigate treatment efficiency and evaluate the energy efficacy of integrated electrocoagulation system combined with ozonation, Fenton, and photo-Fenton processes for successful textile dye-bath effluents' treatment. In this regard, the characterization of physicochemical parameters such as pH, turbidity, salinity, total dissolved solids (TDS), total suspended solids (TSS), electrical conductivity (EC), and chemical oxygen demand (COD) was analyzed to estimate removal efficiency of each treatment process. Moreover, the electrical energy consumption of all aforementioned processes was measured individually to work out cost-effectiveness. Fenton process appeared to be ineffective for reducing COD and other parameters. While the overall performance of ECS alone showed far better results, COD and color removal efficiencies were 57.4%, and 40%, respectively. However, the application of ECS/O3 resulted in complete decolorization and almost 99.7% COD removal under optimized operating conditions including ozone flow 300 mg/h, pH 7.1, Temperature 25 °C. ECS/photo-Fenton process resulted in COD, and color removal of 95.6%, and 97%, respectively. Electrical Energy per Order of ECS was found 1.58 kWh/m3 for minimum removal of dyes and COD. ECS/Ozonation is responsible for 100% decolorization but at a very high cost. ECS/photo-Fenton process proved to be the second-best option in terms of treatment and energy consumption. Hence, an integrated treatment system of ECS with AOPs appeared to be the most feasible and eco-friendly. That could lead to the treated wastewater for reuse and recycling purposes within the industry.

Treatability Studies on the Optimization of Ozone and Carbon Dosages for the Effective Removal of Contaminants from Secondary Treated Effluent

This study investigates the novel and advanced integrated pilot-scale treatment system of removal of contaminants in the secondary effluent from municipal wastewater. The main intent of this work is to assess the combination of pressure sand filter (PSF), ultrafiltration (UF), ozone (O3), and granular activated carbon (GAC) to treat wastewater and evaluate its suitability for water reuse. The experiments were carried out in a following condition: [Formula: see text], [Formula: see text], and [Formula: see text]. Configuration 1 was found to be more effective when compared to the other two and almost there occurred complete removal of contaminants. Whereas configuration 2 had the lowest removal efficiency of all, and configuration 3 had quite positive results. The influence of process parameters such as ozone dosage, flow rate, and filtration time was optimized. The optimized filtration time was 20 min with the filtration feed flow rate of 300 LPH. The best configuration of this treatment process produced a removal efficiency of about 80 to 90% with the ozone dosage of 8.33 mg/L with a flow rate of 4 l/min, whereas there occurred complete removal by the subsequent action of GAC. Moreover, the biodegradability of wastewaters as measured by the BOD5/COD ratio increased from 0.45 to 0.53. The proposed integrated pilot-scale process was effective in removing contaminants to the required level of discharge in the environment or reuse and it will pave the way to provide significant benefits to wastewater treatment.

Cold plasma aseptic packaging

Cold plasma aseptic packaging

MoS2/N-TiO2/Ti mesh plate for visible-light photocatalytic ozonation of naproxen and industrial wastewater: comparative studies and artificial neural network modeling.

This paper presents the results of visible-light assistedphotocatalyticozonation for the degradation of naproxen as a model pharmaceutical pollutant from water using MoS2/N-TiO2 immobilized on a titanium mesh plate in addition to treatment of a real industrial wastewater. The batch studies were performed for naproxen degradation by varying the reaction variables such as ozone flow rate, initial pH and pollutant concertation. It was observed that almost 90% degradation was achieved at pH = 4, ozone flow rate = 3 L min-1 and initial naproxen concentration = 5mg L-1. The catalyst exhibited constant activity even after seven successive cycles. Comparative studies among sorption, ozonation, photocatalysis, catalytic ozonation and photocatalyticozonation revealed that the later process had the highest degradation of pollutant. Moreover, an artificial neural network (ANN) model was developed to simulate the performance of visible-light photocatalytic ozonation in naproxen degradation. The developed ANN model could estimate the visible-light photocatalytic ozonation process under the different experimental conditions. Finally, the applicability of the photocatalyticozonation was successfully approved for industrial wastewater treatment. The results showed that the COD removalefficiency reached 65% within 150min. HIGHLIGHTS: • MoS2/N-TiO2/Ti wassynthesized by the quick electrophoretic deposition method. • The catalyst showed good ability in naproxen degradation via visible-light photocatalytic ozonation. • A three-layer artificial neural network model was developed to predict the naproxen degradation. • Naproxen degradation efficiency through the photocatalytic ozonation was higher than the individual methods. • COD of real wastewater was reduced significantly after thevisible-light photocatalytic ozonation process.

Catalytic Oxidation of Methylene Blue by Attapulgite/TiO2

Methylene blue (MB) is a common pollutant in wastewater of printing and dyeing industry. At present, ozone oxidation is commonly used in the treatment of printing and dyeing wastewater. Ozone is used for oxidation reaction directly and indirectly. However, the reaction rate is not fast enough. In this study, the attapulgite (ATP) was modified by tetrabutyl titanate-ethanol solution. The TiO2/ATP nanocomposite with high catalytic activity was prepared. The synthesized samples were subjected to characterized by X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR). The morphology and particle size of the particles were observed by scanning electron microscopy (SEM). The TiO2/ATP nanocomposite was calcined at 300°C for 2 h, and the degradation rate of 80 mg/L methylene blue was 99.8%. The experimental results show that the ozone, temperature and mass transfer factors are excluded, and the effects of temperature, MB concentration and pH on the degradation of methylene blue are investigated. The optimal reaction conditions are as follows: The ozone concentration is 0.067 g/min; the ozone flow rate is 0.15 NL/min; the stirrer rotation speed is 550 r/min; the catalyst is 0.1 g; the temperature is 50°C; Based on the results, the reaction mechanism was derived and the kinetic study of the experiment was carried out.

Remove of ammoniacal nitrogen wastewater by ultrasound/Mg/Al2O3/O3

A large amount of ammoniacal nitrogen wastewater discharged into the water body not only causes eutrophication and black and offensive odor in water, but also increases the difficulty and cost of water treatment, and even produces toxic effects on people and organisms. In this paper, degradation of ammoniacal nitrogen wastewater by the system of ultrasound/Mg/Al2O3/ozone (US/Mg/Al2O3/O3) was carried out. The effects of different influencing factors, such as initial pH of the solution, reaction time, temperature, catalyst addition, ozone flow rate, and ultrasonic intensity, on the degradation of ammoniacal nitrogen wastewater were investigated. The optimum reaction conditions were determined. The combination of ultrasonic technology and ozone oxidation technology can enhance the mass transfer of ozone and generate a large amount of HO. Due to Mg/Al2O3 catalyst has large surface area, the number of reactive sites and reaction molecule transport channels per unit area increases, resulting in the increase of HO on the surface, thus improving the catalytic activity. The introduction of ultrasound promotes the cleavage of N–H bonds on the catalyst surface, thereby promoting the degradation of ammoniacal nitrogen in the water. Results prove that there is not only a synergistic effect between ultrasound and catalytic ozone oxidation, but a strengthening effect of ultrasound on catalytic ozone oxidation. The research carried out in this paper provides a theoretical basis for the degradation of ammoniacal nitrogen in water.

Topical ozonated virgin coconut oil improves wound healing and increases HSP90α, VEGF-A, EGF, bFGF, and CD34 in diabetic ulcer mouse model of wound healing

Background: Diabetes is a disease that affects people worldwide, including in Indonesia. The prevalence of diabetes in Indonesia is increasing from year to year. One of the most devastating complications of diabetes mellitus is diabetic ulcers, which is a limb-threatening complication. Over the past few decades, ozone generated using plasma medical technology has been investigated as an agent that helps wound healing. This study aims to evaluate the effects of topical ozonated virgin coconut oil (VCO) in a diabetic wound mouse model. Methods: This study was an experimental study with a post-test control design. An ulcer wound model was made in 50 diabetic male Wistar mice, divided into five groups, and a control group of 10 non-diabetic mice. The control groups were given conventional therapy only and the treatment groups were also given topical ozonated VCO with different flow durations (0 min, 90 min, 7 h, 14 h). Macroscopic appearance and wound contraction were observed. HSP90β, VEGF-A, EGF, bFGF, and CD34 levels were measured from the immunostained slices of wound margins. Results: The reduction of wound length was proportionally related to the duration of ozone flow. Ozonated VCO with a longer duration of ozone flow healed the wound more quickly and had the shortest wound length. VCO with ozone flow for 14 hours (16837.10 µm) had the biggest reduction in wound length compared to other groups. The wounds treated with ozonated VCO showed an increase in HSP90β, VEGF-A, EGF, bFGF, and CD34 levels that correlated to improved wound healing. A longer period of treatment resulted in higher levels of wound healing biomarkers compared to shorter therapeutic durations. Conclusions: Topical ozonated VCO improved the wound healing process in a diabetic ulcer mouse model by improving macroscopic wound appearance and increasing levels of wound healing biomarkers.

Mechanism and kinetics of synergistic decopperization from copper anode slime by ultrasound and ozone

Copper anode slime is a typical hazardous waste that is rich in precious metals, rare metals and other valuable metals. Decopperization is the first step to recycle rare and precious metals from copper anode slime. In this work, the synergistic effect of ultrasound and ozone on copper leaching from copper anode slime was studied to develop an efficient and clean decopperization process. The effects of the reaction time, temperature, initial sulfuric acid concentration, ultrasound power and ozone flow rate were investigated. The results show that the dissolution fraction of copper can reach 98.46% under the optimum ultrasound and ozone reaction conditions. However, the leaching efficiency of copper under ozone is only 50.99% at 30 min. The kinetics analysis shows that the leaching reaction follows the classical unreacted-core shrinking model. The apparent Ea value and reaction orders were estimated to be 10.37 kJ/mol and 0.34, respectively. Meanwhile, the leaching kinetic equation under ultrasound and ozone was established using quadratic regression. Surface analyses indicated that the copper compound leached under ultrasound and ozone exposure. The higher leaching efficiency of copper results because copper and its compounds are transformed into soluble copper sulfate under the combination of ozone and ultrasound. The concentration of precious metals in the leaching residue under ultrasound and ozone is the highest, indicating that the synergistic effect of ultrasound and ozone can effectively enrich valuable precious metals. Synergistic decopperization from copper anode slime by ultrasound and ozone offers wide application prospects in transforming harmful anode slime waste into valuable materials.

Intensification of Ozone Mass Transfer and Generation of Hydroxyl Radicals by Ceramic Membrane

ABSTRACT The strengthening ability of ozone to treat the reverse osmosis concentrate (ROC) of landfill leachate is a crucial issue. From the standpoint of coupling intensification, a ceramic membrane/ozone (CM/O3) system was developed to improve the oxidation performance of ozone. The results showed that CM/O3 system could significantly improve the ozone concentration and the generation of hydroxyl radicals (·OH) when compared to the traditional O3 bubble system. The reaction condition, such as inlet ozone concentration and ozone flow, ceramic membrane pore size, transmembrane pressure, and temperature on the concentration of ozone in the liquid phase and the formation of ·OH, has been considered. Experimental results showed that the concentration of ozone and OH in the liquid increased with the increase in the inlet ozone concentration and ozone flow. Moreover, a certain degree of reduction in membrane pores was facilitated to intensify the mass transfer of ozone. The increase of pressure was able to raise the concentration of ozone. However, there was a slight effect on ·OH concentration. As for the temperature, a low-temperature situation was conducive to strengthen ozone dissolution. In terms of the generation of ·OH, a high-temperature situation was a better favorable environment. In order to evaluate the performance of the reactor system, three treatment processes (CM/O3, CM alone and O3 alone) were compared to treat ROC. In the CM/O3 system, the final removal efficiency of Chemical Oxygen Demand (COD) was 81.9%, and the final removal efficiency of Total Organic Carbon (TOC) was 62.6%.

Intensification of delignification and enzymatic hydrolysis of orange peel waste using ultrasound for enhanced fermentable sugar production

The present study focuses on using orange peel as a lignocellulosic substrate for fermentable reducing sugar production with intensification studies for delignification and enzymatic hydrolysis steps. The orange peel exposed to conventional and ultrasound-assisted alkaline pretreatment under ambient temperature for delignification resulted in around 86% delignification and 92% delignification in 4 h respectively. Subsequently, the effect of the enzyme concentration, ultrasonic power and duty cycle on reducing sugar production in the enzymatic hydrolysis has been investigated. Maximum concentration of reducing sugar as 1.30 g/L was obtained in 6 h treatment under 60W as power and 70% duty cycle, which was higher and much faster as compared to the conventional method where the sugar concentration was 0.814 g/L in 24 h. Studies involving advanced oxidation pretreatment based on hydrogen peroxide, Fenton, and ozone performed under ambient temperature demonstrated that the optimum conditions for best pretreatment efficacy are 3% H2O2 loading, 0.5g as FeSO4 loading and 2 L/min as the ozone flow rate as applicable, yielding a sugar concentration of 1.528 g/L, 2.069 g/L and 0.472 g/L respectively. Overall, the work has established that application of ultrasound and advanced oxidation pretreatment benefits the delignification and subsequent enzymatic hydrolysis of orange peel waste.

Enhanced in-situ electro-generation of H2O2 using PTFE and NH4HCO3 modified C/PTFE electrode for treatment of landfill leachate

In this study, the carbon black/polytetrafluoroethylene (C/PTFE) electrode was prepared under the best conditions, and then it was modified by PTFE and NH4HCO3 to make a PTFE-C/PTFE electrode. PTFE-C/PTFE electrode was used to enhance H2O2 in-situ electro-generation and the electro-peroxone process (EPP) treatment of leachate. Various analytical methods results were applied to prove that the PTFE-C/PTFE electrode greatly improved the performance of H2O2 generation and electrode stability. The effects of initial pH, current intensity, ozone flow and Cl− concentration on the removal of NH4+ and chemical oxygen demand (COD) from landfill leachate were studied in the EPP with PTFE-C/PTFE as cathode (MEPP) by one factor at a time (OFAT) method. The initial pH value 7.5, current intensity 300 mA, ozone flow 875 mg/h and Cl− concentration value 4198 mg/L were selected as the best operating parameters. A response surface methodology based on box-behnken design (BBD) was employed to optimize running conditions of the MEPP of leachate. After optimization, Mineralization efficiency of the NH4+ and COD was obtained to be 79.83% and 52.14%, and biochemical oxygen demand (BOD5)/COD ratio increased to 0.38 after 4 h. The removal curves of NH4+ and COD in the MEPP conforms to the zero-order and first-order reaction kinetics, respectively. Three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) analysis shows that MEPP has a good removal effect on organics in leachate. Energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis were carried out for the cathode sediment, which was mainly magnesium ion silicate precipitation and NaCl.

Carbon felt modified with N-doped rGO for an efficient electro-peroxone process in diuron degradation and biodegradability improvement of wastewater from a pesticide manufacture: Optimization of process parameters, electrical energy consumption and degradation pathway

In this study, diuron abatement in aqueous medium and the remediation of wastewater from a pesticide manufacture were studied by the E-peroxone process, using carbon felt modified with N-doped rGO (N-rGO/CF) as cathode and Ti/PbO2 anode. Compared with the unmodified CF, the N-rGO/CF displayed a higher response current, improved oxygen reduction activity, and larger BET specific surface area. Also, the modified CF provided a higher H2O2 production rate. The influence of several effective parameters on the diuron degradation rate in aqueous medium by the E-peroxone process was systematically explored by central composite design-response surface methodology; the approach suggested the optimal operating condition at pH of 9, applied current of 500 mA, Na2SO4 of 0.05 M, ozone flow of 1 L min−1, and operating time of 15 min to attain the maximum removal of diuron. At the optimal condition, N-rGO/CF cathode increased diuron degradation rate and decreased electrical energy consumption rather than CF cathode, in the E-peroxone system. Radical quenching experiment and degradation pathway of diuron revealed that hydroxyl radicals were the dominant reactive oxidants. A possible degradation mechanism was proposed based on hydroxylated and demethylated products identified during diuron degradation. No significant difference of the electro-generated H2O2 after 10 successive recycles confirms the admirable reusability of N-rGO/CF. The application of the process for pesticide wastewater increased BOD5/COD ratio significantly from 0.041 (for non-treated wastewater) to 0.4 during 90 min treatment, showing a substantial improvement of the biodegradability of the wastewater. Accordingly, the E-peroxone system can be utilized as a promising pretreatment step before a biological process to facilitate and shorten the length of the biological treatment. The findings of this study could offer valuable information for practical applications of the E-peroxone system in the treatment of pesticide-manufacturing wastewater.

Optimization of ultraviolet/ozone (UVO3) process conditions for the preparation of gelatin coated polystyrene (PS) microcarriers

The aim of this study was to develop gelatin coated polystyrene (PS) microcarriers with good cell adhesion and proliferation properties. PS microspheres, prepared using oil-in water (o/w) solvent evaporation method, were loaded with oxygen containing functional groups using an ultraviolet/ozone (UVO3) system. Using water-soluble carbodiimide chemistry, gelatin was subsequently immobilized on UVO3 treated PS microspheres. The amount of immobilized gelatin was found to be directly proportional to the surface carboxyl (COOH) concentration on PS microspheres. Face Centered Central Composite Design (FCCD) was employed to optimize the process conditions of UVO3 treatment to maximize the surface COOH concentration on PS microspheres for allowing higher gelatin immobilization. Statistical results revealed that, the optimized process conditions were ozone flow rate of ∼64,603 ppm, exposure time of ∼60 minutes and sample amount of 5.05 g. Under these conditions, the surface COOH concentration on PS microspheres was ∼1,505 nmol/g with the corresponding amount of immobilized gelatin was ∼2,725 µg/g. Characterization analyses strongly suggest that the optimized UVO3 treatment and successive gelatin immobilization have successfully improved surface wettability and dispersion stability of PS microspheres. Moreover, gelatin coated PS microcarriers were also proven as able to support the growth of CHO-K1 cells in high cell density culture.

Topical ozonated virgin coconut oil improves wound healing and increases HSP90α, VEGF-A, EGF, bFGF and CD34 in diabetic ulcer mouse model of wound healing

Background: Diabetes is a disease that affects people worldwide, including in Indonesia. The prevalence of diabetes in Indonesia is increasing from year to year. One of the most devastating complications of diabetes mellitus is diabetic ulcers, which is a limb-threatening complication. Over the past few decades, ozone generated using plasma medical technology has been investigated as an agent that helps wound healing. This study aims to evaluate the effects of topical ozonated virgin coconut oil (VCO) in a diabetic wound mouse model. Methods: This study was an experimental study with a post-test control design. An ulcer wound model was made in 50 diabetic male Wistar mice, divided into five groups, and a control group of 10 non-diabetic mice. The control groups were given conventional therapy only and the treatment groups were also given topical ozonated VCO with different flow durations (0 min, 90 min, 7 h, 14 h). Macroscopic appearance and wound contraction were observed. HSP90β, VEGF-A, EGF, bFGF and CD34 levels were measured from the immunostained slices of wound margins. Results: The reduction of wound length was proportionally related to the duration of ozone flow. Ozonated VCO with a longer duration of ozone flow healed the wound more quickly and had the shortest wound length. VCO with ozone flow for 14 hours (16837.10 µm) had the biggest reduction in wound length compared to other groups. The wounds treated with ozonated VCO showed an increase in HSP90β, VEGF-A, EGF, bFGF and CD34 levels that correlated to improved wound healing. A longer period of treatment resulted in higher levels of wound healing biomarkers compared to shorter therapeutic durations. Conclusions: Topical ozonated VCO improved the wound healing process in a diabetic ulcer mouse model by improving macroscopic wound appearance and increasing levels of wound healing biomarkers.

Effect of Oxygen-Containing Group on the Catalytic Performance of Zn/C Catalyst for Acetylene Acetoxylation.

In this study, a series of activated carbon-based supports with different oxygen-containing groups (OCGs) proportions were obtained via thermal treatment in an ozone flow. Semiquantitative analyses indicated that the performance of the catalyst attained a maximum after 30 min of treatment with ozone flow, and had a positive correlation with the content ratios of carboxyl and hydroxyl groups. Further, temperature-programmed desorption analysis demonstrated that the high performance (63% acetic acid conversion) of the prepared catalyst for the acetoxylation of acetylene could be ascribed to the reduced strength of increased capacity of acetylene adsorption. Density functional theory proved that the additional –COOH in the dicarboxylic catalytic system could be employed as a support for the active sites, and enhancing C2H2 adsorption strength in the rate-limiting step in the actual experimental process effectively accelerated the reaction rate. Thus, the OCGs on the surface of activated carbon play a crucial role in the catalytic performance of the acetylene acetoxylation catalyst.

Synthesis of Nano Ag-La-Co Composite Metal Oxide for Degradation of RB 5 Dye Using Catalytic Ozonation Process

ABSTRACT Nanoscale composite metal oxide of Ag-La-Co was prepared by co-precipitation method for the treatment of Reactive Black 5 using catalytic ozonation process. Further, the catalyst was characterized by transmission electron microscope, X-ray powder diffraction (XRD), scanning electron microscope - energy dispersive X-ray (SEM-EDX) and Brunauer–Emmett–Teller (BET) surface area analyzer for clarity of the phenomenon. The factors such as amount of catalyst (0.2–1.2 g/L), solution pH (2, 7, and 12), initial dye concentration (100–1,000 mg/L), and ozone flow rate (30–60 LPH) were found to influence the process. The characterization results confirm the formation of the composite metal oxide of Ag-La-Co. The degradation efficiency of catalytic ozonation was 63% compared to 32% and 4% in ozonation without catalyst and adsorption on the catalyst, respectively. Furthermore, it was observed that a pseudo-first-order kinetics model fits well with the experimental data. In addition, the effect of tert-butyl alcohol, a hydroxyl radical scavenger, has been studied. Lastly, the repetitive use of the synthesized catalyst showed that even after three consecutive runs, the catalytic activity is not much degraded, and therefore, the degradation efficiency of the synthesized catalyst was comparatively high; about 95% of Total Organic Carbon (TOC) removal was achieved at solution pH 7, amount of catalyst 1 g/L, reaction time 80 min, and ozone flow rate 30 LPH, indicating an economically viable option for industrial wastewater treatment.

Effect of gaseous ozone treatment on the aroma and clove rot by Fusarium proliferatum during garlic postharvest storage

It is known that garlic bulbs preserved with traditional methods undergo considerable losses, ranging from 25 to 40%. A frequent cause of these losses is associated with the development of pathogenic fungi, such as those of the genus Fusarium. The effect of ozone on post-harvest garlic bulbs was evaluated.Garlic cloves inoculated with Fusarium proliferatum F21 and F22 strains, were exposed to a continuous gaseous ozone flow (2.14 μg m−3), during 4 days, 20 h a day. After ozone-treatment, the garlic samples were moved at 22 °C to mimic retail conditions (shelf life). The changes in several quality parameters such as fungal decay and aroma were evaluated on garlic samples, as whole bulbs, cloves with and without tunic, through a sensorial descriptive test, SPME analysis in GC/MS and microbiological approaches. The data collected showed that ozone treatment did not affect the aromatic profile of garlic. A significant detrimental effect of ozone treatment on garlic decay was observed. Our results encourage the use of gaseous ozone treatment for containing garlic fungal decay during its storage.

Visible-Light Photocatalyst to Remove Indoor Ozone under Ambient Condition

Ozone is a kind of hazardous gas in indoor areas and needs to be removed in order to protect the human respiratory system. Previous methods include physical adsorption, thermal treatment, electromagnetic radiation removal, catalysis and photocatalysis. However, they all have limited effects. This research introduced a novel milestone to remove indoor ozone by utilizing visible light photocatalysis technique under ambient condition. The modified sol–gel method was applied to prepare photocatalysts, strontium titanate (SrTiO3) and rhodium-doped strontium titanate (SrTiO3:Rh). In addition, the SrTiO3:Rh was further immersed in N3 dye to improve its photocatalytic performance. Batch system and continuous-flow system were used to quantify the removal rate of ozone and to measure the conversions of ozone, respectively. The results showed that SrTiO3:Rh possessed a higher ozone removal rate under a visible light condition compared with a commercial P25 TiO2 catalyst. In addition, SrTiO3:Rh based catalysts can also successfully perform visible light ozone photodecomposition in the continuous ozone flow system. Note that current ozone converters in aircraft utilize thermal-catalysts, which can only be operated at high temperature. This research reveals a promising catalysts and photo process, which can possibly replace the current aircraft ozone converters with visible-light driven converters, and boast higher performance under ambient condition.