scholarly journals Carbamazepine Degradation Mediated by Light in the Presence of Humic Substances-Coated Magnetite Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1379 ◽  
Author(s):  
Francisca Aparicio ◽  
Juan Pablo Escalada ◽  
Eduardo De Gerónimo ◽  
Virginia C. Aparicio ◽  
Fernando S. García Einschlag ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Magnetic Nanoparticles ◽  
Humic Substances ◽  
Hydroxyl Radicals ◽  
Magnetite Nanoparticles ◽  
Environmental Remediation ◽  
Fenton Reaction ◽  
Core Shell ◽  
Heterogeneous Oxidation ◽  
Iron Based

The use of iron-based nanomaterials for environmental remediation processes has recently received considerable attention. Here, we employed core-shell magnetite-humic acids nanoparticles as a heterogeneous photosensitizer and iron source in photo-Fenton reaction for the degradation of the psychiatric drug carbamazepine (CBZ). CBZ showed low photodegradation rates in the presence of the magnetic nanoparticles, whereas the addition of hydrogen peroxide at pH = 3 to the system drastically increased the abatement of the contaminant. The measured Fe2+ and Fe3+ profiles point to the generation of Fe3+ at the surface of the nanoparticles, indicating a heterogeneous oxidation of the contaminant mediated by hydroxyl radicals. Products with a higher transformation degree were observed in the photo-Fenton procedure and support the attack of the HO• radical on the CBZ molecule. Promising results encourage the use of the nanoparticles as efficient iron sources with enhanced magnet-sensitive properties, suitable for applications in photo-Fenton treatments for the purification of wastewater.

scholarly journals Killing of Bacillus Spores by Aqueous Dissolved Oxygen, Ascorbic Acid, and Copper Ions

2003 ◽  
Vol 69 (4) ◽  
pp. 2245-2252 ◽  
Author(s):  
J. B. Cross ◽  
R. P. Currier ◽  
D. J. Torraco ◽  
L. A. Vanderberg ◽  
G. L. Wagner ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Dissolved Oxygen ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Copper Ions ◽  
Transition Metal Ions ◽  
Fenton Reagent ◽  
Bacillus Spores ◽  
Modified Fenton

ABSTRACT An approach to decontamination of biological endospores is discussed. Specifically, the performance of an aqueous modified Fenton reagent is examined. A modified Fenton reagent formulation of cupric chloride, ascorbic acid, and sodium chloride is shown to be an effective sporicide under aerobic conditions. The traditional Fenton reaction involves the conversion of hydrogen peroxide to hydroxyl radical by aqueous ionic catalysts such as the transition metal ions. Our modified Fenton reaction involves the conversion of aqueous dissolved oxygen to hydrogen peroxide by an ionic catalyst (Cu2+) and then subsequent conversion to hydroxyl radicals. Results are given for the modified Fenton reagent deactivating spores of Bacillus globigii. A biocidal mechanism is proposed that is consistent with our experimental results and independently derived information found in the literature. This mechanism requires diffusion of relatively benign species into the interior of the spore, where dissolved O2 is then converted through a series of reactions which ultimately produce hydroxyl radicals that perform the killing action.

Analysis of a complex produced in the Fenton oxidation process

2014 ◽  
Vol 69 (5) ◽  
pp. 1115-1119 ◽  
Author(s):  
Chang Wang ◽  
Siyue Zhang ◽  
Sakai Yuji ◽  
Zongpeng Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Complex Formation ◽  
Hydroxyl Radical ◽  
Fenton Reaction ◽  
Oxidation Process ◽  
Fenton Oxidation ◽  
Radical Theory ◽  
Uv Visible ◽  
Iron Based ◽  
Fenton Oxidation Process

The absorbances of different concentrations of Fe2+, Fe3+ and H2O2 were investigated by UV-visible spectrophotometry without separating the substances. The law of complex formation was studied by considering changes in the UV-vis spectra of mixtures of these three substances. The results show that upon eliminating the influence of the substrate, an iron-based complex was present in the Fenton reaction, which exhibited substantial absorbance from 190 to 500 nm. Therefore, the presence of an unknown complex in the Fenton oxidation process was verified and its concentration varied with a change in the concentration of hydrogen peroxide. This study provides a strong foundation for further studies into the mechanism of traditional hydroxyl radical theory of the Fenton reaction.

scholarly journals Superoxide dismutase enhances the formation of hydroxyl radicals in the reaction of 3-hydroxyanthranilic acid with molecular oxygen

1988 ◽  
Vol 251 (3) ◽  
pp. 893-899 ◽  
Author(s):  
H Iwahashi ◽  
T Ishii ◽  
R Sugata ◽  
R Kido
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Hydroxyl Radical ◽  
Molecular Oxygen ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Potassium Phosphate ◽  
Radical Formation ◽  
Superoxide Anions ◽  
Hydroxyanthranilic Acid

Superoxide dismutase (SOD) enhanced the formation of hydroxyl radicals, which were detected by using the e.s.r. spin-trapping technique, in a reaction mixture containing 3-hydroxyanthranilic acid (or p-aminophenol), Fe3+ ions, EDTA and potassium phosphate buffer, pH 7.4. The hydroxyl-radical formation enhanced by SOD was inhibited by catalase and desferrioxamine, and stimulated by EDTA and diethylenetriaminepenta-acetic acid, suggesting that both hydrogen peroxide and iron ions participate in the reaction. The hydroxyl-radical formation enhanced by SOD may be considered to proceed via the following steps. First, 3-hydroxyanthranilic acid is spontaneously auto-oxidized in a process that requires molecular oxygen and yields superoxide anions and anthranilyl radicals. This reaction seems to be reversible. Secondly, the superoxide anions formed in the first step are dismuted by SOD to generate hydrogen peroxide and molecular oxygen, and hence the equilibrium in the first step is displaced in favour of the formation of superoxide anions. Thirdly, hydroxyl radicals are generated from hydrogen peroxide through the Fenton reaction. In this Fenton reaction Fe2+ ions are available since Fe3+ ions are readily reduced by 3-hydroxyanthranilic acid. The superoxide anions do not seem to participate in the reduction of Fe3+ ions, since superoxide anions are rapidly dismuted by SOD present in the reaction mixture.

Chemical reduction synthesis and ac field effect of iron based core–shell magnetic nanoparticles

2009 ◽  
Vol 42 (24) ◽  
pp. 245005 ◽  
Author(s):  
Srinivasan Balakrishnan ◽  
Michael J Bonder ◽  
George C Hadjipanayis
Keyword(s):  
Magnetic Nanoparticles ◽  
Field Effect ◽  
Chemical Reduction ◽  
Core Shell ◽  
Ac Field ◽  
Iron Based

scholarly journals 2′,7′-dichlorofluorescin-based analysis of Fenton chemistry reveals auto-amplification of probe fluorescence and albumin as catalyst for the detection of hydrogen peroxide

2020 ◽  
Vol 477 (24) ◽  
pp. 4689-4710
Author(s):  
Teresa Gonzalez ◽  
Franck Peiretti ◽  
Catherine Defoort ◽  
Patrick Borel ◽  
Roland Govers
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Ferrous Iron ◽  
Fenton Reaction ◽  
Iron Chelation ◽  
Intact Cells ◽  
Free System ◽  
Fenton Chemistry ◽  
In Cells

Fluorophore 2′,7′-dichlorofluorescin (DCF) is the most frequently used probe for measuring oxidative stress in cells, but many aspects of DCF remain to be revealed. Here, DCF was used to study the Fenton reaction in detail, which confirmed that in a cell-free system, the hydroxyl radical was easily measured by DCF, accompanied by the consumption of H2O2 and the conversion of ferrous iron into ferric iron. DCF fluorescence was more specific for hydroxyl radicals than the measurement of thiobarbituric acid (TBA)-reactive 2-deoxy-D-ribose degradation products, which also detected H2O2. As expected, hydroxyl radical-induced DCF fluorescence was inhibited by iron chelation, anti-oxidants, and hydroxyl radical scavengers and enhanced by low concentrations of ascorbate. Remarkably, due to DCF fluorescence auto-amplification, Fenton reaction-induced DCF fluorescence steadily increased in time even when all ferrous iron was oxidized. Surprisingly, the addition of bovine serum albumin rendered DCF sensitive to H2O2 as well. Within cells, DCF appeared not to react directly with H2O2 but indirect via the formation of hydroxyl radicals, since H2O2-induced cellular DCF fluorescence was fully abolished by iron chelation and hydroxyl radical scavenging. Iron chelation in H2O2-stimulated cells in which DCF fluorescence was already increasing did not abrogate further increases in fluorescence, suggesting DCF fluorescence auto-amplification in cells. Collectively, these data demonstrate that DCF is a very useful probe to detect hydroxyl radicals and hydrogen peroxide and to study Fenton chemistry, both in test tubes as well as in intact cells, and that fluorescence auto-amplification is an intrinsic property of DCF.

Fe3O4@SiO2@polyionene/Br3− core–shell–shell magnetic nanoparticles: a novel catalyst for the synthesis of imidazole derivatives under solvent-free conditions

2016 ◽  
Vol 40 (5) ◽  
pp. 4575-4587 ◽  
Author(s):  
Elham Dezfoolinezhad ◽  
Keivan Ghodrati ◽  
Rashid Badri
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetite Nanoparticles ◽  
Solvent Free ◽  
Precipitation Method ◽  
Core Shell ◽  
Imidazole Derivatives ◽  
Solvent Free Conditions ◽  
Co Precipitation ◽  
Novel Catalyst

New Fe3O4@SiO2@polyionene/Br3− core–shell–shell magnetite nanoparticles were prepared using a co-precipitation method and were used in the syntheses of imidazole derivatives under solvent-free conditions.

scholarly journals SiO2 Stabilized Magnetic Nanoparticles as a Highly Effective Catalyst for the Degradation of Basic Fuchsin in Industrial Dye Wastewaters

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2573 ◽  
Author(s):  
Jingheng Ning ◽  
Min Wang ◽  
Xin Luo ◽  
Qiongcan Hu ◽  
Rong Hou ◽  
...  
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Environmental Remediation ◽  
Fenton Reaction ◽  
High Performance ◽  
Room Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

Catalytic degradation of organic pollutants by nanomaterials is an effective way for environmental remediation. The Fenton reaction involving H2O2 oxidation catalysed by Fe3+ is an advisable way for wastewater degradation. Herein, Fe3O4/SiO2 core-shell nanoparticles were prepared as catalyst by coprecipitation and sol-gel methods, and this catalyst is used for degradation of fuchsin in wastewater by H2O2. The Fenton reaction between H2O2 and Fe3O4 is proposed to explain the catalytic performance. The coating of SiO2 on Fe3O4 nanoparticles could dramatically stabilize the Fe3O4 in aqueous solution and prevent their oxidation. More importantly, the magnetic property of Fe3O4 nanoparticles endows them with good recyclability. Thus, due to the outstanding catalytic results, almost 100% removal degradation was achieved within 5 min over a wide pH value range at room temperature, which is better than that without catalysts. Temperature is a positive factor for improving the degradation rate, but room temperature is selected as the best temperature for economic and energy savings reasons, because more than 98% of fuchsins can still be degraded at room temperature. Moreover, these Fe3O4/SiO2 core-shell nanoparticles exhibit excellent magnetic recyclability and stable properties after repeated utilization. Therefore, these as-presented Fe3O4/SiO2 core-shell nanoparticles with low-cost and high performance are expected to be applied in practical industry wastewater degradation.

A Systematic DFT Study of Two Elementary Steps Involving Hydrogen Peroxide and the Hydroxyl Radical in the Fenton Reaction

2018 ◽  
Author(s):  
Danilo Carmona ◽  
David Contreras ◽  
Oscar A. Douglas-Gallardo ◽  
Stefan Vogt-Geisse ◽  
Pablo Jaque ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Ab Initio ◽  
Fenton Reaction ◽  
Basis Set ◽  
Basis Sets ◽  
Dft Methods ◽  
Elementary Steps ◽  
Oxygen Oxygen ◽  
Complete Basis Set

The Fenton reaction plays a central role in many chemical and biological processes and has various applications as e.g. water remediation. The reaction consists of the iron-catalyzed homolytic cleavage of the oxygen-oxygen bond in the hydrogen peroxide molecule and the reduction of the hydroxyl radical. Here, we study these two elementary steps with high-level ab-initio calculations at the complete basis set limit and address the performance of different DFT methods following a specific classification based on the Jacob´s ladder in combination with various Pople's basis sets. Ab-initio calculations at the complete basis set limit are in agreement to experimental reference data and identified a significant contribution of the electron correlation energy to the bond dissociation energy (BDE) of the oxygen-oxygen bond in hydrogen peroxide and the electron affinity (EA) of the hydroxyl radical. The studied DFT methods were able to reproduce the ab-initio reference values, although no functional was particularly better for both reactions. The inclusion of HF exchange in the DFT functionals lead in most cases to larger deviations, which might be related to the poor description of the two reactions by the HF method. Considering the computational cost, DFT methods provide better BDE and EA values than HF and post--HF methods with an almost MP2 or CCSD level of accuracy. However, no systematic general prediction of the error based on the employed functional could be established and no systematic improvement with increasing the size in the Pople's basis set was found, although for BDE values certain systematic basis set dependence was observed. Moreover, the quality of the hydrogen peroxide, hydroxyl radical and hydroxyl anion structures obtained from these functionals was compared to experimental reference data. In general, bond lengths were well reproduced and the error in the angles were between one and two degrees with some systematic trend with the basis sets. From our results we conclude that DFT methods present a computationally less expensive alternative to describe the two elementary steps of the Fenton reaction. However, choice of approximated functionals and basis sets must be carefully done and the provided benchmark allows a systematic validation of the electronic structure method to be employed

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