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Developing and implementing technologies that can significantly reduce food loss during storage and transport are of paramount importance. Ozone synergistic catalytic oxidation (OSCO) technology has been developed, which sterilizes bacteria and viruses on the surface of food and degrades ethylene released during fruit storage through the active oxygen produced by the catalytic decomposition of ozone. Herein, we report the hydrothermal synthesis of MnO2 with distinct phase compositions and nanostructures through simply varying the reaction temperatures. Optimized copper-doped α-MnO2 nanorods exhibited remarkable efficacy in activating ozone at a concentration of 40 ppb, and this activation resulted in the complete eradication of indicator bacteria on food surfaces within a 24 h period. Moreover, these nanorods demonstrated high effectiveness in decomposing more than 80% of the ethylene molecules emitted by apples and bananas during the preservation period. The high concentration of surface oxygen vacancies is believed to contribute to the enhanced catalytic activity of the Cu-doped α-MnO2 catalyst in the OSCO procedure by reducing ethylene production and maintaining the fruit quality during the preservation period.

Petrochemical wastewater contains a variety of organic pollutants. Advanced oxidation processes (AOPs) are used for deep petrochemical wastewater treatment with distinct advantages, including the complete mineralization of organic substances, minimal residual byproducts, and compatibility with biological treatment systems. This work evaluates the effectiveness of three methods, namely, ozone, persulfate, and O 3 -PMS (ozone-persulfate) processes, which were compared to remove soluble organic matter. The O 3 -PMS process offered significant advantages in terms of organic matter removal efficiency. This process involves ozone dissolution in an aqueous persulfate solution, producing a more significant amount of hydroxyl radicals in comparison to single AOPs. The production of hydroxyl radicals and the synergistic effect of hydroxyl radicals and persulfate radicals were investigated. In the O 3 -PMS process, transition metal ions were added to understand the mechanism of the O 3 -PMS coupled catalytic oxidation system. The results showed that when the ozone concentration was in the range of 5 ~ 25 mg/L, the dosage of persulfate was in the range of 0.01 ~ 0.05 mol/L, the dosage of metal compounds was in the range of 0:0 ~ 2:1, and the reaction time was in the range of 0 ~ 2 h; the optimum chemical oxygen demand (COD Cr ) and total organic content (TOC) removal effect was achieved under the coupled system with an ozone concentration of 10 mg/L, a persulfate dosage of 0.02 mol/L, a 1:2 dosage ratio of between Fe 2+ and Cu 2+ compounds, and a reaction time of 2 h. Under optimal reaction conditions, the rates of COD Cr and TOC removal reached 70% and 79.3%, respectively. Furthermore, the removal kinetics of the O 3 -PMS coupled catalytic oxidation system was analyzed to optimize the removal conditions of COD and TOC, and the mechanism regulating the degradation of dissolved organic matter was explored by three-dimensional fluorescence and GC–MS technology. Thus, O 3 -PMS coupled catalytic oxidation is an effective process for the deep treatment of wastewater. The careful selection of transition metal ions serves as a theoretical foundation for the subsequent preparation of catalysts for the ozone persulfate oxidation system, and this study provides a suitable reference for removing organic matter from petrochemical wastewater.

The escalating levels of surface ozone concentration pose detrimental effects on public health and the environment. Catalytic decomposition presents an optimal solution for surface ozone removal. Nevertheless, catalyst still encounters challenges such as poisoning and deactivation in the high humidity environment. The influence of support on catalytic ozone decomposition was examined at a gas hourly space velocity of 300 L·g −1 ·h −1 and 85% relative humidity under ambient temperature using Cu-Mn–doped oxide catalysts synthesized via a straightforward coprecipitation method. Notably, the Cu-Mn/SiO 2 catalyst exhibited remarkable performance on ozone decomposition, achieving 98% ozone conversion and stability for 10 h. Further characterization analysis indicated that the catalyst’s enhanced water resistance and activity could be attributed to factors such as an increased number of active sites, a large surface area, abundant active oxygen species, and a lower Mn oxidation state. The catalytic environment created by mixed oxides can offer a clearer understanding of their synergistic effects on catalytic ozone decomposition, providing significant insights into the development of water-resistant catalysts with superior performance. Graphical Abstract

Humic acid (HA), prevalent in natural water bodies, has the potential to form carcinogenic disinfection byproducts (DBPs), highlighting the necessity for efficient removal approaches. This study aimed to develop a stable and high-performance catalyst to enhance HA removal efficiency. An optimal cerium-manganese-modified material (CM-AA) was synthesized via impregnation onto activated alumina (AA). Its innovation lies in the first-time utilization of Mn-Ce synergistic effects, combined with ozone (O₃) and hydrogen peroxide (H₂O₂) to construct a ternary catalytic system. Preparation parameters were optimized through orthogonal experiments, and the material was characterized using SEM, EDS, and XPS techniques. The results demonstrated that Mn and Ce were highly dispersed on the surface of AA, providing abundant active sites. CM-AA exhibited excellent recyclability: after 12 cycles of use, the HA removal rate remained above 90%, which was superior to most reported single-metal catalysts. The CM-AA/O₃/H₂O₂ system outperformed binary combinations, achieving a HA removal rate of 95.5% under optimal conditions (10 mg/L HA, 10 mg/L H₂O₂, 4 mg/L CM-AA, 20 min O₃ exposure). The adsorption of HA by CM-AA followed pseudo-second-order kinetics and the Freundlich model, indicating a predominantly physical adsorption mechanism. This study presents a low-cost and efficient bimetallic catalyst, along with a multi-component synergy strategy to enhance oxidation performance. The system shows promising application prospects in drinking water treatment and the purification of HA-polluted wastewater, though its applicability in real water matrices and large-scale application feasibility require further investigation.

The discharge of various pollutant-rich wastewater in large volumes without adequate treatment seriously endangers the environment. Catalytic and photocatalytic ozonation are the alternative methods to make the treated wastewater reusable. Here, we review the recent advances in metal ferrite nanoparticle catalysts, including the various preparation methods, characterisation techniques, catalytic mechanisms, and modification strategies. We discuss the current application of metal ferrites as ozone catalysts and the synergistic effect of catalytic and photocatalytic ozonation. The average pollutant removal efficiencies are 20–40% for non-catalytic ozonation, 80–98% for catalytic ozonation and 60–80% for photocatalytic ozonation using metal ferrite.

In wet flue gas desulfurization and denitrification processes, nitrite accumulation inhibits denitrification efficiency and induces secondary pollution due to its acidic disproportionation. This study developed a Mn-modified ZSM-5 zeolite catalyst, achieving efficient resource conversion of nitrite in nitrogen-containing wastewater through an O3 + Mn/ZSM-5 catalytic system. Mn/ZSM-5 catalysts with varying SiO2/Al2O3 ratios (prepared by wet impregnation) were characterized by BET, XRD, and XPS. Experimental results demonstrated that Mn/ZSM-5 (SiO2/Al2O3 = 400) exhibited a larger specific surface area, enhanced adsorption capacity, abundant surface Mn3+/Mn4+ species, hydroxyl oxygen species, and chemisorbed oxygen, leading to superior oxidation capability and catalytic activity. Under the optimized conditions of reaction temperature = 40 °C, initial pH = 4, Mn/ZSM-5 dosage = 1 g/L, and O3 concentration = 100 ppm, the NO2− oxidation efficiency reached 94.33%. Repeated tests confirmed that the Mn/ZSM-5 catalyst exhibited excellent stability and wide operational adaptability. The synergistic effect between Mn species and the zeolite support significantly improved ozone utilization efficiency. The O3 + Mn/ZSM-5 system required less ozone while maintaining high oxidation efficiency, demonstrating better cost-effectiveness. Mechanism studies revealed that the conversion pathway of NO2− followed a dual-path catalytic mechanism combining direct ozonation and free radical chain reactions. Practical spray tests confirmed that coupling the Mn/ZSM-5 system with ozone oxidation flue gas denitrification achieved over 95% removal of liquid-phase NO2− byproducts without compromising the synergistic removal efficiency of NOx/SO2. This study provided an efficient catalytic solution for industrial wastewater treatment and the resource utilization of flue gas denitrification byproducts.

In this study, Mn-Ce/Al2O3/TiO2 catalyst prepared by impregnation method was used for synergistic O3 oxidation NO. The catalyst prepared by impregnating Al2O3/TiO2 at a Mn:Ce molar ratio of 4:1 showed the best catalytic activity. The catalyst performance showed that when the molar ratio of Mn:Ce was 4:1 and the volume ratio of O3:NO was 1:4, the removal rate of NO could reach 63%, which could increase the removal rate by 40% compared with that of NO oxidized by O3 alone. BET, XRD, and TEM characterization results showed that when the molar ratio of Mn:Ce was 4:1, the catalyst specific surface area, and pore capacity were the largest. A large amount of MnOx and CeOx were distributed on the catalyst surface. The XPS analysis showed that the oxidation-reduction and oxygen vacancy of Mn (IV)/Mn (III)/Mn (II) and Ce (IV)/Ce (III), had a synergistic effect on the decomposition of O3 into reactive oxygen species(O*), thus improving the catalytic capacity of Mn-Ce/Al2O3/TiO2 catalyst for O3. The O2-TPD analysis showed that the oxygen vacancies and oxygen species in the catalyst could be used as the active point of decomposition of O3 into O*. The experimental results show that the prepared catalyst can significantly improve the efficiency of ozone oxidation of NO and reduce the amount of ozone. The catalyst can be applied to ozone oxidation denitrification technology.

Pharmaceuticals that are present in superficial waters and wastewater are becoming an ecological concern. Therefore, it is necessary to provide high-performance methods to limit the harmful ecological effects of these materials to achieve a sustainable environment. In this research, NiO@Fe 3 O 4 nanocomposite was prepared by the co-precipitation method and utilized in the catalytic ozonation process for the degradation of 1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-yl-quinoline-3-carboxylic acid (ciprofloxacin antibiotic), for the first time. The influencing parameters in the degradation process were analyzed and optimized via response surface methodology (RSM). The optimal ciprofloxacin removal efficiency (100%) was found at pH = 6.5, using 7.5 mg of the NiO@Fe 3 O 4 nanocatalyst and 0.2 g L −1 h −1 ozone (O 3 ) flow, applied over 20 min. Results showed a significant synergistic effect in the analyzed system, which makes the proposed catalytic ozonation process more efficient than using the catalyst and ozone separately. Also, based on the kinetic analysis data, the catalytic ozonation process followed the pseudo-first-order model. In addition, the nanocatalyst showed high recyclability and stability (88.37%) after five consecutive catalytic ozonation process cycles. In conclusion, the NiO@Fe 3 O 4 nanocatalyst/O 3 system can be effectively used for the treatment of pharmaceutical contaminants.

The authors describe a strategy for ozone-induction coupling with plasma assistance (O 3 -I/PA) to enhance cataluminescence (CTL) based sensing of volatile organic compounds (VOCs). A homemade O 3 -I/PA CTL sensor system was constructed based on this strategy. O 3 -I/PA can significantly enhance the CTL response to many compounds that were hardly detectable previously with adequate sensitivity. Without any preconcentration, the limits of detection (for S/ N  = 3) are 20 μg.m −3 (= 5 ppbv) for toluene and 8 μg.m −3 (6.4 ppbv) for formaldehyde. VOCs including benzene, alkanes, halohydrocarbons, alkenes alcohols, aldehydes, ketones and ethers are found to produce a strong response when using this sensor system. Mechanistic studies showed that the synergistic effect of ozone-induction and plasma assistance promote the oxidation of the VOCs under formation of CO 2 . This strongly favors CTL emission. The sensor system can be used as a direct-reading detector for on-line and real-time monitoring of total VOCs. It also can be used as a detector in gas chromatography for the identification of individual VOCs. It is perceived that this work paves the way to both a new kind of vapor sensor and to a detection scheme in gas chromatography. Graphical abstract The synergistic effect of ozone-induction and plasma assistance promote the deep oxidation of the VOCs into CO 2 , which strongly favors cataluminescence emission.

Three manganese oxide catalysts (MnO x ) were synthesized via a simple method, and then they were introduced into the non-thermal plasma (NTP) system for benzene removal. The XRD and EXAFS results showed the MnO x were mainly in the Mn 3 O 4 phase, and from the analysis of N 2 adsorption/desorption isotherms, we knew the MnO x calcined at 250 °C (Mn250) had the largest surface area of 274.5 m 2  g −1 . Besides, Mn250 also exerted higher benzene adsorption capacity (0.430 mmol g −1 ) according to C 6 H 6 -TPD. O 2 -TPD indicated that Mn250 showed better oxygen mobility than Mn300. Moreover, by analyzing XPS results, it revealed that Mn250 exhibited rich abundant of surface adsorbed oxygen species ( O ads ) and moderate ratio of Mn 4+ /Mn 3+ , and the reducibility temperature was also the lowest among all the MnO x catalysts drawn by H 2 -TPR profiles. As a result, Mn250 combined with NTP could remove 96.9% of benzene at a low input power of 3 W (benzene concentration 200 ppm, and GHSV 60,000 mL g cat. −1  h −1 ), performing the best catalytic activity among the three catalysts and plasma only. Furthermore, the “NTP + Mn250” system also produced the highest CO 2 concentration and lowest CO concentration in downstream, and the residual O 3 after catalytic reaction was also the lowest, that is to say, the synergistic effect between NTP and Mn250 was more effective than other catalysts in benzene removal. Graphical abstract