Formation Of Reactive Species Research Articles

Inorganic anions influenced the photoaging kinetics and mechanism of polystyrene microplastic under the simulated sunlight: Role of reactive radical species

The photo-transformation of microplastic (MP) in natural water may involve interactions with various ingredients, but the photoaging kinetics and underlying mechanism are not well understood. This work systematically explored the photoaging process of polystyrene microplastic (PS-MP) in the presence of commonly-found inorganic anions, including NO3−, HCO3−, Br− and Cl−. The addition of these ions led to more obvious changes in the morphology, functional groups and molecular weight of photoaging PS-MP. The evolution of carbonyl index value for the photoaged samples conformed to pseudo-first-order kinetic model, and the photoaging rate constant (k) in the presence of inorganic anions at their environmentally relevant concentrations of 0.6 mM, 1.2 mM, 0.1 M and 0.1 mM was calculated to be kHCO3- = 0.0074 d−1, kNO3- = 0.01001 d−1, kCl- = 0.00783 d−1, and kBr- = 0.00888 d−1, which was higher than that in ultrapure water (k=0.00705 d−1). Electron paramagnetic resonance technique and quenching experiments demonstrated that photo-transformation of PS-MP was mainly mediated by indirect photolysis, i.e., the formation of reactive radical species. The photosensitivity of NO3− promoted more •OH production, thereby accelerated the indirect photoaging of PS-MP. Meanwhile, the presence of halide ions promoted the generation of reactive halogen species, which were also involved in the indirect photoaging of PS-MP. Interestingly, as •OH scavenger, HCO3− had no inhibitory effect on PS-MP photoaging, attributing to the oxidation of CO3•−. This study provides valuable insights into the understanding of photo-transformation of MPs in natural aquatic environments.

The effect of molecular structure of chlorin photosensitizers on photo-bleaching of 1,3-diphenylisobenzofuran—the possible evidence of iodine reactive species formation

In this short communication, we focus on the ability of chlorin e 6 photosensitizers (PSs) with one, two or three cationic groups to generate singlet oxygen species ( 1 O 2 ) in an apolar model medium, viz. 1-octanol (OctOH). The quantum yield of 1 O 2 (Φ Δ ) is determined indirectly by the chemical method for seven synthesized PSs using 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen trap. The Φ Δ values of four PSs with one or two cationic groups occupying opposite positions in the macrocycle are equal to 0.6, which is nearly identical to the values obtained by the time-resolved fluorescence spectroscopy method. In contrast, three PSs containing a 3(1),3(2)-bis-(N,N,N-trimethylaminomethylvinyl) iodide fragment with two adjacent cationic groups have an abnormally high quantum yield reaching 0.8. It is apparent that this phenomenon results from faster trap oxidation induced by radical reactions leading to molecular iodine formation.

Reduction of pesticide residues in Chrysanthemum morifolium by nonthermal plasma-activated water and impact on its quality

This study investigated the efficiency of plasma-activated water (PAW) on the reduction of pesticides, namely, metribuzin and metobromuron, and the effect of PAW treatment on the quality of fresh chrysanthemums. The reduction efficiencies reached 74.3% for metribuzin and 38.2% for metobromuron after 240 s of PAW treatment. Compared with reverse osmosis (RO) water, PAW achieved significantly higher pesticide reductions because of its higher acidity, enhanced oxidizing ability, and increased formation of reactive species. Moreover, when compared with metobromuron, metribuzin was reduced more efficiently irrespective of the RO water or PAW treatments because of its higher water solubility, lower log octanol-water partition coefficient, and more oxidizable chemical structure. Additionally, the PAW treatment did not cause adverse changes to the chrysanthemums’ color, total flavonoid content, radical scavenging, or metal chelating activities, but it did cause a slight decrease in the chrysanthemums’ aroma compounds and total reducing power. This study successfully demonstrated the effectiveness of PAW for reducing pesticides in herbal flowers like chrysanthemums and reveals PAW’s promising potential to treat foods with non-smooth surfaces.

Outside Front Cover: Plasma Process. Polym. 3/2022

Outside Front Cover: The mechanism of formation of Reactive Nitrogen Species (RNS) and Reactive Oxygen Species (ROS) in Plasma Treated Water Solutions (PTWS) is far from being understood. In this paper, we demonstrate how the different composition of the liquids affects the chemical composition of PTWS. Aromatic organic molecules play an active role in the production of ROS (i.e. H2O2). Further details can be found in the article by Valeria Veronico, Pietro Favia, Francesco Fracassi, Roberto Gristina, and Eloisa Sardella (e2100158)

Construction of dual active sites on diatomic metal (FeCo−N/C-x) catalysts for enhanced Fenton-like catalysis

High metal loading of single-atom catalysts enables excellent catalytic activity, but possibly causes serious aggregation problem. Herein, a series of diatomic FeCo−N/C-x (x represents metal content) were skillfully designed and applied to improve the catalytic activity for peroxymonosulfate (PMS) activation toward degrading organic micropollutants. The unprecedented dual active sites, referring to Fe(N3)−Co(N3) moiety and FeCo alloy, are constructed on the obtained FeCo−N/C-x, thereby exhibiting significantly greater performance toward degrading aqueous phenol (e.g., 0.316 min−1 for FeCo−N/C-3) via PMS activation, compared with those of traditional single-atom Co−N/C (0.011 min−1) and Fe−N/C (0.018 min−1). Combined experimental and theoretical calculations demonstrate the independent functions of dual active sites, in which Fe(N3)−Co(N3) and FeCo alloy can decrease the energy barrier of O−O bond cleaving resulting in the formation of high-valent FeCoO reactive species and singlet oxygen, respectively. This study opens up a new platform toward constructing dual active sites for enhanced Fenton-like catalytic activity.

Role of NOM in the Photolysis of Chlorine and the Formation of Reactive Species in the Solar/Chlorine System.

The solar/chlorine system has been proposed as a novel advanced oxidation process (AOP) for efficient pollutant degradation and water disinfection by producing a series of reactive species including hydroxyl radicals (HO•), chlorine radicals (Cl•), and so forth. In this study, the role of natural organic matter (NOM) in the photolysis of free available chlorine (FAC) and the formation of HO• and Cl• in the solar/chlorine system was investigated employing nitrobenzene and benzoic acid as selective chemical probes. The decay rate of FAC was significantly accelerated in the presence of NOM at pH 5.5 under simulated solar irradiation, likely due to the photoreaction between FAC and the photoexcited NOM. The decay rate of FAC increased upon increasing the electron-donating capacity of NOM, which indicated that phenolic components play a significant role in the photodegradation of FAC. This acceleration mechanism was further verified using 4-nitrophenol as a model phenolic compound. NOM promoted Cl• formation and quenched HO• in the solar/chlorine system. The proposed reaction mechanism included the reaction of excited singlet phenolic compounds in NOM with FAC, which yielded Cl•. This study provides a useful insight into future applications for using the solar/chlorine system as a novel AOP for wastewater treatment or disinfection.

High-crystallinity single-walled carbon nanotube aerogel growth: Understanding the real-time catalytic decomposition reaction through floating catalyst chemical vapor deposition

In this study, high-purity single-walled carbon nanotubes (SWCNTs) are synthesized with additional carrier gas through floating catalyst chemical vapor deposition. The presence of Ar during the SWCNT aerogel formation affects to the precursor decomposition and to the formation of different reactive hydrocarbons. Furthermore, the concentration of produced various carbon species is sensitive to the carrier gas compositions. The in-situ sampling methods prove the thermodynamic pathway for the hydrocarbon cracking during carbon nanotube (CNT) aerogel formation process. The addition of Ar promoted the formation of reactive hydrocarbon species, such as CH3, CH4, and C2H4/CO, to improve CNT morphology and graphitization. Ar has improved purity of CNTs compared to when only H2 is used. The synthesized CNTs were narrow in size, and the diameter decreased from 1.8 to 1.2 nm with the carrier gas composition (Rx) according to Ar addition. The IG/ID ratio of the CNTs changed from 78 to 3 at R0.1 and R0.57, respectively. Furthermore, the purity also increased to approximately 10% from 78% to 91% depending on Rx.

Visible Light-Induced Catalyst-Free Activation of Peroxydisulfate: Pollutant-Dependent Production of Reactive Species.

Activation of peroxydisulfate (PDS, S2O82-) via various catalysts to degrade pollutants in water has been extensively investigated. However, catalyst-free activation of PDS by visible light has been largely ignored. This paper reports effective visible light activation of PDS without any additional catalyst, leading to the degradation of a wide range of organic compounds of high environmental and human health concerns. Importantly, the formation of reactive species is distinctively different in the PDS visible light system with and without pollutants [e.g., atrazine (ATZ)]. In addition to SO4•- generated via S2O82- dissociation under visible light irradiation, O2•- and 1O2 are also produced in both systems. However, in the absence of ATZ, H2O2 and O2•- are key intermediates and precursors for 1O2, whereas in the presence of ATZ, a different pathway was followed to produce O2•- and 1O2. Both radical and nonradical processes contribute to the degradation of ATZ in the PDS visible light system. The active role of 1O2 in the degradation of ATZ besides SO4•- is manifested by the enhanced degradation of contaminants and electron paramagnetic resonance spectroscopy measurements in D2O.

Heterogeneous Activation of Persulfate by LaMO3 (M=Co, Fe, Cu, Mn, Ni) Perovskite Catalysts for the Degradation of Organic Compounds

Sulfate radical-based advanced oxidation processes (SR-AOPs) are lately applied for the degradation of various pollutants through the formation of reactive oxidant species (ROS) from activation of oxidants, such as persulfate (PS) or peroxymonosulfate (PMS). In this study, LaMO3 (M=Co, Fe, Cu, Mn, Ni) perovskite catalysts were synthesized, characterized by several techniques, and tested for the activation of persulfate towards the degradation of phenolic pollutants. The effect of substitution of position B of La-based perovskites as well as calcination temperature was studied. Overall, the results showed that the decisive role in the catalytic activity was the presence of structures that enhance the transfer of electrons between perovskite and oxidant. LaNiO3 followed by LaCoO3 were found as the most active catalysts. Finally, the stability of the catalysts was studied, showing that B-metal leaching is significant for both catalysts, with LaCoO3 being the most stable one.

Advanced oxidation processes (AOPs) based wastewater treatment - unexpected nitration side reactions - a serious environmental issue: A review

• Unexpected nitration processes led to formation of several nitro-derivatives. • Nitrogen fixation importantly contributes to formation of reactive nitrogen species in sonolysis. • Denitration and renitration processes in persulfate based AOPs causes nitration of intermediates. • Post-treatment and nitro-derivatives monitoring are important in AOPs. • Risk of low water quality in case of unexpected nitration during treatment process. Chemical compounds containing nitro group (nitro-products) are a one of toxic by-products, that can be formed during wastewater treatment processes. In case of presence of nitrite or nitrate ions, the formation of nitro-products during advanced oxidation processes (AOPs) is very common. It is caused by the reactive nitrogen species (RNs) such as nitrate radical (NO 3 • ), nitrite radical (NO 2 • ), nitrogen oxide radical (NO • ) and peroxynirite (ONOO–). In fact, the oxidative degradation of N-containing pollutants releases nitrate, nitrite and ammonium ions. In some cases, secondary reactions of mineralised nitrogen species (nitrate and nitrite ions) with the parent or intermediate compound generate next several nitro-products. The nitro-products are more toxic comparing to the primary pollutants and act as the precursors of the nitrogenous disinfection by-products. Moreover, some studies reported unexpected nitro-products formation during the oxidative degradation. In case of such processes a special attention should be made to monitor and minimize these effects. De-nitration of the initial nitro-compounds induces the formation of various nitro-products in AOPs. It was observed for UV light driven, Fenton and persulfate based AOPs. The sonochemical nitrogen fixation is a key mechanism for the formation of nitro-compounds in ultrasounds based AOPs. Therefore, this paper is focused on comparison of various AOPs in terms of nitro-products formation mechanisms and the associated environmental issues.

A comparative study of free chlorine and peroxymonosulfate activated by Fe(II) in the degradation of iopamidol: Mechanisms, density functional theory (DFT) calculatitons and formation of iodinated disinfection by-products

Both Fe(II)/free chlorine (Fe(II)/FC) and Fe(II)/peroxymonosulfate (Fe(II)/PMS) have a faster reactive species formation rate than the classic Fenton process, so their efficiencies of removing pollutants are better than that of the Fenton process. In this study, we compared the differences in the mechanisms and kinetics of iopamidol (IPM) degradation by Fe(II)/FC and Fe(II)/PMS. Although the production rate of reactive species of the two processes is at the same level (104 M−1 s−1), the Fe(II)/PMS process performed better regarding IPM removal. Reactive chlorine species (RCS) were the major contributor to the degradation of IPM (73.8%) by Fe(II)/FC, and hydroxyl radicals (HO•) and sulfate radicals (SO4•–) contributed 50.7% and 49.3% to the degradation of IPM by Fe(II)/PMS, respectively. Fe(IV) showed low contributions (<0.1%) to the degradation of IPM during the Fe(II)/FC and Fe(II)/PMS processes because of the low values of kFe(IV), IPM ((25 ± 5) M−1 s−1) and the low steady-state concentration of Fe(IV) in the Fe(II)/FC ((5.1 ± 0.7) × 10−8 M) and Fe(II)/PMS processes ((2.2 ± 0.09) × 10−8 M) at pH 3. Based on density functional theory (DFT) calculations and the MS results, the transformation pathway of IPM has been confirmed to mainly occur on chains B and B’ and the iodine group in between. The formation of disinfection by-products (DBPs) indicates that the Fe(II)/PMS process has lower environmental hazards. In general, we should pay more attention to the type of active species to evaluate the Fenton-like process. This study provides a basis for choosing a suitable alternative to the Fenton process and understanding the process in the Fenton-like procedure.

Physicochemical process of non-thermal plasma at gas-liquid interface and synergistic effect of plasma with catalyst

An atmospheric-pressure plasma jet (APPJ) was directly irradiated at a gas-liquid interface under ambient conditions. The reactive oxygen species (ROS) like hydroxyl radicals (•OH), hydrogen peroxide (H2O2) and ozone (O3) and also reactive nitrogen species (RNS) such as nitrogen oxides (NOx) and nitric acid (HNO3) formed during the plasma discharge were quantified under various experimental parameters. In a chemical dosimetry method, terephthalic acid (TA) was employed for the quantification of •OH and titanium sulfate was used to quantify the H2O2. Quantitative determination of NO3− was carried out by using Ion chromatography (IC). The changes in the solution pH were studied during the plasma treatment. Strong acidification along with the production of dominant reactive nitrogen species and ozone formation were observed with air. The effect of various gases, gas flow rate, various applied voltage and catalyst were studied to optimize the experimental conditions for the best performance. The influence of catalyst Fe2+ salt, TiO2 on the formation of reactive species were studied. The efficiency of the plasma device for the degradation of crystal violet (CV) was also investigated with TiO2 and Fe2+ salt.

An Iron Transporter Is Involved in Iron Homeostasis, Energy Metabolism, Oxidative Stress, and Metacyclogenesis in Trypanosoma cruzi.

The parasite Trypanosoma cruzi causes Chagas’ disease; both heme and ionic Fe are required for its optimal growth, differentiation, and invasion. Fe is an essential cofactor in many metabolic pathways. Fe is also harmful due to catalyzing the formation of reactive O2 species; for this reason, all living systems develop mechanisms to control the uptake, metabolism, and storage of Fe. However, there is limited information available on Fe uptake by T. cruzi. Here, we identified a putative 39-kDa Fe transporter in T. cruzi genome, TcIT, homologous to the Fe transporter in Leishmania amazonensis and Arabidopsis thaliana. Epimastigotes grown in Fe-depleted medium have increased TcIT transcription compared with controls grown in regular medium. Intracellular Fe concentration in cells maintained in Fe-depleted medium is lower than in controls, and there is a lower O2 consumption. Epimastigotes overexpressing TcIT, which was encountered in the parasite plasma membrane, have high intracellular Fe content, high O2 consumption—especially in phosphorylating conditions, high intracellular ATP, very high H2O2 production, and stimulated transition to trypomastigotes. The investigation of the mechanisms of Fe transport at the cellular and molecular levels will assist in elucidating Fe metabolism in T. cruzi and the involvement of its transport in the differentiation from epimastigotes to trypomastigotes, virulence, and maintenance/progression of the infection.

MIL-88A anchoring on different morphological g-C3N4 for enhanced Fenton performance

Fe-MOF/g-C 3 N 4 is a kind of typical II structure photo-catalyst. Some works reported that this catalyst's photo-performance has intimate relations with Fe-MOFs’ morphology. But the effect of g-C 3 N 4 ’ morphology has been ignored. In this work, we prepared three kinds of different morphological g-C 3 N 4 (bulk, tubulous and rod) to support MIL-88A by ball milling method. For tubulous g-C 3 N 4 has larger surface area and largest volume and pore size, ball milling method leads to strong and intimate interaction between g-C 3 N 4 and wrapped MIL-88A, the 6%MIL-88A@tubulous g-C 3 N 4 exhibits high h + -e - separation, which benefits to the formation of main reactive species, performs the best photo-Fenton activity, which is almost 241.5 times of tubulous g-C 3 N 4 and 6.3 of MIL-88A, respectively. Besides, MIL-88A could be encapsulated by tubulous g-C 3 N 4 and keep well stability in the process of wastewater remediation. This work is of significance to promote the large-scale application of Fe-MOF/g-C 3 N 4 in waste water remediation. • Different morphological g-C 3 N 4 were prepared to support Fe-MOF. • Tubulous g-C 3 N 4 supported Fe-MOF exhibit the best photo-performance. • This material obtained high efficiency and excellent stability. • h + , O 2 · − , ·OH is the predominant active radicals.

Sodium silylsilanolate as a precursor of silylcopper species

Silylcoppers function as convenient and effective sources of silicon functional groups. Commonly used precursors for those species have been limited to certain symmetric disilanes and silylboranes. This fact renders the development of silylcopper precursors desirable so that more diverse silyl groups could be efficiently delivered. Here we extend the utility of sodium silylsilanolates as competent precursors of silylcoppers. A silanolate unit operates as an auxiliary to transfer a variety of silyl groups to the copper centre, which was demonstrated in the copper-catalysed hydrosilylation of internal alkynes, α,β-unsaturated ketones, and allenes. Our mechanistic studies through DFT calculation suggested that a copper silylsilanolate undergoes intramolecular oxidative addition of the Si–Si bond to the copper centre to generate a silylcopper, in contrast to the typical formal σ-bond metathesis mechanism for conventional disilanes or silylboranes and copper alkoxides. Accordingly, sodium silylsilanolate has been established as an expeditious precursor of a variety of silylcopper species.

The First Observation of the Formation of Persistent Aminoxyl Radicals and Reactive Nitrogen Species on Photoirradiated Nitrogen-Containing Microplastics.

Nitrogen-containing microplastics (N-MPs) are widely present in the atmosphere, but their potential health risks have been overlooked. In this study, the formation of persistent aminoxyl radicals (PAORs) and reactive nitrogen species (RNSs) on the N-MPs under light irradiation was investigated. After photoaging, an anisotropic triplet with the g-factor of ∼2.0044, corresponding to PAORs, was detected on the nonaromatic polyamide (PA) rather than amino resin (AmR) by electron paramagnetic resonance and confirmed by density functional theory calculations. The generated amine oxide portions on the photoaged PA were identified using X-ray photoelectron spectroscopy and Raman spectroscopy, which were considered to be the main structural basis/precursors of a PAOR. Surprisingly, RNSs were also observed on the irradiated PA. The generated ·NO due to the aphotolysis of nitrone groups simultaneously reacted with peroxide radicals and O2·- to yield ·NO2 and peroxynitrite, respectively, which were responsible for peroxyacyl nitrates (PAN) and CO3·- formation. Besides, a significantly higher oxidative potential and reductive potential were observed for the aged PA than AmR, which is assigned to the abundant RNSs, organic hydroperoxides and PANs, and a strong ability to transfer electrons from PAOR, respectively. This work provides important information for the potential risks of airborne N-MPs and may serve as a guide for future toxicological assessments.

Simultaneous degradation of phenol-Cr(VI) wastewater on air injection plasma electrolysis using titanium anode

Phenol and Cr(VI) are dangerous wastewater were degraded simultaneously by reactive chemical species on plasma electrolysis reactor where direct air injection into plasma zone which titanium as the working electrode. Air injection contributes to increasing the formation of the radical species, such as radical ·OH, ·H, O2·−, and H2O2 molecules, even reducing the energy consumption. The effects of various air injection flow rates, pH, and voltages on phenol–Cr(VI) degradation were observed. The removal efficiency on the binary system was achieved 66% for phenol and 91% for Cr(VI) within 30 min, where the optimum condition of air injection flow rate is 0.2 L min−1 and pH 3.7. The energy efficiency of degradation was compared with that in other competitive processes. Increasing the voltage at constant power decreases the number of ·OH and ·H and increases the number of H2O2 molecules, indicating the formation of new reactive species. This study validated the synergistic effect on the simultaneous oxidation and reduction processes in wastewater.

Antibacterial behavior of organosilicon composite with nano aluminum oxide without influencing animal cells

A technology for producing a nanocomposite based on the borsiloxane polymer and aluminum oxide nanoparticles (Al2O3 NPs) has been developed. Nanocomposites containing 0.001, 0.01, and 0.1 wt% Al2O3 NPs have been created. It has been shown that the nanocomposite with any content of Al2O3 NPs did not lose the main rheological properties of borsiloxane. The resulting nanomaterial is capable of generating reactive oxygen species (ROS) such as hydrogen peroxide and hydroxyl radicals. The rate of ROS generation increases up to 3 times with an increase in the concentration of Al2O3 NPs. It has been shown that the nanocomposite leads to the formation of long-lived reactive protein species, and is also the reason for the appearance of such a key biomarker of oxidative stress as 8-oxoguanine in DNA. The intensity of the process increases with an increase in the concentration of Al2O3 NPs. Moreover, it was found that bacterial cells adhere to the surfaces of the nanocomposite (reduces the number of bacteria on the substrate by 39 times), and the nanocomposite can detach bacterial cells not only from the surfaces, but also from wetted substrates. The ability to capture bacterial cells is primarily associated with the properties of the polymer; they are weakly affected Al2O3 NPs. The nanocomposite is non-toxic to eukaryotic cells, the surface of the nanocomposite is suitable for eukaryotic cells for colonization. Due to unique physical properties, low cytotoxicity and antimicrobial action, this nanocomposite can be used in medicine and prosthetics.

Bacteriostatic and Cytotoxic Properties of Composite Material Based on ZnO Nanoparticles in PLGA Obtained by Low Temperature Method.

A low-temperature technology was developed for producing a nanocomposite based on poly (lactic-co-glycolic acid) and zinc oxide nanoparticles (ZnO-NPs), synthesized by laser ablation. Nanocomposites were created containing 0.001, 0.01, and 0.1% of zinc oxide nanoparticles with rod-like morphology and a size of 40–70 nm. The surface of the films from the obtained nanomaterial was uniform, without significant defects. Clustering of ZnO-NPs in the PLGA matrix was noted, which increased with an increase in the concentration of the dopant in the polymer. The resulting nanomaterial was capable of generating reactive oxygen species (ROS), such as hydrogen peroxide and hydroxyl radicals. The rate of ROS generation increased with an increase in the concentration of the dopant. It was shown that the synthesized nanocomposite promotes the formation of long-lived reactive protein species, and is also the reason for the appearance of a key biomarker of oxidative stress, 8-oxoguanine, in DNA. The intensity of the process increased with an increase in the concentration of nanoparticles in the matrix. It was found that the nanocomposite exhibits significant bacteriostatic properties, the severity of which depends on the concentration of nanoparticles. In particular, on the surface of the PLGA–ZnO-NPs composite film containing 0.001% nanoparticles, the number of bacterial cells was 50% lower than that of pure PLGA. The surface of the composite is non-toxic to eukaryotic cells and does not interfere with their adhesion, growth, and division. Due to its low cytotoxicity and bacteriostatic properties, this nanocomposite can be used as coatings for packaging in the food industry, additives for textiles, and also as a material for biomedicine.

Enhanced Ozone Oxidation by a Novel Fe/Mn@γ−Al2O3 Nanocatalyst: The Role of Hydroxyl Radical and Singlet Oxygen

Catalytic ozonation is a potential alternative to address the dye wastewater effluent, and developing an effective catalyst for catalyzing ozone is desired. In this study, a novel Fe/Mn@γ−Al2O3 nanomaterial was prepared and successfully utilized for catalytic ozonation toward dye wastewater effluent components (dimethyl phthalate and 1−naphthol). The synthesized Fe/Mn@γ−Al2O3 exhibited superior activity in catalytic ozonation of dimethyl phthalate and 1−naphthol in contrast to Fe@γ−Al2O3 and Mn@γ−Al2O3. Quench and probe tests indicated that HO° contributed to almost all removal of dimethyl phthalate, whereas O3, HO°, and singlet oxygen participated in the degradation of 1−naphthol in the Fe/Mn@γ−Al2O3/O3 system. The results of XPS, FT−IR, and EPR suggested that HO° and singlet oxygen were generated from the valence variations of Fe(II/III)and Mn(III/IV). Moreover, the Fe/Mn@γ−Al2O3/O3 system could also have excellent efficacy in actual water samples, including dye wastewater effluent. This study presents an efficient ozone catalyst to purify dye wastewater effluent and deepens the comprehension of the role and formation of reactive species involved in the catalytic ozonation system.