Quantity Of H2O2 Research Articles

Garlic Cellulosic Powders with Immobilized AgO and CuO Nanoparticles: Preparation, Characterization of the Nanocomposites, and Application to the Catalytic Degradation of Azo Dyes.

Nanomaterials have attracted specific consideration due to their specific characteristics and uses in several promising fields. In the present study, Chondrilla juncea was employed as a biological extract to facilitate the reduction of copper and silver ions within garlic peel powders. The resulting garlic-CuO and garlic-AgO nanocomposites were characterized using several analytical methods including FTIR, TGA/DTG, SEM, TEM, and XRD analyses. The garlic peel exhibited a rough surface. The nanoparticles were evenly dispersed across its surface. The incorporation of CuO and AgO nanoparticles affected the crystal structure of garlic peel. The establishment of CuO and AgO nanoparticles was evidenced by the highest residual mass values observed for the prepared nanocomposites. The thermogravimetric analysis showed that the prepared nanocomposites had lower thermal stability compared with garlic peel powders. The prepared nanocomposites were used for catalytic degradation of naphthol blue black B and calmagite. The decolorization process depended on the quantity of H2O2, initial concentration of azo dyes, duration of contact, and temperature of the bath. The calculated activation energy (Ea) values for the garlic-CuO nanocomposites were found to be 18.44 kJ mol-1 and 23.28 kJ mol-1 for calmagite and naphthol solutions, respectively. However, those calculated for garlic-AgO nanocomposites were found to be 50.01 kJ mol-1 and 12.44 kJ mol-1 for calmagite and naphthol, respectively.

Ultrasonic degradation of selected dyes using Ti3C2Tx MXene as a sonocatalyst.

MXene, a new family of two dimensional materials, was utilized as a sonocatalyst in an ultrasonic treatment (US) process for removal of methylene blue (MB) and acid blue 80 (AB). The physico-chemical properties of MXene were characterized using scanning electron microscopy, transmission electron microscopy, porosimetry, and a zeta potential analyzer. Degradation of dyes by US was systemically investigated under several experimental conditions including: power density of US (45, 90, 135, and 180WL-1), frequency of US (28 and 970kHz), pH of dye solution (3.5, 7, and 10.5), solution temperature (293, 303, and 313K), and addition of hydroxyl radical promotor (H2O2) and scavenger (t-BuOH) to concentrations of 25mM. Based on the experimental results, the quantity of H2O2, which was used as an indicator of hydroxyl radical concentration, was an important factor in determining the degradation rate of MB and AB in this US study. Additionally, synergetic indices for removal of both dyes were higher than 1.0 in all cases, indicating the outstanding efficiency of MXene as a sonocatalyst in the US reactor for removal of both, due to an increase in both (i) the quantity of H2O2 in the US reactor and (ii) active sites for adsorbates from dispersion effects. A stability test on MXene in the US process was conducted using X-ray diffraction and five-cycle recycling performance tests. Based on our experimental data, MXene can be utilized as a sonocatalyst in the US process for a high removal rate for dyes (e.g., MB).

Ultrasound-Enhanced Generation of Reactive Oxygen Species for MRI-Guided Tumor Therapy by the Fe@Fe3O4-Based Peroxidase-Mimicking Nanozyme.

Reactive oxygen species (ROS)-based tumor therapy is still challenging due to limited ROS-generating efficacy. Herein, we constructed heparin-conjugated Fe@Fe3O4 NPs (Fe@Fe3O4@heparin, denoted as MNPs) as a peroxidase-mimicking nanozyme to generate ROS for tumor therapy through the combination of the ultrasound-stimulated Fenton reaction and the increased concentration of H2O2 by β-lapachone (La) in a tumor. La was first intraperitoneally injected into mice and induced to generate a considerable quantity of H2O2 through a specific tumor reaction, which was catalyzed by MNPs to produce highly hydroxyl radicals (•OH). Furthermore, the therapy efficacy for malignant tumors could significantly be enhanced by an ultrasonic stimulation. With the help of the increased amount of H2O2 generated by La in the tumor and the enhanced peroxidase-mimicking activity of MNPs by ultrasound, MNPs manifest good therapeutic performance in a 4T1 xenograft model, which provides a strategy for enhanced nanozyme-mediated tumor therapy.

Catalytic Effect of Hydrogen Peroxide in the Electrochemical Treatment of Phenolic Pollutants using a BDD Anode

AbstractPhenolic pollutants are recalcitrant substances that cannot be removed from wastewater using the current treatments. In this study, degradation of phenolic pollutants was studied on the basis of the application of hydrogen peroxide during the electrooxidation process using BDD as anode (EO−H2O2 coupled process). The process was optimized using 4‐chlorophenol (4‐CP) as model compound and later an emerging pollutant, Nonylphenol Ethoxylate‐10 (NP10EO), was degraded using the optimized experimental conditions found. To ascertain treatment effectiveness, experiments with hydrogen peroxide (H2O2), electrooxidation (EO) and EO−H2O2 (coupled process) were carried out. The variables considered in this investigation were pH, current density, quantity of H2O2, and reaction time. It was observed that the coupled process (EO−H2O2) increases degradation efficiency, reaching 81.9 % for 4‐CP and 94.3 % for NP10EO. UV/VIS spectrophotometry, COD and HPLC analysis verified these results. The results of the analysis by cyclic voltammetry after the EO−H2O2 coupled process indicate that pollutants in the solution were efficiently oxidized. It was concluded that small amounts of hydrogen peroxide (250 μL 30 % w/v solution per 1.1 L) are sufficient to attain good results; larger amounts of H2O2 produce inhibitory effects during degradation. The slow cathode (SS) oxidation during the experiments was confirmed by XPS and AFM analysis.

Electrosynthesis of hydrogen peroxide using modified gas diffusion electrodes (MGDE) for environmental applications: Quinones and azo compounds employed as redox modifiers

Although the electrosynthesis of hydrogen peroxide (H2O2) using gas diffusion electrodes (GDE) is a viable option for the production of this oxidizing agent in advanced oxidation processes (AOP) for wastewater treatment, the quest for more efficient electrodes is still regarded a matter of great importance in this area. The present study sought to investigate different redox organic compounds employed as modifiers of carbon black Printex L6 (CP) with the aim of increasing H2O2 production using carbon-based electrodes. Varying amounts of the modifiers, including Sudan Red 7B (SR7B), methyl-p-benzoquinone (MPB), anthraflavic acid (AA) and anthraquinone-2-carboxylic acid (A2CA), were added to carbon black, where the electrochemical activity was studied by applying a microporous catalyst layer on a rotating ring-disk electrode (RRDE). The materials containing 0.5% of SR7B and 5.0% of MPB increased the current efficiency for the electrogeneration of hydrogen peroxide to 86.2% and 85.5%, respectively, compared to 82.8% obtained for unmodified carbon. Carbon Printex L6 gas diffusion electrodes modified with 0.5% of SR7B were studied and the following results were obtained: the application of current density of 75 mA cm−2 led to the production of 1020.1 mg L-1 of H2O2, with an energy consumption of 118.0 kW h kg-1, apparent kinetic constant of 37.34 mg L-1 min-1 and current efficiency of 17.87%. Conversely, the use of GDE with unmodified carbon resulted in the production of relatively less quantity of H2O2 which amounted to 717.3 mg L-1, with more energy consumption of 168.5 kW h kg-1, lower apparent kinetic constant of 21.41 mg L-1 min-1 and lower current efficiency of 12.57%. Based on these results, carbon Printex L6 GDE modified with 0.5% of Sudan Red 7B is seen as a suitable alternative for the production of high amounts of H2O2 which can be applied in advanced oxidation processes in acidic medium.

H2O2 Treated CdS with Enhanced Activity and Improved Stability by a Weak Negative Bias for CO2 Photoelectrocatalytic Reduction

To convert greenhouse gas CO2 to available energy by using solar energy is a promising approach for addressing energy dilemma and global warming issues. Although CdS as a photocatalyst can achieve CO2 reduction to fuel, there are still two main problems of activity and stability to be solved. Herein, a simple hydrothermal method with the presence of a little quantity of H2O2 is used to prepare CdS with Cd vacancies, which can promote the separation of photogenerated electrons and holes for activity improvement. It is found that the best catalyst 0.4CdS demonstrates not only high CO selectivity over other carbonaceous products, but also a considerable CO production rate of 316 μmol g–1 h–1, which is 2.1 times as high as that of pure CdS for CO2 reduction under visible light irradiation. In addition, an efficient solution through an additional feeble negative voltage to improve the photostability of 0.4CdS is achieved, which makes this sample remain 94.2% of its original CO2 photoelectrocatalytic reduction ...

TiO2 photocatalyst synthesized by refluxing method in H2O2 solution

In this study, TiO2 was synthesized by refluxing gel TiO2 in H2O2 solution. Experiments were carried to investigate effects of the acidity of the reactions, refluxing time, quantity of H2O2, and the drying condition to the formation and photocatalytic activities of products. Samples were characterized by XRD, BET, IR, and DRS. Adsorption and phototcatalytic properties of samples were studied by the degradation of methylene blue (MB) under visible light. Results showed that TiO2 was crystallized only from the refluxing baths that were not adjusted their acidity after mixing TiO2 sol with H2O2 solution. Increasing the refluxing time or drying products at 100 oC led to decreasing photocatalytic activities of TiO2. Increasing the amount of H2O2 in the refluxed solutions, photocatalytic activities of TiO2 increased to a maximum level when 25 mL of H2O2 was used.

Protective effect of Codium tomentosum alga on SH-SY5Y model of neurotoxicity induced by 6-hydroxydopamine (6 – OHDA)

Event Abstract Back to Event Protective effect of Codium tomentosum alga on SH-SY5Y model of neurotoxicity induced by 6-hydroxydopamine (6 – OHDA) Joana Silva1*, Celso Alves1 and Rui Pedrosa1 1 School of Tourism and Maritime Tecnhology, Portugal Parkinson Disease (PD) is characterized by the loss of dopaminergic cell bodies in the substantia nigra and oxidative stress, mitochondrial dysfunction and apoptosis seem to be involved in the pathogenesis of the disease. The aim of this study was to evaluate the neuroprotective effect of different algae extracts on the cell death induced by by 6-OH-dopamine on a neuronal human cell model (SH- SY5Y). The neuroprotective effect of methanolic and dichloromethane algae extract (Padina pavonica, Sargassum muticum, Saccorhiza polyschides, Codium tomentosum, Ulva compressa) in the presence of 6-OH-DA was assessed using the MTT method. The activity of caspase-3 and the quantification of hydrogen peroxide (extracellular environment and real time production) production were studied in the presence and in the absence of the macroalgae extracts. The highest neuroprotective effect was exhibited by methanolic fractions (1000 µg/ml; 24 hours) of S. muticum (115.80 ± 8.53% of viable cells), S. polyschides (106.51 ± 4.26 of viable cells), P. pavonica (95.98 ± 3.95 of viable cells) and dichloromethane (1000 µg/ml; 24 hours) fraction of C. tomentosum alga (102.22 ± 4.24 of viable cells), when compared with 6-OH-DA condition (100μM; 24 hours) (67.40 ± 3.56 of viable cells). For the extracts that exhibited the highest neuroprotective effect was studied the possible alterations induced in the mechanisms of action previous selected. The dichloromethane fraction of Codium tomentosum alga (1000 µg/ml) highly reduced the 6-OH-DA induced increase of caspase-3 activity, the less quantity of H2O2 in the extracellular environment and less production of H2O2 on real time (2.58 ± 1.77 UAF mg of protein-1 min-1; 0.0 ± 0.005 µM of H2O2, 54.07 ± 6.66 UAF min-1, respectively) when compared with the 6-OH-DA condition at 100μM (4.5 ± 1:35 UAF mg of protein-1 min-1; ± 0.4 0.0019 µM of H2O2; 214.26 ± 8:46 UAF min-1, respectively). These results suggest that Codium tomentosum extracts has capacity to increase the SH-SY5Y viability in the presence of 6-OH-DA by the inhibition of caspase-3 activity and H2O2 production. In conclusion, Codium tomentosum could be a promising source of novel molecules with antioxidant activity. Keywords: algae, Parkinson Disease, Neuroprotection, 6-Hydroxidopamine, antioxidant activity Conference: IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014. Presentation Type: Poster Presentation Topic: BLUE BIOTECH Citation: Silva J, Alves C and Pedrosa R (2014). Protective effect of Codium tomentosum alga on SH-SY5Y model of neurotoxicity induced by 6-hydroxydopamine (6 – OHDA). Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2014. doi: 10.3389/conf.fmars.2014.02.00071 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 May 2014; Published Online: 18 Jul 2014. * Correspondence: Dr. Joana Silva, School of Tourism and Maritime Tecnhology, Peniche, Portugal, Joana.rita.ms@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Joana Silva Celso Alves Rui Pedrosa Google Joana Silva Celso Alves Rui Pedrosa Google Scholar Joana Silva Celso Alves Rui Pedrosa PubMed Joana Silva Celso Alves Rui Pedrosa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Oxygen and Hydrogen Peroxide in the Early Evolution of Life on Earth:In silicoComparative Analysis of Biochemical Pathways

In the Universe, oxygen is the third most widespread element, while on Earth it is the most abundant one. Moreover, oxygen is a major constituent of all biopolymers fundamental to living organisms. Besides O(2), reactive oxygen species (ROS), among them hydrogen peroxide (H(2)O(2)), are also important reactants in the present aerobic metabolism. According to a widely accepted hypothesis, aerobic metabolism and many other reactions/pathways involving O(2) appeared after the evolution of oxygenic photosynthesis. In this study, the hypothesis was formulated that the Last Universal Common Ancestor (LUCA) was at least able to tolerate O(2) and detoxify ROS in a primordial environment. A comparative analysis was carried out of a number of the O(2)-and H(2)O(2)-involving metabolic reactions that occur in strict anaerobes, facultative anaerobes, and aerobes. The results indicate that the most likely LUCA possessed O(2)-and H(2)O(2)-involving pathways, mainly reactions to remove ROS, and had, at least in part, the components of aerobic respiration. Based on this, the presence of a low, but significant, quantity of H(2)O(2) and O(2) should be taken into account in theoretical models of the early Archean atmosphere and oceans and the evolution of life. It is suggested that the early metabolism involving O(2)/H(2)O(2) was a key adaptation of LUCA to already existing weakly oxic zones in Earth's primordial environment.

Influence of growth conditions and nutritional requirements on the production of hydrogen peroxide by lactic acid bacteria

Lactic acid bacteria (LAB) were isolated from raw and fermented milk samples. They were evaluated for hydrogen peroxide (H2O2) production. Sixty–three strains of LAB belonging to the genera Lactobacillus, Leuconostoc, Lactococcus and Streptococcuswere isolated and all the isolates produce H2O2 with Lactococcus lactis having the highest yield of 0.4279 mg/L in de Mann Rogosa Sharpe (MRS) broth. Among the high–level H2O2-producing strains are Lactobacillus bulgaricus, Lactobacillus casei, L. lactisand Streptococcus thermophiles. They were subsequently selected and their culture supernatants were evaluated at different temperatures, pH values and using different carbon and nitrogen sources. The highest quantity of H2O2 (0.6517 mg/L) was produced at 37°C by S. thermophilus, while L. casei produced the lowest quantity of 0.1132 mg/L at 40°C. S. thermophilus produced the highest quantity of 0.5912 mg/L at pH 5.5, while the lowest quantity of 0.1042 mg/L was produced at pH 7. L. bulgaricus produced the highest concentration of0.6512 mg/L when galactose was used as carbon source and lowest quantity of 0.0210 mg/L was produced by L. lactis in basal medium containing sorbitol as carbon source. L. casei produced both the highest and lowest quantities of 0.1895 and 0.0207 mg/L of H2O2 in medium supplemented with yeast extract and ammonium sulphate as nitrogen sources respectively. The antimicrobial activity of the culture supernatants against Escherichia coli K12, Staphylococcus aureus and Candida albicansusing agar well diffusion assay was evaluated. Cell-free supernatant by L. bulgaricus had the highest inhibitory activity against E. coli K12 with 21 mm zone of inhibition and againstS. aureus with 15 mm zone of inhibition but showed no antagonistic activity against C. albicans. The study revealed that lactic acid bacteria isolated from raw and fermented milk in South-West Nigeria are capable of producing hydrogen peroxide which has antagonistic effect on pathogenic organisms, thus, may be promising sources of preservative that may in future be applied to food. Key words: Hydrogen peroxide, growth conditions, nutrient utilization, antagonistic activity, lactic acid bacteria (LAB).

Studies in mineralization of aqueous aniline using Fenton and wet oxidation (FENTWO) as a hybrid process

AbstractA hybrid process for mineralization of aqueous aniline using Fenton and wet oxidation (FENTWO) is studied. It is important to have maximum conversion of ‘N’ atoms from the waste to N2. The conversion of input ‘N’ atoms in aniline to N2 was 15% during wet oxidation without the Fenton process and was improved to 50% with the Fenton process. Therefore, a hybrid process of Fenton followed by wet oxidation was studied for mineralization of the aqueous aniline stream. The parameters for the Fenton process were optimized (pH, catalyst, H2O2 to catalyst (FeSO4) ratio, quantity of H2O2). The waste obtained after the Fenton process was then treated by wet oxidation for mineralization by having homogeneous CuSO4 as the catalyst by keeping FeSO4 therein. This combined catalyst was found to be more effective for the degradation of the intermediates formed in the Fenton process. Wet oxidation (WO) was studied in the temperature range 473–513 K and the oxygen partial pressure range 0.345–1.38 MPa at pH 6.5. The kinetic data was modeled using a power law rate expression in terms of chemical oxygen demand (COD). The optimum temperature for formation of more N2 gas was found to be 493 K. The treated waste stream was found to contain oxalic acid using HPLC, and NH4+, NO3− and NO2− ions using ion chromatography analysis. Copyright © 2007 Society of Chemical Industry

A new colorimetric method for the determination of free fatty acids with acyl-CoA synthetase and acyl-CoA oxidase.

A rapid and sensitive spectrophotometric assay for free fatty acids using acyl-CoA synthetase and acyl-CoA oxidase is described. It is sensitive to as low as 5 nmol of free fatty acids, and the standard curve is linear up to 100 nmol. The assay consists of the measurement of H2O2 produced from free fatty acids by acyl-CoA synthetase and acyl-CoA oxidase. The quantity of H2O2 is determined by the absorbance at 550 nm in the presence of catalase and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT). This method shows a broad specificity to long-chain fatty acids and the recoveries of added fatty acids (C12-C18) are more than 90%. The presence or absence of serum components or Escherichia coli cell-free extracts has no significant effect on the recovery of added palmitic acid.

The Formation of Hydrogen Peroxide on Fresh Metal Surfaces

The recent discovery by Kramer that freshly exposea metal surfaces emit electrons is considered to be the cause of the Russell effect and of Shaw's mechanical activation. Electrons originating from the surface initiate reactions involving free radicals. With water, in the presence of oxygen, this leads to the formation of hydrogen peroxide. Metals were cut under water containing oxygen and it was found that, under similar conditions, zinc, aluminium, magnesium and nickel yield approximately the same quantity of H2O2. Iron gives ferric ions and copper only very little H2O2. During cutting, considerable quantities of hydroxides become suspended in the solution. With zinc more H2O2 is formed per cut in the early stages of the experiment, owing to the exposure of fresh surface by the dissolution of Zn(OH)2. In the later stages each zinc atom exposed is responsible for the formation of approximately 1.5 molecules of H2O2. The decomposition of H2O2 in the presence of chips of zinc is found to be a pseudo-unimolecular process. The cutting of copper in a solution of ferrous ions yielded ferric ions. The amount of ferric ions produced seems to depend on the quantity of oxygen available in the solution.