Reaction Of Peroxide Research Articles

Total Synthesis via Biomimetic Late-Stage Heterocyclization: Assignment of the Relative Configuration and Biological Evaluation of the Nitraria Alkaloid (±)-Nitrabirine.

The racemic total synthesis of nitrabirine (5) together with its previously undescribed epimer 2-epi nitrabirine (5') is accomplished via a six-step route based on a biomimetic late-stage heterocyclization. This allowed the assignment of the relative configuration of nitrabirine by the lanthanide-induced shifts (LIS) experiment, which was later on confirmed by X-ray diffraction of obtained single crystals. Furthermore, oxidation studies demonstrated that the direct N-oxidation of nitrabirine does not yield nitrabirine N-oxide as reported earlier. In contrast, the reaction of hydrogen peroxide with nitrabirine (5) yields the salt 24', whereas 2-epi nitrabirine (5') surprisingly leads to a previously uncharacterized product 22 under the same conditions. Finally, a Fischer indole reaction gave access to novel tetracyclic nitrabirine derivatives 26a-d. A comprehensive biological evaluation of nitrabirine (5), 2-epi nitrabirine (5'), and all derivatives synthesized in this study revealed general biofilm dispersal effects against Candida albicans. Moreover, specific compounds showed moderate antibacterial activities as well as potent cytotoxic activities.

Expanding role of vitamin E in protection against metabolic dysregulation: Insights gained from model systems, especially the developing nervous system of zebrafish embryos

This review discusses why the embryo requires vitamin E (VitE) and shows that its lack causes metabolic dysregulation and impacts morphological changes at very early stages in development, which occur prior to when a woman knows she is pregnant. VitE halts the chain reactions of lipid peroxidation (LPO). Metabolomic analyses indicate that thiols become depleted in E− embryos because LPO generates products that require compensation using limited amino acids and methyl donors that are also developmentally relevant. Thus, VitE protects metabolic networks and the integrated gene expression networks that control development. VitE is critical especially for neurodevelopment, which is dependent on trafficking by the α-tocopherol transfer protein (TTPa). VitE-deficient (E−) zebrafish embryos initially appear normal, but by 12 and 24 h post-fertilization (hpf) E− embryos are developmentally abnormal with expression of pax2a and sox10 mis-localized in the midbrain-hindbrain boundary, neural crest cells and throughout the spinal neurons. These patterning defects indicate cells that are especially in need of VitE-protection. They precede obvious morphological abnormalities (cranial-facial malformation, pericardial edema, yolksac edema, skewed body-axis) and impaired behavioral responses to locomotor activity tests. The TTPA gene (ttpa) is expressed at the leading edges of the brain ventricle border. Ttpa knockdown using morpholinos is 100% lethal by 24 hpf, while E− embryo brains are often over- or under-inflated at 24 hpf. Further, E− embryos prior to 24 hpf have increased expression of genes involved in glycolysis and the pentose phosphate pathway, and decreased expression of genes involved in anabolic pathways and transcription. Combined data from both gene expression and the metabolome in E− embryos at 24 hpf suggest that the activity of the mechanistic Target of Rapamycin (mTOR) signaling pathway is decreased, which may impact both metabolism and neurodevelopment. Further evaluation of VitE deficiency in neurogenesis and its subsequent impact on learning and behavior is needed.

Microfluidic paper device with on-site heating to produce reactive peroxide species for enhanced smartphone enabled chemiluminescence signal

Chemiluminescence signal amplification (CLSA) is of huge interest because of its sensitive detection in various applications such as food analysis, biomedical diagnosis and environmental monitoring. Due to this, there is a manifold attention to develop rapidly prototyped and miniaturized devices for CLSA. In this context, herein, a novel CLSA approach is demonstrated on a 3D printed microfluidic paper-based analytical device (μPADs), fabricated using Fused deposition modeling (FDM) printing technology. Influence of working temperature, ranging 30 °C–110 °C, on CL signal generation from well-established Luminol/Co+2 – H2O2 reaction was analyzed using a screen-printed flexible heater onto the 3D printed reaction platform. A smartphone-based capturing/detection system provided the amenability for a point-of-care testing system. For the first time, strong and stable CLSA was found with about 255% ± 5% increase in its signal intensity without using any additional external enhancers. The on-site working temperature was directly in proportional to the intensity of CL signal generated from Luminol/Co+2 – H2O2 reaction under optimum conditions, wherein the device had a wide linear range from 50 nM to 1 μM with a detection limit of 35 nM for H2O2 detection. The reliability of the developed amplification method was tested for practicability to detect the concentration of H2O2 in milk as real sample analysis. Overall, such CLSA mechanism in miniaturized μPADs will have strong potential for multiple CL based detection and monitoring application.

An efficient chemiluminescence system based on mimic CuMOF/Co3O4 nanoparticles composite for the measurement of glucose and cholesterol

The development of novel non-enzyme mimics for (bio)sensing applications is of great practical importance. Herein, an efficient chemiluminescence (CL) system is presented according to the significant mimetic behavior of the copper metal-organic framework decorated with cobalt oxide nanoparticles (Co3O4@CuMOF). The catalytic activity of nanocomposite was proved by its strengthening effect on the CL emission of rhodamine B (RB)-hydrogen peroxide (H2O2) reaction. More documents were also obtained using colorimetric and fluorometric peroxidase substrates. The presence of Cu and Co in the Co3O4@CuMOF structure, as well as the high porosity and great surface area of the obtained composite, was responsible for the observed synergetic catalytic activity. The Michaelis-Menten constant (Km) for the composite (0.108 mM) was remarkably lower than that of pristine CuMOF and Co3O4 NPs, illustrating its superior affinity towards H2O2. A linear correlation was found between the CL intensity and H2O2 concentration in the extensive range of 1–250 nM, with a detection limit (3S) of 0.244 nM. Furthermore, the developed system was exploited as a reliable sensing device for individual measurement of cholesterol and glucose after their enzymatic oxidations. The obtained data verified the high sensitivity and selectivity of the probe, which could be linked to the presence of high-performance Co3O4@CuMOF and the accompanying enzymes, respectively. The designed method was appropriately applied to measure cholesterol and glucose levels in human serum samples, and its accuracy was validated by analyzing the standard materials.

Removal of cephalexin from aqueous solutions using the fenton photocatalytic process

This paper aims to study the degradation and oxidation/mineralization process of cephalexin in model systems using Fenton’s reagent for UV irradiation (λ = 254 nm). The effect of pH (2-11), concentration of H2O2 (0,3434 mg/L) and concentration of Fe(II) (0-28 mg/L) on the degradation of 50 mg/L CPX were investigated. It has been determined optimum conditions for photocatalytic oxidation of CPX. Increasing the amount of H2O2 plays an inhibitory role in the production of hydroxyl radicals and reduces the process efficiency. This can be attributed to the reaction of excess peroxide with •OH and the formation of HO2 •, which has less oxidizing power compared to free hydroxyl radical. And as the concentration of the catalyst increases to the optimum, the excess of Fe(II) ions reacts with the hydroxyl radical and, therefore, the efficiency of the process also is reduced. Accordingly, the optimum degradation efficiency of 88 % and 83% for COD was obtained under the following conditions: pH 2,5, H2O2 concentration – 3,4 mg/L, Fe(II) ions concentration – 5,6 mg/L, cephalexin concentration – 50 mg/L, and reaction time – 60 min. Thus, the current study demonstrated that the photo-Fenton reactor can be used effectively as an advanced oxidation treatment unit for degradation of cephalexin under optimized environmental conditions.

Preparation and properties of porous ceramics from spodumene flotation tailings by low-temperature sintering

Porous ceramics were prepared with spodumene flotation talings (SFT), kaolin and low-melting point glass (LPG) powder, whose pores were formed by the chemical reaction of hydrogen peroxide (H2O2). LPG was used to reduce the sintering temperature of porous ceramics and kaolin was used to realize the adsorption to methylene blue (MB) of porous ceramics. The average flexural strength, compressive strength, apparent porosity, water absorption and maximum MB adsorption capacity were 5.60 MPa, 4.66 MPa, 52.27%, 44.32% and 0.7 mg/g, respectively. Moreover, the results of orthogonal experiments present that the sintering temperature and the dosage of H2O2 had great influence on the mechanical properties and apparent porosity of porous ceramics, respectively. The main reason for the improvement of mechanical properties of porous ceramics was that LPG gradually became soft with increasing the sintering temperature, which made the mineral particles adhere to each other closely. Kaolinite was not completely converted into metakaolin at 550 °C, which might be the main reason why porous ceramics had adsorption properties.

Sintesis dan Evaluasi Antimalaria In Vitro Turunan Kinin Terhadap Plasmodium falciparum

Nowadays kinin is the most effective antimalarial drug and its used as an alternative in malaria treatment. However, toxicity of quinine restrict its use as an antimalarial drug. Lipophilicity and long half-life (t½) of quinine that reach 10-20 hours are responsible for its toxicity. The aim of this research is to obtain more polar quinine derivatives by means of hydrogen peroxide reactions to reduce the toxicity. The reactions using hydrogen peroxyde is performed analogously to the procedures reported in the literature. Extract of pure anhydrous kinin is purified in coloumn chromatography followed by structure elucidation. Synthetic product is tested in vitro against Plasmodium falciparum. The characterization of reaction products is performed with proton (1H) and carbon 13 (13C) nuclear magnetic resonance (NMR) spectroscopy. It showed that the reaction using reagents led to epoxidation of vinyl substituents of chinuclidine ring with 61,08% yields. Antimalarial test against Plasmodium falciparum obtained 1.250-2.500 μg/mL of IC50 value. The IC50 values indicated that the synthesis products were not potential for malaria treatment.

BEP-Like Correction of Nonequilibrium Thermodynamic Parameters of the Solvent-Assisted Reactions: The DFT and Ab Initio Study of Hydration, Peroxidation, and Enolization of Acetone and 1,1,1-Trifluoroacetone in Aqueous Solutions.

The mechanisms of enolization and reactions of nucleophilic addition to carbonyl compounds were analyzed by density functional theory (DFT) (PBE1PBE) and ab initio (DLPNO-CCSD(T)) level of theory using the interaction of water and hydrogen peroxide with acetone and 1,1,1-trifluoroacetone (TFA) as the reference reactions. The transition states of the studied reactions were localized within the integrated approach that includes both the dielectric continuum theory (polarizable continuum model (PCM)) and the cyclic or two-cluster explicit solvation models. The considered models provide proton transfer in the enolization, hydration, and peroxidation reactions by the Grotthuss mechanism. It is shown that the calculated activation parameters at a sufficiently high level of theory and a sufficiently flexible solvation model can be additionally refined using the Bell-Evans-Polanyi (BEP)-like correction (in a form of the Bell-Evans-Polanyi equation), which is linear scaling of the model potential energy surface according to the equilibrium parameters of the reference reaction (experiment or high-level calculation). Quite good correspondence of the corrected and reference activation parameters and the lower sensitivity of the calculation results to the choice of the solvation model indicate the high reliability of the proposed BEP-like correction technique.

A bifunctional probe that allows dual-channel fluorescence turn-on detection of protein aggregates and hydrogen peroxide in neurodegenerative diseases

Protein aggregation and oxidative stress have been suggested to underlie alternations and loss of neuronal function during the development of neurodegenerative diseases. It is of importance to differentially identify the formation of protein aggregates and the generation of reactive oxidative species in the same microenvironment. The current work reports on a bifunctional sensor based on arylboronate-pyridinium, in which hydrogen peroxide (H2O2) reaction and protein interaction lead to differential fluorescence spectral responses in separate channels. While free sensor was weakly emissive in PBS solution, its fluorescence significantly enhanced around 600 nm towards protein aggregates, and increased around 530 nm from effective response to H2O2 over a range of bioavailable H2O2 levels. It also efficiently detected intracellular protein aggregates and H2O2 in separate emission channels. The dual-channel fluorescence turn-on ability provides a facile tool for differential detection and imaging of H2O2 and protein aggregates in solutions and in cells.

Accelerated Redox Reaction of Hydrogen Peroxide by Employing Locally Concentrated State of Copper Catalysts on Polymer Chain

Back Cover: In article number 2100274, Shigehito Osawa, Hidenori Otsuka, and co-workers design a polymer chain containing copper complexes in the side chain to build a locally concentrated state of copper complexes in an aqueous solution. In this image, the facilitated catalytic activity against hydrogen peroxide decomposition generates hydroxyl radicals, eventually attacking pathogens.

Nitric oxide protects against ferroptosis by aborting the lipid peroxidation chain reaction

Ferroptosis is a type of iron-dependent necrotic cell death, which is typically triggered by the depletion of intracellular glutathione (GSH), which is associated with increased lipid peroxidation. Nitric oxide (NO) is a highly reactive gaseous radical mediator with anti-oxidation properties that terminates lipid peroxidation reactions. In the current study, we report the anti-ferroptotic action of NOC18, an NO donor that spontaneously releases NO, in cells under various ferroptotic conditions in vitro. Our results indicate that, when mouse hepatoma Hepa 1–6 cells are incubated with NOC18, cell death induced by various ferroptotic stimuli such as cysteine (Cys) starvation, the inhibition of glutathione peroxidase 4 (GPX4) and treatment with tertiary-butyl hydroperoxide (TBHP) is significantly reduced. Treatment with NOC18 failed to improve the decrease in the levels of Cys or GSH and the accumulation of ferrous iron upon ferroptotic stimuli. The fluorescent intensity of C11-BODIPY581/591, a probe that is used to detect lipid peroxidation products, was increased somewhat by treatment with NOC18 under conditions of Cys starvation, and the accumulation of lipid peroxidation end-products, as evidenced by the levels of 4-hydroxynonenal, were effectively suppressed. The pre-incubation of TBHP with NOC7, a short-lived NO donor completely eliminated its ability to trigger ferroptosis. These collective results indicate that NO exerts a cytoprotective action against various ferroptotic stimuli by aborting the lipid peroxidation chain reaction.

Accelerated Redox Reaction of Hydrogen Peroxide by Employing Locally Concentrated State of Copper Catalysts on Polymer Chain.

Copper complexes act as catalysts for redox reactions to generate reactive oxygen species that destroy biomolecules and, therefore, are utilized to design drugs including antitumor and antibacterial medicines. Especially, catalytic reaction for hydrogen peroxide decomposition is important because it includes the process for generating highly toxic hydroxyl radical, i.e., Fenton-like reaction. Considering that multicoppers/hydrogen peroxide species are the important intermediates for the redox reaction, herein a polymer having copper complexes in the side chains is designed to facilitate the formation of the intermediates by building locally concentrated state of the copper complexes. The polymer increases their catalytic activities for hydrogen peroxide decomposition and promotes reactive oxygen species' generation, eventually leading to higher antibacterial activity. This reveals the virtue of building a locally concentrated state of catalysts on polymers toward drug design with low amounts of transition metals.

Visible-Light Photocatalyzed Oxidative Coupling of Benzylamines with Nucleophiles: Synthesis of 2-Aryl benzothiazoles and α,β-Unsaturated esters

The oxidation of amines is considered as one of the important way for producing key synthetic intermediates such as aldehydes, ketones, imines, oximes, amides, nitriles and nitro compounds using suitable reaction conditions. Recently, the utilization of light as an energy source in organic synthesis have gained significant interest and has delivered the key development to the visible-light photoredox catalysis. Herein, we have developed the oxidation of benzylamine derivatives using rose bengal as a photocatalyst under visible-light irradiation followed by trapping with nucleophiles like 2-aminothiophenol and dimethylmalonate for the construction of 2-aryl benzothiazoles and α,β -unsaturated esters. The proof of concept has been established by synthesizing five benzothiazole derivatives and five α,β -unsaturated esters. The key features of this method are metal-free, no external oxidants such as peroxide and ambient reaction temperature.

MoS2 co-catalysis promoted CaO2 Fenton-like process: Performance and mechanism

Fenton reaction is widely applied to treat organic contaminant through hydroxyl radicals (HO), which is formed from the catalytic reaction of hydrogen peroxide (H2O2) and Fe2+. Nevertheless, its well application for actual wastewater has been confined by the narrow range of pH, disproportionation of H2O2 and inefficiency of Fe2+/Fe3+ circulation. To overcome these shortcomings, an improved Fenton-like method applying calcium peroxide (CaO2) as the substitution of H2O2 and molybdenum disulfide (MoS2) as the co-catalyst was proposed. The results indicated the efficient rhodamine B (RhB) removal (98.6%) was achieved under the conditions of 1 mmol L−1 CaO2, 0.5 mmol L−1 Fe2+, 0.3 g L−1 MoS2, and initial pH 5.85 within 5 min, and this system could well degrade other dyes, antibiotic, and phenol. The MoS2 addition could promote the Fe2+/Fe3+ conversion and H2O2 disintegration. The radical masking tests and electron paramagnetic resonance demonstrated that the HO was the main active substances during this process. The decomposition intermediates of RhB were identified through the mass spectra analysis, and their ecotoxicities were assessed by the toxicity estimation software. Finally, this process also presented a favorable performance for the real wastewater treatment, which is a potential route to promote the development of Fenton method.

AIEgens-based fluorescent covalent organic framework in construction of chemiluminescence resonance energy transfer system for serum uric acid detection.

A covalent organic framework (COF) with aggregation-induced emission (AIE) property was successfully synthesized through in situ marriage of a commonly used AIE molecule tetraphenylethylene (TPE) with Schiff base network (SNW-1) through a simple one-pot method. The TPE@SNW-1 was characterized with different techniques of Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and nitrogen adsorption/desorption experiments. The fluorescence of the TPE@SNW-1 strongly depends on the composition of tetrahydrofuran-water binary system. The AIE property of TPE@SNW-1 was directly supported with particle size distribution by dynamic light scattering technique. With the TPE@SNW-1 as an energy acceptor, a chemiluminescence resonance energy transfer (CRET) system was constructed with bis(2,4,6-trichlorophenyl) oxalate (TCPO)-hydrogen peroxide (H2O2) reaction as an energy donor. The chemiluminescence (CL) signal displays a good linear relationship with concentration of H2O2 in the 5.0-1000.0 μmol·L-1 range, and a detection limit of 2.34 μmol L-1. The system was further exploited to determine uric acid based on the fact that equal stoichiometric amount of H2O2 can be concurrently generated under the catalysis of uricase. The procedure exhibits a linear response to uric acid concentration in the range 10.0-150.0 μmol·L-1 and a detection limit of 4.94 μmol·L-1. The practicability of the method was demonstrated in the determination of uric acid in human serum samples.

Physicochemical properties, antioxidant and antimicrobial activities of Nigerian Polyfloral honeys

Natural honey is widely applied as food sweetener, food preservative and in folk medicine for treatment of varying degree of human affliction and diseases. This study evaluates the antimicrobial activities, physicochemical, phytochemical and antioxidant properties of four Nigerian honey samples collected from Ekiti, Kogi, Osun and Ondo (coded as A, B, C and D respectively). Physicochemical determination of honey samples include: pH, free acidity, electrical conductivity and density. Determination of phytochemical was carried out quantitatively using phenolics and flavonoid; while the total antioxidant capacities was measured in an in-vitro system using inhibition of lipid peroxidation, thiobarbituric acid reactions and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Agar diffusion method was used to measure the antimicrobial activities of the honey samples against some selected microorganisms (Staphylococcus aureus, Bacillus subtilis, Psuedomonas aeruginosa and Escherichia coli). The results of the physicochemical characterization showed that the honey samples were polyflorals characterized by low pH (3.76 ± 0.02, 4.17 ± 0.15, 3.94 ± 0.10 and 3.77 ± 0.01 for A, B, C and D respectively) capable of inhibiting the growth of most microorganisms and density ranging between 1.38 and 1.45 g/ml. All the honey samples showed antimicrobial activity against the selected microorganisms at concentration greater than 60 % v/v. The antioxidant investigation also demonstrated ability to inhibit lipid peroxidation and thiobarbituric acid reactions and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity possibly due to the reasonable amount of flavonoids and phenolics therein.

Interfacial kinetics in olive oil-in-water nanoemulsions: Relationships between rates of initiation of lipid peroxidation, induction times and effective interfacial antioxidant concentrations

HypothesisA detailed quantitative description of the effects of antioxidants in inhibiting lipid peroxidation in oil-in-water emulsions can be achieved by determining the relationships between the rates of initiation of the lipid peroxidation reaction, the length of the induction period preceding the propagation step of the radical oxidation process and the effective antioxidant interfacial concentrations. ExperimentsWe successfully prepared and characterized a series of olive oil-in-water nanoemulsions and allowed them to spontaneously oxidize. Their oxidative stability was evaluated by carrying out in the presence, and absence, of antioxidants derived from gallic acid, by monitoring the formation of primary oxidation products with time, by determining the corresponding induction periods, and by determining the effective interfacial concentrations of the antioxidants in the intact emulsions. FindingsResults show that both, the length of the induction periods and the antioxidant interfacial concentrations change concomitantly, increasing with the hydrophobicity of the antioxidant up to a maximum at the octyl derivative; longer aliphatic chains decrease their efficiency. The ratio between the interfacial antioxidant concentration and the induction period remains constant independently of the antioxidant, demonstrating that the effective concentrations of antioxidant at the interface control their efficiencies in emulsions.

Dimeric-serotonin bivalent ligands induced gold nanoparticle aggregation for highly sensitive and selective serotonin biosensor

Chemically modulating monoamine neurotransmitter serotonin undergoes a physiological reaction of enzyme intermediated peroxidation to reconstruct dimeric self-assembled complex. A standard bivalent ligand approach dimeric serotonin increases structural and functional scaffolding with recognition-binding sites that are fundamentally more friendly than monovalent binding sites. Dimerization reaction accelerates the catalytic activity of one-electron oxidation at the C(4) position of serotonin to generate dual phenolic radicals in the presence of horseradish (HRP) and hydrogen peroxide (H2O2). Herein, we suggest the dimeric serotonin-based colorimetric assay, which presents a new rapid, sensitive, selective, and quantitative visualization. The dimeric serotonin possesses the capability to recognize intermolecular interaction units that cause aggregation scaffold of gold nanoparticles (GNPs), providing inexpensive and straightforward analytical needs. As a proof of visual and spectral analysis, peroxidative dimeric serotonin demonstrated sensitive and robust results. The calorimetric method enables highly sensitive detection of serotonin in phosphate buffer, and in human serum samples at nanomolar levels with a LOD of 2.6 nM and 2.81 nM, respectively, and the sensor possesses a dynamic range of 100–300 nM in buffer condition. Also, as proof of concept, visible color imaging of immunosensors which is appropriate for fast visible testing at detection limits as low as 2.90 nM concentration.

Ameliorative role of trans-ferulic acid on induced oxidative toxicity of rooster semen by β-cyfluthrin during low temperature liquid storage

Current study was designed to evaluate the effects of β-cyfluthrin, as a toxicant substance, and trans-ferulic acid (trans-FA), as a protective agent, on different parameters of rooster semen upon liquid storage. For this purpose, semen samples of roosters (Ross 308, n = 10, 32-wk-old) were collected twice a week. Good quality samples (≥70% progressive motion) were diluted, pooled and then divided for the purposes of the study. In the first experiment, motility of spermatozoa was evaluated following exposure to different concentrations of β-cyfluthrin (1, 2.5, 5, 10, 20, 40, and 80 µM) at 0, 24, and 48 h of storage. In the second experiment, constant doses of β-cyfluthrin (10 µM) alone or in combination with trans-FA (10, 25 mM) were assessed on motility and viability of spermatozoa at 0, 24, and 48 h time points. Moreover, amounts of malondialdehyde (MDA), total antioxidant capacity (TAC), total nitrate-nitrite, total hydroperoxide (HPO), and activity of superoxide dismutase (SOD) were evaluated in the homogenate of spermatozoa-diluent at studied time points. Results of the first experiment showed that amounts of β-cyfluthrin greater than 5 µM, significantly reduced the motility of spermatozoa at 24 and 48 h of storage (P < 0.05). The second experiment demonstrated that, trans-FA especially at 10, 25 mM doses restored the motility and viability of spermatozoa compared to β-cyfluthrin treated group (P < 0.05). Amounts of MDA (10, 25 mM), hydroperoxide (10, 25, and 50 mM), and nitrate-nitrite (10, 25, and 50 mM) were lower and TAC (10 and 25 mM) were greater in trans-FA + β-cyfluthrin treated groups compared to β-cyfluthrin alone treated samples (P < 0.05). However, activity of SOD did not show significant changes by the treatment (P > 0.05). It seems that trans-FA could ameliorate toxic effect of β-cyfluthrin via reduction of peroxidative (as evident by measurement of MDA) and nitrosative (as evident by measurement of nitrate-nitrite) reactions over cold preservation of rooster semen.

Optimisation of COD removal from the olive oil mill wastewater by combined electrocoagulation and peroxone process: modelling and determination of kinetic coefficients

ABSTRACT The olive oil extraction industry is one of the most extensive industries, especially in the Mediterranean region. The wastewater produced in this industry contains high concentrations of organic pollutants, resistant and toxic compounds that, if not treated, can threaten the health of the environment. In the present study, the optimisation of the combined process of electrocoagulation and peroxone using central composite design of the response surface methodology with the help of Design-Expert V.11 The parameters of current density (0.06–0.73 A dm−2) and reaction time (5–45 min) in the process of electrocoagulation and the parameters of hydrogen peroxide concentration (4–12 ml) and reaction time (10–90 minutes) in the peroxone process were investigated on the COD removal efficiency. The design results showed that the quadratic model was significant for both processes and was determined as the selected model. The optimal conditions determined by the software in the process of electrocoagulation were 0.5 A dm−2 and 34 minutes and in the peroxone process, concentration of hydrogen peroxide and the time were obtained 12 ml and 62 minutes, respectively. In these conditions, the COD removal efficiency of the processes was determined 79.8% and 52.8%, respectively. Under optimal conditions, in peroxone process ozone consumption was reduced to 0.88 mg per mg of removed COD. Also, according to the results of Pseudo-first-order kinetics, constant rate increases with increasing of hydrogen peroxide concentration. The results obtained in this study were confirmed the application of electrocoagulation process along with advanced oxidation of proxone for effective treatment of effluents of this industry and similar industries.