Oxidant Research Articles

Soluble Gd6Cu24 clusters: effective molecular electrocatalysts for water oxidation.

The water oxidation half reaction in water splitting for hydrogen production is extremely rate-limiting. This study reports the synthesis of two heterometallic clusters (Gd6Cu24-IM and Gd6Cu24-AC) for application as efficient water oxidation catalysts. Interestingly, the maximum turnover frequency of Gd6Cu24-IM in an NaAc solution of a weak acid (pH 6) was 319 s-1. The trimetallic catalytic site, H2O-GdIIICuII2-H2O, underwent two consecutive two-electron two-proton coupled transfer processes to form high-valent GdIII-O-O-CuIII2 intermediates. Furthermore, the O-O bond was formed via intramolecular interactions between the CuIII and GdIII centers. The results of this study revealed that synergistic catalytic water oxidation between polymetallic sites can be an effective strategy for regulating O-O bond formation.

Cobalt phthalocyanine (CoPc) anchored on Ti3C2 MXene nanosheets for highly efficient selective catalytic oxidation.

Quinclorac is an important precursor for pharmaceutical, agricultural, and synthetic chemistry. The state-of-the-art synthesis of quinclorac via condensation, chlorination and oxidative hydrolysis often uses homogeneous catalysts and strong acid oxidant agents to promote the catalytic oxidation, which requires huge manpower input for the late-stage purification process and is usually environmentally unfriendly. In this work, we successfully fabricated a stable cobalt phthalocyanine (CoPc) Co-based composite (CoPc/Ti3C2) by anchoring CoPc on the surface of Ti3C2 nanosheets for the selective oxidation of 3,7-dichloro-8-dichloro methyl quinoline (3,7-D-8-DMQ) into quinclorac. More impressively, CoPc/Ti3C2-4.5%-Mn-Br exhibits a high selectivity of 91.8% for the catalytic oxidation of 3,7-D-8-DMQ to quinclorac in acetic acid, with a quinclorac yield of 87.5%, which is approximately 2.46 times higher than that of pristine CoPc-Mn-Br. The obtained heterogeneous catalytic system shows good reusability. Detailed mechanistic investigations reveal that the system works through the free radical mechanism via the formation of Co2+/Co3+ redox cycles. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the design of catalysts for selective catalytic oxidation.

Varying the degree of oxidation of graphite: effect of oxidation time and oxidant mass.

In this work, we employ a fast and less toxic modified Hummers' method to develop graphene oxide (GO) with varying degrees of oxidation and investigate the effect of the latter on the structure and the thermal properties of the synthesized materials. Two different key parameters, the time of the oxidation reaction and the mass of the oxidation agent, were systematically altered in order to fine tune the oxidation degree. All graphene oxides were characterized by a plethora of experimental techniques, like X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) as well as infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) for their structural, thermal and chemical identification. The results revealed that for a certain amount of oxidant, the time does not affect the final degree of oxidation of the materials, at least for the examined reaction times, because very similar structural patterns and thermal properties were obtained. At the same time, the oxygen-containing functional groups were found very similar. On the other hand, the degree of oxidation was found highly dependent on the mass of the oxidizing agent. XRD analysis showed a systematic increase of the interlayer distance of the synthesized GOs with the increase of the oxidant mass, whereas both the enthalpy of reduction and the % weight loss were increased. Moreover, XPS measurements provided a quantitative evaluation of the amount of carbon and oxygen in the materials; the increase of the oxidant mass led to a decrease of the total carbon content with the concurrent increase of the total oxygen amount.

(Invited) Limitation of Molecular Twisting: Upgrading a Donor-Acceptor Dye to Drive H2 Evolution

Dye-sensitized photoelectrochemical cells (DSPECs) have attracted wide attention to convert solar energy into high-energy chemicals. A DSPEC consists of a photoanode performing the oxidation half reaction and aphotocathode performing the reduction half reaction. In this presentation I will demonstrate how the performance of a dye-sensitized photocathode can be manipulated to enhance performance and even produce hydrogen! We have used a state- of-the-art dye (D-A P1 dye) on the surface of optimized NiO, and co-adsorbed myristic acid (Tetradecanoic Acid), which has a carboxyl anchoring group and a long apolar alkyl chain. Time-resolved photoluminescence and Density Functional Theory studies show that twisting lowers the energy levels of the photoexcited D-A dye, while twisting is inhibited in case myristic acid is co-adsorbed on the NiO surface. The presence of myristic acid also favors light-induced charge separation, as apparent from femtosecond transient absorption, and increases the apparent photocurrent. Very interestingly, only in the presence of myristic acid, light-induced H2 evolution is observed in aqueous media, despite the absence of a H2 evolution catalyst. We assign the H2 generation to a synergetic effect of inhibited twisting of the D-A dye radical anion increasing its electrochemical potential, combined with charge transfer and conversion of H+ on the hydroxylated NiO surface. Our work illustrates the importance of understanding effects of photoinduced intramolecular twisting and demonstrates that control thereof offers a simple design approach for efficient solar fuel devices.

Lanthanide Vanadate: An Efficient and Stable Oxygen Evolution Reaction Catalyst for Enhanced Water-Splitting Applications

Hydrogen fuel production through water-splitting reactions offers a sustainable approach to store renewable energies. However, the efficiency of this process is impeded by the oxygen evolution reaction (OER), a complex four-electron oxidation half-reaction. In this study, we present a highly active and stable OER catalyst, lanthanide vanadate (LnVO4 - Ln = La to Lu), synthesized using a straightforward hydrothermal method. Comprehensive characterization of the electrocatalysts was performed employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis. When applied to nickel (Ni) foam, lanthanide vanadate achieved a current density of 10 mA cm-2 at an overpotential of +280 mV in a 1.0 M KOH electrolyte. Furthermore, exceptional stability was demonstrated for over 5 hours of continuous operation. These findings highlight the potential of lanthanide vanadate-based materials as promising catalysts for efficient and stable overall water-splitting processes.

Revealing the Nature of Active Oxygen Species and Reaction Mechanism of Ethylene Epoxidation by Supported Ag/α-Al2O3 Catalysts.

The oxygen species on Ag catalysts and reaction mechanisms for ethylene epoxidation and ethylene combustion continue to be debated in the literature despite decades of investigation. Fundamental details of ethylene oxidation by supported Ag/α-Al2O3 catalysts were revealed with the application of high-angle annular dark-field-scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (HAADF-STEM-EDS), in situ techniques (Raman, UV-vis, X-ray diffraction (XRD), HS-LEIS), chemical probes (C2H4-TPSR and C2H4 + O2-TPSR), and steady-state ethylene oxidation and SSITKA (16O2 → 18O2 switch) studies. The Ag nanoparticles are found to carry a considerable amount of oxygen after the reaction. Density functional theory (DFT) calculations indicate the oxidative reconstructed p(4 × 4)-O-Ag(111) surface is stable relative to metallic Ag(111) under the relevant reaction environment. Multiple configurations of reactive oxygen species are present, and their relevant concentrations depend on treatment conditions. Selective ethylene oxidation to EO proceeds with surface Ag4-O2* species (dioxygen species occupying an oxygen site on a p(4 × 4)-O-Ag(111) surface) only present after strong oxidation of Ag. These experimental findings are strongly supported by the associated DFT calculations. Ethylene epoxidation proceeds via a Langmuir-Hinshelwood mechanism, and ethylene combustion proceeds via combined Langmuir-Hinshelwood (predominant) and Mars-van Krevelen (minor) mechanisms.

β-Ketoallylic methylsulfones synthesis via inert C(sp3)–H bond activation by magnetic Ag–Cu MOF

Herein, the one-pot tandem synthesis of β-ketoallylic methylsulfones has been achieved from readily available dimethyl sulfoxide and acetophenones as coupling partners in one step. In this procedure, dimethyl sulfoxide serves as a triple role including solvent, dual synthon and as an oxidant agent. The use of magnetic Ag–Cu MOF as a bimetallic catalyst is the key to the progress of the reaction due to its accessible active sites. It provides facile access to various β-ketoallylic methylsulfone derivatives from direct C(sp3)–H bond activation and functionalization of aromatic methyl ketones especially acetophenones with electron-rich and electron-poor groups. Moreover, the present work offers a synthetically powerful strategy to form products in good to excellent yields (74–96%) with the atom, step, and pot economics. It has also delivered a new chromane-4-one derivative from 2-hydroxy acetophenone with intramolecular Michael-addition of related β-ketoallyl methylsulfone product. In the final step, the electronic properties of some products have been predicted with the theoretical studies.

Therapeutic effects and mechanisms of action of ginger and its bioactive components on inflammatory response, oxidative stress, the immune system, and organ failure in sepsis: a comprehensive systematic review

Abstract Context Sepsis refers to a usually lethal medical condition that results from an extreme, uncontrolled, and multifaceted immune system response to infection. Ginger (Zingiber officinale Roscoe; Zingiberaceae) is 1 of the most popular spice. It is widely used as a traditional herb and as medicine in the treatment of some inflammatory conditions, such as vomiting, pain, cancer, diabetes, and cardiovascular diseases, because of its varied medical characteristics, including anti-inflammatory, antioxidant, antimicrobial, and antitumor effects. Objective The aim of this study was to demonstrate the potential roles of ginger and its elements in sepsis. Data Sources This systematic review article was conducted and reported by following the guideline of the Preferred Reporting for Systematic Reviews (PRISMA). Electronic databases, including Web of Sciences, Google Scholar, PubMed, Scopus, and ProQuest, were searched using related key words up to January 2023. Data Extraction Among 141 found articles, 48 eligible articles were included and reviewed for their details. Data were extracted, including the first author's name, year of publication, name of origin country, study design, number and type of subject, dosage and type of intervention, study duration, assay, and main results. Data Analysis The data from the included articles showed that ginger and its bioactive elements, such as gingerol (1–300 µg/mL or 1–100 mg/kg for 24 hours to 14 days), shogaol (0.2–100 µg/mL or 10–40 mg/kg body weight for 24 hours to 8 days), gingerdione (1–100 µg/mL for 20–48 hours), and zingerone (2–20 µM for 4 hours to 8 days), can be effective in sepsis via suppressing the gene expression and production of pro-inflammatory cytokines and oxidant agents, downregulating immune response, and protecting against sepsis-induced organ failures in experimental and animal models. Conclusion Ginger has potential therapeutic effects in sepsis. Human clinical trials are recommended. Systematic Review Registration PROSPERO registration no. CRD42023373613.

Response of the antioxidant system of wheat seedlings with different genotypes to exogenous prooxidants: the relationship with resistance to abiotic stressors

Oxidative stress is an important component of heat- and drought-induced damage in plants. However­, information on the relationship between the resistance of cultivated plants with different genotypes to environmental factors and their ability to maintain a pro-/antioxidant balance remains contradictory. This study aimed to compare the growth responses and adaptation ability of the antioxidant system in different wheat cultivars to oxidative stress agents hydrogen peroxide and iron(II) sulfate. Etiolated seedlings of common winter wheat (Triticum aestivum L.) Antonivka and Tobak (heat- and drought-tolerant), and Avgustina and Doskonala (not resistant to heat and drought) were used for the study. Three-day-old etiolated seedlings were exposed to 50 mM H2O2 or 5 mM FeSO4 for one day. It was found that seedlings of Antonivka and Tobak cultivars treated with H2O2 or FeSO4 were able to maintain relatively intensive growth, accumulated significantly lower amounts of endogenous hydrogen peroxide and lipid peroxidation products, significantly increased anthocyanin content and had a higher activity of SOD and catalase as compared with non-resistant cultivars. The non-tolerant cultivars’ response to stress agents was only to increase proline content with a simultaneous decrease in SOD activity and anthocyanins content. The identified varietal markers of the antioxidant system adaptive strategy can be used to develop new approaches for screening wheat cultivars with cross-resistance to major abiotic stressors. Keywords: antioxidant system, drought resistan­ce, ferrous sulphate, H2O2, heat tolerance, oxidative stress, Triticum aestivum seedlings

Ferrate as an all-in-one coagulant, oxidant, and disinfectant for drinking water treatment

In this study, ferrate was synthesized and applied as a green and multi-purpose agent for simultaneous coagulation, oxidation, and disinfection to remove turbidity, TSS, COD, UV254, and pathogens from Hau River water. Statistical analyses showed that pH, ferrate dose, and their interaction significantly affected the removals of turbidity, COD, UV254, and coliforms. While ferrate provided the highest removal efficiencies of disinfection, COD, and UV254 at low pH (pH 5), suggesting its role in the oxidation process, it is necessary to raise pH (pH 9) to achieve high turbidity removal via sweep flocculation. The single use of ferrate at pH 5 and 5 mgFe/L resulted in the removal efficiencies of 75% of turbidity, 92% of COD, and 100% of coliforms. The combination of ferrate with alum (2.5 mgFe/L, 8 mgAl/L, and pH 7) followed by sand filtration achieved 95% removal of COD and 100% removal of both turbidity and coliform.

Spectrophotometric Determination of Amoxicillin Using New Organic Reagent <i>via</i> Different Analytical Methods

New and simple spectrophotometric method was applied for amoxicillin determination by oxidative coupling with an organic reagent 1-(4-aminophenyl)-3-(5-(4-nitrophenyl)-furan-2-yl)-yl)-prop-2-en-1-one (H) to form an orange colored dye with λmax of 490 nm. The molecular structure of the new compound H was characterized using spectral analysis including 1H-NMR, FTIR, Mass spectroscopy, and UV-visible. The concentration range of oxidative coupling obeyed Beer's law was 2–50 μg/mL, the correlation coefficient was 0.9995, molar absorptivity was 0.63 × 104 L/mol cm, and the detection limit was 0.189 μg/mL. The concentration range of flow injection obeyed Beer's law was 1–150 μg/mL, the correlation coefficient was 0.9994, molar absorptivity was 0.295 × 104 L/mol cm, and the detection limit was 0.407 μg/mL. The proposed method was successfully applied in pharmaceutical formulation for amoxicillin determination. The results showed that amoxicillin could be reacted with a new compound H in the alkaline medium in the presence of oxidative agent NaIO4 and automated by flow injection analysis. The proposed methods have the advantage of simple, fast, very sensitive, good precision and accuracy. The suggested technique was effectively used to estimate amoxicillin in both its pure form and pharmaceutical formulations.

Effect of pro‐oxidants on the aerobic biodegradation, disintegration, and physio‐mechanical properties of compostable polymers

AbstractBiodegradable polymers are gaining momentum to resolve the globally acknowledged plastic waste problem. Understanding, characterizing, and developing new generations of biodegradable plastics is crucial to provide industries with alternative green materials that can fully satisfy biodegradation rates and lifetime specifications. This study evaluates the influence of metal pro‐oxidant additives on the degradation properties of various biodegradable polymer systems. For this purpose, iron (III) stearate (FeSt3) and bismuth oxide (Bi2O3), as oxidant agents, were incorporated into poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), poly(butylene adipate‐co‐terephthalate) (PBAT), cellulose acetate (CA), poly(lactic acid) (PLA), and thermoplastic starch (TPS) bioplastics. The material performances and biodegradability properties due to the additives on the resulting bioplastic formulations were investigated. A mechanism was proposed in which both pro‐oxidant additives can accelerate the thermo‐oxidation processes under composting conditions and cleave the polymer chains into smaller fragments to stimulate the biodegradation rate through microorganisms' activity. The study revealed that both pro‐oxidant additives, FeSt3 and Bi2O3, effectively improved the biodegradation process for all tested polymers except TPS, which already had a very high biodegradation rate. The observed change in the barrier and mechanical properties due to the additives were within tolerable limits of corresponding neat polymers.

The Mechanism of Action of Cotoneaster Manna, an Iranian Herbal Medicine, in the Treatment of Neonatal Jaundice

Background: Neonatal jaundice is a common clinical problem caused by the deposition of bilirubin in the tissue. Natural products have long been used to treat jaundice, and Iranian medicine can be a good source of natural treatments for this purpose. In this study, we investigate the mechanism of the effect of Cotoneaster, an Iranian herbal medicine, in the treatment of jaundice in neonates.
 Methods: We investigated every article that evaluated Purgative manna, Cotoneaster manna, or Cotoneaster in the treatment of neonatal jaundice. We searched the databases of PubMed, Scopus, Web of Sciences, SciELO, CNKI, and Google Scholar for English articles, and a search was also done in Persian in Magiran and Scientific Information Database (SID) published until August 2023.
 Results: The exact mechanism of Cotoneaster in reducing jaundice is not known, but the following mechanisms have been suggested. The most common mechanisms include increased urination, increased bile excretion from the liver, and increased defecation, as well as neutralizing the effects of oxidative agents and free radicals.
 Conclusion: Considering that most studies have stated that Cotoneaster combined with phototherapy is effective in treating jaundice and herbal medicines alone cannot treat jaundice. Therefore, identifying the mechanism of Cotoneaster in reducing jaundice can lead to the creation of methods to strengthen its effect. More detailed biochemical and pharmacological studies are needed to understand the mechanism of action of Cotoneaster in reducing neonatal jaundice.

Preparation of Ordered Nanostructures by Anodization of Ag Substrate with Depression Patterns

Nanostructures composed of Ag oxides are key materials with various potential applications such as sensors, catalysts, and batteries. We successfully fabricated nanohole array structures with an ordered arrangement of pores by anodizing a Ag substrate with a depression pattern in an ethylene glycol solution containing NH4F and KOH. Under these anodization conditions, each depression acts as a starting point for pore generation in the early stages of anodization. In addition, ordered nanopillar array structures were obtained by anodizing Ag substrates with depression patterns in ethylene glycol solution containing NH4F and CH3COONa. This is because the depressions formed by Ar ion beam irradiation act as masks during anodization, and the depressions remain during anodization, forming a nanopillar array structure. This is the first report on the fabrication of nanohole and nanopillar array structures by the anodization of a Ag substrate. In addition, this is the first report to show that ordered nanohole and nanopillar array structures can be fabricated by changing the electrolyte used for anodization. The Ag oxide nanostructures obtained by this process are expected to be applicable to various functional devices.

Ex vivo identification of transcriptional regulation landscape and potential therapeutic targets against oxidative stress using Alzheimer’s disease patient‐derived dermal fibroblast: findings from BICWALZS cohort

AbstractBackgroundReactive oxygen species (ROS) is considered as a central pathophysiology for neurodegeneration in Alzheimer’s disease (AD). Many studies using in vitro cell line or in vivo mouse model have shown the possible association between ROS defense mechanisms and cellular damage. However, that connection was not elucidated well in AD patient‐derived cell or brain organoids. In this study, we aimed to identify transcriptional regulation landscape and potential therapeutic targets against oxidative stress using AD dementia patient‐derived dermal fibroblastMethodsFor the purposes of ex vivo research, we performed skin biopsy and stabilized dermal fibroblasts in vitro. Total of 20 AD dementia patients and 22 cognitively normal older adults were assessed. All of AD dementia patients were amyloid positive on PET imaging, APOE e4 carrier, and cognition was imparied. On the contrary, all of cognitively normal older adults were amyloid negative on PET imaging, and APOE e4 non‐carrier. We applied H2O2 (600 uM) to dermal fibroblast for 24 hours as an oxidant agent to promote oxidative stress. After that, to identify transcriptional regulation landscape against oxidative stress, RNA sequencing was performed.ResultsTotal of 406 transcripts (up = 61, down = 345) were commonly differentially expressed in both of AD dementia and cognitively normal older adults derived dermal fibroblast by ROS‐H2O2. These transcripts were enriched in GO categories related to cell division, cell cycle, and DNA repair. Interestingly, 133 transcripts (up = 41, down = 92) were only differentially expressed in AD dementia dermal fibroblast by ROS‐H2O2. These transcripts were enriched in GO categories related to DNA duplex unwinding, cell division, and DNA replication. Total of 147 transcripts (up = 67, down = 80) were only differentially expressed in cognitively normal older adults dermal fibroblast by ROS‐H2O2. These transcripts were enriched in GO categories related to negative regulation of cell proliferation, notch signaling pathway, and NMDA glutamate receptor signaling pathway.ConclusionWe identified transcriptional regulation landscape by ROS‐H2O2 in AD dementia and cognitively normal older adults dermal fibroblast. Further bioinformatic analysis with computational tools and validation experiments will be performed to find potential therapeutic targets against oxidative stress.

Unrecognized Role of Organic Acid in Natural Attenuation of Pollutants by Mackinawite (FeS): The Significance of Carbon-Center Free Radicals.

Organic acid is prevalent in underground environments and, against the backdrop of biogeochemical cycles on Earth, holds significant importance in the degradation of contaminants by redox-active minerals. While earlier studies on the role of organic acid in the generation of reactive oxygen species (ROS) primarily concentrated on electron shuttle or ligand effects, this study delves into the combined impacts of organic acid decomposition and Mackinawite (FeS) oxidation in contaminant transformation under dark aerobic conditions. Using bisphenol A (BPA) as a model, our findings showed that oxalic acid (OA) notably outperforms other acids in enhancing BPA removal, attaining a rate constant of 0.69 h-1. Mass spectrometry characterizations, coupled with anaerobic treatments, advocate for molecule-O2 activation as the principal mechanism behind pollutant transformation. Comprehensive results unveiled that carbon center radicals, initiated by hydroxyl radical (•OH) attack, serve as the primary agents in pollutant oxidation, accounting for at least 93.6% of the total •OH generation. This dynamic, driven by the decomposition of organic acids and the concurrent formation of carbon-centered radicals, ensures a steady supply of electrons for ROS generation. The obtained information highlights the importance of OA decomposition in the natural attenuation of pollutants and offers innovative strategies for FeS and organic acid-coupled decontamination.

Structural evolutions under surface oxidation of AgPd Alloy: From Orientation, composition and strain effects to catalytic application

The surface oxidation of AgPd alloys can significantly impact their catalytic activity, however, the detailed understanding of such dynamic mechanism and the prediction of catalytic activity is still lacking. Herein, a comprehensive investigation combining ab initio molecular dynamics simulations with experimental observations is performed. The surface oxidation of AgPd alloys is highly dependent on oxygen concentration, where AgOx forms in oxygen-poor environment and PdOx forms in oxygen-rich environment, and shows highly reliance on the orientation, composition and strain state. The oxidation level of Ag, Pd and AgPd alloys follows the trend of (111) < (100) < (110) under 1.0 ML of O coverage. Both Pd single-atom and Ag matrix atoms in PdAg single-atom alloys are susceptible to oxidation under 0.5 ML of O coverage, with the increase of Pd atom number, only AgOx forms. Tensile strain promotes the oxidation of Ag(111) surface by facilitating the inward diffusion of O atoms, while compressive strain promotes the oxidation of Pd(111) and AgPd(111) surfaces by facilitating the outward migration of Ag/Pd atoms. The oxidized AgPd(111) surface with tensile strain under 0.5 ML of O coverage exhibits the optimum electrocatalytic activity toward formate oxidation reaction.

Unprecedented Selective Synthesis of Imines by Photocatalytic Oxidative Coupling of Primary Amines under N2O Atmosphere**

AbstractIn a climate change context, N2O contributes to global warming with CO2 and CH4. As an inert molecule, its upgrading as oxidant still constitutes a challenge in chemical synthesis. Here, the synthesis of imines was unprecedently performed using nitrous oxide (N2O) as a novel and highly selective oxidative agent for the photocatalytic homo‐coupling of amines. In a similar way, unsymmetric imines were produced through cross‐coupling of amines with alcohols. Promisingly, this greenhouse gas showed excellent performances towards the target reactions when photocatalytically activated at atmospheric pressure, with silver photodeposited on titanium dioxide as catalyst. Relevantly, reactions under N2O atmosphere exhibited high conversion rates and turn‐over frequencies, and higher selectivities than the ones carried out under a dioxygen atmosphere. Mechanisms for both reactions were detailed, showing the release of nitrogen and water as benign by‐products.

The effect of in-situ Pr6O11 phase formation on photocatalytic Performance: Mono azo dye degradation

The structural properties of TiO2, which finds wide application due to its excellent properties, can be improved especially by doping with transition metals to treat wastewater containing dyestuffs in a cheap, sustainable and environmentally responsible way. The positive impact of in situ Pr6O11 phase formation on the catalytic characteristics of the praseodymium ion doped (Pr-TiO2) photo catalyst produced by the acid sol gel method is highlighted in this study. Pr ion doping concentration of 1 wt% and calcination temperature of 400° C were selected. The properties of a Pr6O11/TiO2 composite structure (Pr-TiO2) synthesized utilizing XRD, XPS, and FTIR methods are discussed. Furthermore, the surface area of the pristine TiO2 photocatalyst was 19.22 (m2.g−1) and rose to 101.51 (m2.g−1) in the Pr-TiO2 catalyst, according to BET surface area measurements. The adsorption properties and photocatalytic activity of the catalyst were determined by the examination of the mono azo dyestuff Basic Blue 41 (BB41) degradation in a batch reactor using suspended system photocatalysis (ASF). No oxidation agents were used in this system. Azo dyestuff removal efficiency was measured by total organic carbon (TOC) and the color pollution change of wastewater was measured by UV–vis spectrophotometer.

Food Industrial Effluent Treatment with Oxygen and Ozone Using Activated Carbon for Catalytic Oxidation

ABSTRACT A catalytic oxidation treatment to remove coloration and chemical oxygen demand (COD) in an effluent from a food industry was carried out using oxygen and ozone as oxidizing agents and activated carbon as a catalytic. Different experiments of oxidation were conducted using 25, 50 and 100 mL of activated carbon bed to treat 100 mL of sample and constant flow of oxygen 7.2 g/min and ozone 0.034 mg/min, maintaining initial pH of industrial effluent. Almost a complete coloration removal and COD reduction of the sample was achieved for catalytic processes; however, time of treatment and agent oxidant doses were different in each case. According to volume of activated carbon beds, ozone doses for discoloration and COD removal were 8.5, 2 and 1.7 mg/L, whereas the oxygen doses were 2860, 770 and 500 g/L, respectively. Consequently, to eliminate the color in the industrial effluent, the dose of oxygen was higher than that of ozone. In addition, the oxidation agents promoted the regeneration of activated carbon, showing that its activity is declined after 60 cycles of effluent treatment with ozone, whereas with oxygen treatment, the total depletion was observed in 18 cycles. In turn, single adsorption showed activated carbon depletion in 5 cycles of effluent treatment.